the quantum zoo

THE QUANTUM

A Tourist's Guide to the Nctvorendlng Universe

MARCUS CHOWN

"IF±' ' _ pall .. ,' , tI ......

THE QUANTUM

THE QUANTUM

A Tourist's Gu ide to the Neverendlng Un iverse

Marcus (hown

lrutph H..,'Y,.,. ... WaohinBlon. uc.

Jo .... h li en". P .... • SOO Fifth Sttftt. NW • Wishin~ton. DC 20001

Tht l""Ph Htnry I'rus •• n imprint of tht ""tional Acod..,.i .. PrflS. w .. c .... t~ with tht S""I of m.kins books on ode""e. ted"'ology • • nd h •• llh rnor< wi.kly .... il.hI. to prof""ional •• nd tht puhlic. l""Ph Htnry was """' of tht founders of tht Nation.1 Academy of Sci<ncn anJ • kod<T in • .,ly American ",itn"'.

A"1 opinion .. finding •• cooclusio ... or rtCOmnltndation. np.-.....J in ,hi, vol""", .... thoot of ,ht au,hor anJ do not necnsarily rflIoct ,h~ .i ...... of ,h~ Na,ional AcaJ~nly of !ki<cn«. or iu .lfdi>lN in .. itulio ... .

Cltoown, Marcus. 1he q....,tum zoo: " ourist. ~id. '0 tht neveKndi"l! uni~1$owrL

p. an. I""ludos bihlios,""phic. 1 ...-f .... ncn .nd ind ... ISHN 0·309·09622-7

1. Quo.ntum thtory-J>opularworks. 2. ~lativity ( Physla)-I'opulor works. I. Tid •. t.,'C17U2.C486 2006 SJO.12---dc22

Copyright 2006 by Morc", d>own. All right> ... ...-1.

Print~ in tht Uni'N St .... of A"",rica

ACKNOWLED6MENTS

My than .. to th. fulkrwing pt<>pl. who .ithtt htlpnJ mr dirtClly,

inspi~ mo, or oimply """"" .... g<:10 .... Card"" .. Urian Cltgg. t>rofruor Tony Hey. Kat. Oldfield, Vivien lames, Brian May. Dr, Urua 6 .... 11, I.>r. Larry Schulman, LJr.

\\Iojci«b Zur.k, Sir Manin R<n. AlI;"'n O!own. Colin W.Uman. Rosi. and To m o.own, Patrick Q'Halionn. )uli, and Va", Maya., s..ph.m HalFf. Sur O'MalJ.y. S ..... h Topu;"n, Or. David Urut>d>,

A1cnndn Ftach.m,Nick M.yh ..... -Smith. E1i .. bc,h Gtlk<,A1 10 ...... \)o.id H<>u!h, F..,J lIornum, !':am Young. Roy P.rry, Ha .. 1 Muir.

51.art and Nikli Clark.Simon 1"5'- lI>.rr1 F"",SptnCft "'i&l>l. Karttl Gunnell, '" Gunnell, Pat and Brion Chil ....... Std. Barlow. 5i""'"" Mazzon. IIarhar. ""II and David, ,u1i. i!;oltOOn. An"" UrsdJ, !\arb, .... Ki....-. L>alt ;' FrKd~. Jan Hollan.!. Martin Dollard,lIrian Clegg. Sylvia and Sarah Kofyll .... , Matilda and I.l<nni. and AmaO><b.1Id Ar.drcw Budky. funo and I'rt<r ond Cioran .00 Lucy Tomlin. Eric Gourlay.

""ul B .... ""ford. 11 goes w;lhoul saying. loop<. Ihal nont of Ih ... pwplo .ro ~lH>"sil>1o r", anyo",,...

,

FOREWORD

On. ,,(,I>< following i. tr"",

• E ... ry bre •• h you lak< ""n,"in, an atom br ... he<! out by Marilyn Monrot .

• Th=i>.liquid ,h .. <on run uphill You .go fast«., II>< lOp of. builLlin~ than., II>< bottom.

"n at"", can be in many iliff.rem pl;w;:n at "nc., Iht "'luivo-1<111 of you btiIl!l in Ntw Yo, •• nd London a' the Silme tim •. Til< mtirt human ,aU _uId fit in "'" voIUJ'DI' or. suprcut... 0". ptr«nt of the statk on a td .. ;sion ."1It<! bc1wct" .... • ion< i, the r<~< ofth.lli~ ~g. Tim. , ... vol is nOi forIHddon by til< I.w, of physics.. A {UP "r coff .. ~shs mo .. wh"" it is"'" ,han wllm it i,

00". Tho r ... ,or )'Ou 1"'''''~ tho slimmer )'Ou Ft.

No, I'm joking. They or< 011,"'01 , ... ",ien« wril.r I om <OII>tan,ly >maud by how much "ranger

$ci<_ i, thon >cim"" fic.;"n. how mud. mo ... incm.lihl. tho< Uni • ...... ;.'~n anything .... could possibly ha"" ;"",nl«l. LkJpil' ,hi .. h~r .... '1 r ..... ofth< ",,' ~n.ary di..,., ..... ia 0f ,n., ~t ""ntury

... m to havt 'rid:JN through into the pubIX:coMcio .........

•

n.. 1_ IC/\O'tting och~m"". of lilt pas! 100 yars.rt q~.n-1 urn lhoo<y, our picturt of 'I<)nu .nd ","ir con>liluents, .nd Ei ... ~in '. g",<raJ Ihtory of rdati.ily, Our pic1urt of 'Pact, liIM, and gra"ily, lk1 ..... n tlltm ,''' t_ ~~ploin .,.;rl .... 11y .... ry1hing .boul 1'" world ond aboul us. In fOCI, il an bt argue<! Ih.t quantum Ihto<y b.ao oclu· ally ..... lrJ 1M modern world, not only aplaining why 1'" ground btnnlh Our f .... i, ",lid ond why tht Sun shin .. bu, aho making

po";bl~ compul~rs and I ...... and nucl~ar ,..oclon. I!<!ati"ily may not bt as ~biquilo\U in Ih~ ....... )day world. N~"",'IIttes... il has ta~ghl u. tha,,~ a", thing. <;allot! bla.ck hoi .. from which nothing, not ~ ... n lighl, an .. cap<'; lhal lilt Uni...,.... has nol ajote<! ~r bUI was born in. titanic apl.,.;"n calle<! ,''' Uig Uang; ond lhat limo mochin.. ""tarkably-may bt i><'"ible.

AI, bough I ha ..... od mony popular occounts of ,....., topics, , ... uplanalion, ha.,., ofkn Itll mo bam..!, """" wilh my oci<nct b.d· ground. I can only gue .. what ;, must be like for nonoden,i .....

F.i ... ,';n sUI: · Moll of tM funolam.ntal i.ltas of ><iro« art <II.

$<nti.11y $imple anJ m.,.. as a rulo, be "P"!ilS<'J in a languo!!" com· p""", ... ible to ....... )'O/Ie.· All my .. p ..... n« ",lis mo lit was right. My id •• in writing this book was to try to htlp oRlinary p<'Ople unJ., ... ".nd 1M principal idoas of 21'1-<:""ury phl"ics. All I had to do ..... identify 'M key i.lt .. behind quantum 'htorr and ",lotIYity. which lurn oul 10 be ..k<op1;""ly .imple, and thtn ,how how ab<oluldy <y.

ery,hing do< follows from ll1tm logically and unavoidably. &1;'" said than Jono. Quanlum thtory in panicular;' . pat<h.

_rk oflTogmenls, occrued "" ... IM pas' 80 yeo .... Ihal nobodY"'nu 10 ho.., ....... n logelM inlo a ... mtes. garmont. "''hat'. mor., cM.1 pi«n of tM thtorr, . uch .. ".ltwher""",,"-wnich uplai'" why .t· oms bul nol p«>plt an be in 1_ ploces at on"" «.'" to be btyond 1'" I'O""'r of physici ... to <ommunica« in any in«lIigiblt way. Aft ... corruponding with m.ny "<:<ptr": and btgi"ning 10 Ihink llul o.kco ..... nc •• bould be ",,,,,m«l "incohem>,,,,; i, dawr>«! on melhat maybe tht ""p<'r" didn'l compltl<1y und ..... nd il Ihtmod ...... In. w"f ,hi . ..... Iiberaling. Sin« a cohtmo, pic1u .. _mod not 10 .. iot, I

•

, .. liuJ th.t I had 10 pita together my own from insig,h1S !It • .-..d from .J.iff~ .. n' p«>plt. 1Ie< ..... .,f ,hi •• many of ,he ... pana.io ... gi~ htK)U" ... ill 001 find anywM'e ..... [ """'" thty btlp lift..,...., or lht f"l! that . urrounJs ,he key ioJ ... of modern phyoics and ,ho, you can

~in to app""';",. whot. t.r .. thtakillflly . mazing Uniwnt .... fOld ou .... lYnin.

C O NTENTS

vii

PARTQN[:SMALL THINGS

IItUlhing in Ein.(rin , , Why God Plays IJic.o .. ilh 1M Univuse " , The Schizorhr~nic Atom

• UIICC"'1>in ly and tl>t Limits of Koowl«lge

, The T.lop. lhic Un;.. ..... " , kknlic.ln ... _nd 1he I!oo(. of Oi ...... ily

PARTTW0:8JGTIHNGS , 'The Vealh ofSp>« and 11 .... " • E. _mt! and 1M wright of Sumhi .... ,~

•

9 TM ForctofG ..... ityUonNOIf.xiSl

10 Tb.t Ulti""'t. Rabbit Out of 0 Hot

GI ..... ry

Funb.tr R<aJinS

InJu

'" ,~

,~

,., '"

PART ONE

SMALL THINGS

BREAlHlNG IN EINSTEIN

"~ .. ~OI'IIiO IIW 11'1I1mo.lI_ III IdllIoI'i .. D lUI 01lIIoI'; W IIIlIM IwPh WIW

A .\:loll,,"" •• ,_ ;". <r/I., Ih< "'" of..., "'* ..... on« po .. of"" .... ,.....~ ... ""No.

IV~"......,. had an, ;"'''''''''' ~f oding ,It< WRlpolL l:Iu, !/rt, ""'" .""h ~ ,trribly ""'ubi ........ "'ce. Thty ; ..... 1n1 on IM"f ... ". ,lit ...... ""'. Je • • tnt< all 0'" ./fom al '''''.IInI" .... Wit.., 'hq firn! "'n, "U'''' ,,"ch, .llXtpi/t "r a..r ship. ot/!i/in8 high abo ... ,h.;, b/.w pMnt/, "." ",,';'rIa .imply ,II" 0"'.

n." "",a/'l>n ...... ,im/'k bu, tffoc,i>'t. /, "i_~1 ""' all Ih, om,.., .pa<t from "",nIT.

II. ,Itt """",.,,,tiI.,. <1our Si"",n cr/'t'/iriolt """,,,,;,,ttI ,It. obi",· mn<i"g ",,"'ilie oob<. OOm! I """'m.....-","",,,, M >It ...... /til pri""", itt<J,J dt.,..,i";ngiy. Harolo btlit' ... ,ltd, ,hi, ...... <>II ,/wi, ...... I4t of,he -""m"n mc?!

If the kit. of ,he m,i", human ra<. fining into m. ,..,1"mt of. ,ug" cut.. .IOun<is ~kt scitna fJCtion, think .gain. It i •• "' .... ,labl< foct th., 99.9999999'J99999 p««n, of tho volu .... of onIin • .,. maU., u empty .poet. If thtt. were """ ..... Y to "lute"" all Ih. nnply!pace oul of ll>< alOnu in our bodi.., humanity _uld i....t«d fit into the

.pa« <>«upi«! by. ,ugo' cub..

,

•

n.. appalling .mpti ..... 0( alOnu is 001)' on< of tI>t <oc,raorJ;nory du.roc~ri .. iu of the building 1>100;1<. of mott.r. An"tht •• 0(

courst, i. Ihn •• iu. It woulJ l.ke ]0 million .1011" Laid tn<llo end to

.po.n 1he width of. 5inglt ~ on Ihis paS<, whH;!. .... i ......... ques

tion. how did ..... "', diocovcr th.l .,.,.nything is ""''''' nf . 1orn. in lhe fint pbct~

Tho< ;.l •• th.t .""rythi1\j\ is moJ, of . ,0m' was .<t....uy Ii ...... g_ geslN by III< Glttk p/lilooophcr l.lemocriM oround ..w 8C.' Pick· ing up • rock--<>r il may h.", Nnl • br.r.ch or I day pol-il< _""«I himodfth< '1u,,'i'>n: "If I <;\I, this in Iulf. ,ho. in half again, <on I go

on cutting ;1 in half tiIr.",rl" His ."._ ,.... an emph.tic ""- II ..... inconc.,;vabl,1O him thot maun-amld be ... WividoJ f~. Sooner Or 1.01 ... "" rns<>ntf mmn- wouk! bt r<><htd th.1 couk! be CUt no .maller. Sino: th, Grtdt for"ur":'m. bIc· ...... -~·,_· [)<"...., i tu< calkd In. hypothdiaJ bWlding bIocu of all ""'II"· atoms.·

Sino: .lOnl$ .... '" 100 ""'.1110 ........ " with lh, ........ fillding ovid,no: for th.<m ..... always &Ding to .... Jif&WL ~nh<l<$$ •• ... ")' waco found by 1M 181h~tury Swi .. matht""",icion lJanirlll<,..

noulli. Ikrnoulli ,...1izN Ih.I, although oloms ""rt impoosihl. 10 oboer>ot dirt<:lly, i, migb' "iU bt p" .. ihl. to o~ thorn indir«1ly, In parli<:u.lat, bt ,....",td Ihal if. lars< .nougb numbt, ofoloms >atd IOg .. he<,lhey mighl h.,.. . big tnOugh eff«l1O be 00v;"u. in 11'1< cvn-ycl.,. ...,.-Id, AU 1'1< nmltd w.U to find • piau in notu", whcrt ,hu ""ppe11«1. ~ found one-in 0 "gas.'

II<Tnout~ irn.gintd a guli .. ai, or " .. m as • ",tlKl;"n of bil· l;"n. upon billion. of .,""'. in ~~UlII frtnzitd molion like • • WoIrm ofong'y btu, Thi. vi.id piaurt imrntdia",1y .uggesttd an ~1an"ion for ,1'1< "p......." •• of. po. whim "P' • ""Iloon inflaltd

'Soon< of th<o< id< .. -...".........j i n my.ori i<r book.1II, M'U O! Fo.-. (Orlord UnMrsity Pr<oo, N ... -. .1(01 ). Apoiop« to _ who 110 .... rtad

il ln "'" dd'"" ... i, io -arr to know 00<1>< b.ui< lhinp abo., II>< OIom ill 0 ..... 10 'I'P'~'" lh< ""'1'1'" ,hOI foll<M On quo"''''" ",,,,,'y ... hdl Is <»rntiallyo throry of ,he .tom;': "",rld.

.... mUNG IN "~"'''N ,

or p .... h<J 'g.ains,,1It pi"oo of a"~am ~ngi"". WI!tn .:onfined in .ny """,.il><r, lilt .'0 .... of. g .. ...,ulJ Jrum n:1""d.,.,Jyon tilt waU.

liXt hailstontSon • 'in roof. ""ircomhined nrK' woWJ ho '0""'''' • ji"ery fOl"a .ha" 10 our ""' ........... would....,.. liXt • .:onslOn, fora pu<hing hack ,lit wall •.

lIul IIernoolli', microocopic ""pl.n"ion of p .... ur~ proviokd mort ,han. con""n;'n' m.n,.1 pi".u .. of wha, w .. AOing on in • gas. Crucially, i. IN '0 ' spKiflc pn:dic'ion. If. gas wen: "lU¢<ud in.o half ill original volume, lilt gas .. 0 .... would n~ 10 fly only h.lf .. for b.t~ ""Ui,ion, wilh ,lit .:on .. in ...... ..u .. They woulJ ,herno", coI1Kk ,wiu .. frtquen. 1y wi,h ,hou .... 11 .. doubling tilt p"",un:. AnJ if . 1It goo wen: "lu..,ud in'o • min.! of its volume, ,lit "oms would .:ollide 'h ..... tim .... f"'lu...,dy. 'r<bling tilt ptn<u"'. And so <>fl.

Enctly ,hts i>duvior ,... OMcrvro by tilt EIIJ!li<h oci<ntist Rob· ert lloyIe in 1660. II conformNlSernoollf, pic.u", of a gas. "nd ,ill« IIernoulli"' piclU" wa, of liny ~ ... inlikt .lOm. nyin~ hi.lltr .nd Ihilhtr Ihrough <"mply '1'>«. i. hoi" .. ...! .1It ~ for tilt .. ;"me. of .,""'.. I.lcspi,., ,hi. ''ICC '1' ~ .. , defini'i"" .. id<nct for ,bot ~x· i,trnce of .10 .... did not "0""" un,il,llt i><!;inning of lilt lOth ""'" 'ury. It ..... buriN in an obocu« plltnom~non ",UcJ 6rownian motion.

_ni.n mOlion ts ""mN.fItt Rohtrt 6rown .• bowIts' who .. ilN '0 Aus, ... 1 i. on • bot fl i nd .... expedi,ion of 1 flO I . lJ uring his I ime Jown und ..... lit das.<ificJ 4.1)00 spectd of .ntipod •• n plan'" in tilt proce .. , lit di~n:d lilt nudeu, of living coils.. 6uI he i, ho" r.· m<"mhortd for hi. oo..rva.ioo in 1821 of poll..., grains wspendN in ...... r. To llrown. "luin.ing Ihrough ..... gnify;ngltlU, i • .,..m«I .. if 'he groi"" ...... undtrgoing. curious jiuny motion .• iguuing ,lIt,r .... y Ihrough ,lit liqui<llikt drunbrds lurdling I>ome from. bar.

_n ""rtr ",1m! tilt my:s .. ry of . 1It "'Y"'.n.! poll..., 5f'I.inL "Tho, bn:oklhrough hod '0 .... i' for All>..-. Einsl";n, .g. 26 .nd in lhe mob. of tilt "" ..... "'pl<><ioo of cr""ivily in tilt hts'ory of oci...,,,,. In his "miraculous ynr" of 1905. nOl <>fI1y did Eins";n ."..,.,hrow

•

N ..... 'on. suppl.nting ~Ionian i<k ... bou! "",lion wilb his sp«ial 11>00.,. of rd.tiv;ty. but he finally p .... , .. ,ed the 8O-)'O • .....,IJ myotr.,. of Brownian mociGn.

n.. r ...... n fOr the , .... y Jan« of poll"" grain .. oc<onling to Eins,";n. was WIIMy wtrt undtrcont innal macbi ...... gun bomNnl_ men! by tiny wot .. molecules. Imagine I gi.nt inn.tabl. rubber boll. ,.U .. tt.an • I"'l"IOn. brill!! pu<hN .boy • • fidd by. I.'!!" numba- of

~Ie. Ifea"h p<nOO pwbcsin their own f>I"icul .. di~ion,wilhout.ny rcpnl for thtOlh<fS, "'"ny inOlon11her. ",m b< sligh~y mort ~It on one oi<k ,lun .nOlher. Thi, imbala"'r i, .""ugh '" "' .. , .. the NlllO IttO'ICc erratically about the fodd. Similarly. lht orratic molion "". pollon gr;tin can he "US«! by slightly mor< ... ", mol=l .. bombording it from one sKIt th.n from another.

fin ... in .Jc.viscd ..... 'hc .... 1H:a1tlleory 10 deocribe llrowni . n motion, It prt<licttd how far and how f .. , tht .... "'g. polltn g ... in

should, .. "" in responoe 1<, the ... I<nll ... banering il was l'«,;v;"8 from tht wat<, mol«uJ .. all .round. EV<TY'hing hing«! OIl thr.u.. of tht wa ..... m<>l«ul<S.oin~ tl>< biggrr .... y ~ thr bigger would b. 111< imbal.nc, 0( foras on 11>< poIltn srain and 111< ""' ... .".gg .... ,«l ito <Onstoj,.,." llrown;"n """ion.

Tb.t frtnCh pl\y>i< pmlic60n. 0( Ein .. ,in~ thtorr. H, 101" abl. 10 .s.,.!u« ,11< Ii .. of wat ... "",ltcules and h<nc. ,11< alOms out of which tlKy _'" buill. H. <ondudtJ ,hat ,10m' wer. only aboo, on< IO·billion,h 0( 0 .... , ... across-oo .mall,ha, il would tok< 10 million, Laid end '0 end, '0 'Pan ,11< widlh 0( a period.

A,om. 101.,.., Ii<> .mall, in f .... , ,ha, if , he bill;"", upon bil~o", 0(

lh<m in •• ingl, b",",h ...,.., .p ... ad Nally ,hroughou, Eal1h', a1m<>-.p""",, ..... ry b",.th·';..,! ..,Ium. of ,11< "'''''''1'11<", would ... d up ron1aining ~ral 0(,,,,,," 110ms. I'u, .nothtl" way. tvtry brnlh Y"u 10k< ron,.i", a'l .... ' on< a,om b",.,h<d ou, by Alber, Ei",,';n-<>r ru~us c....ar Or Marilyn Monrot Or ....... th' 1.0 .. Tyrannosau"," Ru

'0 walk Eanhl

.... mUNG IN "~"'''N ,

Wha, is mort, Iht .. om. of Earlh', ·bio.pht .. • a .. colUlan,ly rrqcl.,L Whtn an "'Pnism d~ il .l.o<O)'J and its c<lIISlilu.rll .. om, or~ r<1urnN '" lht II<>il and ,he .. """pbtrt 10 bt incorporalN in", pion" .ha •• ,.1., ... ~"n byanimalund hum.n~ "" urb<>n .",m in my car.J.i.., musde was ""..,. in Iht lail of. din<><>.ur: wrilts Norwe· gi. n """"list ""'ein Gaa.u .. in Sopllie', W .... Jd.

_ni.n "" " ;"" w .. ,ht mOil. po"df..J .... ;&nu foclht ex;"· m« of .,0 ..... Nob<>cly wll<> p •• rod down a microoco~ and Ja'" ,he cru, dan..,. of poU~n grai ... "nd .... Imllt .. bomb.:ordmml could d""b,ilial.ht ...,rld ..... ul'i ma'ely mode from ' iny. l,ull .. like po ...

liel ... Hul watching jillrry polltn 8Ui~ht <ffK' of .. omJ-.....

"'" 'ht Ja""''' ..,nully ""ing"Onu. Thi. hod '" ",ai, un.iI'9F1O anJ Ih. in",nlion of a .. markablt d .... ict aUN lht ""nn"" lunntling microocopc (STM).

The idn behind m. STM, " il btcarnt known, was "''1 ' impk "blind ~""'n an ..... JOm«If1~'. fa« limply by ",nning a fing .. """r i, .nd building up. pinu," in .h.ir mind. TheSTM works in. ,imil .. "'"Y- The cliff ..... « i. ilia •• ht "fingor" is a fing<r of rn<tol •• liny Jlylu. rnninisCotnl of.n old-faohionnl gramophone .,....jlt. lIy dragging .ht nottllt ..,,,,.. .t.. .urfact "fa m,IIdi.1 and f«ding its up -.nd-clown mol;"n in",. compul«. i, i, posoibk 10 build up • d ... iltd pin"", of.he unduIOl;""'O( ,he . ,omic , ...... in.'

'Of _. d .. ,. .. "" woy . ,..,.&. can ..,."'Iy fed . ,wfoc< ~lo:r.

human M~'" an. ''''-w,. if Ill. _. is choflll"l willi "«Irieily &nd pbc<d ""'tmtIy <100< ",. roo.do.cti", .wfa<t •• min....,... b .. _",bit .. «1 • .,"" ..... ,' .. 1" ,he ~ bt ......... 'htripoftho n«dI •• nd ,he .",foc<. h is ."""'" ... '''''' .... i''ll "'mnl, and i, ha. 0 <n><ial propmy Ih .. con be <>:pioiltd, Tht oiu of ,he <U~, is enraoro:iinooily om •• i .. to lhe width of Ill. pp.lf 111 • .....0. is rnov«I ........ 011 .... dootr to tho IUffa«, ,he corrftll ~rows...., .. pdr. if io ;, pulltd _. rr..:tion, ,he <W .... , plumm .... Th • .... of ,he,,,,, ntIi"_ '" ' ..... ' tt>t"""" ,..,..,... ,h. dio .. "", bt ........ the "fflll. tip.nd ,he ",rOO. It~ .... lhe t>«dl< on orlillcial om .. of_ct..

•

Of CO"rs<, 1M", is. bit mor •• o itlhan thaI. Al.hooth lht principlo <>f tM i~li"" wu.impl •. Iht",~. r",mi<lablo p .. "icoldif_ r","I, i .. in its ""li ... iO<l. For ;lUtan", .• nttd]" h.ad to bt f""nollk •• w .. A ... enough 10 "r .. 1" atoms. ~ Noboll'ri..,commiu .. u". inly r«ogniud II>< Jilft<u.hi ... 11 ..... rd«l Grn.l Hinnig and Htinrich !too, ... ,.be 111M rnmdlcn behind 1M STM, 111< 1986 NobeIPri .. for Phpia.

Binnig and Roorer WOK 'M firs. ~Io in hi'tory 10 actually ...... In alOm. Thrir STM images ....... some of III< mo •• ,.."...rkabl. in 11 .. hi"<>rr"r .d..,,,,,, ... nking along.ide ,hal of Earlh rioin! above

I'" groy dtwlalion of lht Moon or 1M 'Io'ttping opi",,] ... i,..,... 0(

UNA. Moms lookJ lik tiny 00«<'1" bolb. They look.!. lik ""'", ... ot>cktd in I>ous, ~ "" row. lIul mOIl. of all lhty looked lik<."" tiny h. ro grains of n,aU" , h.1 L>emocriIU' had Ken $0 c10arly in hi' minJ', C!"'.l..OO Y""'" btfon>. No 0'"'.1« has <"Vtr rno.k. predic_ Ii"" lha. for in odvara of aperi",mlol c""lirmalion.

lIut only on< ,i& of 1M .tOm was , ...... I..! by tho< STM. AI. t:.o.""",i.1U him .. lf had ,..Jiz«! .• tom, _ ... k>' ~ ,han .imply

'iny~ ... i ... in , .... 1< .. 1OO,ion.

NA1\IRE'S LEGO BRICKS

At""" .,~ naturt-' Lc~ bricks. Tb.ty rome in a ... ri<ty 01 dilfttrnt ~pa . nd sizes, and by joining them togeth .. in any numberof dif~nt .... ,.... it is pmsibl< to make. ro .... bu of &old. or • hum.n being. Everything i. in 'he combinations.

n.c, American Nobtl Priu win"", Richanl Feynman .. id: "If in some utaclyom all 01 ",im'if", knowWg< ~ dntr<>y<J and only 0"" .... trnct l"osN nn to ,uectt<ling 8."" .. tion •. ",hat st"ttnn1t ""mid con-...y tbe ",.,., informalion in ,be fewest ...,.,w" He ..... in M d""bt: "E.nytrun8 is m>d. oI.tom<.·

n.c, ~y step in proving ,ho, """,.are na,ure'. Lego brkks ..... identifying the dill ...... t lcin.t. oI.t""'<. H.".."..,. the fac t tha,.toms ..... re far '00 small 10 be perctivtd din:c,lyby ,he ....... made ,he .. !k

..... ,,""" '" E'~"'U" ,

• ....,. bi, .. formidmlo .. prO\ling 'hat a'o ..... won ,iny i!J'Iinsof IN''" in « ... 1 .... m<>tioo. Tho only _y '" iden'ify differen' typn <>f .,""'. wu,o find sub".ncn ,!\,a, ....... ma.k o:chuivdyou, of .. om, of. singl. kind.

In 1789 ,he Fn'nch .ri"oa-o' An,oin. I.;""i ... , compiItJ 0 ~"of

,ubo'. nces 'hOI he beli."",, could not, by any m.a .... bo broken down in'o .impl<r .ubo ... ncn. Thou w«< 2J · .Io .... n"· in lavoi<i<,~ li". Though som.la'or,u,ned 00' not 10 bo.lo .... n ... lNny-induding gold, ,ilve-" iron, and mm:ury-won indwJ .Ionl<n'al Wi,hin 40 )'Oa.,of lavoisid, dea,h ."he guil.,tin. in 1794, ,he li" of <1"",""" had grown '0 includt <100< 10 50. Nowadays.. .... koow of92 n.a'urally <><curring oJ.m.n, .. from hyJrogon, tho ligh ... t, 10 uranium, ,he h .. "i .. t.

tlu, wha, makes 0 ... . 'om diff ..... " from al>O,he,~ for ins ... n«, how don • hyJ",!!rn .,"'" diff.,,- !"rom • uranium .,""'! Tho .ns .... ,

"""'kI co .... only by probing ,heir ;n,ernal "'uc'u ..... Bu, alOnu ar. IO fantu,;ally small. l' l<"<m«l impos&ibl. ,ha' 011)"0'" ,""uld ..... , find. W2f ,<> k>ok i"';.1 ....... lIu, on< man Jid_ Now Z<a1. n.J., n.amed Ernes' Ru,hnford. His ingonious ;.I .. WU 10 US< .,""'. '0 look insi<k 0Ihc< .,,,,,,,.

Tti£ MOTIIINTHECATIlEDRAL

Tho phenomel>On ,ha,l.id bare ,he mUCInre of 110m' was radioac·

'ivity. di.lcov<ml by tho Frmch chcrnisi H.nri lI«qu<T<1 in I 896. lie·

'''''Nn 11101 and 19')), Ru,herford and ,he English chemist fmlerick SodJy foond strong .videllCt ,hat. radiooc' i .... atom is';mply. h .. 'Y 110m ,ha, is _,hing wi,h ""«>II m"!Y' I"""iubiy, .fro, • "",on.! 0'

• yn' or I millioo )'Oars. i, shed, ,hi. surplus .... rgy by <XJ>tI~ng """'" kind of partido ., high ,p«<l. Physicist> .. y i, di,in"gra''', 0'

• Jt.cay.; in,o an "om of. <lightly ~gh''''- dnn.nt. On •• uch <kay p"nicie was ,he alpha panicl., which Ru,herford

.nd ,he )'<>ung Gtnnan physicisi H.ns ~ig<' dt"",,,,,ratN was .im· ply In atom of helium, ,he stCOnd lightes' .Ie"",., anor hyJ"'I!m.

" In 1IlOJ, Ru,htrford had ....... UrN 1M sp«<l of alp,," p.nicl ..

oxpo:U.,J fmm aU,,,,, "r n><lio.,,~ <aJium. It was on .. ,,,,,i,hing 25.,000 kilo"""" ptr .... ond-IOO'OOO Ii",.. fo.skr than a p ........ ,-day possen! .. j ... H .... , lI.u' ...... ford ~.U..,J, was. ~«1 bulle!!o .m .... into atom< ar..I r~ wlu.l was d«p iruid ••

n.. ide ..... "",pie. fire alplo.a particles into an alom. If they

."""un'.....! ''')'Ihin, Iu.rJ blocking th<ir .... y. tlKy _u1d bt "". n«led from their path. By firing ll1ou .. ,,<I. upon ll1ou .. ,,<I. of alpha particles and obocrvi", 110 ... til<)' ""'" <1.0«1«1,;1 would bt pouibl< '" build up • .ktailotl pictu .. of .... in',",,' of on "om.

Ruthnford', ""ptrimml WU Cilrrial OUt in 1909 byGtiger and • YOu,,! N ..... z".Ion.! phy>ki'l ... moJ Er ...... ~brsJon.lheir·.lph.

scan""nS" uptrimnu u<t<I. small .. mpl< of uJium. wh;rn ftml off alph. p . .. kln like mk""",opic fireworks. Tho sample w .. p""'ed

bdlind a I .. d ",,<to cont.ining a narrow oIit. so. thr .. d·,hin ..... ,"" of alph.a panicles emerged on the far .ide. II w;u the world', .nlilleS! m..:hin. Sun .... "ling 0'" micro$copi< bullru.

In .n., firing lin. Goi!!"," and M.,..J.., pla<al. ,hm. of gold (<HI only a f ..... tllo .... nd aloms thick. It ..... ins.ubst.antial tnough that 011 lhe alpha p.rlid ... from the minialure machin. gun would p .... Ihrough. llut it ..... subst.antialtnough that. during their tl"l.n';I • .IOmt

would p .... do .. rnough to gold atom. 10 bt den«\N olightly from lheir path.

Allbe lime of~ .. and Marsden', experim'nt, 0 .... p;o.nide from ins;.Je the .. Om IYd al..-ady bun iJrn,ifi...!. Tbe .I«tron had

bun diseov<rN by the Ilrilish physicist "I. J." Thomson in 189S. Ri-diculou.s1y tiny p;o.,.,ide, M'b abouIl.ooo limes ...... 11<' thon ..... n 0 hyJrogon a.,m-hod lurnod QuI 10 bt the .10 ...... p;o.rtid .. of <1«_ tricity. RippeJ fut from aIO",",. they 'urgod along a copptr wire amid billion. of oth ..... creating an .\ectric currenl.

Tbed«1ron ..... the firSt subatomic p;o.rtidt. It arriN a "'5"tivt

.lectric charge. Nobody k--. exactly ""'at .1ec.ric charge is. only thot it co ...... in t_ formll: ntgativt and po';t ;"-•. Oniina'l' mau ...

which consists of atom .. bas no .... t d«1,ical charge. In ordi~'l' at-

.... "'UNG 'N "~"'IJN " nm" IMn, lht n<go,i", ch.rgt of 'M .I«'ron, iulwayo pcrkctly 1»1-.nced by ,he p<»i,i", ch,,8" of some,hing .lse. II i •• charac,eri"ic of .I«,rical ch.1'5< w, unlik ch.t5<' .ttract .. ch o,her ........... lik charges repel .... h ",he,. Co",",!u.n,ly, ,he~ i, a f",,,,, of .ttraction be,W<'<n an a,orn', nega,ively charged d.<,ron. and ito "".itivtly

charg«l some,hing .lse. I, i"hi, am ... ion ,ha, glues'M whole 'hing '08",11<"

No,I""g afier'Mdiocov<ry of ,he .I«,ron, Tho"""" ..sat ,hnc in.ights '0 concoc, ,he firs '· .... , scien,iflC pic,u,.., of ,he .. om. He .; .... 1;...1 i, .. a mul'imdo of tiny.lcctro ... "",bedded "Iiu raWn, in a plurn pud.Jin!"in. diffuse b,aJ1 of p<»iti", charg.,I' ", .. Tho""",,', plum puddi ng model of the .,orn lhol Geiger 000 MarsJen .. pected '0 confirm wi,h ,hei, .Iph ..... n.,;ng n.pn-imcnl.

They ~,.., to be di .. ppoinl<d The 'hing W, blew .... plurn puddi"l; rnod<l "'" oflll< .... 'er

..... a .. ,.., bu, remarkabl ..... nl. 0 ... ou' of evcry 8,000 alpha par· ,ic I« fi....! by .... mi n;'l u'" machine Pln a<'Iually bounaJ back from ,he gold foil!

According to Thomson', plum pudding model •• n atom """i .. «1 of. multitude of pin·prick elc<trons .mbttl<W in a dilru .. gk>bt of pruili", chargt, The .Ipha particks ,hal Geig..- and Mal'S<!nl ...... firing inlO Ihio mm>y :llTangemen" on ,he other hand, ~,.., un .. op· p.bI •• ul»'orni< "p, ... ,,..i,,.,.ach .. he....,. a. arouOO 8,000 <1«. ,ron .. The chance of,uch. rna .. i", pa" ick being wildly del1<C1<d frorn ito path ..... abou, .. g .... t .. tho, of .... al ""p ..... 'rain being d .... il«l by. run ..... y doll carri.ge, '" Ru,h.rford pu, it:"1t "'I' 01· rnoo'" incrtdibk .. if you firtd a l~·in<h ohoU 01 a pica of'i ..... papn- and i, ca",. b..ck aOO hi' you!"

Gtig..- .nd M.rsJen', .x,raordin.ry .... ull could ""Iy rn •• n 'hat an atom w .. not a mmS)' !hing .. all. SO .... 'hing buri<d <kep inside il could stop •• ubatnmic n.p, ... lroin dud in il< ,rod .... and lum i, around. Tha, """<thing c",,1d only be a liny nugget of posi,i", chargt sitting", til< dead Unitt of an atorn and r<pcl~ng ,h. positi'" chargt of an incoming alpha panide, Sinu ,he nugget ..... capabl.

of standi", up to a moss;"" alpha pa"icl~ without bting knock<d .0 kingJom """", it.oo mu .. bt mo .. i"". In f""t, i. mu .. ""nlOin .1· most all of tho moss of on "om.

Rucho.-fonl had di"""' ... .,,! II", otornic nucl.".~ Tbt piClu", o(!he in.erior o(!he . tom .h ••• mOlllN w .. .. un·

likt Tltoorn"",·, plum pud,Jing pic.u"' ...... pouible to im.gi ..... It was a mini.tu ... ""la, 'Y"m1 in whicb fK!!a."'d.y cha'!!.,,! .Itc.roru

we ... a'''"ClN co.he po';t"'~ eha,!!, of che nuclouJ . nd otbitcd it likt pl ..... ts around .he Sun. The nud'lIJ had.o "" at I ... c as m .. ,i"" .. • n alpha poniclo---4nJ prob.obly a 1", """" so-for m. nud .... with

which it collided nO! .0 bt lick<d 011., of."" atom. II tl>crcforc had 10 ",n'a in mo", th.n 99.9 ~n. o(.he •• om·.m .... '

The nucl,u ...... vn-y, _1 .iny. Only if natu'" ... amrnN a 1",#

po';tiv. <Iu.'!!. inco . vn-y ,moll ..,Iurn. ""uloJ. nucleus ...... c a ",.

pW1!vt forct "" """rwhdmi"l; that it roWJ mal<t an alpha panid.

'X«IIl<. V·turn. Wha. "". moo! " riking about Rutherford', vioion of an .. om ""~ m.r.rorc. iu appalling <mptin .... n.. p~ight Tom S'oppuJ pu, it b<autifully in hi> play Ha/'f!JO<l: "Now m.k. a fist. Ind if your fISt isa, big .. tilt nucleus of an 110m .hen tho otom i,

.. big .. $I !'aul"".nd if it happo'" to bt. hyJmg"" atom then it has

a .inJ!lcd.«tron Hitting.bout lik. I moth in an <mpty cath...tral now by cho OOrn •. now by.ho .Itar:

Dcspit. its "rpoara"", of .IOliJi.y, tho famili .. world .... ",tuaUy

no"""" ",botant .. 1 than . ghost. Matt .. , whether in the IOrm 0( .

chair. a human bti"" or • ,tar • .... alm""t .. du,; .... 1y ""pty 'pac<.

'twnlWllly, phyUciol< woold di ocow, tha, .ho n ""I<", rotIuin, IWO par· ,d<S' 1"'<;'i...-ly du<fO<d pn,l<' ... ODd onclu.<J:t<I, or "''''ro!. "''''r<H'I~ Th< numw of p., •• , .... in a n"",", ~ _)'$ ...... 1 bol. n«d by ,n «t...t n .... ·

W of eWet""" in orb;' oboul d. The diffc-rcra ............. . 1Omo ~ .. III. num .... of prolOll'" ,lvi, nud,i (.t"d """«t .... dy "'" nwn .... of <1«. 'rono in orb;'). For in"'I>«, .)'1, .... h .. OM prot<><> .. il< ""' ...... 00 ."niurn. whopp",," 91.

.... m"1''' 'I' "~"'''I' " Wha • • ubslara an ",om p<>SO<ssN resid<d in ill impos.sibly ,mall nudous-1OO,ooo ,i..,.. . mall.r ,han a romplo .... ""',

Pa' anolhrr "'>y. mann iuprtaJ u ' .... ndl' .hinll'.1f i . ........ ]>0<

,iblo '0 """""'" ou, all, ....... 'Plu ..... ply spo«, m."", would tak up h.nlly any room •• aU. In rae ••• hi, is p<rkctly possible. Al.ho"3h an ."y ""I' 10 "Iu ........ hum.n race down lO.he .i .. of • >118"' cube probably Jo." "'" nisI. a w;ry don ",is, 10 "Iu ... ", the ma".r of a massi", OIar in.o .1Ie .malla' voIum. poosibl •. The squ<,<ling i. done by ... mendouoly mong gra_i,y. and .11< .... ul. i. a n .... ron OIar. S""h an obi<'<1 p""kt lhe ."",mous m ... of. body III<.iz.o of ,he Sun in'o a ",Iurn< no biU ... . han Moun. E"' ...... •

THE IMPOSSIBL£AlUM

Rutll<rfonl', pidur< of . 1>< atom .. a mini •• u .... solar .,..t<l'll with

tiny "I«. ron. flitting abo ut a ~n ... 'omic nucleus li« plan ... arounJ the Sun woo<. trn.mph of ""I"'rimental ",irn~. Unfonu· nately, il Iu.J a slighl problem. [, waco ""ally ino:ompa'ible with all known phyoiat

Ao:oorJing to M=wdl', lheo<y of .1o.;1rollU3netisrn-whidJ ~. scribed aU .1«tOOI .nd m"l!netic plxnomtn_whene",r. dwsnl panicl. acccloraln.clt.>nging i,. ~ or dir«lion of motion, it gi ...... ou' d«trollU3netic ... ,es-~gh •. An d«tron;, a ch.rgnl partide. AI. i, ci .. lo • • nudeu .. i, pu ""ually ch.nges its direction; >0 it oho"ld act li« a min;;"",", lighiliousc, "" .. tanlly broaJeuling l~ht wa ......

into spa<t. The problem i. that ,hi. woulJ be. c .... troplle for any It""'. Ali ... all, ,I>< tntrgy raJi .. nl •• I~h. has 10 come from..,.,..,· wher •• anJ it can only rom. from the .Ir<;'ron iuclf. s.p~ con' ina· Illy of e"'''gy, i. should spiral ..... do .... 1<, tl>< Cftlt ... of the atom. Cokul.,ion. ~ ,n., it would cotli~ wi,h t'" nudeus within.

's.. OIapler 4. "Uncenal,"l' and the Limits of Know\Nge."

" m~'" hundrtd-miUionlh or. ~d. By riSh, .. "oms should 001 oxi ...

But Ole_do ",,;.c. We and 1M ""rid around u •• rr proof tn""5h of thot. For from npiring in • hundreJ_mill;"nlh of. o«onJ, atoms h.>vt .<ur.iwd in,ac, sin .. tho .. ,liHl l i"..... of tht Un;"""" olmOl' I~

billi"" ~ars ago. Some crudal ingredient mu.t be missing from RulhmorJ'. piclun' of tho . tom. That i"l!M.!;"nt is • rnuiuli" ... ,y now kind of physics-<.j .. nlurn theory.

WHY GOD PLAYS DICE

WITH THE UNIVERSE

How III _,n nw MIIi!" nn WOIUU' 'lOllS

...... HlllIIlliSOIlJ AI,

JI 1'Io;!o..plorr -. .. 01. ' /. ;,. -..-, "" ,10< ..... , .... ,,"" of.o...... tIoo, tII ... _ <fJ'Idili .... aI-r-~ r/J< ""'" ",.IIS.· !<til;

''''rdot<'t!

'r',2025 QJtd hig~ on" dtsoI<J" ",,,,,main,,,,, Q l iaM! ,00-......... ,.1<""P' ,nod< ,,""'.,.] 'ht nigh •• q. It !«bOnl" Q P"""'I"W:r ", twtdgr of'lo<: ob1cwbie Un;...,... a,.,j frtbk ligh., "'hkh IIa.< b..,,, 'nwtli"8 ,h",.gh If'<'<e ... "" '''''8 btfotr &If'/h "'" bo, ... is """""'trnk'J ~r !he .&«:0/" mirror on'" uI' ..... " ... ti .. .wCfnm;c ,kuaon. In>i.k 1M uk·

'"~ do""" _ltd at a "",InI""".1 "", unla. 'he unHit of 1M ,,,,,,hip Ent..,.p~. lit. a_."..." "",rd! Q fuzzy imax< of 1M 8"'1""1 .wi'" jn'" ,,;..,."" a """1""" "''''';IOr. So_,tnt Iwm. "1''' .. uJ.ptdUr and a dtafrwinK rn><k/t filb ,It< "'nrrol..., .... /, "",nJS lilt """'hi ....

pm fi"' it_"'" lib min J"'mming "" a 'in roof. /n foci. ;1 iJ tloi: ""md of';", ,,,,,,kin of/igh. "';";"8 down "" ,lot "lnnJpt', de".""" from Ih. >YTTd'pr/" of """<.

To 'hn< a<I"'nom .... who ~nJ lI"';r ca.ur •• tnining '0 ... thr "",ko .. soon:cs of light in .he Uni .. ,...., it i . ... If·..,.iJ<n' filet 'h>l

"

" light is • ",urn or tiny buU<1lik.< ponicln-poolons. No! long "S" ~,the sc~t;fic C()IIImuni'y haJ ,<> be dnwJ kicking and """,amingto an acctpt.nc. of this id ••. In (0<,. if ' f.i, 10 say lhallht di",o~ry ,ho, ~"'1 com .. in discrete <hunks, or 'l""nIO, was the

sinsl< mOil' sIIocking di"",vnr in II>< hi .. "ry or scitnu. It """"plOw,oy the security blonktt of pre-20lh-century Kiene. and ex ...... d physi-C;It. 10 "'" h.on h .alioy of an Mic.;w IlI>n .... ''''''J uni ...... wh< .. things hap~n boa .... lhty happm. with un .. dist.gar<! for 1M civ;liudl.",. of caus< and elf",,!.

Tho< fin. P"""" '" ",ala. 1M' light was made ofph.ooons was EinSkin. Only by imasining it ... ", ... m or tiny parlicl .. could lit "",kc .. n .. of. phenomenon known ... the phot.,.lo<;tric orr"",_ Whtn )UU walk into. suptrm.rkct .nJ Iht.loan 0\'<'" roc!"'u automalkally, Ib¢y ar. being controlled by the pho 'o<ltclri c effoet. Cnlain mdals, wlxn ""J><"l'<l lo light. <joel partidts of <itdricily.1«1.0 .... WMn incorporatN inlo a photoctl~ such . metal g ..... , • .... • ,mall ..I«tric <Urntl' .. long ... light ~m i. f.llin~ on i,. A show .... who bruh ,h. boom <hok<$ off" ,ho. Curr.n'. s;pul in~ ,I..

'"l'<"m""I:<, doors '0 swish .. HIt. 0 ... cl ,I.. many J'«"l i.c cha.O<t<ri"ic. of ,I.. phor<>d""ri< of

f"" i. thaI . .....,n if • ,...,.y wNk li&hl i. uoN. II.. ri""rono or. kicktd ou' of'h< mwo! ins"n1.ntOIJ.>ly-,h .. is, wi,h no <kloy whalSO<Vt •. ' Thi. i< inrxplh:oble ifli&hl i •• wow. ",. .. ....,n i< Ih., a ....... brin~. spr .. d-ou, Ihing, will ;n .. roc, wi,lI. 10'1' "umbo. of ,Ioc,rons in ,ho. mwo!. Som. wiU in",i .. bly br kidtJ 011.1 aft ... othrn. In f""' .£<1 .... of

'Anolht, iJX< .... "" charact<r ..... 01 tho phcoto<I<nr" <If .. , is tha, "" """ron ... oil ... ""~!«I.".\he ........ if ~ to iIluntin>l«l.". 1"", with. ~t.---. m .. ,"", 01 ,I>< d4 .. _ bc1_. '""""i ..... '" <r<O_ obov<. «nain ,hmbold. This, .. E",,,rirr .... iud. i. hoc.,. .. phoooo. 01

!.ish' ....... n '""'"fJY"'" ""'-. widr inc ...... """"<rl$Ih.And below. «""'" wav<I<rl$I" tho pI\oI<Jru ...... inoulfoci .... '''''OJY '" kidr an <ltrtron "u,o(,htm<tal.

" the ol«lron. could .. ';ly "" nnin<J 10 min"ln or so .ft .... lighl i, , ....... on the m«ol.

So how i. it J'O"ihie Wilhe tl«lrons art xicktJ Ou1 of lht mtlOl instan ....... ouIy! ~ to only 0 ... way-if each electron is kickJ.

out of the motal by Q "nJk /"Irlidt oflight. E~n monge ... i~no: Ihlu light con';, .. of tiny bulledike por·

lid.scom .. from tl>< Compton di"«'I. Whrn <I""""' •• r< .. pos<J to

X·r~ high-olcrgy kind of lig./ll-lhey recoil in cxaclly III< woy they """,1<1 if lhty ..... ,., billiard NIl, bting"rue\:; by <>Iho, biW.rd bali •.

On the surface, 1M disc"""'1' lhallight bthavn ~k< ........ m of 'iny p.orlicles .... y no! oppo" ""'Y """,ubbl. or surprUin!_ Hut it is. The ,.....," i. Wlll>tt. i •• "" abundant and compd~n8 tvideno: thai light .. something as diff.reI" from a me.m of !",'Iides as il is poMiblelO irnagi...-. w....,.

RIPPW ON ASEAOFSPACE

AI III< bqinning of III< l'JIh «nluI)'. II>< EngJi1" ... jnolopendtndy "r tho FmlChrnan 'un Fran.,.,uo..mpoUion. looi. an opoq"" .o<rttn, rN<k two .... tic .. ,HIS in it .... ,y do .. log ....... , and ,hone lip>1 of . singlt

color onto lhtrn. If light ""''''. wavt. M ",a!OM.! ... ,h slit would

servt as a now _ra of .... va. which would 'P"'oJ oUI on 1M IiIr .iJc allM ""1ft" likt CO""'nl riC rippl .. on • pooo.

" " .. rocleri"k property exhibited by wav .. i. interference. Wlltn lW<> ';milar waves p"'1h",,,,h each other.1i>ty reinfora each o.her ~ Ihe unl al 0", waY< winc;.b wilh Ihe c"''' of anOlMr. 000 Ihry c."",1 ooch Olher out ",herolho <usl of 0 ... coinciJes wilh

Ihe lrough of tl>o Olher. Look ... potddle during . ",in shoW<r and

l"u will .... lht ripples from uch raindrop ",,,,oJing oul and "COOl· "",ct;vtly" and "d"'",clivdy' inleffering wilh each o.her.

In tl>o palh al tl>o light <m"lling from hi< twO oIi1< Young inler·

poKd a o<cond. white, ""Iftn. He immediately .... a series of aher·

" nl,i", dark aooligh! "",,,Ical 'Irip<'S. much lik ,I>< lines on a "'1'<"mork .. b.r oodo. Thi. in'.n.",,,,,, p.mern P~'I> "" ,he ir .. fut_ .blt tvidtl'>Ct th.t li8hl "'as ..... ..,. IVht .. lht ~5hl ,ippln from ttlt 'WI) slito _'" in '!<p. matching crest for ere", th. 'igh1 was boosted in briglnr>nS; ",1Itr. !My w<'" out nr.ll.". !he ~&hl ..... ,."",Itd Out.

Using hi. "double .lit" .1'1' . .. , .... Young"'" abk lO ~t ... mine .Il< lnVO:l<ngth <X KgllI . He Ji<cov.m.I i, WI" m<'" .""","-ndlll of . millimclrr-far smaller than lhe width of • human hair- .... tly explaining "'by nobody had guesKd light ..... . .... '" I><to ...

For ,I>< nut two ,..,turin. Y",mJ" pie,,,,,, ofligh. as ripI''''" on I st. ol 'Pace "'ignN suprtm< in •• plaining III ""OW" phtnom."" involving 1igh'_ But by ,he end of .... 19th ""nlury, ,,,,uble was b",wing. Al1ho"llh kw plOplt notiet<!., firS t, lh, pictur. ofli3htl •• w_ and til< pktur. of lb¢ alom os. tiny mote of man..- w~ ilWCOIKiI.blt. n..- difficuky wu ., til< intmoc •• the pbu wh<rt light n>«t.

maner.

lWO FACFSQFASINGLECOIN

Tho in • .,..,,;"n be1~ light . n.! nult.,. i. of cruci.1 imp<>rl>n« '"

th .. ,.,ryd.,. worlJ. If the "onu in tht fiLam.nt of. bub did IIOt .pit out light, ..... cooW not mumi ... t. our bomn. If tho . lOm. in tho

... tin. of your.,.. did IIOt absorb light. )'Ju wool.! b< un.ble to r<od

t ..... wom •. Tht troubl. i. that tho emi .. ion and .boorption of light by ,tom> .... impo .... bl< t(} unJ.",""" if ~gh, i •• w;n ...

lin alom i,. highly Iocali2.C"d thing. "",finN to. tiny ... gion of 'pau, who ...... light w.~ i, • 'pr<ad·OOt thing th;tt fill • • largo am(}unt of ,!,oce. s." whm light it ,b><>rW by an >tom , how .I_ . uch • big Ihing m .... g. to kfutt"tt inlo . uch • tiny Ihing? And ...... n light i.emittod by an alOm, howdoto ,w:b. """II thing m. .. ,..ge to

rough Out such • boJ! thin81 Common ......... yo that tho only _y lighl can be .boorW or

emitt""! by. "".11 localized 'hing i. ifi! tOO it. "".!Uocalized thing. " Nothing fits in.ide •• nak< lik< anotller .... ke," .. the saying goa.

" Ught, howe ... ", i. I:nown 10 I>< • wa .... Tho oolf ""a)' out of !hot conundrum _ . f.,.. rhr>i<iot"Q ,h..,.. up their Iu.oo. in despair.nd iVUd;!insJy ocapt th., ~5ht i. boIlI • "'""c and • p.rtid<. But ",,.Iy oom<1h;ng n nn.,. I>< simullaneoouty Iocali"d an.! op......wut! In ,he nttyJ.ay world. this is pnfc.:tly trat. Qucially. h~r. we art no1 ,.Iking aboutth< ev<r)'Jay world; we .... talking about the microscopic I'IO,ld

Tho microsc<>ric ""rid of Itoms.1Id pholOO. tum. OIIt 10 I>< no.hinglikt \"" f.mili., , •• Im of trtn.oo clou..u.oo pwpl<. Sin~ it i,. J""",in millions of .im .. omal1 ... th.n ,he ,.,.Jm of f.mili.r obj«ts. why should it I><! Ligh, ,ully i. both. partido and ......... Or "', ... ''''l"«Ily, I igb 1 i. "JQm<l hi"8 .Ist" for wh ",h l~ i. n" """" in OUr ... ryday Iangu<lJIC and nOlhinJ! to comp.rt il wi, h in th<~· oryday world. Like. coOn with two facn,.l1 "'t can s« ar. its por,kle· [iOt (oct • ..J its "'''''''Ii ... fou. Wh.t ~sll1 aauall, i. is .. unkl'lOWabk

.. the color bl~ is to. blind man. Light """ .. ;mrs bdu._ lik< ..... Y< an.! """ .. i"", ~kt • "'urn

of partid.,.. Thi, wall an <ll.rtmdy dill"",uh . hing for , I>< phyPri ... of

'he .. ,Iy 20th ctllI,,'Y to occ<pt. B", tMy had 00 <hoi",; i' ..... wha, rutu~ ..... Itlling them. "On Monda)'>, Wt<lnesd.o,.. aM Frida,.., "" ,eKlt ,I>< W;lvt thtory and on Thtoday .. TIturS<il)'> and Sa,,,rday. tht p.rticle thtory:;ok<! the Engli'" physki>1 WiIIi. m IIr-.gg in ,'21.

Brag" pn,!;ma,i'm ...... admirable. Unfortuna,tly. i, w.o nOl mough to >ave physics from dioast<r. As EinlCein ro ... , realiled, lhe

du.al w ..... p.rticle rut",.. of li,!;h. w". CiWlropl><. It ..... 001 iout impoooible '0 .is\Ialiu, ~ ..... compl<1e1y incompa,ible wi,h .11 ph)'>· ia ,ha, had gone btfurt.

WAVING GOODBYE TO CERTAINTY

Tilk<. "';ndow. If)'O" look closely)'O" con '". f.i n, rtfltclion of

)'0'" fact. TIti, i, boca"se gJuo i, 00' perftcdy , ... nsp.rtn,. It 'rans· mits .bou, 9S pet"'n' of , I>< light .linking i, while ",fltcting ,I>< ",. maining S percent. If Iigh' i, • wave, thi' i, perfte,ly e.,y '0

•

~nJ .... tanJ. Th< "' ..... imply split. into a bi8 w .... thaI ~ ,IIm",1I lhe window • ..J • much ..".J\or .... ", that """'" bo.ck. Think <:L the bow ........ from up«Jboot If it .ncounl .... a h.lf-sul>mtrgtd pita or dril'twox>J,. I.". p;trt oft'" wavr "".uin .... on iu way whil, • • mall par1 Jouhl .. bad On ;15o<1f.

But while 1hi. ~vior i • .... y to und ...... nd if light i. a ~, i1 i. al=ndy Ji/f1CU1l1O unJ.",.nd if light i •• " .... m <If idtntico.l bulk11i~ part icles.. Ali" all. if ail tile pholonS .... idenlical, itotan..u 10 ... ...,n Ih.1 each .oould bt aff<CIN by 'h, window in In identical wq. Think of DoviJ IIodham toling. fr .. ki<k av« .00 ""'" apin. If th.t 00<= b.a.II,.", ;Jen,ical.nd he kicks cach on< in tu.ctly ,h, .. me way. they will all curleh"",gh 1'" .ir and hil1I>t5O"",.pot at

1ht Nd of "".I.ll~ b.anllo ;""'5;"" 'h, majority of ,h. balls ptpptr_ ing 1h ... me .pot while. minorily fli •• off 10 ,he cor ... , nag.

How. tt.<",;. i1 rossihlelha' •• lr .. rn olabsolultly iJmtical pholonsan impinge"" I window and 95 p<r«f1t can go righllhrough while S ptr«tl t rom. back! As Eins,.in rnliz...!, th.t", i, only ont

WOY' if th.t "",nl "i<l<tJ,iGl"1ut • ~'1' diff~nt rnnning in thr mi_ croscopic world ,han in ,I>< .~yworld---1l dimini.hN,C\t,-down m.anlng.

In ,I>< m~pic dom.in, i, 'um. out. ;d<nlicol,rungs do 00' htha~ in iJen,ki1 ways in kl.ntic.1 cil'C\tm".nce., 1Il>~aJ. ,I><y m~1y h..., an idtn,ki1 ""'_ af I>duving in any particul"r way. Each iOOividual photon orriving at ,I>< wiOOow h .. COKtly ,I>< same ""'''''' of ~ng 'rammil1t<! .. • ny of iu r.,1~9S 1"'''' .... ,_ 00 <ne' ly ,I>< JaIM ,""II« afhting ~n.c,t<!-S 1"'''' .... 1. n.. .. i. 'Molu,riy 00 way '0 know for certain what will h.ppm to . gi""n pl>oloo. W"'t~ it i. tr'Il>mint<! or ~«ttd is ""timy down to r. OOom ch.net.

In ,I>< .arly 20th cen,ury. this unprtdicl2biUty w" OOn><,hi"l! radically ""'" in lh< WO<l<l. hnogin .. roult". whM and. b.n jounc_ ing .. ""nd .. ,I>< wbod 'pill>, W"hinkof'I>< numb .. ,I>< IxIU com .. 10 ... ' OIl wh<n lh< wh«1 finally hal" .. inh<r<n'ly unprt<!ictablt. ~u, i, i. 00'- 00' ... Uy. If ;, W<r< po.iblt '0 know ,I>< ;ni,;ollr' ;":-

tory of the ball, tilt initial >p«d of tilt whtd, tho ""')' tho air CUrmlU clu.ngttl &om i ... tant .0 i ..... n. in tht <:Uino, anJ '" on, tilt lows of

ph~ia could be u«oJ to pmli<t with 100 pnant artainty ",Mr. tht bon will eOO up. The oamo ;"ru. with tilt ", .. ing of a coin. If i. w~ poosibl.1O know how mlKh rom, i. appli«.! in tht flipping. the end

.h.p< of.1It coin, aOO so "'" lilt laws of physic .. o"IJ pmlic. with 100 p<Tant artaln.y wt.t1MT lilt coin will com. Jown htad< or toil<.

Nothilll! in In. tvtryday worlJ i. fuOO .. ",mlally unpr«!ictablt; nothi"8 is truly random. 'Tht rnson "",anOOl pmlict lh< ootan.of. pm< of roul<ne or oftl>< "'" of. coin io that","" is >imply too mudt

informillioo for us tol.l:t inlOaccounL llul in principlt--ooo this is tl><

key poin.-d .... is nothinS to 1"""<'" us &om p..&:tlnS hod>. Conlra.t this with t l>< microsrop;c worlJ (jf photoo~ It m.tt.rS

no. the .Iight •• t how much inform .. ;"n we ha .. in our I"' ..... i"". It

is impoosiblt t(j pr.dict wh<th.r a !Mn pilot"" will be t ...... miuN

or .. fkaeJ by. win<low~n in principlt." roultn. boll Joe. what it do.< for a ... _n-b« ..... oftbe inl<Tpl.,. of myri..J ",btl. forrn.

" pho.on .lou what it .I"",. for no .. ason wh.""",v<r! Th.

unpmliclability of tn. microscopic worlJ i. fund." .... nl.L It i. truly .."..,.,hing ..... uOOer the Sun.

And what is !rut of pllot(j'" tur ... oullO be \rut of all II>< dmi..... of tilt microscopic .... Im." bomb d<ton .... bouu.sc its tim<r t.U. it to (jr bouu ... Yib",tion disturbs it or btausc its d t ... nical.

h .... . uddml), b«oot. dtgradeJ. "n un.table, or "r..Jioaaiv.: atom .imply dnonat ... 'Tht ... is .blOlut.!y no disurniblt dilf<r.n« 1><. t""Nn 0 ... Ihat ,",.""atcs . t this "",ment and an iden.ial • • om that "",iu ~ui<1Jy (or 10 million yurS bd'ort blowilll! itself 10 pi=<. 'Tht . ho<:l<ing truth, whkh ...... you in the ~ ""''Y tim. you look ., a wiOOow. i.that II>< wholt Uni ... ,.. i. foon<IN on ranoom chanet. So upset was Eins.ei n by this i<ko ,hat lit >Iud OUt his lip aOO J«brnl: "God do.< nOl pi.,. dice with tht Uni ....... l·

The .roubl. i. He does. lis ilrili.h ph)'fici>l Stephtn Hawkilll! h .. wryly point.,] out: "Not only do.<God play diet with tht Uni_.

h. throws tilt dice wher< we •• nnot 0« tlltm!"

Whm EilUt';n tl:'CtivN th, Nobd Pri .. fOr ""ysics in 1911 it wall

n<>l fQr hi, m"" f."""" t htory of «lot ivit y but f"r his apla ..... tio n of tht pbototltctric '1f«1. And this was "" .btrralion on tbt p .. t oftht Nobd commi nte. Ei nst'; n h im .. lf co nsio.ltr..J hi • ...,.k 0 n tht · q wontum"th, "nly thin~ ht nTr dMl in ..,inlet that ..... truly moIuti"n_ ary. "ndtht N<>bd <o",milt .. complet.ly .gr«<! with him.

l.)uaJltum throry. born out of tht SlruW. to r«oncile light and man.r, wall fundamentally.t odds with .n ..,ienet that hod g<>ne bt· f"",. Physics, p",·I'.IOO, wall buically a recipe for pr..Jicting tht futu", with ab5olut. ""n.in.y. If. pbnet is in. p.nimlar pIaL. now. in. clay'. ti".. ~ will h .... Rt<»'N 10 .nOlhtr pbct. which can bt p"'die.ed with 100 pertent <:onfldene<: by using Newton', 10 ... of motion and .ht I ... of ~ity. Contrasl this witJt an ""m flying thro",h .pae<:. N<>thing i, knowable with e<:n.inty. "II .... can nTr pr..Jict i, i1< probable poth. i1< probable fin&! pOiliti"".

whtrt .. 'lWOnlum i. booed on uncC1"tainty, tht ",,, of physic. i. butd on < .. wnty. To uy tltis isa problem fur pltysi""" iso bit of on und..,tat."",nt! ·~hysiQ It .. 8i~ up on the problem of trying to pr..Jic1 what wolllcl happen in 0 gi~ circunutane<:; .. id Richard F.)TIman. 'We can only pr""ic1 tht odds.'

AU is nOlinot. I>owt ... r. If the mic"""",1d w .... '''tally unprnlictable, it WQIIId bt ..... Im "f tOlaI <ha.os. aut things 0'" ootllti, bod. "lthough what at<>nl' and tbtir likr gct up t" is inlriruic.lIy unrrtdietoble, it turru ".n that tht unpredict.bWty i. at Ie .. t predictable!

PREDICTING TIlE UNPREDICTABIUTY

Think of tht wind_ ag.in. Each phooon has. 95 perctn. < .... IK. of bring transmitt"" and. S per""1 du.ne<:"fbring rtfl«ttd Hut what Jeterm; ..... t ..... probabiliti.,!

wdJ. tbt lwo din'ertnt pict.,," ollight--as 0 particle and o. 0 wave-must produce the .. me ou.come. If half th. w . ... goes through and half i1 rtfIect<"<l the only woy ." r«oncilt tht wa .... and particle pietu,," i. if.KIt individual particle "fligh. has. 50 I"'""""t

•

probability of ""illi l~nsmillN onJ • ~ ptrCtnt probability of beins mk<t<tl. Similarly, if95 1'"'<",,1.,( the _,.. is '""sm;UoJ and 5 pnunl i. ",OWN, tbe corrt.p,,,><ling prohahili'i .. for the lransmi,.ion 01><1 .. fle<t;"n of inolivid",,1 phocoru m ... , be 9S ptl'«1lt .nJ 5 pm:cnl.

To g" agrffmml bel ..... " the tWO pictures of light, the p"rlicle· lik •• p«l ollight m"" """"how b< "infonn"'- .bout how to 1... h ••• by iu .... ,..liu asp« •. In other words. in lhe micl'OKOpic domain, waves do not simply b<h~ m ... panicles; tho .. ra " icies bd>a,.. lil« .......... as "",UI ~ i. ptrf«t .ymm.try. In {"t. in •

.." .. ,hi> ""nn..,1 is aU you n«d 10 know .bout ~ .... ntum lhfilry ('por, from 0 rew deI.ils). E~hing 01 .. follows "1U""MhbIy_ All ,h. wrinln .... a11lht amazing rich"... of lht microscopic """id. i •• direct <')!'seq"""'. of this w;we-p."icJ. "d ... li'1· of the basic building block< of ,..Jily.

1M how <naly does lighf' _",Ijllt asp«! inform ilS particle

Ii .. "I'<'<' about how I" Nh~ Thi, is not an '''1 qu .. tion 10 .ns .... r.

Ughl f't'Va1. ;lodf rithtr OS • "",am of p."ida or as. wa .... W • ....... '..., both Pd .. .,rthe <:<>in .. tho .. "", ti"",_ So when "" ~ li~1 "" a "rnm .,r particlts, I ..... i< no wave in ai<lme. 10 info"" t ....... p;1"idc. w..ut bow to bthavo. Phyo.id.u therefor. h .... a p.-oo. Inn in ",ploinin~ tho (acl thaI photo ... do thinp-for in .... ""'. fly Ihroogh win"""'- if di.tclw by a ........ .

l1xy >o1vt lhe p.obkm in a p<'CU~" way. In the .boom", .,r a rnI ........ , lhey imagi ..... n ab ... ract .............. mathematical w ..... If this oout>ds ludicrous. thi ....... putty much tilt ",action .,r physici .... whm the idea ...... firs' propo,w by ,he A .... 'ri.n phyo.i<is' Erwin Schrlklingtr in tho L9.!Os. Sch.Minge. imaginC"d an ab ... ract math· tma,ical ........ ,h .. 'p",,..J throo~ ",ac., meoun .... ing obSiades and bri"5 ",fltcttJ and t"' ... mitttd. j .... llik ...... t ....... ,.., 'p",aJjng on a pond. tn places wh<,.. tilt lltigbt of the ..... ,.., ...... large, the p.ob. bil· ity o( finding a p;1rtick was high .. t •• nd in locatio ... wbcn it w"" .mall, the probability ...... lowell. In thi ...... y SChrlkling ... · ...... ,.., o(

u

prohobility dlrimn<d .1It ..... "" function. inlOrm<d a ~rticlt "",.,10 do, and no' j",' • pt.o.on ...... ny m;';"""",p;.; p."icl., from an at""' 10 a "",!liluml of an .'om lik an o!Klron.

n..r. .... ubtle1y ........ PhysicislS oouloJ make Schr/ldins"", pictu'" accord with rt.~ty only if the prob.bility of finding a p .. tid •• , any point wos relaled 10 the oqu.art of the Img)1I oft,," probobWty w .... at ,hat poin', In oth<r _nl., if In. prolNbil"y ... ow at.lOm< point in sf"'Ct i.,...;.:O as high .. it is.t another point in spa«, the

Jnrtide i. four times as likriy to bt foond llltrt than .t the ochcr plo«.

n.. fact thaI it i. 1M "lUI'" "r,he prob.ability w .... aM""" tilt prob.bility"''''' itself 'hal h .. ",.1 physiul meaning to this .L.y co"", <itb;ok about ,.htt"", the """" i •• ,tal thing lurking btnuth the .kin of d •• world or jus, . 001'1""";0'" m.thematical device for calcul.ting thing •. 10.1"", but 001 all p«>plc ra"" the lan tr.

no.. probability wa •• is cruciilly important btcaux it makes . ronna:,;"n b<.WUJI thr ,.,,, .. Kk.. upect of rna" ... ano.l familiar wavcs

"fall kin.u. from w;a, .... waves '0 sound ~ 10 .. r1hquakr waves. All ob<y a ",..,.lItd ... "" "lllalion. This dncribes how Ih<y rippl< 'hrough '1'"'" and .IIow, phy,ici", to prtdi<1lhe ... "" heigh, at any \O;:;01ion al any tim •. Schr&lins<r's gral Irium ph W;IO to ftnd lhe wov<

"lUll\ion lhal dos<ribtd the bth"';or of lhe probobili'y wa... of .. -oms an..! lheir Iik ••

By ",ing II>< Schrllding .... "lual"", il i. poooibl< '0 do'.,min"he probability of finding 0 particl< at any I",at;"n in 'poc< at any t im<. For i ... ,an«, il can bt used 10 describt p!>olons impinging on Ih. obAacl< of. wir>dowp .... and 10 pmli<1lhe 95 peranl probabilily of finding 0 ... on the fa,.kIt of tho pan •. In fact, the SChrMing .... "I""tion can he ....-.llo pttdiCl tho probobility of any p'r1ick. bt il • photon or an alOm, doingj ... t about anything. II provido. the ,,,,d.1 boos< 10 lhe mic""""l'H: ...".W, , lIowing phl"ici'l> 10 pmlict ''''''y_ ,h;ng ,h., h,pp<n.,h.....-if nol w;lh 100 perc.onl =ta;nly, .,1<0>1 with prrui"abl< unc.rtainly!

•

Wh.", is .U this tall: of prob,ability ....... I .. di",! W.U. !M fOCI ,h., .... YeS beh .... lik p;tn"," in 11>0 m;';"""",;'; world 1...& un ·

rvoidIbly to 1M , .. liulion thal.1>< microo<:opH: world <lanen to an "",iuly diff ...... , tu .... thon ,hal of the .~ryday work!. 11 i, 8o~rr>td by ",ndorn unpr<'<.lictabil i1y. Ttti. in iudf was • .!ho<ki II,!;. ronft<k nu· draining blow to physicist. 000 lMir belief in • predictable, clock· work un;"'nw. Hut thi., it ' urns Oat. is only ,IK bqinnillll. Nata,. had rmny """""hod, in 01 ..... , The fOCI ,'''', ........ not only bdl . ... as panicles but.bo ,hat tho .. partidn behav< as ........ lead< lO the r.,.] i ... tN>n tha. all thr thing. that famil;.., W2V", lik. _t.r W",,", and

sound "' ...... an Jo. so tOO an til< probability .... ve> ,h. , infonn lht b<+w..ior of . "' ..... pho"' ..... nollh<ir kin.

So whal! WeU. w;l"" an do an awfullo! of iliff....,n! things. And ."'" of, ..... Ih ing> tur ru OUt to h ••• • semi-m; rae ulous 00"""'1""_ in II>< micro«opic _fil. Ttl< rn<> placn at on"", th< Njuiwl"nt of ftlU bo.i"l! in wndon .nJ Nnv York ., 'M $am< ,i"",.

THE SCHIZOPHRENIC ATOM

If,.,.. i....,m. riot difJt" .. " "''-''.n oknIJ .M ,~, .",.1,1', Jot"" ~"P~'tr, ,.,.. _101 It;' ""'''''''''riot bd"", ittJdi"l af _ .. ..dI "",,, ",,-fOJ • 9'"'WIW .. """".. ... ",..JJ "" ",mr-tJ ,.;111 rio,,,,,,,· pu~ .. -, .. , .

, ..... I!.rown

11'.1041. A. bcr si" a, " "',"pU'" in hiJ hn/,,,,, ... It~ "or an ~rJjn .. ,., "'''puler. /,', II 'I"""'."' "''"P"t .... TN boy glvn'~ """',..,,,, II .<Uk ... anJ im"m,l, if .pli" in'" .h".""ndJ ~I'<'" ,/row","d. af ..m;"", of jut//. ."'" ~ "'hkh ",,/b "" II .. ""lilt. ,/Til,.} of In. "..,bIt ... _ Fin"U".

"fin j ... ,,, In<! ""OftJ~ ,It. "",..J., com. """* fOfl"/'<r a"d" Ii,,!" " ........ ""'lots Oft ,h, ''''''I''''tI' JUpid,_ /t', "" """'"" 'M' .11 Iitt no,· mal <omp"'~ in ,Itt world pur togtrMT "",,/J haw ,"un a "illion ,';U.", J'f"" '" ji..J. $<I'isfWJ. ,lot bcr .... uI>.1ot comp"' ... .lown and

g«s ow/ I" pi"" hiJ "ip.l~ h..........,rI: Jone.

Su~ly, no computercouk! po .. iblydo wh.,.,," boy'.comP"'''' has ju" .1"",,1 Not only could • «>rnpu ... Jo .w:h • thing.aO&<k ~rSioru

.rt .!rudy in <lI;.~a ,<>.by_ The only thing in ..,.iou. Ji.pul< i. wh<'h<or ouch • quantum romp"'''' m<rdr bma_ lik ... $I multi_

plicity of rornput." or """"her, as some 1><1 ... 0. illil.rally ""ploit. th. computing 1'0"'"' of multiple copits of it .. lf .. isting in po .. IJ.1 , .. Ii'i<s,,,, uni~

•

TIl. O<:lIll.OI'Il"-'''1C Am .. n

Th. k<y p","y 0( a ~ua"'um compu, ... ----II>< abili,y '0 do many cakul.,ion ... on~oIl_. di,...;tly from two Ihingo ,h., """'in and Ihnd"",.., microscopic p.rt idts suc h os .. om •• nd ph<>Ion .. which boho ... like _'<>--<:an do. n.. fi ... , of ,ho .. Ihing. can bo><tn in , I><.,....of ocnn """ ....

On II>< o«on ,hor< art t.o.h big w ..... at>d ""on rippln, Bu, .. • n)"On<" who has w.tchN • hury on On • h«<zy d.y know>.. you can II!" go,big, roUing wa .... wilh ,iny rippl ...... p<1"impo><J on ,h.m. Thi. is a g.., .... 1 pl"Of'<rty of all """ve>. If '10'0 iliff ... n, ........ can mot . .., I"" can. ""mbi .... ,ion, 0' . uporpooilion. ofth< wa_ n.. fOCI ,ha, .... porpmi,;on. can .xi" i. pulty innocuous in ,I>< NOryday world. H.,.,.....,., in lho world of atom. anJ ,hoi, COOS'il ....... , i .. im· plications art nothinJ .hart of . arth.,holt.ri",.

Think apin of. pho,on in'pinging on a winoJowplIn •. n.. pho· ,on is informW .boul wha"o do by. probabili, y """"".<l«crit...! by ,h. SchrOdi"g'" <qual""'. Since II>< pho,on can ';,h ... "" ,ran.."i, · ,..I or ml«'N, th< Schrodinll"r <q .... ,io" m",' pnmi' th< ai<tcn'" oflwo laY........,"" rorr .. ponding '0 lho photon Joing IhrouJ h th< window and anotn.. rorr .. ponding 10 ,I>< pho,on hound", Nck. Nothing .urprising hort. Howov ... , rt"",m"", ,hoI, if IWO wa .... Ort

pormiltN '0 nis'.' ,uporpooi,ion of 'hnn i. also pormil'N '0 .xi". Fo, ..." .... at ... ouch. con,bina,ion i. no,hing oul of ,h. ol\linary. 8u, h.rr.,1>< <ombin.,ion <OfTdpond. '0 """,""",ing qui,. nlr"',· dinory-tl>< photon boi", bo,h ""n..,,ined anJ rtOoe,N. In 011><, _1\1,. th< photon COlI ho on bo,h ,HI .. of ,h. win<iowp."" "mult.·

~.." And 'his unbtlk-v.l>I. p,..rty foil""" uno",idobly from ju",

'10'0 &,:", ,ho, photo ... art d<s<ribtJ by w ...... nJ thaI ouporpooi. ,ions 0( wave> art pouii>k.

This i, no tho:o«Iicol fantasy. In ~rirncn .. i, i, OCIually poo. ,ibl.,o ot...r"" a photon or an atom Ming in '10'0 placn at once--th< .>«rydoy <quiva"'n, of you being in Son Francisco and S)'I".y at , ....

.. "'" ,im<. (1)1,,,.., accUr.II.Iy. i, is pouibio: '0 oo..r.., , .... "''''''I .... ,.'''. of I photon oron ,'om being in two placn 01 onee,) And .ino: ,hOR

i. no limil 10 III<- number of wa"" Ihal c.n bt ."l'C"p" .... t. photon or an ",om can be in th~ ploo;n, 10 placn.. million places .. on"".

BullM probahilily wa~ :wocial«l with. miao"""pic particl~ does m= thon inform it ""'""" it could be l<>M'td. I, inform. it bow tt>h<'hawin all riffi" ... '.r",,, tdlin~ a photon. for inotan"". wbdhtt or not to be t ..... min«l or rrilect«l by a ron. of glass. Con""'luenlly. alom. and thooirliu <an not only be in many placn 01 on«. th.y <an d<J ""~r dtj~g'~1 ""a. tho equivalent of )'<>IIcle,ning the h<>w<. walking the dog, and doing the....n.ly .upermarkot .hopping IU at the .. m. time. Thil i.,hoo _"" behind 'M pn>digK"" ~r of. qUln_ 'um romp"ler. It apl"''' the ability of .to"", to do many thing>.t on«. to do many calC\lIa,iono a' ona.

DOING MANY THINGS AT ONCE

The twk elemen" of • conventional compu, .. a", ,ran.istors. Th<K Iu", two distinct volta~e .tat .... 00< of which i. U$«I to "'l'r<Mnt the billuy digit. or bit. "0". thoo other '0 "'P'<$<II' I " I." A row of ,uch uroo.nd 0 .... can rq> ..... nt • larg.t number. which in the comp",er call be add«l •• ubtr2<ted, multipli«l •• nd dioKkd by .notbtr I.rge number. ' lIut in a ~""lItum computn Ihe basic elemenls-which may be oingl . .. o............a.n be in . superposition of .ta,<o- In other wonh. thoof can "'l'''''''"t I uro and. on. oimultan"",,,.Iy. To di<tin_ guioh them from IIOImal hi". physkim call such Khizophrmic en,i,i" quan,um hi .... or ~uhit ..

'Binat)' w .. invent«! by .h. 171lo_.mtuIJ .... th ..... 'ici.n GonfTi«! l<itoni .. It i ...... y of r<p' ..... 'ins numbtn .. .. tring< 01' uroo and on«. Uou.ally. "" ... dtcinuI. 0' boo< 10. ",., 'if;h,.t..r>d d;pr ..." ....... 0 ,he"""" ''"' ..... d;~;1 ,I\< "' ..... If>.,.,.. I,", 10 . 1(1o,.nd >oon. So. fo,. ; .... _. 9,2 17 ma .... 7 + I • 10. I x (10 . 10) + 9x (10 x 10 x 10). In binat)'.orbo.<l.lh. 'itt;h,-han<! diP. ~ ... nt. the on<>, the ..... ditt;it the 1W<r&, "" ..... the I x

l ... nd ooon.Sofo< inllll>«, I.IOJ m ...... I .O x l+ I x (2 x l) + I x (l x l • 2). whOdt in d«imoI ~ I J.

TIl . ""IIIWI'II .... "'" Am ..

On. 'l"bil an bo in lwo SI ... , (0 nr I). Iwn qub~. in four (00 or 01 or 10 or II ).Ih,«, qubi1t in oighl. and 00 on. O>~U<n~y. whoon )"U calcubte with •• il\3l. 'lubil.)"U con do 1_ cakul.,ioRS "mol ,.neou./y. w;,h ,wo qubi .. foor calcub,ions, w;,h . hree oigh" .nd 00

on. If thi' donn', impm. )"u, wi,h 10 qubi .. )"U could do 1.ol4 cakula,ion • • 11 .. onc., wi,h 100 'lubi .. 100 billion billion billion! No. ,urpri.ingiy, phpici". ro,i' i"dy .. li"",. at the 1'''''1''''' of quanlum compute .... For some cakulalion •• 'hey could massively nUlperform "",,,,,,,ioNl compuI<rS, making conv<lniooal 1' .... ,,, •• 1

com pute .. 'P~'" J'O'iti""ly ", .. nled. 1M for. 'l"anlUm compultr 'O _rk, wove "'~rposi'ions.",

nol ... fficien, 00 their own, n.q. n«<l . nolher ...... tial ..... "" ingr •. d;"',: in,nftrrna.

The inlerftrrna of ligh, obstr....J by TIw>rn .. Young in ,he 18,h ,"'''ury .... the ~ oh<tr,..,ion that """"inwl nft}'OOe ,h., Kgh' .......... "". Whrn, at lhe boginning of,he 20th an,ury.ligln ..... also ,00Wn 10 boh,,,,, lil<. ,,'nam of pani"' .... YOUI\3', doubl .. li . .. peri. mml ... um..! a new ... d un .. pectNl imron,~, "",'ns of .. posing ,he «nlral ptCUliari,y of ,he microscopic world.

INTERfERENCE IS TIlE KEY

In ,he mo<krn incarl\lUion ofYoul\3', ex~rim .. n. a double oIil in .n opaque screen i, iIIumiRa'..! wi,h ligh,. which i. undeniably "'nam of p&<tid ... In pr..:lic<. thi' """n. using a light IOu"''' SO fubI. ,ho, i, 'pi .. ou, pho,oo, on .... lime. Sensi' i .... <1<1«10 .. II difT.",n, posilion. on ,he....,nd """"" COIInl ,he arri,..1 of phoion •. After the •• ~""'n' ha> ~n running for. while. lhe detea"" show oom .. hil\3 remarkabl •. Som. plactO 00 ,he ocr .... gCl pq>~rNl ",i,h pbocons while or""," pl. ..... n compl .. ely ovokl..!, What i. mon. ,he plac ... ' ha' art: pep~r..! by pholon • • nd lhe pl:><n Ih .. are . ",ided .Itern ... , forming .... .,ical Slrip ........ ""ctly .. in YOUI\3', oripn.! .x~m.n'.

Bu, .... i' • minute! In Young', aperimrn' ,he clark and light

•

NOO •• " cau.s.t<l by inlorft,,,,,,,,,, And • fundammlal f"lur~of jnl~rf.,.,,,,,,, io lila, it in....,l,..,. tile mingling .,r two .... of ......... from tn. .. me -.,« Iht lir,ht from "". oJll with 1M light from lht och .. slit.llut in thi, """ 1he photons.'" arriving 01 In. double slit 0 ... I I • lin><. EM" pilot,," ;. comr1ttdy lIone. wilh no otbCT ph"''''' t<> mingle wi1h. How, lhen, can there be .ny ime.rcuJ>Ctt How can it ~ wh< .. its fdlow photon. ,.ill 10001

There ,""uld '~"10 b< only on. way-if caeh pIIolOn tomeIIow I!O<S through ~h slil. ,imul tll'ltOll$ly. n."" i1 can in1m.,., wilh i ... lf. In ".hoT word.., _" rho''''' m ... ' be in I ,uperpo.i'i"" "r two

SI.l •• -{>" u ....... corresponding 10. pholon going Ihrough lht loflh.noI ,lit anJ lho "l~' ~ CO ...... p"Ming to • pho''''' going through lht right_h.nd ,Ii !.

n.. double ,iiI expmmenl can be don. wilh pilot"'" or .Wms Or any othn micros.copic pa,tid ... 11 ' '- 5 ... phically how lht boo· !lavi .... of .uell panicles-where they can .1I<=Il-;'or<h<$,ra,.J by th<ir w;o ... liu .h<r<g<>. Hut this ;. not all ,I>< double .lit <Iprrim<nt demoll$l"'<$. Cruri.lly. it ........ 'h.t ,II< indiyiJUlII ""\Iff thai ..... 1:,0, up .... ~tion .... not rwsi'" but ,"0 I<ti",,1y inter/" ... with ~ach otll<r. It i , ,hi, .bili,y of ,II< indi_

yiJual ,,,,'nof a .upttp<lSitio" to ;n"rfttt with .ach othtr t""l i. th • • bsoiu" kq 10 til< mkroKopk work!, 'I'.wni~.11 ..... nno" or ""iru qUllntum ph.nom .....

Tak. qu.ntum """'pu l ..... The .. lSOn tll<y can .. try OUt ",.ny c.kulat;o",.t on!" i. b<au« tIxy an .. ist in a supttpG.; tion or

stain. Fo r inst.nc., I lG·.lem,nt 'lUllntUm rompu •• r is simulta· n"" ... ly in 1.024 ."'1eS and cln III<,d<>r< arry OUt l,oZ4 akubtions . t 00<,. lIut .11 tl>< parallel " .. nds of a aleu.ltion .. ~ of absolutely no u" unless Ihty!., ""'...., IOgelhtr. In"rftttnu i. tht m .... by which thiJ iJ oeo>mpli>hoJ. It is til< m ..... by wh;dJ til< 1.024 ,,,,1eS or tht .upttpG.ition cln in ..... ., and influtne •• I<h othtr. 1!Ko ....

or inlmtttno:, the single .......... ooughtd ou. by III< 'lUllntum <:om-

put.r iJ Ibl. 10 rdltcl Ind .ynlh .. iu wt..1 ..... I!"ing On in 011 !host 1,024 ~rallel .. Icula.i .......

TIl . O<:lIll.OI'Il"-'''''' Am .. " Think of a probltm diviJed inlo 1.024 stpara,~ pieces and 0".

p<nOfl working"" .ach pio«:. Fo' Iho"",bI.m lObo ooIvod,lhe Im4 pt'Oplt m .... ' communial< ",ith.ach atM' and tX<ha"ll~ mull" Thi. is wha, in,m ... "", ""'''''' pouiblt in a q .... n'um comp~l<'.

AIl imror'.n' point worth m.king htrt i. that, although .uper_ positio", a .. a fundammtal ("",u .. of ,he microocopic workJ. i, i. a curiou. proptT'y of ",.Ji' y ,Iu, tMy a", n ...... octually ohoa....!. All .... ~....,. ....... ,''' con""'lumen of ,hoi, a i".nu-whal results ..... n ,h. individual wavn of a ,u""'posilion ;''''rfrrt wilh .ach ., ....... In .he <;.,. of.he d.,ubl •• Ii ... ""rim .. ", for in .... ""'. an ... • '.'ftC .... i. an inlOrftrn>et l"uem, from which ... inftr,Iu, a" d«-'''''' was in. su""rp<>Si,ion;n which i, .... nl .hnmgh b<>th olits Jimul· I.noou<ly. It i. impoMibie '0 aclu ally <A"h . n "ertron JOi"ll through both .lits a, 011«. Thi. i. wha, woo ..... n, by , ... ~a,lier .... '.mml ,h., i. i. pewibl. only 10 ohoa ... Ih< ron"'l",,,,,,of an atom bting in lwo place. a, 011«, 00' ;, act .... 11y boinS in two places . , 0""'.

M ULTIPLE UNIVERSf5

Th .... ~i ... ry ability of q .... nlum oompu" " 10 do . normo .... num Mrs of ak"lalion •• imullanoo.",y posn a puu It. Though prac.koI q""n,um oompu'." . .. CUITm'Iy at • prim i.; ... ,,:age, "",nipu· lating only a lundful of qubilS, i, is ncvnthdr:u "" .. iblt 10 im_gin_. quan,um cOOIpu'tr'lu, an do billions. 'rillm. or qUlldriliion. of calc .... 'ion. oimWtanrou"y. In fac •• il i. quilt pouiblt llu. in JO or 40 yea ..... win "" obit 10 buikJ . q .... nlum oomp<l,tr 'hat an do more alcub.i"", .imultanrou"y 'h.an , .... '" art particles in , he Un;· ....... Thi. hypotMica1.i.u,a.ion posn a .. ickyq ..... i"": Whtrta·

ac~y ",ill .uch. computer "" doing i .. caJculations! Af'tr all if such a oompu .. , an do mo .. caJcula,ion, .imuh.anwwly 'lun , ....... '" particles in lilt Unim-u. il .tand. '0 rea""" Iha, tilt Un;. .... Iu. ;",uff",;'n, compuling mou"", to carry Ihem ou'.

On. a,raonIinary possibilily, wh;rn provides. WZ'f oul of Ih< conundrum. i.,h ... q""n,um oompu,., does ; .. calcul. ,ion. in p ....

alld ,cali,i .. or univtna. Th< idr. gOts bloCk to. Princt10n gradu." O1udrnt na",..J Hugh E""rw III. who. in 1957. W<)OO~ why quan_ tum lhto,y is such. brilliant dtllCription of tM microocopie ,.",-Jd of

.tom, but"" """"r actually 0« "'p<fpO.~ion .. Eve1'eIt' ... ,,,,,,nJin.ry am"", ""'" that tach .Ilt", oftht superpo';tion ~xi<l. in . tOl.lly .. porat. r •• li,y. In Other words, ,heu exim. multiplicity of reali,i.........,. m~I'iw". ,.1Kr~ all pruoibk quantum n<n" OCCUr.

Although Everet t propooe<l hi' " Mlny WOrldo- ide. long boro ... the adwnt of qu.ntum cOntput ...... it an sMd tom< h<lpfulligltl on ,hem. """'ruing to the Many Worldo iJu. when a quantum <;ont

putt, i, giwn a probltm. i, .pli,. into mul~plt ""rsions of it .. lf. tach living in. ~rate reality. This is why the boy'. qu.ntum peroonol computtt at the .Iltrt of this m.pttt .p~1 into to "...ny copi ... Each ve<sion of the coml"'''' worQ "". "raOO of , he problem, . OO tM " .... ndo a,.. brought to#1her by intttr.r~nc •. In Evtt<tt'. piet",... theretOu. interfttttlce h .. . ""ry op«ial .ipifiance. It is tM .U-impo .... nt hridV btr-rn .. p ..... uni"" ...... thr m<an' by which they int ... "", and inA ..... ce.ad> oth<r.

E"""'tt hod no i<ka ..-11m- all the paralJd univencs .... rt \ocaIN. AOO. franlJy. nor do the modern .d.oy propo"""" of the Many Worldo HIt •. M 1)0",1 .. Adams wryly ob .. n~ in Tht lIitdmikn', GwiJt ., '~ GoI"-')": "The-r< art two thing. )"0" >houlol remember when de.ling with pa.-..llel uni""ruo. On<. thtyh not .... 11y pa.-..lld. and two, they· ... no, .... llyun;.. ...... !-

Dt<pit. such pum ... h.lf. century .fi ... E ... "", pm~ the Many Worlds HIea, i, is uOOergoing an upsurge in popularit y. An inc ..... ing number of physici<ls. most ""tably Invid l.ltu!.IICh of the Uni~tyofOxfoN ..... taking it .... io .... ly. -n.. 'luamum theory of ". .... lJd uni"",... is ""t oom< t",ubl...""., optional intttprtlation emerging from . mn< ,hto ... ,ial considerations: .. Y" J)eu!.IICh in hi, book, Thr Iilbri< <I{ /lM/;.,.. " 1t i. '''''",planation-th. oniyon< that ;. tenabie--of. """ark.abl. and count"';n,ui,;... realit)':

If)<H& go along with l.ltu!.IICh---<oOO th.c Many Worldo HI ... p ... _

die .. <nair ,he .. me oul<Ome for ~ ... y conceivable aperimenl"

TI" OCII,WI'I'UN'" AW .. •

mort oonllttl,iona] i"'.rp"""ions of quan,um '1Iwry-,h.nt ~""n ·

'urn <ampu ........ " "''"thing ....JuUy new undot-'I>< Sun. Th.:y ... ,he wry fin, madti .... hwnans h,a"" ..... built ,h., ""pioi, ,he ",. _'as of mukipl ... ali,i ... E,..n if you <10 "'" be:U ..... ,h. Many Wo,lI. id .... i, ,,;n pm, ;.I«. 'imple and in'ui' iv ... .,. of irn..gining wit .. i, going on in ,he myst.rioos ,!",,",um worlJ, For insuno:, in

,h. doubl. oii, ap<rimro', i, is "'" n««<ary '0 im.gin< a .ingl< pho,on going 'hrough oo,h olits simuluneously . nd in,.rfmng wi,h i,·

o<If. hu,ud,. pooton goOng 'hmugh on< ,Ii, in,m."" wi,h ."",he, phoo,," going 'hrough th< OIM sli,. Wh., 011><, photon,)'Ou m.,. .. k? A rOOlOn in a nrighboring uni ....... of oou ... 1

WHY AREONLYSMAU TH1NGSQ UANTUMI

l,luaJI,um rompu ..... art ""'''''''<ly difficuh to build. TI>< rras.on is ,ha, ,he abili,y of ,he individual " .... 0( 0 quan,um superposi'ion '0

in,.rf ... wi,h.ad. O'M is d«troy..J. Or on<rdy d.grad...!, by 1M mviroorn<n'. This d .. trw:tK,. C.n I>< vividly -" in ,I>< douhlo .~,

""peri..,.OI.

[f ..,mt l<ind of 1""'H;1e .kt"""", is u>«l to 'PO' a particl. going 'hrough on< of II>< ,lits.,ho in .. rkrtno: stripes on 'ho 0<rt<1I immedi.t<!y ... nish. '0 be: ",,[a«d by mo .. 0' Itso unifo,m illumi ... ,ion, Tho 0<, of oMerving which .[i, tht particle gO<O 'hrough is &11th., i. n«d.J to de"roy ,he ,uperposilion in which i, goes 'hrough both ,lits oimuhanrou.ly. And. p .. tH;1e going through On< oli, "nIy is .. likely '0 .,.hibi, in"';;' .. n",, as you ' '''0 I><or 'he _nd of one hand clapping.

Wh,a, h. ,,..J1y happen...! Me is th,a, an '''empt h ........ made

'0 00".0.- m • ...,"'.'h. partH;\t by ,I>< 011";.1. world. KnowINg< of 'he .uperposition by II>< OII,>ide ..,rId i, all ,ha, is n..,.J.,J '0 de"roy

i,. It is .[moo'"' if qu.nlum .uperpositioliS.rt.:I«rtt. Of COlI ....

once ,he wo,ld Knows .bou, ,he ..., ... , lhe """'" "" long ... ais .. ! Suptrpositio ... a rt cOl"jnw~ll, being ,",,",um! by thtir .nviron·

menl. And i,ukes only. single photon '0 OOUII« off. 'UptrpOoil ion

and tal;" infOrmation ooout it to tho .... t of tl>< world to dntroy tho ,uporpo,ition. T hi. pr"", .. of nat"<>.1 m, .. u~m,n' i, callod ~ho~nc'.It;' tho ultimot. nason ... do oot..., ... inJ ~u."tum behav;"r in tho ,~y world.' "'lthough n.i .... ly ... m.y,bink of qu.antum bth .. io, ... P"'P""ty of small tbil1&S liM .tom. but not of big things lik< pwpl, .nd ,r<n, thi' i, 00' ""m .. rily .... l.)uantum behav;"r ;..<1 .... Uy. pr<>p<nyofiool.,od thing>. Tiwo rnson ....,..., it in tho microocopic world but oot in the ~ryday world i, ,imply Mea ... it i, , .. i ... to i",l.t, a ,moll thing from its surroundings than .big'hing.

TIt.< prict of <Iu.ntum ochizophTtni>. ;. tl><rtfOTt i><>I.tion ..... Ion, ... mkrol<Opic pa"icl,likc.n atom can ~",..in ioolatod from ,ho outside ..".1.1. i, un Jo many JifftTtnt thinp.' on<t. Thi. i. oot di«"",I, in tho microooopk ..".W. whc~ q .... n'um ochiwphreni. i, .n < .... ryJ.,. phooomroon.. Howntr. in tM Iars.·ocalr worIJ in ... hich ...., live, it is nearly iml"l"ibi<, wi,b countle .. quadrillionoof photons bouncinB off <wry objra ~ >«ond.

K<orpinB a qu.ntum rompu, ... i$oI.o,od from iu surroundinB' is 1M moin obotacl< facing physidsu in trying 10 corutru<1 such • mo

chi .... So far, the biWS' q .... n'um oompu'or,h.ey Iu ... m.""god.., build Iw bttn oompootd of ollly 10 atom ... 1I0ril15 10 qabilS. KHping 10 atom, ioolatod f...,.,.. th,iroulTO\Indingo forony I .... gth of lin,. 1.k.rs aU thti, in5"n"';ly. If. >ins!< photon bounctO off ttlc romput .... 10 ochizophrenic al""" in'tantly bt<:om, 10 onlinary """'0.

'I am ,otaI.l y -..-. that aU ,hi> talk of q .""t."",... b<-inS •• ..., ..... ,hat

i,dr$tm,.-d i(,ho ... , ofth< world 1<..". obolu., i' ;" romplrt< fudgt. Bu, it io ",ffia.:nt fO< 0", dio<u/.oi"" I><r<. D«oIl ... ncr, th< ........ by _ ,I>< q .... t. m -.:I. wi th it> ><hiwphrrni< ,u_~iooo. bocom<> 'I><..-.rydoy

world .......... "N' .n<! r«>rI< .r< ""'" in '""" pIo< .. at ""'<0 .. . a n of wo,m , with which tho <!Ip<IU.r< .. il w .... ~in~ F<>r ...... upU""ion._ a..1'I<' So 'Th, T<I<!"'thi< Uni ...... :

TIl. OCIIIWI'II"-'N'" Am .. •

lI«oMrtnet ilIlIO,ra,n I limi1a1ion of 'l""nlum compu .. " 110' ofi~n publici«<llm;dlh~ hYJ'" .... rn;mn<!inJ .uch Jovi=. T<> .. trl<l In """~, somtOnt from lh< "" .. ;de """IJ----JUU-mllO' in,..-I<! ,hi, ne«$OOrilydemoy.the ' ''pn-posil;''n. T ... q ... nlum compu'<r mo..-.. ,<> Min,; an <>nJjn.Uf rompu .. r in •• in" ....... A

lO""<Iubil machine. in~eaJ of .piuing "'" III< .n ...... " '0 1.024 .. p • • ",I. akulalioru. 'piu ""t jllOt on •.

Qulntum romp"te".rt therefore rt~ric1rd '0 p .. IUci ,"lcu"· t;"n. thot OII'P'" only I ';ngl~ .ns ....... Coo,"",!u..-uly. only. limitN numb..- of pl'Obl ..... art .... n«l'o ..,Iu, ;"" by 'lwm,um ''''"pu .... • nd much in""nuily is retJuirN '0 find 'h<m. Thty.rt nol." i. oft ... cl.in,.,.!. , ... ,rt .... t thing ,inet olicrtl ~;>d_ Nevtnl>dess. wh .... prohl .... i. r""oJ ,hoi ploy< '0 lh< ~ .. ngW of. qu.an'um ''''"pul..-> ,t can m"';""ly oU'p<rfurm a CO<lV<f\,;"n. 1 CO<l'p"ter. cakub.'ing in s«onds what oth..-w;'" mighl take Iong..- than II>< lifdim< of the Uni .........

On the ",I><, hondo J.cohn-<nct. whi<h is ,h. 51''''''' .""my of , ....... ~rugglin8 '0 bu,!J qua",um "","pu'~"", also !heir ""a'''' friend. II i. boa .... of d"",hermce •• fler .Il lho, tht glan, .upn-posi,;"n of. qu.n,um "","puter wi,h aU 'u mu,u.olly 'n,.n"'ng ",""", is finoUy d"'~ i, i. only by being d.,'roy<'ll-mluct<l lo .. inglc "ate "",moen', ng a si ngle answer-that anylh in! us<fu I ro",.. out <>r .uch • machi"". n.. world or the quan,um i. il>.ktd • paraJoricai

00'

UNCERTAINTY AND THE

liMITS OF KNOWLEDGE

Wtrr IllIAII .VII OOW'l.l1l! WOIIUI UIlIll __ AIlIIIS I ... nl llIIS.on .... ~ UOIIS I'IMIIII

"""m,.fo"~ ... 1Io"""h rio. _,,"''" Io...! ................... , 9";" • "" of .. 1m "'<rrftj"~ ph""""""" _h .. .... "'Um _";I«J, _ «>OIkl "" .... y "" IoaIw.r alL "";"1 '" 1M' , ... ~ ......

Gto"" Gamow

fl, "'"" ~ ,ping mad. Only lItO"""" btfo .. lot Iwl /",rW Itis >iii", rtd fnnIri in ,lot 8""'8'. If. Md ffl'n $10M ,Itt ... fJn ,lot Jri ......... y. tIJ· "'iring /tis pride and io/ unlil tlot I"" po#i/Jlt ""' .... nI, Q, ,II. QU'<>",,,ri< J_ ...... ng .hut. /Jut/lot. /U Itt ,",,,,,Itt.! ~ ,11. 8"'''" '0 It;. /roo, J_ ,It<", Iwl bun d <111""'"' ruft/ing of tIw air. Q {<liM ,"'""" of tlot l"",,,d. H. Iwl w/tMtJ ""mJ. And Iltm, "1""'';''8 b""t "" Itis J.;........,.. in fro", of.1ot SI;U.IocW 11""1;' Joon. WQf IIi>: ,-",ifol .. J <_ .. , ~"."

Sud> HouJin i_likt f~'\$ of ...... p<>Iogy.'" n ...... of COlI .... S«n in tho tvtryday world. In the mlirn or tho u1'r.um.u, howtwr. thty art. common oco"",n«. 0 ... in".,,' an . Iorn un ht lockLJ up in • mi_ croscopic priso"; III< "0' it Iw shed ;t. shadl .. and >lip~ aWilY ojlrolly into tho nigln.

•

UNClIITA'><rt' ..... UTII. UMmOF "",",,'LIDGE

This miraculous Ibil ily 10 esape esa 1* p roof prison. iHnlirriy

due '0 ,n. wovo!ike face of mi<:roswpk pI"kl"" wIIi"" ~nabln 0,om. ond Ihrir corulilutnlS 10 do OUln.lllinll' 11 ... wo· .... can do. And

on. of ,n. .... ny Ihinp waves con do i. pen<'''1< 'PPOf.n'ly impen_ ...... ble burin>. Thi. i. nol an obvious 0< wdl_known wO>T propn-ly.

Bu, i, an be donlOllSl .. ,ed by. ligh, beam , ..... ling,hro"'" • block

of 111- and ' rying ' " nape in,OIn. air I><)<>nd. The key I/ling is wh31 n.ppens .. II>< edgt of,he gl ... block. ,he

boo.dory wIIt~ ,he 81'" mt<t.,he oir. If ,n. ligb, hoppens '0 llrih ,he boondory .. a oh.ll"", angle. i, F" rd1ec,ed ba~k in'" ,he glau

block ond foil. t" esape in,o 1M ojr be)<>nd. In dftct. il is imprisoned in ,be 81 .... Howevt'I'. som.,hing codially diffo""" h.ppens if

anow,- block of 81- is broughl cbst '0 ,be bound.ry. leovinll ' ,n .. 11 pp of .ir beI~n ,be ,wo block>. Ius, I. bef~. some of ,be

ligb, i. ","K,ed bock in'o ,I>< 111_. 6u'-aJld 'his i. 11>< cflIcioi ,hing---wme of,he ligh, now kaps,be air gop Ind , ..... Is inlo lbe

!«Ond gla .. block. The p.a • .u.l betw.o<n ,he ""'rari elaping its go"11< and ,he hgh'

tICoping,he block of 81'" may not be vtry obviooL l1owe ... r. fOr all inltn" and pu'J""'<'loo ,he ojr pp ohouhl be j"" OS impene'rable.

banier '0 1M ~gb' • • ,ht 5"~ woU. a,.., ' o 1M ftrrlri. The rnson,he ligh' wo ... an pen", .... ,. ,be barri.,..nd <S<ape

from ,ht block of 111_ i. ,h., ........ is no' a 1 .... Iiu<l'hing bu, somC1hing .pread ou, ,hrough ,pace. So w!>en In. lighl ......... mikt ,h. gIau_ai, boundary ,nd IT~ ..,/]«,ed bKk in'" 11>< Ill .... they IT~

no' actually refkc,ed from ,be "".," boundary of In. glau. lns,.aJ, 'hty pef\C1r11t I sIIon distance in,o lhe lir beyond. Conooquen,ly. if ,heye",,,,,n',, .noth .. blod< of III ... bef",~ they GIIn .um ba<:k •• hey can conlinut on Ihtir .... y. Place 0 KCnnd 81 ... block .... illtin a bair',

bread,h of ln. r. .. , ond. hey p"'''''' 'heligh' jump.,he .ir pp .nd tIC'pes i .. prison.

This .blli,y to pen", .. 1< an app . ... n'ly impen<1rablt barrier is common '0 .II'~of ........ from ligh. wa ..... ,,, sound w""", to 11>< probabili,y """ .... auocia,ed wi,h .,"",.. II 'herefu ....... nif .... ilStlf

in tilt microocopic ,."".Id. ArS""bly. tilt moot .triking =mpl~ i. tilt plltnomtnon of alpha d..,.y in wh"h on alpt... panicle broab out <>f lilt appartnlly e .. apt-proof prisoo of an atomic nudtus.

BREAKING OUTOF A NUCLEUS

An olplu pon"k ;..1It nud ..... of a htiiWll a.om. An u",lobl •. "" radioacli ... , nudow. """"'timn .pit. OUt an alpha paniclo in a <Inp<r.tle .{{empIIO lurn ill<lf inlO I !ishl«.nd mort ... ble nuclou •. Tilt p""'"" po ... a big puzzk, ~.1Iy righ .... n alpha pan"k should 001 bt able to get oul of • nud .....

Think of an Olympic high jumper penned in by a S-metor-high mdal r.,,,,,,,. Evtn l"""-5h lit i. Ont <>fw btot high jumpt" in lilt _rid, tlltrt ;. no ""y lit can jump ""or • fon", that high. No hum.n bring ali .. has ",If .. itnl 'I,mglh in lMi, I'l!" WdL.n .Ipho panidt inside.n atomic nudeu. finds ill<l(;n a .imibr po.ilion. Tilt barrier .lut 1"'''' it in i. <RatN by tho nudo .. for"" that oporal<>lid metal f""'" i. 10 lilt high jumpt"

Conlr>ry to all exp«:ta.ions.~, olpho pa",,"" do """'I'" from 'Iamic nuclei.. And t/t.ei, ncapt i. tnlirdy due to llItu- """dike &C •. !.ike light w ...... trappod in a 81 ... block, they can pen .. rat. an apparently imptrlttrablo barri .. and slip .... y quietly into 1ht out_

.id. world. This p ....... is calla! quantum tun .... ~ng anJ .Ipha parlidn art

said to '"tunnel" oul of an .tam" nucleus. Tun ... ling is "'1""Uy an instana of. mort soneral phntomenon knOWlt as uncertainty. which put .. fundamontallimit on what ..... can a...! Cinoot know about the microscopic w""ld. T ilt doubl~ .~t tlptrimtnt i. an exedkn. J.monstration of u ..... n.intY-

THE HEISENBERG UNCERTA INTY PRINCIPLE

Th. ~...,n • mi""""'l'iOf'Iilinglo Iht p.rtid. goi"5 Ihrough one oJil and ,h. OIherlO 'M p .. ,i<l. going ,hrough Ih. OIM' '~I. lIu,1hat is nol .uff><icn' to g ..... rutt.., that its ochirophrm;" 1><. ham willI>< noliud. For ,hat ' 0 happen, an inlerr. ....... p.n...., mlU' appear on tl>< -..od !I<,....". lIut 'his. oi rou .... , requi~ thr indi.id ..... 1 w .... in.he oup<rpOSiti"" 10 iolm ..... ".. focI ' hot in.er· f.,..,,« is. crurial ingr<Ji.nt fo' tho d«troJl to ""hibi, wri,d qWIn'

'urn bth."io, 'u,n> ou' .0 h .... profound implica, ion. for wh., .... tu~ ptTmi" \IS '0 know .bou, Ih •• I«tron.

Say in ,he doubl •• Ii, •• ptTim<n, ~ try '0 loc ... ,he .I~ _h .l«lron go<s 'hrough. If ~ .w:uro. thr in~rft,t1IC. 1"''''''' on thr second K"",n disappears. Af,er all, in,erf ... nu requi .... 'hat two

thinp minglt. If the d«tron .nd i .. _;.,..! pmbabili,y w ..... go

'hrough only on •• Ii', ,he .. i. ""lyon. Ihing. How, in pr.oc'i<., <ould _ I", ... whkh .lit .n .I«tron S<><>

'hrough! W.II, '0 maltt the double '~I .. ptTimon' a bi, .. ~ .. to .i,u.Ii~, "'ink oi an d«tron ... bull .. from • mo.chin. pn.nd the oattn .. a 'hid. mt1al shot. wi,h '''''' ....-,;"al ~ltl .~". IVIt.en bull ... a .. fiml allh. oattn, "'",. cnlt, ,h • .tits aoJ go "'rough. Think of ,he .Hts .. deep chan .... l. cu' 'hrough ,he 'hid< ..... tal. The built .. ricochtt off lhe in .. rnal .... ll. oi"" ch.n .... k.nd by ,hi. mean. reach ,he ... 000 ",,,,,,n. They can obviously hi' .ny point "" th • ..."oJ oattn. Bu!, for .implicity.im.gi .... they.oJ up ."he mid· poin. of ,h. second ", ... n. AI", for simplici,y, .. y ,hal" ,hi. point tho prob.bilily w ...... _i.t..! with the bun ... in'erfe~ """"""" 'i ... ly, '" i, i. a plac. ,ha. gelS p<pptad ",ilh lots of bulltts.

Now, when • built! ricochets off ,he inside oi. olit, it co. ..... the m ... 1 oattn '0 r<a>iI in ,he opposite dir«lion. It'. th ... m< ifyo<t .r. playing ,onnis.nd a r ........ rw ricochets olf yo<tr ....:q ... !. Your

•

rOC<Juet ,«oils in III< "1'1"''';'< dil'<'Clion. Crucially, lht """il of III< ~ <on be u>eJ '" <k<\w;. whid. slit. buU~ goo> through. A~ .. 011. if lht >Crttn mC>VtltO tht !tfl. lht bun., mus, n. ... 11"11< th""'5h lhe Itri· ... nol slit; ifi, roo .... 10 tbe right, it m\lSl h.'" b«n III< right_

h.and slit. H~r, .... know lhol if .... locale which ,IiI a bull.t goes

through.;t d.o,roy. 1M in.nf.",n«' paUan On .11< s«ooo 11<,...",.

This i. Olraighlf" ....... 'd to undersland from the W,"", point of view. W. art as unlil:.<ly 10 .... on< thing inl.rf .... with it .. lf as ..... rt 10 lit ... tho ""und of <>n. hand <lappin,. lIu. bow do ..., make WI .. of Ihin~ from Ih, «I.oUy nlid POrlidt point of .~?

IltmombeT that the in~n.~. pau""" 00 lht sow...! screon i, lik • ,uptrmarktt bar cOOt. It ",m;SI' or ....-lical -Slri\,<"- wh.", no

bulkls hi!, . 11.." .I ;ng with ",,"kal ,nipes where 10(. of bulltts hit. FOT ,irnplicily. think of III< striJ><" oS black and whit •. Ttl< Uy q ..... lioo ,heref"r<;o: From tilt hllcf. point of view, what would i1 lake

10 J«uu,. 'he ;n .. rf<Kflu p .... m? Tho< .",wn i •• littl. bit of ,idowayo jit .. ,. If <ach bull .. , in.\ltod

of flying untrrinsly lOw.Ird I black shipt", pos.s<ws I li.lIo sidtways jit~, in il> t'"jtaory '" .hat i. ""n hit .,;.ho,.ho black .. ripe.". In IJjactn. whi.e stripe .• hi. will bt .ulf~n •• 0 "."" .. Gu." . ht in.c,f=nee plu ... n. S.rip" .ho. ~ fo'",,'1y whi.e win btcorne black..-. anJ "rip'" WI ~ ronnerly bLock ,.ill btcorne whiter, Tht nt ... -

sui. will bt I uniform g'ay."The intmemlce ratter" will bt .",...red ou'.

Ikcouoe i. mu", be imp""'ible'o 'enwl>ether. give" bulle. will hi. I blod: IlripeO' an .Jjactn. whi •• llripe (or vice versa) •• M jiuery .idowayo """"'" of each buller muo' be enti",1y unp,..Jktablt, And III this mu" COmt to p ... for no otl>n- ", .... n .h.n .hot ..... a .. loclfing ,.hidJ ,IiI each bulle. goes .hrough by .he 'ewil of ,ho "" .... n.

In atht, "",rd ••• he >ny oc. ol pinning down . ht location or. particle like an elo<t"'" adds unpredictable jiu .... m.king il> veloci.y unttrtain. And th. "Pro.i'e is trut .. wdL "The acl of pinning down lht vdoci'y of • p."ide makes its location unee".;n. The firs. pe'-

UNClOTAI><rt' ..... uTII.lJMrnOF "",",,'LIDGE " son 10 ~nitt anJ quantify this cff«l was tht German physicill \\~rn.c H.i .. n"",,. onJ it i, calIoJ Iht H.i .. n"",, u"",.,uinly prin. cirk in his hOIIo<.

AccorJing 10 1M ulloC<nainty p'indpl<, il i. imposoibl. to know both th.loation and tht -.d.xityof a mi,"""",ic paniel. with com· plett , ... tainty. Thm: i. a traJ.-oIT, 1Iowev..-. ",. nlOR pr«i .. ly ill l.xat;"n;' pint>al down. tht ""'toO unttn .. in is ilS ""I.xity. And "'" more pI'tCi .. 1y ilS ""I.xtty i. pinned down, the ""'''' ","""nain ;11 l.xat;"n.

lmagi ... if thi, """" .... inl also appl i<J tl) wh .. t w< muld know about tht .""ryJay "",,\d. If w. had PI'tC; ... knowJe.dge cl tIt.t .p«J cla itt . icplo ......... would n<>t be abk to ,.11 wh .. htc it was.,.,.,. N_ yo,k or !.os Angelos. And if ..... had pl"t'ci ... knowkJg< of tht Ioation cllM airplan •• w. wool.! be unablt tl) .. 11 whtthtr it was auioing at 1.000 kilo""'t." ptt hour Or I kilom .... p<'r hour_nd about to

plumm.t oot of the .ky. ",. u nttI"tainty principle .. im '0 prOUd qUoin tum th.ocy. I f )'<>U

,,"uld m .. ,ill< "'" p"'P<ni .. of atom, anJ thtir like be"ec , han "'" unartain,y principk Jl<'rmilS,)'<>u would d .. ,roy tlt.ti, wa"" I>chav· ;"~r«if><.Uy. int.ri .... "" •. And wi,houl in .... f .... "" •• quantum th<ory would lit imposoibl •. M.a<uri"l! tbt po.ition and ""Iocity of. panicle wi,h S ....... , aceu,""", than tIt.t unttl"tainty principk die .. , .. mu<IIh..-tfO<t be imposoibl •. Ika...., of tIt.t Hri<rnberg "nttrlainly principk. wilen ..... lry to Iool closely at the mieroscopic world, it "a.t< 10 g., fuzzy. like a new'pap"r picture Ihat ha. been ~rmagnified. Infuriatingly. na,u" does n<>t pttmit u< to m."", .. p~1y .11 ..... woold like '0 m."", ... Tht .. is . limit to 011' know!·

~. This ~m;t i. not simply. quirk oftht doubk slit '"'Jl<'rimtnL Iii.

fun.larntnl.l As Richart! Feyn .... n """arked: ·Noon.Ius ..... ' found (or ...... lhoughl 00 • way .round tht unttrtainty principle. Nor art 'hey ...... likely 10.'

It i. btcau .. alpha partiel .. ha"". ,...,.dike charxl.,. Ihat they con escape ,ht appa,....,,1y escape·proof prison clan atomic nucl<uo.

H~ •• 1It Htistnl><I"! ul'>Ctrtainly principl< m.k<s i. p" .. ibI. 10 unJ ....... nJ ,lit pt,....,m.,H'" from ,lit por,id. p<>in' 0/.;....

GO ING WHERE NO HIGII , UMPER HAS GONE BEfORE

~.Il .h .. an alpha part id. in a nuclew i. lik . n Olympic high jump"" ""nail...! by. S.n>n.,..high froc<. Common "~"Y' ,h., i, i. moving about in~ .1It nucle .. wi.h inoullk;'n •• p«<t '0 launch i, .. lf _, ,lit barri ... Hu. common Kn" applieoonJy '0 ,I>t ..... yday world. not .o ,lit microooopic world. fn .... r"" in i .. nud..r p'''''''. lilt .Ipha p.tlidt i. ""f localiz...! in spoc~, is. ilS posi,ion ;. pin""" down wi,h g~'1 oc<uracy. AIxonling '0 ,lit H.i .. nbtTg un· c .. ,.in,y principle. ""'n. ilS . docily mu ll n«:nS>.rily I>< ... ry "nur· lain. I, could, in 0' ..... wo ..... , I>< much g<nltr ,han ... 'hink. And if i, i. B~"". ""'n. conlr.ul' 10 .U " pK""ions. II>< .Ipha patlkl< c.n l.ap ou' of lilt nucleoa-a f •• , ""mp.rabl. to ,lit Olym pic high jump"" jumping , lit 5·m<'''' f.nu.

Alpha p.nicl<$e"",,,. inlo ,1\tW<>r1d ou .. id. ,lItir pri",n ... u .... pri.ingly .. 1M Ferrari.merged inlO ,lit world oulliJt iu gorag •. AnJ ,hi. "Iunnelin!" i> due '0 ,lit H.i .... herg u~ ... in'y principl<. 6u. lunn .. ing ;.. ',..,..Wily proa:ss. Not only can .... b;olOmic p. tlid .. Ii"" alpha particles ,un"" ou' 01. nude .... IlIty can I"nnd in.o il 100. In fac' ..... ch ,unneling in,..,....... IItlp. apl.in. (!.It" rnyst<ry: whyllltSun.hines.

l1JNNELING IN T HESUN

Tilt Sun g<n.<n'" he .. by gluing '01l",he. prolOnr-ilie nud'; of hyJro8tn .lOm~o make ,II< nudei of IItlium 'IOm~ ' This nude .. fuoion prodw;n ... by·product • .L.m bu ... , of nudear binding on· tIM. which ul'ima"1y .... rlPfrom III<Sun ... un~ghl.

's.. a..pt<r 8. "f_ ..,..,.nd II>< W~, ofSunolli""."

UNCI""""'" ..... uTII.lJMrnOF "",",,'LIDGE •

lIu, hydro,,,,, r .... io" has a probltm. The rOl'Ct or a"rae,ioo ,h .. gl~. '~h" pro'"no-.he -"'O"g nude., r"",,"_lu. • • n e.· 'r<mtlyoho" ranst. For ,wo prolOn> in , I>< Sun I<> com< und.,. ilS infl~n« and be ,n. ppod I<>g01htr, 'I><y mu" pOlO .. ,,,,,,,ely cl .... 'o uch o,htr, lIu""'o p,ot" .... by .i"~"r1bcir .imilar electric charse. rtptl e",h "tl><r feroci<,."Iy. To " ... reoolt 'hi' flC'l'Ct rtpul,i<>n, tl>< proto ... m"" colli.!< ... "",mo." op«<l. In pra<ti<t. obi< R'quim. the core of ,he Sun, whe .. nude .. fus.ion g<>es on, '0 be II an ex· t .. mtly high leml"rature.

~hr>ici ... caIcuJ.,od ,I>< n...,...rylem~'u .. in ,I>< 1920"j .....

OS ""'" OS it was ""p«tod tha, tl>< Sun .... runni", 00 hydrog"" r",;.,n. II 'urnod "Ut ' 0 be roughly 10 billion <kg....,.. 1Mi .. ~. pru«l. probltm. Tht ttm~'ur< at tl>< hnr' "r ,!It Sun wos known '0 be oolyaOOu, IS milliondegr<eo-'<>ughly . '..., .... nd ,ime. k>wu. I!y rights. , he Sun ohould not be .hinillg a t all Ent .. tl>< Gn-man physid .. Frill Houle,man •• nd the Engli.h .. ' ronome, "obert AlkirlO<>n.

When a pro'on in ,he <~or,he Sun appmacheo .n",her pro.on .nd i< p",hod badr. by its fieree rtpulsion.. i, is j .... t OS if it ""coun'''' • high brid ... 11 ",'rouOOi", ,he..."OO pro'on. A"be 15 miUion d'8,en ttm»tn'u" in the heart of!he Sun. !he pro,on would apl"ar '0 be moving rar too"owIy '0 jump !he ... u. H~, ,he Hei .... be<g unctTtainty principle changes nttylhin5-

In 1929, Houle,n .. n •• nd A,kin..,., carried OUt ,I>< "Ie .. n' cal· <uLo,;.,.,.. They di.!a>......J ,ha, ,I>< fi"t prolon Cln ,un"'] IlIrough

the . pp .... n'ly imp<""rablo harrier around the secood Prolon and .uccesofully f .... wiob it t ....... t!lt "I1ral"'" 'tmp<r.ltu ... of 15 mil· l ion.lt~ W!u, i. mort, ,hi, upLoin . l"rkc,1y lheo~ hn' OUlput of!he Sun.

Tht nigh, . Ii .. Houttrrnan, aOO A'kinoon did !he calcuLo'i<>n. Hou"""'''' rq>OrttdJy tnN to impress hi' girlfriend with • ~ne that nobody in histo,y had u...J btfo .......... I><y.tood be ..... h. perfect moonlt<o sky. he botitt<l ,hal I>< w .. !he DIlly penon in 'he world who knew why.he ... rs wm. 'hining. It must ha .. worked. lWo )'tars

101.,.. Chari", •• 1I.i<f ....... hl agrttd 10 m.rry him. (Actually. she marri.,! him twi",. bUI thOl', ."",hot- . tory. )

Sun~Jht apa,t. tl>< Ilti .. nb<" unc.rtainty principle uplains """, •• hing much do .. , 10 home:.1>< very .. is.en", of tl>< alo"., in ou, bodi ...

UNCERTAINTY AND THE EXISTENCE OF ATOMS

Hy 1911 II>< Combridi' ""peri men" of No:-w Zealand physki., E .. ",,, Rutherford .... d ~al"! thr .tom .. ..,..,.,b!ing. m;n;",uce ",lar

0),>1""', Tiny .k<:lrons flinN.boul a COmp><1 atomic nucltus much lik pia..,,, .",und tl>< Sun. Ilow ....... ao:ording to M ...... U·.'heory of .1«Ir"",apltl isrn. an orbiling d«1ron should rod;",. lig,1 ''''''5Y and, within. m~ hur>dred· millionth of. >«onol, .pil"al in.o tl>< nudtu •. "A,om,," a. ll.id ... nl !'<ynm.n pointtcl Oul. "a,.., oornpl<1dy impossibl. from II>< d;wical poinl of vi"",: Hut atOm. do ni,l. Ar>d II>< opl .... ,ion comn from q ... ntum lheory.

An electron C.nnOO F' toodo .. to • nudm. b..au ... if it d;J. i" location in 'P"'" would b< ""ry prtd .. 1y known. 6uI according 10 ,h. Il.i .. nl:t<rs un",,"'inty principle, thi. would mean that it> vdocily woulJ b< >"tty u"""l. in. It could t.«o"", .... ormou~y hug<.

]""'gil1< on angry b« in. ,hrinking 1>0>:. ".. . "",IIe. II>< bo>: 5 .... '1>< anpin II>< b« and thr mort violen,ly il Mltcn ilS<lf ag.iinsl ,I>< walk of iIS prioon. This i. prtuy much II>< .... y.n ,1«lron be· .... '"" in .n .'Om. If i, .... rt "Iu ... =1 in'o ,I>< nudeus i""lf. i, would .cquirt on enormous . p«<I-for 100 g ... t 10 ... y """finN in th, nudew.

Tb< Il,.;"",b<" """en.in'y principle. whkh ""piai". why d«_ Iron. do nol .pil"al inlO Ih.i, nud";. ;"h,rtfore Ih. ullim ... rt.IOn why II>< ground ben .. ,h our fffi i, soIi.l. 6u, tl>< principle does mort Ih.n ,imply explain Il><o.isl .... a of .Iomll and thr soIidily or man.,.. It .. plai", why atom ..... '" big-or 01 \east SO much bigg.,.,han tl>< nud"; .. thrirco .....

UNClIITA '''''' ..... U TIlE IJMrnOF "",",,' LEIXiE •

WHY ATOMS ARE SO BIG

Rtull,h ... 'ypKal .,om is aboul 100.000 'im .. bigg~' lhan ,ho nucleu, a, its ctnLtr. Un ...... tandin~ IoIby thtrt i, 'urn a fan, ... ,i< amoun, ol ~mply 'pau in a'"m. rtqui .... brinS a bi. m<>rt pitt;" .bou"he Hei ..... be'1 unc ..... in'y principle. S,riclly speaking, i, sayo .h., i, is. p."i<lr·, p<>«iUon.nd mornmlUm-, •• he, .lu.n ;"'" ito ... Iocity-tlu., ,,"nno' oimub."""usly be ..... ~rmined wi,h 100 per. «n' un.in,y.

The m"",.n'um ol I partid . i. ,h. product ol i10 ....... and .... lodty. I, ', 'o.Uy j"," m""u,~ olhowdifficult i, i"o ""I' ." .,,,,,hing ,h., is mo~ing. A ""in. fo, ill<'.nct. h ... I 101 ol m"",on'um rom· p ...... to • co', tv<" if ,he ca' i. ~n! f ..... ,. A I"""on in .n alomi< """It", is abo., 2,000 lim .. mort m.assi ... llu.n an oketron. A=rd· in~ .0 tho HriOC1IbtTJ u...,.,.tainly principlt. then. if a proton and an ol« .. on ... confined in 'M sa ..... .."Iu ..... ol.poo:, lh •• 1« .. 00";11 b< "",,"ing abou, 2.000 limn f .. , ... .

"I .. ady ..... gt1.n ioklin! ol ..... y , he electro .... in In .,om m"" h ..... for biur' .."Iumelo fly abo., in llu.n tho proton. and Il<U' trono in tht n",,\tu$. Hut atoms ar. not just 2.000 tim .. biUff th.n thoi, nudoi; thoy ... mort Ii .. '00,000 'im .. bi~. Why?

The an ....... is tha. an "I«tron in an alOm and a pro,on in a nucltus .,.. n01 in tlt.t Srip ol tho .. m. foret. Whil. , ho n",ltar parlicies are held by lhe ro-rful ~strong nudea," foret, llt.t ole<:· lrono a .. hold by ,h. much .... ak .. ol.etric forc<. Think of tho ol«trons flying about , he nucl ..... allodlN 10 S"""'m ... ,hrtads of "'$lic whil. tho prolons and tho IItU'rons a .. "'RO,,...inN by .I .. tic 50 tim .. ,hicktr. H ... is the ~xpl.ana'ion for why tho 110m i, • ......,p. ping 100.000 tim .. bigg~' than tho nuel"" ..

Hu, tho .I.elrons in an atom J.o n01 orbit at 0 .... particular dis· tanct from llt.t nud",,~ n..,. a .. ~'mill"" \I) orbit 3t • ,...n80 of di ... """. Expl.aining this rtq.i ........ ni"ll10 )'<t another ~ pic. lu~is 0 .... i"",lvinS "'pn pi!,",!

•

OF ATOMS AND ORGAN PIPES

Th= or. ,MY> many Jiff<m>t -yo olIQOking •• thing. in the quan· tum world, tach a ~impu of. truth that is fruOlratinsir dwivt. Ont wII)' is to think or 11>< probobility >'<Rtf ossoci .. tJ with an . ,,,,,,', el<ctron. as !>ting like ><>unJ wa ..... confi....J to on organ pi~. I. i, nol p<>«ihl< to make ju>' any nol. with ,II< "'P" pir<. TI>< ""un.! can vibrate in only. limited num""," of .lifT ... "'" wayo ... eh wi,h. MUlil< pitch. or f=;u<ocy.

Thi' lum. oot 10 bt • senoral proptrly of ""' ..... nOl ju., sound wovn. In. wnfi....! SP"" tMy em •• i" <mly.t pank"I .. , .1m";'. ff<'<Jumcin.

Now think of on eloctron in on atom. It both.,.". like. wave. And i, i. gripped lightl y by.1>t electrical fora of .he .tomic nucleus. Thi, may not b< Clactly th< .. m. as bri"l! tr.lppcJ in a physiool cont.;".,.. Howev<1", il confin .. til< d«lron Wave .. surely as .11< .... 11 of an orp " pip< ronfin .. uound ...... n.. d«.ron waloY can thrrrfo", ... i" ., only ' .... ,.in f,",!uencies.

Tho< r .... u.nci .. ae.hu""nd _ . ." in an organ pip< .nd "ftll< .ltc,ron ......... in an .tom doptnd on til< characltrinia of tht "I).n pi~ ,.,.,all orpn p~, for i", .. """. p,.,.!u«o higl>er_pil,ht<l notes lh.n a bij! orpn pij*---llnd on 1M Char><k,;,lia of 1M tkcl rica.l fora of 1M alomic n"cI." •. In srnn-a1. lhoug.. lhttt ;. 1owrsI, ," funoJ. .... nl.I, f""'l umcy .nd • orries of h igl>er -Imj".ncy· _non ... •

A hig...-. Imj".ncy ~. h .. mo~ rr.k1 anJ lro"g.. in • &iv<n 'r-. II i. ""'ppier, """" .ioIe'll. In 1M .... of.n 110m •• ",h. w .....

<orr~ponds to. fastu-movinM. mo~ en,,,lI"ic eI<Ctron. And I [asl<rmoving. """" energetic eI«tron i •• l>Ie 10 defy 1M ,,!«IriaJa" .. eIi"" of 1ht n"'l .... . nd orbit f.rfhtr away.

n.. piel,,'" lh., nnerg .. i. of an ei<Ctron lIu.l i. ptrmilltd 10 orbit '1 only ~.in orrdll distancn from tM nude .... 1Mi, i. qui .. unliktour ..,1 .. 'Y' .. m whtre. pl.nel ,lid! as Earlh wukl. in pr;n<ipk. orbil.l any diStilnct wtu1SOcV<cr from It.. Sun.

UNCI""""'" ..... uTII.lJMrnOF "",",,'LIDGE

This prop""y highliJh,. onOlh ... importanl diff ..... a bt, WttII ,''' miO'OOWpi< world of .. o ..... and ,''' ~y wort.i In , ....... ,!)'<by worl<t oIl,hings .re ""n'inuou ...... pl.nct can ,,,bi" M Sun . n)'W ..... i,liks. proplc con bt .oy ""igh,,~ lik-whtrt .. things in 1bt mic"'scopi< world a .. di",o",inuo.u-a" ,1«,,,," CO" ais, in only an.in orbi,. .round . nudNs. ligh' and manercon co,"" in only ttr' ain indivi"bl, chunki. ~hysicim call,h, chunks qu antawhich i. why Ih, physics of , he mi<roscopic world is k""",n .. quan· ,urn Ihwry.

n,. in ..... ....," orbil or . n dwron in In atom i. d.,..rminal by Ih, It,is<nbtrg u l">Ctn.inlr principlc---by jlS borncllikt resi.tana 10 bring confinal in ...... II . p>«. !lut I'" Heisenb<'l unttrtainl)' prin. <;Pic docs nOl . imply prt ... nl ,mall things like atom. rrom shrinking without limil- uitim .... y e""laini"8 lhe solidity of maner. it 0100 ptnCn" far hiM"'" things from shrinking withou, limit. n,. rar big. g ... things in q .... tion .. estars.

UNCF.RTAI~ AND STARS

A SIlIr is. gion' boll o f gas",1d I"Sether by t'" g""';"'i",,01 pull of il> ""'" maUer. Th., pull is "" .... tantly trying to . hrink 1bt .tar and. if unopp....w. would "''1 quickly collap .. i, down to ,he me.esc 'I',d_ black hoi,. For 1bt Sun thi. would takt 1m th.n half.n bou,. Since ,he Sun i • ....,.. deIlniICly nOl .hrinking down to. s\,<,<1<. thm' m"" bt ano,"'" fern <ounl<raCling gravity. l1><nt i .. I, co ..... (rom the hOI rna"'" inside. n,. Sun_Io"8 with .... '1 other norm.1 .'.r......;. in a d .. ica,. state of bola nee. ",i,h ,he iowarJ foru of gravity .... n!y matched by t'" OUtwaN fon;, of il> hOI interior.

This IWana. boIoIt ..... is temporary. n,. ou,warJ fora can bt mainta ined only while ,htrt is fuel to bu.n and ktep the SIlIr hOI. Soon.,. or lo t ... t'" fu .. will run out I'<Ir th, Sun this will O"'If in . bou, a"",h.,. S billion yea ... When ,hi. happens.gravil)' will be king. Unoprootd. i, will cru<h ,bt "ar .• hrinking i, ........ md ...

• Jju, oJl is noI IoSi. In lht <It"... bot .nvirnn ..... n. in,ide. Sl.1r.

&eq""", and viol"", ,oUi,ion. bot~n high .,p«d .",m, "rip ,hem of .Mi, ,IK'ron ... ,u'ing a pi..."., • po of OIomic n...:in m;-J in with. pi of d.<,roos. Ie i. the tiny ele<1rons ,ho, u .... poctc,Jlyco .... lO . he m.:ut ofth. fasHhrin lcins .tor. M the dKtm ... in tbe ... r' • ..... lIe, _ ;.mm«l ..... d .... ' IOgC1hc1", they buzz .bout .... r mort v;"I .... '!y btca_ of lht HriKnt..r5 un«'rl.iinty principle. Th<y b.,_ '.r anything try;", 10 conr. ..... hem. ond this wlkeli ... b,mer;", ... nit. in • tmne1l<iolu ou, .... N foret. Ewn'ually. i. i. mough 10 .1_ .nd Iul. 'M .hrin~ oft'" ,tar.

A ........ 1Wan« is ,',ude with the inwanl pull of gravity lWanuJ n<>l by ,he OOtw.lN for« of ,he " .. '. hoot moUer bu. by lht ""kc,J fora: of jlS el",trod~ I'hys;am call it dcgtntrocy p""",n. Hut it'. ; ... , • fancy 'Ofm for the ,ni.una of eloc'ron. to bc;ng "l""~ tOO eio« '''5<1ha-.A .t.r ",pported ',",ins' 5"'V;'1 byekclron p"' ....... i. known as • whit. <I" .. rf. Will< mort than the size of Earth and occupying .bo"t • mil~onth of ,t.. ".r', forma ""Iurn< .• whi .. dwa,f i, .n ~normo .... ly d~R$< .,bj«t. A ,~prcut.. of ito motte, -;p.s .. mudt .. lht f,IInily carl

0 ... doy It.. S~n will bocom •• whilt dwarf. S",h .,." Iu,.. no

m~",. of rtploni.hing thti, Io<t htn Thty"", oothi"ll more tlun .. ell .. embers, oooling i ... """,bly.nd gradwolly fading from view. 6~t lht ti«tron p, .... "" Wt prt>ttLto whitt dwarfs from shrinking

~nder thei, own gravity Iu, ito limit .. The moK ."....i .. a 'Ia', tht ....... F' ito .. If.g .... ity. If the .... , is m ... i .... ~nough. ito grovity will

be powerful ..,OItgh to ...... rcome .. .., tht "iff milt.na: of tht ,u,·, fleetron ..

In fact, ,ht Ib' i, .. botagood from both OIttoide ... d inokl •. The "rooF' tht gravity of a,,",. tht more it "'Iu ....... tht gas inWt. And Iht moK a ps is "lu ... ..,J, the hotler il get .... an)'> ... who h .. ...,..J

• l>icyclo p~mp lui ....... Sin ... htat i. nothiJt5 mort th ... tht micJ<>. ""pic jiggling of mauer, tht oI"",rons inside tht .... , fly about .....

fas'tT-so flSl. in fact. tha, lht tfk<,. of Mativi,y bocomt impo,'

UNClIITA '''''' ..... U TIlE IJMrnOF "",",,' LEIXiE •

lInt.' '"'" .I«lron. g<1 mort mw.i ... ",hor than much r .... ', which mean. thq.n: In> .ff«liv<.t batt .. ing tho waU. of thoi, prison.

'"'" .u, suITt .. a <loublt wh.m my---<:~ by "ron5" gravity .noJ .imultano:owly robb«l of tM ability to fight b;w;k. Tho two .f· f«1< eombinc 10 <nsUr< ,h., tho hoavi<st I whitt dwarf can b<;'.

m .... 40 pero:nt mo,. mo..i ... th. n the Sun. If • "ar i. h •• vier Ihan this <lLanclr_kh.r ~rn;l. tltel",n p~r< i. p<>w<'Tkso to IuJI ;1< h.adlong coIlapot l noJ il just goes on shrinking.

lIul.onu aglin.ill i.,..,. ..... EvtnluaUy.lho .ta, shrink>'" much tha, its .Itct"' .... d .. pil. thoi' Ir<m<ndous .... <>ion to b<ing """ . fin«! in a sm.lI ",Iurn.<. ar. aclually "1"«1.0«1 in'o tit.< a'omic nucki. ,"",n: ,hoy """,t wi,h protons ' 0 form nculrons, 00 ,ha' tho wIooI. "or b<co""" onc !!i.nl rno.. of "oulmn •. ~n , ... , . 11 p."idts of "",'«.-not just ,Itct",n_resi .. b<

in, confinro boa ..... of 1M HriKnb<" unc..-tainly principlt. Nu·

Iron. ar< tho .... nili of tim<s mor< mlSOi"" 'han .I«,rons. Thty thord'oc< Iu", to bt squ«=l ;nlo • vol"m. 'ho .... nd. of limn .maIl ... to brgin to put up oignif",. nt rr>i$tanu.ln (OC,. ili<y h.,.., 10

bt sqUttlN 1"I!<lhor un'illhty an vi"ually louching btfOl'<' th<y fi tully IuJt ,ho shrinbg. of ,ho .ta,.

A .... supporttd agoill<l gravity by nculron Jogtncrocy p ........ is ""own .. . nout"", "or. In .ff«l, it i • • hgc a'omic nueltus with .11 tho <mply .pa« squ«=l oul ofit< ""'tl<r. strICt atom •• ", ",OOIIy crnp'y .poo:. with ,00, nllClti 100,000 ti""" ""all .. t"'n thoi, "". rounding cloud of orbiting.l«trons. ntutron ..... ,..., 100.000 limn ."",11 ... th.1n I norml l SI.r. This makes thorn only abou, 15 kilom<· It .. across, not much bigg<' th.:tn Moun, Ever .... SoJ< ... i •• ncu' tron .... , thaI. "'prcub< of its ma"..- w,.;ghs .. much .. tho ,n,i .. human ,oct. (Tlti., of COu .... i. an ill"",ation of just how much crnpty 'P"C< tho .. is in ill of LU- Sq,... .. it .U out .noJ hununity "",>ill fil in )'Ou, h.nd.)

's.. OIa)'l<r 1. "Th. Dath of~.r>J Ti ...... •

•

Such ......... lhoushllO form .ioln1t1y in '\1~"""Hxplruions. Whil. tho ",,'.r rqioo. of •• ta' .'" blown in", 'l'oco. lb¢ in".. ""' .. shrinks to form. """Iron Slor. NNtro" ....... btin8 liny and cold, <tuy" 10 be diff",,,I. to .pol. However, ility ... born spinni"l! .... ry fa.i . and pro.luu IiJ!htM"'" bea"" nf roJio wnrs th.l A .... a,., .. ",<1 lhe sky. Such pubaling ntu'roo .u rs, "r simply pulsars, ... "",pIIo .. • h<i, ",is,,",,,, to ... ran""' .....

UNCERTA INTY AND THE VACUUM

White d .... rf. """ lIeU'''''' .tars "por'. ptrbap,s Ih, moll ",,,,,,,kabl. "''''"'I ...... '''' of ,h. }kistn"",,, un~;nly principle i, the mod.,." piclurt of nnpty sp.u. It . imply annol bt empty!

n.. Hri .. nbt'l! unttrlaimy principle an bt mormul.IN 10 say ,h.t it i. impoosihlt 'n simultanrowly "'ta ... ", ' .... nnn of . pa,_ tido and the intnva1 of time (or which il h .. been in .. im ... "" Con"'l"enlly. if "" ~ what hapP"'" in I U!!ion of emply .po« in • ~ry tiny in • .....,.) of , j .... , ...... will bt. largo ,,"""rtainty in tl>< <n<rgy conlenl of lh.l "'ginn. In o,ber wonls. energy an appear Out "fnOlhing!

Now, ",us i •• fonn of rn«5Y.' Thi. mun.,h., ",....100 can .p~ar oUI of nolhing. Th. Pf(IVOO is lhal il can .p~" only fo. a mnt .plit _ond i><fOK di<.or~arin8 again. l1>t I ..... of natu«. which u .... lly pr • ..-enllbinp from ap~.ring OUt of nothing, appear to turn a bli...! ~ to ....... 1$ thaI hap~n 100 quickly. If. rath.tt liu a l .. Ng .. ·.dad nol nolicing hi. oon has borrowed lhe car for Ih. nighl as long as il gelS PUI N.=k in the garage brlort Jayb ... ak.

In p.-..;ti"", m ... i. ronjured OUI of emply 'P"'" in the form of microoropic particles of mat .. ,. l1>t quantum vacuum is aclually. S«Ihing 010 ..... of micros<opic par,icln.uch a •• le<tron, poppi"8

UNCI""""'" ..... U TIlE IJMrnOF "",",,' LEIXii " in,o aj".na ond II><n vanishing "pin.' And "'is i. no m<r< 'hwry. II "", .... 11y h;u <Jb .. ,.".b1. """>«!~n<e>. n.. roiling ... of ,he q""n· 'urn ~""uum .<luaUy buff .... ,he Ou"r .I«tron. in a'om .. v.ry .ligh'ly chonging ""''''"''8Y of ,ho light 'hoy p .... out.'

n.. {""" h .. ,h. La .... of Ra'UAc "",rru'lIOm<lhing 10 corn. ou' of no,hing h •• n'" esc.pod c ... lllologi ..... people who think .oou, ,he origin ofthe Uni .... rx. Gou.IJ i, 1... they ,.,.."..j.,. ,Iu, II>< .n'i .... Uni·

....... i. oo,h;ng mor.,h.n I Guan,um 11""' .... 'ion of ,he vacuum! If. In '''raordinary ,houg.ht.

'"",..ally. ""<rf ""nick ct<ot«I ;. cmol«l oIonpid< its .,'iponle",. ""nid. wilh orposn< prop«1;'" So. "'II'tiwly chafll"l <WI"'" ;. always

, ... 1«1 wi"'-. ~;..,Iy cha.-".d )XI$it"''' 'Thi. <1'''" i><oIl«I ",-, lamb "'ift.

THE TELEPATHIC UNIVERSE

HIIW >.rolf,; toll IIIfWllI:l lIO mu ll!illlrlll M , d . '* _, 'Il0l1 01 tal U,Il'!I\(

A "'in iJ .p;n,,;ng. ~""jn is in ... lr<><Ig bw: silting in ,~, mud ~IIM

bo'",m "f'''''dupe .. 00>I1t ""ndJ. /)ott" ask ",II", It.u~, .hao'" .,..". ninK or ,.."", i. /inpinl if spi""i"f. In,. ;"", II >WI1.,h""lhf.<JI" '''''-,! n,t poi", i. ,,..,, 1M'" i< an jJ,miatl ",inning coin in an jJ"",;'al box Jim"g M II aJ/J """'" in II JUt"'" g.>iouyon ,Itt for .;Jell{ ,h, Vn~.

Th. fim""" "''''''' d .... ,. """I~ Im/ant""",",i" wi,,",,,, tho mn· nl .pii'·s«<md of deb,. iN coo.sin /0 bill;"" I;glll_,,,, .. from &,ril "'"..,. do ...... it,.

Tht min on Earth rould cqu.ally _II " ... come d""", toil •• nd iu

di"ant cousin heao.U. This i. no' imrorlanl. Tl>t ';pificanl1hing i, rhOl ,h. min on 111< far .ide of the Uni ....... kit""" in'Unl1y the SIal. of iu Ji<tan' krK<lrw co"'; ........ nJ.!oro .11< opp<>< .~ of hgh •. ' Sine. ,II< ooi ...... 0<pu;a • ..J by 10

billion Hgln-y ....... inlOrm.,ion .!>our lht s'al. of"". coin musII.1«

•

• minimum of 10 biUion yars to rnch thtother. Yet lhty kn_.bout .och oct.... in I .p lil oewn<l.

This kind of"'rooky action II • JisI.na" ,u"" Out 10 be 0, .. , of the mOOC remar""bl. r .. , urn of the microooopic world. Ie SO "psel anSl,in that he <ltd.rn.I that q ..... ntum theory rnUO' bt "''''111;. tn

fact. Einsc..in "' .. "''''''lI. In tht I'd 20 yar>, physic .... ha"" obonvN tht btkMorof cain<

that are ocr.ralN by largo di.tances. ~ coin ..... quanlum coins. and 1M .lis,."" .. If" nOl of .:<>II .... as larg< as tho width of the Un;........ ' Ne .... nhtl .... tho exporimo"to ha..., ."""",fully<k"",ns'rated 1h.1 llOnu aAd thtir kin can indtN communicat. irunantal'ltOusly, in tol21 vi"lation of the .p«<l...,r.ligll1 barri.r.

Physici'" h .. " duiSl<n«l this wrinl kind of quantum Id .. ",lhy nonlocal~y. The be,t way to unde .. und it i, byo>nsidtrin! . pteuIi., partido Prop<'r' Y alltJ spin.

SPOOKY ACTION AT A DISTANCE

Spin i. uniqut to til< microscopic W<lfid. !'articles thai po ....... pin bdw...., .. if they .n: ""' ling lik l iny .pinning top .. emly ,hoy .r.n~ octually spinningl Onu "Pin. we com. up .g.a;rI>' lhe f"oo.mrn,.1 ungrasp;tbility of the mkroscopic.......tll The .pin of po,c;cln, lib: thti, inhtrtnt unpmli<t.hility. is IIOmtthing with no clirt'Ct anal,,!! in 'he ev<,yclay world. Micros<opic p."idescon have clilfe .. nt .mounts of .pin. 11>< el«tron h.pp.·,,, t<, carry tl>< minimum quall,ity. Thi.

' In f"" •• tho qum'um coins ..... to bt c ....... ,~ .... '1I<n .. pot ......

lO""OW .poo>i<.y OCI""., • dis .. "",. whidl ~ onoth ..... ...,. ,bt Wt of <nino on dil'f<r<", .ide> or. .... Un;><nO< """oId., bt uk<n _ kOoo.~1 ..... pOin,'"

""'.;, ;",', • W<l1· 1ho~'..,'" >tory. ~ a;,,' ....... ' to ~ on< omuiOK u.th ,nd Oft< ''''rin$ ,ruth eon/y-Iha' ...... "'urn Ihoo<y 1""miIS ob;.ru to ;,,0 ......... ><h oth ... in ...... "",."..,. ...... whtn "" _it. <idts of tht Univ<n<.

Jl<'rmil> il 10 .pin in I ..... p<Wibk "'oyt. Thil\\; ol il .. 'pinning nih" ck>ckwi .. or .n'id""kwi .. (oIl1.o ... gh of 00"'" i, isn',OC1""Uy .pin_ nin~", .111).

If two ,l«:lro ... a .. cr .. ,eol'oge1b.ot"-, ... r.rst with ck>ckwi .. • pin, ,ht....:ond with antick>ckwiM 'Pi n-thrir .pin. cancel Physi_

dOl. oay 'h,ir '0101 >pin i. zero. Of coo ... , I'" p;>i, of eltc,ron. can 01 ... ha.., a IOta! 'Pin ol zero if thr r. ... , <ltdron Iw .n aJllick>ckwiM

.pin .ndlM >«<>00 • d<><kwi ... pin. NQW. ,h< .. i •• 1_ of .... , ..... ,h., oays I'" '0,.1 .pin ol.ucll •

• ,." .... can n.- cII.n!!". (I,'. oc'u.olly ""Uod thr law of """ ...... I;"n of .", ... lar mom..,,"m. ) So onet , ... poir of dtel""" has bten c .. -a,od wilh • 10101 >pin of .. ...,.Iho p.ir', .pin must .. main..", .. long as til< pai, .. main. in <:li"tnct.

NOIhing ou, of , ... oo.!i ... ry ...... However, the .. i •• n","', way ", on,. , ..... tltc,ron. with. 10101 .pin of z<r<>. R«a11 ,h.,. if two

.,.te. of a microscopic "y"em a .. p<Wible, ,lien . ,uperpooilion of ,ho IWO is.t.o po$$ihl<. Thi, m ..... i, i, "" .. ihl< 10 = ... a p;>i, of electron, 'hOI or, .;m"hanoo .... ly dockw .... _.ntidockwise and on ,ic lock wi .... cl<><kwi ...

So who'! W<ll, .. m,,,.~r that .uch a .... per""',ti"" ""n Gi" only as 10"8 as 'he pai, of tltctro ... i. i<olatocl Front il> ..,,,ironmenl. Th, mom,nl Ih, outsKk ..... rld in .. !"OCt> with i,_nd ,hal inW"a<tion co ... ld be somtOnt chtd.ing '0 _ wh.t tht tltctro ... Ort doin_t ...

• upcrpooition "ndergoesdecoberence and i. clesl~ U ... hl< 10 <X-

i" on,. long .... in thoir s<hizoph .. nic ...... the d«tro ... plump for bei ng ,j lher d ock wi ..... n licl<><kwise or .ntic Iockwise·clock wise.

SliD no,hing out of I'" ordin.ry (., 1< .. 1 for , ... microscopic ..... rloll). H~, imagine that, alier thr el«""" . ... c_ted i n thrir schizophrenic .UI •. 1hty , .... oin isoIOlod and nobody look<., th ..... 1 ..... 0<1. one eitdron i. uk.., away in • 00. to a ral2WOy pi""". Only IIIen does so......., ... finaUy open tlt.t box and obon-.., tlt.t 'pin of tht eltctron.

If tl>< tl«tron at tht r.~ plac., ... rn . out to Iu.., • ck>ckwiM

'pin, t"'n inllanUneou.1y the ",her ,ltctron must IIOf' being in ito

TI" n"''''TIIIC U~" ..... •

Khirophmlic s'a" and ... urn< an an,iclockwis< spin. "Tho ,oco! spin . • f' ..... U, mus' .1_,.. ",main ... ro. If. on the o'her hand, ,he o1«. ron 'urnS oul '0 bo spinning anliclockwis<. ilS C<>II.sin mu.ll inuan'a· nwusly usum •• clockwise .pin.

II dotS 001 m.U.r if 01'1< d«.ron is in • ,1<<1 box h.lf_buricJ on .he se.floor and .he o,her i. in a box on .he far sid. of th. Univerw. On. d«1ron will r«pooo insunlan.'"ul,. to the ochrr·s .II,"'. This is 00' ...... Iy some esocmc .heory. lnotan .. """", innuena has aCIU·

.11y bmI obstrvtd in .he Iabor.,ory. In 1982, Alain """",'aoo hi. <olb", .... ,he Un;"""'i.,. of Pori,

Sou.h " ... ed p.irs of pIIo'on. and senl mnnbtrs of each pair '0 dOl«'ors separ .. ed by a Jistana of 13 ~ ... The <ie1ew>rs mea· sum! • he poIari>..otion of the phoco ...... propn-.y ",lated '0 • heir spin. .... pee ... t .. m ~ tha. measuring the polari .. tion of photons •• on. dct«.or .ff«ted ."" poIari .. tion m .... um! .. the ochrrdOl«' or. The innu."", that "aveled b<twffn the <ie1«tors did so in Ie .. th.n 10 nan<>«<ends. Cruci.Uy. thi' _. qllH!<rofth.,i"", • ligbt boam ....,uld h ..... Ill~ ' 0 bridg.,he 1 }.rn<1"- pp.

A. the 1>0 .. minimum. some kind of inn""",," .ravtled botween the dtt«:lors .. four ti",.. the ,pe-ed of light. If the ted>no""y 1u..I maJ. il poosibl. '0 m ..... "'.n ~ sm.11eT lime interval ..... peeI

ooulol have >I>own the """.Iy innuena.o bo ~en f .. t ... Quo-n.um .h_y _ right And Eirulrin-hl ... him-was .. mnll-

Nonlocali.y <oulol ......,. h.ppen in the ordinary, nonq .... ntum _rid. An air mass migb. spli l in.o t_ .o" .. do.o.. on. spinnins clod:wise '00 ,he OIher an.iclockwise. 6u.th .... ,he _,. lhey wOIIkl "oy~inni"8 in "P1""i1edi"",ions---<In,il r",.Uy'hey bo.h ran 00' of ".am."Tho crucial Jiff<m>a in ,he micmsoopit:,'l".:m'um wodd i, .h •• ,,,,, .pins of pa"id .. a", undetermined un.il.ht in .... nt1hey a", <>bse~.And. bof"", the .pin of ""eel«lron in the pair is<>bserv«l, il i, 101.11,. unpmlicl.blt. II ha, • 50 [>ttttnl ch.noe of bri"8 clock· wise aoo 0 50 percent cha"", of bring a",iclockwise (one. o,ain we com. up .gains. the l\al;ed "'ndorn ..... of"'" m~1ol1.lIul ..... though Ihrr. i. no _,. of knowing ,he .pin of 01'1< eleclron un,il i. is

•

obstr....J, th. 'Pin of lho ocllor ,kelron mu.' seliit .I""", 10 bti", <>ppo';,. i ..... n .. ...., ... l}--no mo".r how f.r '_y thoo'ht, I"'nid. happtnslOM.

ENTANGLEMENT

At tIK hn.rl of Mnlocmty i. tht tcnJrn<y of I'lrtid .. th .. inttroct with each och<r to become mtwined, or <nallllN, to thai the prop<rli .. of ...... art r"........,. d<!,<,ndtnl on III< proptrli .. of III< 0111< •. In .he cu. of , ,," p.ir of 01«."",0. it i. their .pi'" ,ha' btwmt J<ptn_ dtnl on acb othor. In a vory ..... 1 ...... , "">nslN p.nidts "'..., 10 have . .. p ...... n;'len<t. Likt . much· in·~ <oopk, they bewmt . _in! joinN-.Hh .... h.ip .... tity. No mott .. h"'" rar apart thty art puned, !bey .. m. in fort ..... connected.

Tho .... in/ .. ' m.niFn,.tion or .... tang.l<n><nt is, without daub!. nonlocalily. In fact, il """,,)d <ftrn ,II;" if .... could horn ... il .... could er .... an ;n". n .. nmu. commun;,a,;on< 'y".m. With it Wt

'<>u1.} phon. the ".h<r ,idt of, ... _rid wi.h IN) tim. &1"1'. In bo. "'t could phon. tho <>lilt, sid, 0( the Univnv with no liom <kayl

N" I""F' would .... ,...d to b< inronveni"","" by tho pt>ky .~of-liw.l harri ...

frustratingly, I>owev<r, nonlocality can".,. be ho.r ... -.lto ernC. an in ll. ntan.., ... romm~n;c,C;"n. system. Au.rnpc. co ..... th.t .pin

of p."icln to .. oo a n>CSSaF "",,>s. large dill . nca miSln ..... one dir«.ioo of . p;n Co cOO. for. '0' aOO tMoth.r ro.. " J." HOwntt. to know cha, you ~ .. sending a "()" or • " J; you would h.~ CO chocl:;

'M 'Pin of ' M p.rtid •. Hu, checking kills ,h. >uporpo";'ion, ",hich i • .... nlia! fOr , 110 i ..... n'. """ ... <If"",. [f you ",nl • _g. wi.h.oul

r,rst looking, you could I>t only 50 ptrant ' u" of .. OOina' " [: • I~I of ~nc<r .. iH1y .hat .ffectivdy ""mbl., any m.aningful mnsag •.

So although in ... n .. n..,,,,, inO.,..,,,,, is • fundomt ... 1 f.ature of Our Univtnt. it turn. 00' that natu .. dots aaclly ...-hat is r«[uirtJ to mok< it unwabl. for .. OOing rnl informa1ion. Thi. i. how it penni ..

TIl . T .... I'ATIIIC U N" 'Eli:.'

'he ,p«d-<>f-ligh' !>Mri ... to bt brokn "'i,ho~, aC1~aUy bti", bro

kn. Wh .. ",'u .. !i,," with """ h.nd il <TUdly I.kes 'W2)' wi,h tho .... TELEPORTATION

Arj!;u.bly, "'" .u~, rot .... 'ial ~<If ... tangl<m<'Tlt inv<>lv .. 'akin~ an <objec, .00 ...,di", • compl.,e descrip,ion "f ,he <>bjec' '" • faraway place to ,hal' .uitably de ..... mach,,,,, al lhe other end an construe!

• ~rf«;t copy. Thi, i, <If "'u .... It.. =i~ fQl" It.. Slar Trd Ir.IU· p<>r, .... which "",'intiy "b .. me.I" crew membtrs ~ and forth t..

I~n pion .. and ""ip. ",. '<chnok.gy to U"C.OTI<1ruC1 a...,1id <obi«t merdy from"'" in·

form";"n describing i, i, <If cou .... w6'f bey<>nd ou' curren, 1<Ch",,· l"!Iical capabili' ;'" lIu'. ac,u.alIy.,M idn <If crta,ing' prrfN' copy "r In obj<'<1 II I rcm<>te k>calion fOunders on tom .. hing much """. bu;c 1~ Ihi$. Acron.ling 10 1M H<nlxTz ununainly principle. il i> imro.';b!e 10 ~tly ~;be . n oo;..:.-,he po';lions of all it>

.. ""'., ,he elec,ro,,. in tach of lhoot alom ... nd to on.. Wi,hou"uch

knowlodge. ~" bow can OIl e<lCt copy ........ be .... mblo:<lt Entangltmen,. rtm>,kably, off ..... .... y ou'. The rt....., i. 'hat

.... '.n!led particle, bthave like. ,i",l. indivi,ibi •• n'i.y .... , tome levd • • hey l"..,..nch other·, Jttp01IS« ......

Say .... have a par,ido, ~,.nd ........ n' to mak. prrf<'<1 copy, p' . It Mands '0 rtaSOn ,luI in onk, '0 do .hi. i, i. n«nSary ' 0 know p., proprr'ics. HOW<"VCI", accon.li", '0 ,he Hci..., l>erg uncerlain,y prin' ciple. if .... measurt lilt. pI"iculor proper'y of ~ pr«isd~ i" I"" .. ion-.... in .. itahly I""" all knowlo:<lge of ")1"" '" I,.,- proprrty-in ,hi. " .... it< veloci'y. N<-vorth<Ies<, ,hi. ctipp~ng limi,",ion an bt cir",m ... n~ by an i"' .... i" ... usc <If ... lOngkrn .... '.

Take ''''''M' p.rtick .... , whid!;' similar '0 bo,h P.nd P·."" imp<>rlanl ,hi", i, ,hOI" Ind P· . .. . n .... '.ngled pai,. Now .... tangle

" .. i,h P .n.J mak a m<"urtm<'Tl' <If 'M pair 'ogtthtr. nus wiU 'eU US .bou, some propn1y of V. ""cording 10 lhe He;...,1xTz u""or'

t.i"ty principl~. hoIo ......... 1ht m",u"'mt11t wiU ;" ..... it.bly i"voI ... us kJoing knowloJso ,,( so"'" ",n.,. P"'l"""ty"( P.

But all i. 1"101 kJol. Ika. ..... p' "'as ~ntan&1N with A. it rrtaim knowINg. ,boUl A. And b.cou .. A wa •• nlanglt<! wilh P. il rtt.im luI_INgo about P. Thi ...... n. lh.l P·.llK>uf1h il has """ ... Wen in touch with P ......... 11101 ... knows i1> occ""'" Furl"","mort. wbm1ht " " ,=>rnt-.sonadoonA.nd P ~ondinfOnnotion aboul "' .... prop<rty,,( P .. ",,,.I 10 bo Ioo~ i!lSlanl........us/y ~ bccam< ovail.1blt 10 A·. 1"111"0<1". P· . "Thi. is 1110 miraclt,,( mlanglmo<nl.

SiR« _ .t.udy know . bout tho "' ..... prol"""' ;""( P. ob .. inal from A. _ now h_ all _ n«<llo maU 'ur< P' has t:Ka<I/y lh, auribules ,,( r.' Thu. _ h.a ... ""ploi,.,J m tonglt"",nl to ci="","nl th, .... lriclion.s of lh, H,i<mbo'l! unetTl.inly principle.

Tho ' maIi", thing is lh.al .• lllo.ough _ hovo ""pJoilal ,nlan&1~ monl 10 maU ' parl id< P' with 1ht aaol prtJpaties of P •• l no timo did _ ........ po ...... ny inform.lion OboUl111o missing p""I"'rlyof PI It was t .. mmi" ..! out of our sighl through tllo gholl ly ronn«:tioru of "ntanglommt.'

Calling lhi. schtrn, 1,loport.t;"n i •• bit of. chttky """WtilIi"" .inc. i, sotvn ""Iy 0 ... ,,( Ih. m. ny prOOl""" in making. $la, Ttrl: tran.porta. Th. rnnrth .... of courot kn<-w this. Bul lhoy aI",

k ... w. thing or two . bou' hoIo 10 grab ...... pal""" lIoaollinesl As i 1 h.a I'P"m. 1ht Achill .. · 1>«1 of tho S la, T rrl tran'porta t urm

oullO bo ... ilh ... pinning down tho position. and soon.,,( ~ . tom

>no. infonn .. ion on ,Ii< oril!inall"nid •• P. m .. ' bo , .. """i,1«I by or· dinary "" ........... , io."""'" dun ,o. ,pord 01 light. th. """""., ,pord I .... i'. So...., if I' .nd P' .... f. .. aport. tho ,tra,,,,,ofP'-tho p'.f",<O»!' of 1'_...,. in ...... ...., ... 6<01';" ,Ii< r..r. ,ha. communico,"" bo,,,,,,, th.

''''~ ponida.. A and P. i. i!lSla"'_. ' I, ;, wonh <mf'ha>~ tha, ..... ,..;th ... ansI ....... '. ,o. moor yo"an

<V<t do ;, makr. <OM' of.n oIIjt-rIat tho <.<J><II'< of ""'"",ins ,o. orisinal. Mwn~.",1'7 and krrpi"" tho oriKinai io iml"""ibIr.

TI' " TU''''TIIICUN,n ...

in a r<rson~ body nor a...",bling a coM' of tho ptrSOn from ,ha, informa';"'" II', ""WIlly ""","';lIi"l tho sheer volu .... ()f informa· ,ion ntNN '0 dnai!>t a p<NOn aemu .poc~. lIillions of Ii",... more inform .. ion i. <>«dod ,han for ,he recons"""ion "r a two·

dimmsional TV im.gt. Th. nbvio ... ""'y 10 smd ,h. infomution ;. .. . .... i .. "r blnary"bits"-,Jou and dashes. If ,he informa'ion i. 10 !>t """ in a """,,,obi. ' imo.,ho pw- m .... obviOll!ly bt .I>ort. i!u,

ul,rashort pul .... ~ posoil>k only wi,h ullra·high·~ .... 'lIY light. As

scionet fiction wri, .... Arthur C aark< h .. poin'N OIl', !>taming up Cap .. in Kirk ""uJd .",ily ... k< ~ .... <gY , han ,ho~ i. in a ,nuJl 83luyof ... n!

TeioporlO'i()n and nonlocality ... klo, ,he m",' mind·bl<>wing con · O«J""na of m'.ngl~m .. " i. wha, i, m~ .... for the Uni ...... as. whok. At 0"" ,im • . aU I"'rlkles in ,he Uni ...... """" in ,I>< .. me " .. ~ bK ...... all par1icies ,.. ... ,Ogttbtt in ,ho lIig Illng. Conuqumtly, all

partkles in ,he Universe .... '0..,.,.,. '''m' ~n ... ngkd wi,h ~adt o,ber. n,.", i,. W-dy wet. of qlUJltum mnnK,i"". <ri!.5<",,,ing tho

Universe and coup~ng)<>u and ..... '0 ~ Ia" bi, of mallor in tho m"" distan' galuy. W~ l~ in a ,dtp .. hic uni ....... Wha, thi' actually means phy>ici'" ha ... nOO )'<, figured OIl'.

Entlngl!:mtn, m.y.1>o help ""plain ,he OII .. tanding quntion pose<! by qUlln,um 'heory: Wber. doe. ,he .... ryday world come from!

WHERE DOES mE EVERYDAY WORLD COME FROMI

According '0 quan,um ,heory."";rd >uperpo";,ion. of II .... art nOO ""Iy po"ibl. bu, guo .. n'.,...L An alOm con bt in many pia<n a' Onet

or do many ' hingo a, CIrIU. It i. ,he in,~rft~nct I>tt"'«n ,he .. posoibiliti."ru.,I .. oh Jirectly 10 many of tho b"'r", phonome ... ~ in Ih. mkroocopk "",,"Id. lIul why is i"h .. , whm Iars~ numben of .. om. club 'ogt,her 10 form everyday obj«:lJ, ,ho .. objects ..... r di.play quan,um be ...... io,! 1'<1, i",,"nct, ,rttS now.- bth ... as if , hry

•

art in 1_ plaas.l 0""0 and .... anim.1 bthavn as if il is • combi ... -lion of. fl"08 and. gi ... rr •.

Tho tint .uempt 10 uplain the .<>nun<irum ...... m.d. in Copenhagen in .he 1'120. by 'luancum pi"n~r Niet, IIoh •. The Coptnh'l!tII InlCTpr<l.tion, in ,ff«., di.iJn II>< Univcnt into r.ro domains, ruled by diffemu laws. On the one hond. the .. i,,1>< domain of th.< V<T)' .mall wh;rn is !Uk<! by quantum throry, .nd On tl>< olher the .. i. the domain of the ""'y big, ruiN by normal, or dus;cal. lrw~ According 10 ,II< Coptnh'g<n Interpn:1I1iOll, it i. wh<n. 'lu,ontum 0/';',,, litt an ""'" in ........ with. d ... kal wj"", that it is forced to SlOp heing in a i<hiwphrmic ,up<rpoiIition ond .tart bthaving oensib!y. n.. d • .,;col objt<1 could be. del«,;n8 .!.:vice or .... n I human bring.

lIuI .... I><tant/y. what ""nsti·

M ... clwkal 00ftcI! Aft .. an, an 'Y" is JUII • biJ! collection of Itom<, which individuallyob.y quantum throry. Thii ' u,n< oul to he .he khill<$' h.d of thr 0>p<nlugen lnt<rp .... 'ion and .1>< rN>On it

hu a1....,. • • ppcarN 10 ..uny 10 bt • """Y ~ns.ali.foclory aplanalion ofw~lhe~ world c.,..,.. m,1fL

Tbt Coptnh.gtn [nttrprrlll1ion ili .. iJ<:s lhe uni ........ rbitntily. inlO Cwo dom.ins, only 0 ... of which is !O""med byq~.nturn cheo<y. Thi. in i1<df i. ""'1 dtf<oci<!. MCn- 01[. if quancum lhcory is. fund._ m~nu[ d~"'ription of ,nlily, surrly it should .pp[y ~""Y"'lIere-to ,he 'IOmi< wo,ld .nd the c=yJ.oy world. The id~. Chat ic is. uni"",_ .. Itheo,y is, in • nuul>e[1, what ph)'Sici.u bdicv~ loday,

It Cu,n. o~t wt n~ ..... obotrvt • quantum .)'SI.m di""'t[y. We only obotrvt its off«, on it. ~nvi",nm"'L Thi, may bt. ~ .... ring do:vi<e 0,. hum.n ty< or. in g..,<raI. cll< uni ....... for inSl'nct, 111< lighc from.n <>bj«1 imp;"!", on tbt miJu oflhe~)'t and mak ... n im_ p ..... iooI cller<. Whal tbt ob"""" he ... i. in"'1' ... bl. from .. h.l cll< obser"", is. Now, if quantum theo<y .ppli ... ""rywherr, wt ha"". quancum obj«1 obll<'TVing, or """"rdilll!, .notha- qUaJIlum obi«',

TIl< emu'.[ qu<sciool can th<rtfort be ..,UtN: why do weird "'hi ....

TIl. T .... I'ATIlIC U N" ...... " phrtnic ""ts f.il,o imp ..... ,hem .. l"" on, or "'It~nglt ,I><m .. l"" Wilh, ,he environm',"I, wherr .. "eryJay "ne-p l",e·"·"ne-'i..,. ".'tsdo! An tumplt may help.

If. high .sp«d ",balomic por.klo flits 'hrouSh ,he .ir, i, knocQ dec'ro .... from any 0I0ms i. ~ d" .. ,o, Im'gil'!< it war poMiblt 10 ... a lO-«n.im .. er-Io"ll po<,i<>n of its.racl<. And, oar in ,hal ,0 (<'Tn;"' ..... the ponide h ... 50 p<rttn. diona cL in,uac,ing wi.h

one elec'ron, kicking i, 00' cL ilS p ..... , 110m.

The parlidr. thertfort, eilher knocQ oul an rlec, ron or doesn'l kn<>d ou'.n e\ectron. lIu. beca~ ,he "'"" o£knockin! ou •• n dec· Iron is • q .... n'um Ntn" Ihrrt is .noll>tr p<>£<ibilil~he 'u~pooi'ion "fthe two Ntn\>. The port ide b<>th knocQ ou' an droron and dOtsn', knock oul .n droron! The qu,",ion is: why, wh ... Ihi. Ntnt

""lOnglt' it"'f wilh the environ",..", clots il "'" 1< .... an irwkliblt imp ..... i""! M lw:k _uld Ilavo i'. it it poosibk ' 0 actually IN on eleclron ejecli"" e ... nl wilh on in!!,"nioo, devie< known .. a cloud

"'-"". Clouds form in .he .ir when a drop in 'mll'ft"l ,ure "'~ .... , ...

dropltlS 10 conJtnoe 00' cL .... t ..... po<. But this procns happe .... ... pi<lly ooIy if ,here arr 'hings like dout p.orticb in ,he .ir 'ha' 0<1 ..

"O«ds- around wh;ch ...... r dropltl:l un grow. Now the S«d----ond thi, is thel<ey 10 lhe cloud diamber', opc ... tion-neecl no,. be as big ... dust grain. In fact, i, neecl heonly a 'ingle OIom WI h .. Io ... n electron-an ion.

A do...! chamber i. a 00. fille<! wi,h ..,,'<'1" "'P'" with. winJow in ito oi<l< to look through. Ouciolly, the w.'er ""PO< i, uhropurt, '" therr art no O«ds .00"' which the ... po< can condtnoe. The ""PO< is held in. ''''e in whi<h it i, .bO<>lu'.lyclnpe ..... to form droplt,., but it i. fru ..... 'rcl beeau .. therr art oo:l<t'cls. En'er. high-spetd suI>lIomic p.ortide. where il knoocl<o an droron out "f . n a",m, a .... t .. droplet will in<laJIdy!VOW .round the ion. The dropltt i. small but big enough to ... through the window of the cloud <hambe, if prop . ... Iy illuminotrcl.

So what would )'lu ... if)'lu looked Ihrough the wind.......t The

·n.wer i. of coo .... j ... , 0 .... of Ihe l"''''bi~lits rilher •• ingle waler .1"'1'101 <,. IN) wa'er .1"'1'10,. You would n ......... ,upe<p<»i'ion of both---<! ghostly .1"'1'101. "","<ring hoolf in <:li"e"", .nJ h.lf oul of

<1i ... "",. The '1utslion i .. """ happon. in ,he cloud chamb«" 10 prcvtnl il fmm rttOrJing thi"up<rpoiIition?

Tak.,he ...... , in which a wale, J"'I'ifl form .. II was trigg • .-N by • oinglt ioni"",.,n .... The .orr .. at"", Hi.,. in ,he tvrnt in which nn

.1"'1'1<1 !O,med. I, jw;, Jots n'" get ioniud, ... no water Jroplet forms

.rout><! it. Say, this .'om is pointed ,..,J in both cases to mak< it SI.nJ <JU' (for!.' the f ..... ,hool you cont point an at""'!)'

Now. in the tvtnl a J"'I'let fOrm"lOOm in nn on atom ...... the

,..,J "om. W .... i • .I....." lhoon wate' vapor; ,he a'''"'' a'" clooe, 1(10-gether. Corutqumlly. tht.lOm in qucotion wiU be doon- 10 the,..,J

310m lhon il is in lhe .... nl in which no wate, dropl<1 form .. For ' hi' ' ..... n. , he probobility w .... '<prnonlting tht .t"", in lhe firS' ...... t

only p"niolly ovcrl.1" willi. lhe probobilily ....... of lhe .am. atom in ,he _.I n<nl. Say. f ... aampl •• ,h., thei, WlI.~ only Iu.If ...... ,lap.

Now tok • • serot><! atom in ,he firS ' ......". It '00 will ... do ... in

lhe firsc .... than in ,he second On", O!'in. lheir probability waves will only h. lf overlap. If ... DOW oonsi<k,.he p«>b.bility....,.. <"<1''''.. nting Ihe two .tom. Iogtiher, it will overlap only o ........ ua, .. , with

lhe JOCOt><! case, sin", 'I, x 'I, • 'I~

Str wl>tt. this is g<>i ng? Say the ..... t ... .1"'1'1<1 oontoin •• miDion

010ms, which ""uallycor~t><!s loa ""y ,man J"'I'Ie .. How m..m will tht probobi.]ily ........... p ..... nting. million atoms in ,he firS' .",nt ...... rlap with lhe probabilily wo ... re-p ... stllting 0 miUion atoms in lhe RCOt><! ......,t! The .". ... ri. 'I, x 'I, x 'I, x ...• million Ii ...... .

Thi, i. on atr-.linarily ,mall nurnb..-. n-.... wiU the ... f ....... .... .. nljolly zero o....-l.p.

Jlu' if 'wo .... ~ don" overlap., ol~ how con they in .. rn~ The .nswer i .. of "'unt. they connn .. lnternrtn«. hoW<vn-. is.t lhe root

of on Gu.ntum pl><1>0"",na. If inlerf .... nce ""~n lhe two ........ is imp""'ibl< ......... ither one ownt or the other but ......... the eff«' of 0 .......... , mingling wilh II>< o,hotr, 11>< esstne. of quanlumn ....

TI" T .... I'ATIIIC U N" 'Eli:.' •

P~li'y .... "eO ,Iu, do no, ov..w.p and so ",nn"" in'ttr.,. ar~ said '" Iu,..I.,.l ~""'. or '" h"". dtrohtrnL 1.Jeo:>I>o,."", is tho ul,ima,. ,taj(Hl .... hy tho 'KOI'd "f a quan,um .... n' in ,n. omi,..",menl, whidt always colUi ... of a 10' of "'''''''' i, n ...... quan'um. In ,h. ca.<t of the do...! dwnbtr> ,n. "",vi,..",ment" i. ,h. million .,. """ . round ,he ioniudinonioniIN al"m. In g~neral, ho~, ,he envi"",men, consist< of Ih< round ... q~I~"ns of a'om. in the

Uni ......... Llecohe,."", is 'herefor. hugely eff«tiv~ at deslroying any _,lip N'''''''''M probabHily IoI>"n of e,..nts en .. nglal wi,h the "",vi", nmen'. And ,i ne. ,Iu,'. ,he on Iy W2)' .... <on ""perlen"" ,hem""'"' ,n. oboerv<r h"'<n i. i .... p.rahl. from ...... , tho obott,...,. ;..... n . ...... di=dy see 'lu.antum bt+>ovi<>r.

b

IDENTlCALNESS AND THE

ROOTS OF DIVERSITY

HiI'II III( ""UM ... _1'1 Of TlU mlfOO_1 SillS 1lI0II1111

'AU TW '" WWllllWJI(I" lumoo

I """ ., ..... _'"Oot ~n4 .n ", ... , ""If /uod "". , ........ Q..t ,....

p/Mftl "" ,XII<> d.,~"" ...

n.,. rum. frrtm fo. dna wid< 10 .... j,_,~. ri..,. '~d' row uphilL /.

flpwnJ ""It'M fishing I'M. c/imbnJ Ih",~gh Ih. <'--,...aid """>Go btfort ",,,,..Jtring wI' ,.,<http-II""'n hillsUl. 1o 1M ''''lW' ,um",ir ",...,-looking 1M ' ....... S'<l"ltd _gwlls bobbed on if. &ri~ child .... "'n htliJr ;1. lind ", pitn;': 1<Ibi .. ",mid. pub< ail ..Jons ,,,.. riWI', Ie .....

fflIrl><'I. ddytrifY't" "" lTt1<ts{uU "" Ihis ""IWkr of "alu,. .... bar ~I" II...Jil, up r/" ,id" of ,/wi, bar g""'" and quial, tml"i<J ilUlf onlo

,Ite """.J.

Su~ly. thr .. i$ no liquid tlu. <on Jrfr gravity hk this.OO run uphiU!

~marbbly",,"", i .. I1'. ~ .nOlhc",nstq~"'. of qu,mlum '~'1'. Alomund 1M, kin can do manyimpoosibl< thi"5' bt{ou bruk

n... Fo<'r.obl< born ..... and !-now .oow1 each "the,- in.unlly ncn when on diff ... nt >ide. of the Universe. They Ort . 100 lOully unp .. •

•

dkubie, doing things ror no ...... n 0' .ll-~rl>aps lilt moot shock· ing and un .. ttliJlfl of "II too, m.'a<trriMic ..

All of lheK phenom"". ul!im.~1y como down 10 til< ...... ' p.nide 'harae ..... of d<etro .... pho., .... and th.<ir Iikr. Hu. tM po<;U'

Ii .. dUll "'uro of microocopk obi""" is nol Ih, only thing ,h.1 moXa .h ..... profoundly difforont fTom .~y objt<;u. ThtTe is sorn<Ihing tlst: Wi, inJiJtinpioMhiliry. frtry dtclron is idrnlial to .~ry other ,1«lron, ~ rho!"" i, identical to every Oll>or pho. ton .• Iki.., on.'

AI fin, sight ohi. ""'1 "''' .... m I ~ry rrrnukabk prorrrtY.!lul think of obj«1> in 1M everyday world. Allhough two cars of 1M sa .... mood.nd color .pp<ar til< sarno, in .. ali.y thry-.rt 1'101. A urd"u1 in'p«lion ...,uld .-..veal th.t thoy diff ..... Iighdy in Ih, ............ of 'heir point, in the .ir p ..... u"' in ,lItir';m,.nd in I ""' .... 00 othor minor ways.

CollI .... ' this wilh tbe world <>f 1'" very smaU. Microscopic p"tidncannot bcS<r.lIcht<i or mark.«! in any wily. You ann", 1.11100 an .1«"'0.,1 They ... u".rly indistingui .... ble.' The sa .... i.l",. of plioton. ond on othc1" dmi ...... of lhe microocopic world. This ir.dislin· gui.hability i. truly oom<thing n.w undo, .he Sun. And it ho. ,,,,,,a,klbI. consoqu.ncn for bach the microscopic worIJ anJ ,he..,· <rytlay world. In faL •• ;t i$ fa;, to oar . hot ;1 i$ th< ~_n ili< _,Id ,.,. I;"'" in is possibl<.

'su.:. pi",,,,, .. C<I .... wit h diff<r<-n' ............ ..w, w< , ... oJ Clion for why tJ«tronI .... un.tIy ind;";"~ishalll, bo"" ... the ... is only Of>< tJ«tron it! the Uniwn<! It _...,. bodwanl and II>rwarJ it! time

Iha tlu .. dll"in~ bad<.nd .. ,th thro""-'" t_'1. w .... tho multilud<of pbcft "".,. tho .hr<oJ S<><' thro""-,, tho fob,i< of the tap<ll'1 and miotalt· Mly ""iII"".ad> to. _ .... <Itc."",.

•

TH INGS YOU CAN'T TELL APART INTERfERE

Ke<;.n ,hal oll tho bi .. m: boh.ovi<>r in , ... mkroswpi<: ...,rld. _Ltd> as an .tom', .bi~ly I<> be in m.ny pucn ., """'. co".... down to in,e,r""'net. In the double slil "'I"'rimnlt. for <'Urnplt. il .. II>< inttrfe,· en« be1w«n the .... ~ oorrt>pO<l<linglo a par,iclt goinglhrough the

loft·h. nd oIit an.! tho ..... corrap<mJing to tho par,ide Koing through the right-hand ,Ii, that proJ..cn the characteri.,ic ~u ... n of .11 . ..... ' ing dark anJ ligln .tripe$ 011 .1.. $«onJ $<r«n.

R"".U aJ.<> ,Iu. if you ....... I<>..c up ",me mnn. of deI<rmining which '~1 <och p."klt goo> 'h""'g~blinl!}'<Iu to Ji"inl!ui,h Mlwe<n I'" tWO all.ma,;' • ......,nt.-d'. intnf~nct , 'ripn Ji .. p-I"'ar boousc fir <kw ...... nct. Intorr. .. """. il ,urn, ",It, hOPJ><'" <>nly if the .I,.,.n.,i", .",nlS . .. iltdi>,inguis/lablo>-in 'hi' aoc, .1>< 1"Ir-tid. ~illfl through Oil< slit arol,l>< p.rtid. going through tho otl><r slit.

In ,t.. c ... of II>< Joubl. $lit aprrim<nl"h< al .. ,n;o,;" ''''"1$ .'" indi.tingui.habl. just as long IS nobody looks. 1M i,",ntical par'idro. such .. 01«,,..,,. .. raise ,h. po";bi~'y of .n'ir<iy now kind> of indi>!inguishablt • ...", •.

Think of. , ...... g. b<>y who pIons '0 go ou' dubbing wi,h his girlfri.nd. who hopptns to ha"" an idtn,ic.lrwin .i ... ,. Unbtknow" to rum. hi. girlfi-itnd d«idts 10 <tay in .00 wa,ch TV .nd "00' htt ,win in II<r pI"",. !leeaus< ,II< ,wo girl. o~ar j,Jm,ical '0 ,II< b<>y (.JthoU&h 'lI<y art nOO of cours< jJm,icaJ .,,11< micn>OCOpic bdl. ,II< oven" of going clubbing wi,h hi. girlfrimd alld going c\ubbi"8 wi,h hi$ girlfi-;."d·, sU'" or. iOOi>!inpishabl •.

["""11 .uch II ,hi. Ont. which a", indil1illguishablt .imply 1><<au>< .h<y invoM 'ppor<n'1y indi$tinpishablt thing •. haw 110 ..,ri_ 0"" conK<Jllttoeel ill III< widtt world (.p.r' from aUowing idmlical ,win girls '0 run rings around their borfritnds). However. in thot mi_ cros<opic ....,.,.Id, th<y ha"" truly profOuOO cDllS«jIltnces. Why! ticcau" " .. n1l 'hot .'" indi"ingui.habl.-for . ny "' .. On whllOO<V<r-.\rt ablt '0 inl<rf .... with each OIl1<r.

TIt ECOLLlSION OF IDENTICAL THINGS

Take two atomic nud.i that ",UiJo.Any ouch <;ollioi.,........,.nd this PO'_ t;.,wat point .. ill ~ 10 be taktn <HI lrust--<an be lookN at from. point oCv;'" in which the nud'; fly in from "I'pooit. Jirn:tioru., hit. th.n fly b;w:k OUt in opposite Jirn:tiollS. In F"'rol, ,ho in 01><1 OOt dirn:tion. Of. no' the S&mt. Think of a dock fOC<'. If tho nudoi fly into tho colli.ioo point from, "y, 9:00.1><1 J:OO, tbey might "y out tDWard 4:00 anJ 10:00. 0, 1:00 anJ 7:00. Or any ooh.<T poi, of Jiuction>. .. long .. tho illrn:tion •• ~ opposito nch otho •.

An .. pori"",o'., """It! toll which ill'''''ion the 'wo ml<;iti riooclt.tt by placing ddectoro.t oppo.ilt.idts of tho imagina,y clock faa: .n.! tbon moving lhom . rouoo .be rim t"!i<lI\eT. s..y tho Ot1t<1Oro.~ ploc...t at 4:00 .nd 10:00. In thiJ """'" tho~.~ tWO possibit ways ,ho nuclei can gn tn tho .1"«10'" T1>ty cowd "rike <ach othor with. 8l .... ing blow so ,hat tho 0 ... coming from 9:00 hits tho d<l«to< at

HIO anJ . ho """ coming from JotlO hilS th.. on. al 10:00. Or.hoy conlt! hit htad on, SO that tho """ coming from 9:00 bounces b;w:k 0111>0$' tho way i. "'''''' an.! hits th.. d.t«.or at 10:00 an.! th.. 0"" coming from J:IIO bounces back al"""t tho way it co"", and hi" tho d"""tOO" at 4:110.

l1>t JitKtioou ol 4:110 anJ IO:llO.~ in no way .p«ial Who .. "" tho t WO dtttctoro ... positiontJ. tho .. will bt tWO allt ..... t;"" ways tho nuclei can Ft .0thom.Call thorn .",nlS" and 6.

what happtns ifth.. tWO nud'; a .. JifftKtIt1 Say tht on. that

flics in from 9:00 i ••• lICit ... ol arbon al><l'ho on. 'hat Bics in from 1:00 i$ • nucitus of h.lium. wtI~ in . hi> """". it i, alw.,.. poMihlt '0 Jillingui.h bet ..... n "" .. no" anJ 6. Aft ... all, if. carbon """it ... is pi<:ktJ up by thtdtk<;to,at 10:OO,it i. obvio ... that """n' "<><cur=!: if it iJ picktJ up by tho dtttctor at J:OO. il must h.a", bn:n """"' 6 instead.

What h.appcru., howeYtr. ifth.. tWO nudri .~ tho .. ~ s..y each iJ. nud .... ol ho~um! \~I~ in this cax. it;' impoMibk to distin_

gui,h b<t ...... """nts" and II. " holium nucl ... "h.a. is picked up by

•

111< dc'C'C1or in 'he di....,.;on of 10:00 could h""" gou ... ,her. by <'i-1""," rout., ~nd the ......... ,rue for. h<~um nudo ... pickttl up in ,he dittC'ioo of ~:OO. E~n .. 11.00 110 .. now indjstin~uishahl •. And if lwo ~" .. in 1he microscopic ""rid .rt indistingui .... bl., 1he woves ....xi.,td with thtm int..-ft .. ,

In lhe collision of two nuclei, intenC1'ellct nukn • huge ditk,... enu. f<>< ;nllan«. it;' po.lib'" that the two,.,."", """" .. IN with lhe tWO indillingui.habk ",Uision e>'Cl1ts dCSlructively interf ... , or '"ncol .... h OIher ou,. in.1I< .Ii""";",, of 1(1:00 and 4:00. If.., 'M .k1«;tQl'S wiU pkk up IN) nud.; ... u. "" mal~r how many ,i".,.. the oxptti ..... n. ;. "'I"",N. 11 is also possible thai lht lwo Wll>'eS conIlrU<1ivdy int.rf .... or ",inf""",."", <>.ht., in 11>0 <Ii,«,;"" "r 10:00

on.! 4:00. In ,hi. au. 1he de1«lon wiU pid up an unusually 1&1# numb...- of nw:lei.

In J''''noI. bK."", "r intnftKl'OC<, '''''r. will ht <..,-ta;" ""twanl dirte';"'" in which lhe wa ..... ""re.ponding lo~nlS II and Jj cancel each otM and cnta;" ,,,,,,wart! dir«tion. in which they .. infoK< ncb othrr. So if.n., aprrimm. ;, rq><at<d ,nousanJo of ,i",.. an.!

,II< ,koch<l;ng nud.i .'" pidtd up by dt1«tors .11 .roun.!lh. rim "f ,II< imagin.rydock &<t, ,II< dOl""''''' will sec a 'mtI¢nWuo ... ,i._ lion in the numbt, of nud": .rriving. Somt d.,«,o,.. will pick up

",.my nud.i, whilt 0111< .. will pick up "" .... , all

Bul thi.;, dramoticaUy .lilf .... nl from III< "' .. wll<n 1ht n",I":

.... dilf.mll. Then Ih .... i. "" inlmemICe, .n.!lhe dt1«tors will pick up nud": ri<:ochrting in .ll .li,<CIiDll1. 11><re will bt no pl.cn aroun.!

,II< dock fa", where nuclei a ... nol oteI1.

Thi. llriking dif!t",,,,,,, btll<o'ta1 the oulCOmcs or the aperi""",'

whtn til< nudei .... the .. me .nd when 1hey.", diff ...... t i, ""t bt-

ClIu.. of the .lilf .... "'" in rna .... of the nud": of "'roon .n.! hdium. alth<>ugh this ha> • ..".n elf<CI_ It i, truly.lown 10 wh.eth.r <oIlision

.... nto II .n.! B .r • .liolin!Jll"hohlt 0.- not. If ,hi. kind of thi", happened in ,be ",al wo.-Id, think who, it

would mtan. A ml bow~n~ hall and a hlu" bowling ball lit. ..... "'_

pea1edly collided 108'<ll1<r would ri<:ochrt in.n poosihl. directions.

•

But ..... ry1hing would he chang"" mttdy by poinling ,he ,oJ ball bI..., .., .hoe ,_ boll. ~ in.liotinguWubk Suddtnly, tho« would be .Ii· rte' io .... in which th.t bolls ricocht'N far more of'tIl tlu.n when ,hey ...... difforen. colon. and .1;=,;"". in which ,hey ....... ' ....... rico·

"""". Thi. fact, ,hat .... en\$ in",,"'ing iden'H:ai particles in the micro

scopic worM an inkrf .... with .. ch .,.IK., m.y OKm ~"k mort than I quantum quirk. Bu, it ;",,',. 11 i. the .. ...". why ,he .. art 92 differC1\t kinds of naturally occurring lIonu !';UMr than jlU' 1. In short. it i> rnpon>ibl< f.,.. .ho v:arirty of the world _ liw in. Un.krs .. nJill3

why, ~r. rtqui .... appreciating 0 ... mort ... bcl<1y of 1M proca.s in whkh iJ.mical particl .. collide.

TWOTRIB ES Of PARTICUS

!!<ali.,," ase in which ,h. n""I~ .rt ditTorenl_ carbon nud..,. .nd • hdium nud .... _<mJ ron$iMr again II>< two "" .... bk roU;'ion .......... In on<, the nw;l<i .. nkr .od. O'M with. &lo"";n8 blow, and

in.1I< OIM lMy bit b<:aJ on and 110""". bad almosl,h< way 'h<y < • ..,.. \\'luI ,hi, m ..... i. thaI, f.,.. the nu.cleu. ,ha' """' .. in .,9:00, ,h.", i •• WI .. corrnponding to i. going oul,'4:OO ar.Il "' .... corr~

.ponJin! to ic goi,,!! "", oC 10:00. ",. kty ctung Co und~,.~d h<tt Ii ch.c Ih~ probohililY 01 on

•• • •• Ol i. nol ... I .. N to 1110 lIoighl 011110 wa .... associ.cN wilh dllu ....... c b.n Co tllo sq ... r~ of 1110 hoight of ,h. wa .... ",. probability 01 ch. 4:00 ..... nl i. IIIo ... fOR 1110 sq ...... 011110 wa .... h.WOl in lh. dir«' cion of 4:00 .ndlilo prohabili lyof ch. 10:00 ....... 1 i. tho squore of tho wa ... I><ight in lhodir""t"'" oflO:OO. It is 1>< .. thot lhocru".1 .ubtl<1y com .. in.

Soy Ih. wr.>: corresponding to 11>< nud .... llul A;.. oul.t 1000 is flipped by ch. col~.ion. SO cl>ot il< Crough. 1><0:>0,," il< p"w . nd il< p .. '" become its 'rough •. W""ld it m.ke . rt)' dirk .. """ to 1110 prob· .bili'yol.tt.< ....... t1 To ."',...,- .hi •• considero wa.er ... ...-..,.in of . llern.,in8 pe.ks and lrough .. Think of 1110 ..... rag.It .... 1 of.ho waler

•

os corresponJing 10. Mighl aJuallO uro 00 ,hallht IInghl of til< I"'.x. i •• po9t~ numbt.--ay plu. I me • ..--oo the height "c Iht ttoUflh. is. II<'5i'tirt numbtr-minu. I mel ... No ... il mdn no difference whether roy sq""",1>< height of a ""ok or d .. htighl of • trough .in« I ~ I _ 1.00 _I ~ _ 1.1so "lu:ilil. GoTl<t<jurnlly, flip_ ping lhe probability WO~ .....oci.IN with. rioxhcling "..d ..... makes no difl'ttm'" ,n "'" "",nf . probabi~tr.

But i.,here any ' .. ..,n 10 believe,ha, 001< ........ might gel fljppN~ Welk 1M 10000 colli.ion and 1M 4:<10 coUi,ion ..... ""'1 diff .... n' """nl$. In 01><, .t.: , ... j«tory '" ,he "ud .... hardly "".ng .. w~ in tht OIhtr il is tumN ";"1<",ly bad OIl il.ldr. It is at Insl pl ..... ibl. ,hot.he 10:00 ........ might gel nip~L

Ju.' b«. ust somttlling i. pb .... iblt dotS JIOI mtan il ""1""Uy h.p""ru. T", •. In this case, however, il d.,..l Nalur. h .. two pooIoIbiliti .. a...iLoblt to i,: I. Can flip th< WoiV. of on. colli<ion ntnl n, i. can 1._ it aJon •. II tarnsoul lhal il avail> i,self of both.

lIu. how I'roulJ _ <v<r know .boy •• probobiJi,y .... .... 8 ... ln8 flippa/! Aft .. .n. lht ""Iy thing an ""penmm ..... an ~u", is .1>< numbtrof nud'; picktd up by a <i<{<,etor which J.ptnds "" tilt prot>obi~ty "'. po"i<ubr ",lIision ......,t. Hut this is J<tormi...,J by tilt "Iu . .. '" the wov. lItiw.1, which is \be <a",. .... htther \be ....... i. fli~ or noI. It ""ulJ ...... that ...... t actually happens to tilt prot>.hi~ty ... a... in tho collision is hiJd.n rrom vi .....

Ir the OlUiJing particles . rt ditk .. nt, this i. certainly true. But, crucially, it i. nOl ifth<y .rt i<i<nti<aJ. n.. ,...,., i • • ha •• Il< wav ..

Olrresponding to indi"ingui.hable '1Ien" interfere wi.h tach other. And in inlerf....""" ~ maUe ... trnnenJoosly .... httlltr or nOl a ....... i. fli~ ""be i. ,,,,,,bin .. wi.h o...,""r wave. I. "",l.! m""n \be ilif_ f . .. """ betw."n pniu and trouw.. roinciding or nOl. bet.....,n the ........ caneding or bo<»ting .ach OIher.

lV""t h.pr'ns tlltn in tilt Ollli.i"" '" mntial p.rtiOnd 10 tilt t .... altornative coili""n ......,,, ;ntmere with

" tach orMr oo,maUy. Ii""", ... ,. for <>Ihtr p."icles-for in<lana •• 1«· '''''' ..... hingo .... rodicolly iliff,,,,,,,. n,. w:ovn "",~r.din8 '" tho tWO oIl"".,i ... coUision .~I> int.rf ..... , hut only afttr 0,,., has bttn

Aip!,",!. Nat"",', baoi< building block:! tum out to be diviJtJ into lwo

nibes. On the "ne hand, ,h.,.. ar. panicles """""" wava inlm .... with tach otl><r in th.< normal woy. Th~.r< known .. bo;o,,~ n.q. include phoconund sravitons, the hypothetical carrkrsof tho gravi· ,.tional fOra. And, on the 0Ih<r hand, the .. art ~r1icles """"'" w .....

int,rf.,.. with one wa"" Aipp«!. ~ or. kn""", .. fonnio .... n.q. indud •• 1«lrons. neutrinos. and moons.

Wht,her p."kln.'" form;"". or boSOno-lhat i., whetlw:r or nol , hty indulgt in ""'vtHipping-lurn,out to J,ptn<l on thrir .!pin. I!tall that ""nkln with more spin than orbm bch~ OJ if thera .. • pinnin8 ("'n- .t.o.n their axio (al,hough in ,hot bu..lTt q..antum ""","lJ pmicl .. that po ...... pin . ... 1'101 actually 'pinningt). Well, it 'urns out , .... , tt..r. i •• bui< indivisibl. chunk of .pin. ju .. liu tha. i>. ~ indi.i>ibl< omnk of owrything in II>< mi<ro$copil: w.,..ld.

For his.oric moon .. 'hi> "quantum" of 'pin i. 'I, unit (don't worry whot t~ uni" o",).l\QoQn,lu"" intog ... spin-O unit .. I unit.2 unit .. • nd SO ",,_nd fermioru h."' ·luJf-inte...-· .pin ___ 'I, unil . 'I, unit .. 'I, units, and .., on.

Why do partidd with h.lf.intog« .pin indulge in wovdlippinllo whereas part ides with integer .pin do ""t~ This, of roUrK. is a ...... y good q .... tion. Hut ~ brings US to th •• 00 of wlut can .... ily l>< ron· ""~ without opaqu. m.1tl><m.tia. Richard Feynman . t l .... t came <kiln .oout thi" "Thi'lftm, to l>< 0"" of the f .... ploceo in physia ....... r. th.", i. a ruk whi<h <;an be >tal.,} -=r . imply but fi>r whid! "" <HI. h .. found on • ..,. expLanation. II probably mnn. that"'" do not h ..... . oomplm undtrs .. nding of t~ fundo_ntal prindpte. in· ",Ivtd:

F<ynman. who wo.W on th. atomic botnb and won t~ 1965 Nobrl I'ri.r. for Physia. was "'llWlbly 1M 5fC01 .. 1 physicist of "'" pool""' ...... If you fond the ide .. of qu antum th<Ory • linle diffICult,

yo~ a~ thomor~ in ..... y good .:omp.ny. h i. fa;, .o .. y "'" •• 8O-odd ,.. ... aft ....... birth of qu.an tum theo<y. ph)'>ici .. , .r ... m waiting for .ht rog to lift.., .ha. Ihty can cltarly Itt whal i. ;. ',ying'o •• 11 u. aboot fundam.ntal reality ..... F,)","'an himself .. id: O[ .hink [ <an .. fdy say .h •• nobody undm •• nd< qu.an,u", mtehania.·

Uru,hing Iht .pin my ... ". uOO.r tht carpet. w. come r. ... 11y to

.ht I"'in' of all this-tht implica.ion of w.o...nipping for Fnmioru

.1Kh as .!octr"",. In .... d of.wo htlium nudei, think or ....... Ioc.ro .... each of

which ",Ilid .. w~h another I'Irticl •. Aft ... ,ht ",Ili,ion. ,hey ri<ochot in aim"", 'ht .. "'" dit«tion. Call .ht .Ioc.roru A and H and call 'ht di=.ionol .nd! ( ..... though t"'ya ... Imost t ..... m.di=tion). Exa<dy as in tht cut or I ..... idential nud.i, thor< are tWO iooi<tin_

guiohabl~ """,bili.;... EJ«tron A could 'icocbet in dir«tHm 1 .00 t1«lron H in di=lion 2. or .1«I,on A could rico<htl in di=,;on 2 and d«.ron H in dir«tion 1.

SiDa .J«tron, .r< f .. m;on<. Iht w.o~ cort<'$p<Klwng 10 on. po;<

'ibility will ... f1ippotd btf<>r< it in t..r.~ with tho ~ "", ... pond_ ing 10 tho OIher """,bili'y. O",;oUy. 1Iowovff, .ht walla for tho I"", I"'soibilit;" .r< i<kntic.1, or p .... y idtn';,;.l After all. "'" .r< talking aboot I ..... idenlical p.rticles doing almoo. ;J.nlia.l . hing •. Hu. if you add 1 ..... idtntia.l wa ............... of which has been Oippotd-tht pe.ks of 0'"' will aaclly m.,ch tho .rough< of tho othe,. They will.:om_

plct<1y canul ea<h othtr ooto In o.htr '. 'or .. lo. lht p~lily of two

t1«.ron. ri<o<h •• ing in ",o<tiy ,ho sa"", dir«t;on i. ttm. It i • .:om_

pl"~1y impossible! Thi. raull i. actually far mor< g ..... raJ Ihon i. appea ... It .urns

out th. t t ...... I«.""'. ar< not only furbidd ... from riw<h .. ing in th.t .. m. di=.;on, lhty ar. fOrt>idd.n from doing tho .. m< thing, period. Th i, prohibition. k""",n as 'ht I'. uli .w,..;.," prin.ciple .• ~ ... Austrian phy>i<ist WolfgaI\5l'auli.luro,<>u1 to bt tho ullim'''' ... ..,n for the .. i" ... "" of whil< dwarf •. While it is < ..... inly trut th. , . n . I« .ron anno, bt confiR«l in too ,mall. roIun>< of 'p""" ' his lIill docs not "ploin why on . ht d«t"'ns in a whit. dwarf do not .imply

" c........J '''I!c,h ... in exKtly til< sam. s.m.aU ...,I"m •. Til< Pou]i ""'hai"" prindpl< l"""iJ .. the .......... Two .\t<;l",,,. c.nnOl bt in ,he sa..,. ~"onl"m .l.1It. Ek<Irn ... or. husely an,i>ocial and amid uch olh<r likthcplagu •.

Think of it thi. wiIy.lkau<t of II>< Hri.."bt'll unctrl.inly prin. ciple, 111m: i •• minimum-.iled "bo.· in which an 01«,,,,,, can be sq~ by II>< B"vily of. white .!warf. H""", ..... , bK."", of "'" Pauli ... dusion pri neip,e, each electron demand> • box to iuci f. Th ... t"" <if«'" worl:.in! in conart, give on app.",n,ly Him.y S" of .1« • • ", ... 11< n«<>ury ·"iff ..... • •o mi ... bting -"1=-"'" by a whit. d .... rf'. ;mm .. ". gravity.

"'tully. ,he ... is )' " another .ubli«y hor •. Tho """Ii .",haion prinei,,1t prcvml.< two f.,mioM from oolnS the same thing if they

ar. iJen6cii. lIul 01«1""" have • wo1 of being d iff....", from each OIna t..n ..... <>f th.rir .pin. On • .:an bdt",.. as if it i. !pinning dock· wi .. and one as if i. i. 'pinning ontidockwisc! Ikcaux of this propmy of .I«tro .... IWI> .l«tro<J ..... I"'.mitt..! to <>«upT til< oam< .,.,I~ of '1'0«. n.q. may bt unoorioblt. but .hq are 110' <omplt •• lontrsl Whit. d .... rfs.,.., hardly • ....ry<by obj«1L H~. til< Pauli

..d",i"" prindpk has mud> mo,.., mundane impli<otio",. In p .... ti.:ul3t. it '''plain. why ,hrK .,..,." m.nydiff ...... t types of atom. and ""'y the world . rounoJ us i. til< rompk. onoJ inle,..,"ing pia« it iL

WHY ATOMS AREN'T ALL THESAME

R<all that,jus' as iOIInd ........ confinotd in an organ pipe <on vibra,o in only , .. ,riCiN .... ys. ... ' oo can,,," w ..... ossoci3tN with an 01«· tron confinotd in an .tom. Each dUti n<l .ibration ,orrespondo to.

]><Wible orbit for an electron., • particular dis",n", from tho etn,ral

nuckus . nd wi,h. I"'"kul., .... '!Y. (""""IIy. or cou ..... ,II< orbit u

' PbytlcilU.oII two al"''''tM' spi" "up" ...... pin "down." IkIt that is j"'to.«tmO;ali'y.

" m~"'ly the.....,., proh.ablt piau to find.n <I«lron tinct tI>t ... i. "" .ud> .hing '" a 100 pt=nt ""r\llin poth for on eI«tron or any OIh.or mic",scopic po"id •. )

I'hyski'" ond chemi ... numbo< II>t orbi' >' 'The innermo.' orbil, a1", known .. !he Srnul>.! " •• t, i. nurnbtml I, and orbiu ... ccn

.i><tty ~ JiSUnl from the nucleus .... numbered 2,),4.'00 so "". Til< ""i<t.nc. of til&, quantum nurnbrn. .. tlKy "'" call<d, omph._

li ... )'C1 Ii,in how '''''y1hing in tile microocopic world-.. ... n 'M orbit. of nOClrons--<Of1)CS in woe", ..... ps with 00 poosibHity of int<rm,..n.t. val.,...

WhM....,. an ,""Iron "jump'· from Od. orbit 10 anOlMr orbit do .. , to the notdeus, ,he at""' looes <""'Iy. whidl is gi~ out in ,he fonn of. pl>oton of light. Tbot mttgy of lhe photon is aoctly C<!u.1

10 the differ ... "" in tRC'lllY of two «bit., The opposite process in""two an atom .b",rbin~. pboton with an rnn-V<'qu.IIO.he differ_ en« in en<l1Y of two orbit •. In ,hi. case, an eleclron jump. from one orbit to anod"" orbi, f.rtM from th< nud<U$.

This pK'u", of ,he ".miooion· and - .b$orption· of hght arb .... why pholo ... of ooly .p«ial .... rgics---<om:.pondi'" to 'pecial rrtquo:n<>.. .~ sp.t out and ,wallow.J by ""'" kind of at"",. n.. sp«iol ."rrgin Ort simply ,ht tlltt5Y dilf..,.,,,,,,, I>rtwttn lht d«,ron ",bits, 11 is boco ..... th.~;,. limito:d numb<cof ptl"m; l1N <><bits 'hat ,h.,.. is 0 .... ' ric' N number ol."-bi,a1"' r1.n<i,i",,, .. •

BU11hings art nol quit< Ihi, <implc. n...lec,,,,,, wa .... ,hat Ort

~rmiUN 10 vib ... " i",id •• n .'Om C&n lit qui" <""'pi .. ' h .... • dimens.,nallhinp. Th.y may colTCSpood.o on .1CClron ,11.11 i, nol only mOOlliUly '0 b< found 01 0 certain di"onct from lht nud .... but """"liuly '0 1>< found in """.di"",io", .... th ... than Qlh.,-s. F",

inlla"",. on .1«,,,,,, 04.,. mig.hl 1>< big ... ovtr "'" north ond SQulh polts ol the .1Om than in Qlhtr di...:1iono. An dec."", in ouch .n orbil would mos, ~uly 1>< found""", Iht nor1h ond .\Qulh polts.

Describing 0 di..."ion in Ih .... ·dimon,;onal 'pO« '"'luim 1_ numbtrs. Think of a t.rrtslrial Aiobt ........ 0 1 •• ilud. and IongiluJ • • rt rt<luirtd Similarly. in ..wi,i"" .0 lht nun""',. spa:ifyin! its di,·

t. net!Tom til< nud ....... n ritctron .... ""...00.. htight ch. ngtS with dil'<'<tiQn '"'lui"", two"",~ qu.amum numbero 10 describe it. 1Mi, maw a total of thl'tt. In '<eognitiQn of til< foct thot cltc.ron orbits Oft towly unlil<c more familior ",bi_f", i". ... n«, tilt orbiu of pionrts around tht Sun-they a~ &ivtn a .j>«ial name orbi .....

Tht pr«ilt .hapt of ritctron otbit. l. turns out 10 be a\lcially imp<>rl.im in .!<Iennining howiliffer<n, .t""" .. ick togrthtr to m.u moltcul ...... ch as .... t .. and carbon dioxide. Htrt, til< k<r el«lrons .r< tht out ... moIIt ones. For i"'tal>ct, an OIl t ... tltctron from Ont at"", migh' be sh. rt<! with anothtr a",m.crwt iJll;' CMmkal bond. WOOt tuctly til< OIIt .. moot tltctron is .ltarly pl.,.. an important mit. Jr. f", n . mplc, it has its higb<>t probability of being found ."""" til< at""'·' north.nd south polts.. tht at"", will moIIt "asily bond with . t"",. to its north or lOuth.

Tht ><iroce th.t co""",,, .. ibtlf with aU .he myriad ""0)'0 in which .tom. c.n join togetll<r i. chemi .. ry. "lOm •• ~ til< ul1i""tc Lego bridt.o. !ly combining them in diitt .. nt 101.,... it is po$$iblt 10 m." • roo'" '" • gold har or • hm. n beiJll;. !lut ....:tIy how tht Ltgo brid" combint 10 c ... 1t til< btwildtring varitty of objtct. wt ..... in tht world .round u, i • .It\trmincd by qu.antum theory.

or COUIY. an ob.iouo '''lui",,,,..,,t for til< "",<Inlet of. ia'J" numbtr of oornbina.io", of Lego brick> is ,ha, ther< be more than ont kind of brick. Na,u", in foct uses 92 Lt8" bric ... They rnI3" from hy,jrognl, til< light . .. na,urally oc<urring atom, to uranium, the heavi .. t. Sut why ... the", SO ""ny diffioll'nt .tonW Why art they no' aU til< .. me. Onet again, it .U com .. down to quantum tlltory.

WilY "mMSARENOT "U TIl E SAME

F.Itct""" tnlpped in th. "ltctric fore. firid of a nud ...... '" ~u foot· halls trapped in a .t«p valley. Sy right. they should Nn rapidJyd""",· hill to ,he 10wt<I "","ible pIoa-thc inntrmoot orbital Sut if this

........ hat tht tltctrons i n a'oms really d j,J, . 11 at"",. WO\I ld be roughly

,II< .. m. siu. Men ...nowly, .ina ,II< ou,ormO>l okc, rons .1",.,minc !.ow .n a'om bond •.• 11 .tom. would bond in ouoly 111<...,..

"'-t. Notu .. would ha", only" ... kind <If lAc!\<> brick ' 0 ploy .... ith and

111< world would be • "'If.luD ploc. ind«<!. Wha, "'"""to tho ""rld from bti"l!' dull plact i< ,II< Pauli tridu_

s.ion p,inciplo. If eloetron. were oo.ono, i, i. cenainly t= thaI an

. ,0m·, <lec""'" would all pi!< on top <If <a<h "tl><, in ,h. in....,.m",,'

orbilalllu, .Ioe""", a .. nOl be",n .. Th.y a .. f.'mio ..... And formions .bOO, bti"l! crowded '08<111<,.

Thi. i. how i, worQ. [)jffe'~t kin.u <If a tom. haY< diffe'~t numbers or .Iee""", (aI .... ,.. 0( ""' .... haLanced by.n cq..al number of proton. in Il><i' nudei). For instance, lhe ligh,... "om, hydrog ... , has on< dec."", and the h.,..i ... ""'",,,Uyoccurrin5 ot"m. un nium. has 92. In Ihi. di","""';on lho nuel ..... i. 001 impoft..nt Foe", inSleooJ

on tho .Iectron .. Imagillt sta,'in, with. h)'lrog<n "om .nd thon adding .ke,,,,,,,, Ollt at • lim •.

The fint ... il.bleorbi. i< tho innenn"'" on,. neo,'" ,h. n"'I ..... As eke,,,,",, .ro .d.JNl, they will firs ' go into thit Orbil. When it is full

and con .. k.< no mort elee.","". ,hey "'ill pile in.o .1>< ... x' ,,,,iLablt ort>it, f,nher ..... y from tl>< nudow. Once .ha. orbit i. fulL .hey will fill .1>< nttl moIIl di.tanl 001<. And '" on.

AU ,he orbital. at a panicuLa' distance from lho nuclt\lS-lha1 i.,

wi,h difF .... n' dir«1ion.il quan,um numbtro-a .... said 10 malt up. sheD.11I< maximum numbt, of eke,,,,",, IhOl can occupy lbt inllt'

m"" .hell,urn."u' t" bt ............... d«1",n wi,h dockwise .pin and

Ollt wi.h an.idockwi ... pin. A hydrogen atom h .. on •• lec'ron in 'hi< sbtIl anJ an olOm ofbolium, the na. biM'1I ",om, h .. t_

The nex' biM'" OIom is li1hium. It has th_ electron .. Sina 'h ..... i. no mort room in the innorm",,' ,hell •• 11< .hi,d elec,ron .ta,,,

• IItW .hell f.nMr oul from 11>< nucleus. 111< capacity <If ,hi. ",-IIi.

eight Fo, otom ..... ith mOrt .han 10 .ke"""" """n .hi •• hen i. all

usN up, and an<>lMr begins '0 fin up)'<1 far1Mr from ,he nudeu .. Tbo !':Iuli udu.ion principl •. by forbidding more than two <1«_

,rons from boing in lho .. "'" omi,.I-Ih •• i .. (rom ""ving ,he .. "",

" ~U'"IUm ""mb<.. is III< ",uon thai atoms .'" diff~rtnl from taCh ".her. It i, also respon>ibldor ,he rigiJilyof mott,r. " 1t ;"hof.., ,ha,

.lKlrons connot #1". lop of tach ow, 1!tIi maW t.hI .. and tv

erylhi"8 .... ..,lid; soid Ilicltlnl F<ynrn,m. 5i"". 1M m.rultt in .. tuch an at"", bttt...s-iu very idtntity_

d~noJ, on ilS oultr elC'Cl"'''', .!Oms with . imilar numbers of 01«lrono in tIKi, oul<m"'" ,1><1" '.00 [0 11<1> ••• in a ,;mil., '"f. Lilhium, with ,I> ...... 1«lron., has ...... ,loCUM in iu <Klier sheD. So 100 does oodium. with 11 _"""rons. Lithium and t<J<Jium Ih<refen bonJ with oimilar kinds fir •• ""," and h.~ oimil., p"'!'<ni ...

So much for r..-mio"", .... hich ... sub;«l to lht P.u~ ";cell"j",, prino;iplc_ What about booon.t I*I~ sin« .... ch por,;.:Its:m nOl g<1'l-n-n«l hy III< cuelu,;o" r<iocipl<.!My ar' f'O'i ,i""ly JR'Slrio .... And this ~.rio ......... leads to • />oM of rem.,bbl. phenom .... , from I....,. to .1«lrieol Curr<nU 'hal nnw fo~r to liquid. tlul now uphill

W HY BOSONS un TO BE TOGEll-IER W ITH THEIR MATES

SoY'WI) boooo pu,id", "y in,<> a small rq;.,n of ' 1""<' On. hits on obllruction in i" ~th and ricochtu; tl>tother hi" a.\t'COnd oollruc'ion and ricochtts. It doesn', .... n ... whot ,he obolruCling bodi .. ore; thty .... y I>< nudri or anything .I"". The irnrort.nt tlti"3 her~ is tht direction in which they ri<ochtt. "'hid! i. 11>< .. rn. for bolh.

Call the ""rticies A and II. ond call the dir«tio ... they ricochrt in 1 ond 2 ( ... ·en ifthty or. OI"",lIlhe " lM direction!). Th.,.. or.'wo poooibilitin. One i. thot port~ A .nds up in dit"<"CIion I and porticlo II ... d, up in dirK';o" 2. Thr othrr it ,Iu, A ends up in di=,ion 2 and II in direction I.lkcoust A and II or. rchizoph .. nic d.ni ..... of ,he mic",,,"I'ic world. thr,.. i, a ...... '" _"'>pOnding '0 A going in direction I and to II in dirKIion 2. And tht .... abo a ........ corr<· .ponding to A going in direclion 2 and to II in dit"<"CIion I.

If tht two booo .... ,.. dilfrr ... , porlid .. tht,.. COn he nO intnf ... •

enor between ll>em. So tl>e probability thO!. d.tC"C!or piciu up tl>e

•

''''' ricoch<ling pan icles i,simply til< kJUI'" of tI>t !!tight of th, r.n' w_ pi ... the squa", of 11 .. height of the 0«<>00 _,.., sin~ the prob.hi~ty of .n)'lhi", h'ppmi"3 in lhe microocopi< __ 1<1 i. olw.ys tht S<jUlct oft ... height <>f.b.t wave associ.,.,J with il. Weu, i1 turns 00\

ud thi< will ha", to he I.k<n <>n lru.<I-Ihallh< h"" prob.hiJiti .. art roughly'M sanlO. 50 lhe ovenll p..oo.bilily simply i •• wict .he prob.bi~tr or urn .....,nl happ<'nillfl ino.iivid..ally.

~r the wave.~. hci8ht of 1 for both P""""". This would mt.n that If,h<y ""'" toqUlrtd ond odd«l to gOl tht prol>mility for both ~. it "",,1.1 be (l • 1) .. (l • I) • 2. Now. probabiliry.,c

I cornspon<h to 100 p<''''''''',''' a probability of 2 is clndy ,;JicuIouslllu, hear with ,hi .. I. is >lill p<>SSible ,<> mak. compar;"'n of probabiJ~ic<, wltidl is wh.tt •• U this is leading.

Now. say 110. two"""'", ar. i,Jm,ki1 pallicle .. In ,hi,~, lhe ,_ rossihiJiti..-A Boing in direct;"" I and II in dirtttion 2. and A

going in dir«.ion 2 and II in direction 1_1'< indi,'inguishable. And 1>«:0"", .h<), &r< inJistinguishabl •• 1M ~ a$OOCiat«l with th<m <an inlerf .... with .""h ot~. n..ir combinal hrigt" i$ I + 1. n.. prohobilily fur both prt""'t' .. i$thtrdo,. (1 + I) . (1 + 1) _ 4.

Thi. i$ twi<e OS big OS whon tho booo ... w= nol itl""ti<al. In othor word .. if lwo bo", ... ,to i<knlia~ Ihoy art IWiu OS lik<1y 10 ricochot in tl>o san .. dir«lion OS if ,hoy wo,.. diff.,.nt. 0. to PUt it ,n<llh.,. "'"y .• boson i. twi< ••• lihly to ri<och<1 in , par1~u.br di· rtClion if . no,hor booon ricodt." in ,ha, dirt-ction too.

The "",,. 1>000 ... thou .... , ... mar •• ignifiant , ... <ff«l. If n

boson. are pre .. n" ,1>0 probability ,ha, 0,," ~ particl. will ri<o,hoi in ,ho .. mtdi"""ion i ... + I ,imt. biuer ,han if noo,her booono .,.. prt><nt. Tolk .bou, herd bohrnorl n.. mo,. prn<nce of ",her boson. doing oomrthing gtoa,ly inertoseo ,ho probobili,y 'hat ono

mOrt will do ,1>0 sam. thing. Thi> grogoriouon ... tur ... oul,o h~ impOTlOn, puc,ical'ppli.

, .. ions-for in.IO"'., in ,1>0 propaga,ion ofliglll.

LAS ERS AND LIQUIDS THAT RUN UPHILL

All tho pr<><n>es.., for """.;.lore.! h;tv~ in..,M:<! panicles coIlidill3 Ind ricochrting in I plrticulatdirMion. Hul Ih .. i> not n&<nlial. ",. "'l!umtnb -..r couW apply "IualIy wdl 10 wonl;"" 01 plrlido« for instanu, lho "crealion" of photons by Iloms lhol ~mil lighl.

Phelons Ir< 00.0"" '" tho probability thaI In Itorn win troit I phelon in a plnicular direclion wilh I pmicular ~lIO'l!y i, increased by a £octor of n + I if ther~.,.. alIudy n photons flying in that direc· lion wi,h Ihl l ""orgy. ~ ".w pholon ~mined inc' ..... lho chlnu oIan<>th<r phelon ~ng ~mil1ed. Onc~'~,,~ ""'u .. ndo. ~ miU;"" .. Hyin! through sp ... logtihtr, tht probabili, y or ~ plioton. ~ng .mined i, ""ormou.sly ~nh.nce.!.

",. const<j~nces ... drama,ic. wr.. .... a normal ligh, >our« Ii.., tht Sun produc ... dJ.otic mi.lu .. of phelon< of all diff~ ... nl

morgies, a 1 ... , gm .... ' .. . n un""ppabl~ ,iok 01 pho,,,,,, 1"-', ... ... through $p'" in perf.." Ioch'op. r-.... ~r ..... far from tht only con""'l"""''" 01 ,he g .. gariou."... of bosonL Take liquid he· lium. whidJ i. cornpoo.o;l of atom . that ... 00.0 ....

Holi.m· •• lhe """nd moll common .'orn in tht UniYo"s.<. i> 0". oI""tu .. '. most peo>lior ",bot""""".' It was<ho only d~mont '0 h ..... twn discovtt<d on tht Sun hef<n il was di""""reJ on Earth •• nd il h .. lho ""-,, boilill3 poinl 01 any liquid. _269 Jtgren c<!<ius. In foct, il i. the only li<;uid th .. ". ..... freezes 10 bocomt. ootid, at 1 .. 11 no' at normal """"phair p ...... ur~. All th.ut thinss. howtv..-, pal~ into inoig.nif~nc~ ~ ,ho bdI •• iot 01 htlium below about -271 J<!!r.." c<loius. l!dow 'hi> "lambda I"'int: i, bocom .. a su~uid.

U ... aUy, • liquid "';11 •• ny .11tmpl 10 """'" ont port .. llli .... to .not~. For instanu, tr~d~ mist. whon ,.,.. .. ir it with. _ and

' li<l.ium-4 b .. four ""rtid •• in i .. nud .......... "" P"""'" and two ""u_ trona. " has .Iturommon rooWn, l>t~um·J, which .... ,,, ... """ nwn""" of rrotOIlO bu, Oil< f<wtr "",'ron.

• WaItt .. .;.,. whtn )'O<Il'y to swim through il . Physici,lS call ,hi. ,.. i ... "", viS«>li'y. It is ",.uy j~ liquid frktion. !lUI "'hem ........ used ,n frielion both."",n ..,Iid. movin~ rtl.UM to each OIba-for in.co""" , ... friClion bttw«n. co.'" tim.nd tho ..,..,J- wt Ort not runili" ,.ith II>< friction t><tW«JI poru or ' liquid rn .... ;n5 ",I.,~ to .ad! Othtr. T .. acl<, boca .... it ... iSlS Mro"lly, is .. id '0 have. high yt.msity. <>< .imply to I>t v..-y viM:ou. ..

Clearly •• ;""""ily con manifest ;'stlf only when on. parI of • liquid rn ...... .!i!f<Rndy from 111< rat. III 1M microscopic 1evel of 1I0mo. ,h .. """ns that i. rna .. 1>< I"""'ible '" kn<>d som<liquid .u,"" in.., SI"ts In.! an diff<r<n' from too.. occupiN by Oln., li<Juid atonu.

In a liGuiJ at nQr"",] """p<'I"o'Urt, ,''' .to"'" a n bo in many "", .. iblt .t., .. in .ach ol wtudlthty jigglt about ., difftttn[ . p«<l •.

!lUI as the l<rn~ralu" falls. they boron .. more and n>O/'C sluggi,h on.! fcw., and fcwtt . .......... <>p<n to lh<rn.lJnpit< ,hi. "ff •• :!, how· ""'t, not all a1om. will be in the .. n .. ,'ale, ev<n a, til< lowe .. 10"'~ra'u .....

lIut things . .. JilT ... ", for. liquid ai 00..,,,,, . uch " liquid .... lium. ~"",mbtr. if 11 .. ", art alrtady ~ 000.0n. in a porticuLar .cac •. 1'" p",bobili.y ai . noth ... o ... entering til< .tat. i. w + I bigg ... liu.n if lh ........... no otllt, portid ... in c ... se.t •. And for Iiqui<! "'~um. with countl ... "'Iium .tom .. w i •• "''1 I.rge numb..- ir><l«d. Coo~ q""ndy. t ...... «>mn. Ii"... ... liquid "'~um i, cooled to suffici ... ltly low lempo:rotures. when.1I t'" "'Iium .,.,m,.uoJdenly try to Cf"O"oO'J into tilt so"... se .... I,', ClIlIed , ... 1Io .. · EinSkin condensation.

With . 11 1'" II<lium atom, in til< .. em se.t •• it is imposoible-or .1 ka5I ."t .. "",lydifficult-forono part ait1l< liquid to """'" ditkr· en'ly from anotll<r pan. If 00"... atom. "'" movill3 .long .• 11 til< .t· oms h ... to m""" along tos<lhtr. Co""'lunttly. tho liquid iI<Iium ""' no vi..".ily wh.t..,.....,.. 11 ""' becoem •• upo:rfluid.

In supnfluid li<Juid iI<Iium Ih"'" is a kind ai rigidily 10 til< me>Ii"" aitho atom .. It i . ... ry hard to "",lot til< liquid do .nything be· caw< you .ithCT ha "" to #I 011 of its atonU 10 do 111< thing lognhtr or

.. ther-imply do nOl do tI>t thing . ,.11. Fori .... ".., if you put .... '.rin • bud., and >p;n ,he bU<kt about ito His, ,he _,.,. will en.! up

.pinning with lht bucktt. This i. 1>« • ...., ,he bucktt drop .round the w;t~r .,,,,,,.-riclly ~aking.l'" ..... It, """""I ....... h .. a .. in dirrcl """laC, with the <iJn.and I~ in turn Jr&jj around the atom. (' Miler from the ,ides, and so on, until I,," mIl,. body of water is lumin~ with ,1'1< oockt. Ck.rly. for lht wat.r to g<1 to th< ..... in which it i. 'pinning along w~h the buckel, iliff ..... t parI< of the liquid mull rnOV< rd.,i""oeach other. BUI .. juO! poinIN OU1, this is .... ry Iunl for a .upcrAuKl. All the . tom, ~ ",,<Iller or 'herd<> nOl rn"" a, .n. Con>«junllly. if suJ><rOuid liquid ht~um i. put in a bucktt and ,II< bU<kt i , .pun, it Ius no moa ... open to it to attain the .pin of 1M b..ck.<t. lrutead, 1M suptrlluid htlium .tays .IIubbornly

SliU while ,he buck., .pi .... 11>< roapt'rativt mOli"" of atoms in sup<'f8uid liquid h<~um

Ind. 10 evm"IOR bizarre pM""n ...... For I ..... "" •. ,he .upcrAuid .an now through imp<>Uihly small hoi"" ,hal no ",n.,. liquid an /low through. It i, _Is<> tM only bq~;.j thot a n now uphiU.

In' .... 'i"'ly, holium .... _ ra ... , ligltlwrigh' co .... in. fI.lium-l turns ou, to b¢ a nor mal, boring r;'l~iJ. n.. ... ...,n i. that h.ri~m_J

par'id •• ar< form ion •. And .uporiluidi'y i< • proporty ",1.ly of ....,. "', ..... Uy. 'hi< i.n', tnlirdy Ir ••. Tho mi.:n>WIpi.: """Id i. f.U of

'.'Pri.i", phmomona. And in a 'p«i. 1 <u<, formi"'" can bdl . ... li ... booon<l

ELECTRIC CURRENTS THAT RUN FOREVER

Th. sp«ial cas<, ...... n fffmion. bdu .. IiI:< booon .. i. thaI of an .1«tri.: cur...,t in • m.taL Ik<:ou .. th.c OUtermoo, .learons of mcul . tM" arc "''Y 100 .. 11 bound. they can Jrn,ak fr<'t. If. ",1la5' i. th.cn . pplied bc1wecn tho .ndo of the nI ... 1 by • battery, all the countless

libtratN .l«!rons .... ill .urgo thro",h th. m. tmal a. an .Itcl ric <"",,n{.'

fJtcltOd. or<, of C<>II. .... fn-mions. which mt. ns Ihty or< .nlOOdollmogin • • Iodd..-. with tbt rungs oorr<.ponJin! to ~ high...''''''M .Ial.~ Eltclrons _ uld fiU up II>< rungs two 01 a Ii"", from Ih' bou"", (bo!<Ins would happily aowd on III< lowell rungs). Th< .....J for. I<po"'l< rung for <Kh pair of .ltclroll. m.ons thaI tht ,ltclrons in • mtlal ha", for mort morgy on ...... go than mighl bt ....... Iy txp«IN.

lIuI "''''''thin! .... lIy -,rtl happ"'" whon .. mttal i. """ltd to

<loot 10 aboolut. "'-0. II>< IC>IO'eSI poosibk Innp<nlur<. U .... Uy •• ach Oltclron l .... veI. through the mtt.ol.ntirdy inJependenlly ofall other .ltclronS. H".. ...... as lhe I.mp .... tur. fllls. lhe mrtal.loms vib"'t • .... r mort .Iugi,hly. Ahhoogh they art thouoond. of timn mort mas.sivt than dtctrons. II>< aUrac!ivt .ltclriaol fore. bet....,n an <ltc_

Iron .nd a mel al alom is .nough 10 tug the atom towartl it as th. <ltclron pO$$« by.' Th< tug..! atom. in tum. '''l!s On ,,,,,the,..I«_ 'ron. In this .... y. an< oltctron ." .. <t, """ther through tht inl<"""_ diary of III< motol .tom.

Thi, eiftc' r3<liaolly changes II>< natu,.. of the c",,..nl flowing 'hrough III< mtlalln'tead ofbting composed of ,i",l.d<CIrons. il is compooeo.l of p. irtd-up oltctron. k""WJI as Cooper poin. lIut the ,ltclrons in tach Coop..- p.ir .pin in an <>Prosil' mann..- anJ aneel oul. Con""'!umlly. Cooper poirs .... boooo.1

'Why thM oo..n',. m<taI foIl.pon! n..fuU .... "'nation r<qoi .... quan·

I"", Ih<oty. B".ltlnplisli<d~ .... O1ri]>?<d. or "","o<Iio .. e!«1ron. form .

O<J!"ivdy ct..'jO:d ,!mod I'<'""",;nl til. m<taI. h i!. tho .nn><'tion bet....,.. thi!. cIoud.nJ .... pooitivcly <ha'jO:d d<ctron-ttrippcd "",tal iom til .. ~_

tho m<taI """til .. . 'Stri<dy sptoItinf.. .... at""" .... rooi';'" ion .. the no .... li .. n to_ ...

llIat h ... loot d«tro<t~

•

A Cooptt poir i,. p<'CUliar thing. Tht ri«1ron •• !>at mm i. up may no' oven bod" .. to .odt <>,Iw:r in.hot me .. 1. n.... ,,,,,1<1 .... i!y bt 'ho ..... n<l. of othtr .Itc' roru btt"""n on. mnnbtr of • Coop<r po;,.nJ il> I"'''n ... This is ju ... curio ... J . .. il, ho~ .... Tht key thinA i"hat Cooper pair1 art 0010 ..... And a. tI>t u1tnolow ItnlJ><T" lure o{ Ihe supm:oodu<tor . n ,h. bosoos c",..,.,j into the same .Ia~. Thty ,h.rdO .. bd>a ... as • • ingk. inni<libl. tnli,y. Onc. ~ "'" flowing en m .... , i. i. <I,,..,,,.ly difficult.o Slop 1I><m.

In I nonn.1 m<"lilan eltel,leal cu"~nl i. ",si'IN by oonme,"I, impurity a tom •• wh;,;h 11'" in ,II< way of .Ioamn .. obo'ruc' ;ng ,hoi. pro~ through 'h, mttaI. But whtrt .. an impurity alom can .... ily hinJ.r on d«1ron in. nonml metal, i, is .... rly impo .. ible for ;110 hind .. a Coopn- ",ir in I suptTCOndw:tor. nu. is b«au .. nch Coo· peT pair is in ]oc""op with billio.,. upon biUioo. of o,he", An impurity .tom COn nO Il'H>K 1lI....-' this O_ll>.n a single soIdi..- an .\lop Ihe advara of an .... my .rmy. 0"", ourIN. lhe cur .. nt in I ,up¢!"" coodu<tor win flow ("Inn.

PART Two

BIG THINGS

1

THE DEATH OF SPACE AND TIME

How,", _110 nw uurr IS IIII.U • • 101 TlU Ulmllll

~ ",.aD 1IIO TIM'" wou: 1II \II1fIl", WIllS

"'",", ...... " "rs wirh .. pm'T~rl /0< _ h.>ur. it ...... Iit., .. m'"ul<.

But /r, hi". ,i' ..... !ooc ....... fo< .. mu,w,.-;,' ""xn 'lwn .... ",,"t.

1Mt'.m..tm/y! AI""', Ein",in

", ,II<: most /,<""/;,,, 100 ""'''' .n~ Ita. "'" "~IL As ,h~ >prin, ... ~ owt of ,II,i, ,tort;ns Nod" o"J gt/ jnlO ,lin, ItrW, ;1 IN"" I" ,Itt "......,"" in dJ~gmnd"aM 1M' ,II<' ",n"", gt/ , ..... ,/im","_ /110"1 '" .n., d.JJh ,.,,, tlw </w,ing cr-.J. ,lit, .."".,." ... p,.. '" """",,,,,-u,., ,"",; not tilt ",,,,,, {>«U'i .. , .hing-"", by a '''''8 fhot. T1It arms

ornl I~ of ,n, .lhJeleu~ ,.,"'pi"8 in wl/NSI"", """""', ... if Ihty"~ .un"jlll "or 1iI"",!h ai, bu, 'hroug/r ",oIou..,. Jtlrmd,. tIw ="" H btgi"";ng 10 sI.>w-"",w·dap. Sc_ "",pl. arr ~ ripping up I~' lid· ' I! ami a ng,il, ' ..... ng lit.", i",,, .Itt air. At 'his {XItMr ic N" of ptr>JTrn.

il o>ulJ 10k ,,,, holt/" for'M <prin'''' 10 rt4<h ""finishing 'apt. Vis",or.,! otul Jisappoin,td, ,Itt 'fW1a'"" 1<' "I' from .heir ...... aM. ~ by _. '''';1''' "'" of lilt' ,,4J,",",

Thi' scm. O«m' !oc.lly .i.liculouo.llul. oct •• Uy. it is wrong in ....,.,. ,wly only on. dnoil-th<.pc«! ofth. sprint .... If th<ycou.ld nm 10 miUion tim .. fast." thi' i. <naly what evtr)'O"" would 11ft. When obi""" fly p ... at u.l' ..... igh op«d .• p~ $hrink$ whil. tim. $lo~

"

• down.' It'. an i ..... il.bl. con"",!"",,,,, of 0 ... lhi"l-lh< imposoibi!ity or"", catching up with • ~ghl btam.

Nai>t!y, )OIl mighllllink thaI II>< only lhin81t..l is not catch-upablo .. something , ...... ling.1 infinil •• p«d.lnfinily. after aU, i, de

finN .. th. tqg." numbtr im1!lin.ble. Whatt....,. nurnbtr you think of, infini!)' i. biU .... So jf llm'o were ",mething that cook! lr ... l inflni,dy fa.!. it i. cit., you muld n.,..". gel .b",ast or il. It would Iq'", •

.. nllhe "himale cmmic sp«d limit. I1£ht 1",,,,1. lr<mcndowly fas,-.lOO)XlO kilom. ' .... per "",,1><1

in ...,pry sp>o«---O<I1 thi, i, far ,hon of infinite .peN. Nev.nhd~ •• you can novtr caleh up with. ~ght bam. "" matlor bow fas, you , ....... lln our univero<, rQ'~'" nobody <;Qmpk1.1y undt .. und., Ih,.pttd of light plays lh. mle of ;nfUlil' .p<'t'Il. It rep' .... n\< II>< ultimate cosmic spwJ limit.

The /i", p.non In ,<'<ognize this rtculi.r raCt wi< AIM,! Ei",,~in. IltpulNIy at tbe ago of only 16, he askN hi"""lf. What would. IInm "flip" look lik., if you <ouId cuch up wilh it!

Ei,"'tln could .... "",h • qu .. t;"" and ~ to an$W<T it I>llIy Mea .... I>f a discov<ry mad< by II>< Sconi.h phyoicisl "'mes Ckrl: Max ..... lI. In 18611, Maxwdl ,umma,i..,! oJl knI)Wn ~1«1,ical.nd m~n<tic l'I><oomcna----from tht """""ion I>f oltctri.: motl>" II> tho beho";",.,( ma8M~th • h ... ,J(ul .,( d~nt mathematical equa,ions. Tho unar«1tJ oonuo.,( Maxwtll', """"lion. was lhot thty p~t<d tl>< aim'll'" .,(. hitl>trlO unsusp«t<d W"", . ...... .,( d«'ricity and magn<ti<rn,

MaxwtU', ...... , which prop. galN Ihroll8h 'pO« like. rippit 'pr .. di", on a pond, had • ...,.Y '!riling fa,""" It t""dtJ 01 JOO,OOO

'Stricdy 'l""kin~ <ado run".,. will a"" '1'I'<1f'O "''''',10 tho..,..,... "'" wi!l.n..,..,. of tl>< fat aid, of taeh of thom--<h< aid< faci"' .... y from ,I>< tvand ... nd, whim woold .."mally I>< hidd<n. This p«Ulisr ,fftc, .. _ .. ..m,;o;'''' .,,,,;,,,,,or ,.!o,;.is,","""m;"~ 1-.." ,;' ;, ~nd

tl><><op<ofthisbook.

TI" I>I.A TIl OF"""",,,,, U T"" •

kilom~trS ptr oocond-'he same as ,he ,p«d ofligh, in emp' y ,pKt".

II "'as ,oo much of a win.citk""". ~~II gu..,.J--w,~dy-'''''' ,he ~e of d«' rici, y and rna!" .. ;"" was nollt other ' .... n a .... ..., of light. Nobody, apar, ptrhaps from ,he .1«lric.1 pion~, Mic ..... 1 faraday. had ,I>< .!Ii8h'rSt inkli", ' .... 'Iight was connt<ttd with .1«. Irici,y . nd mogn<'ism. Bu"hou i, ..... , ""illen indelibly in M ... ""U·, «Juo,;"ns: Lig,' was an d«"omagn"ic watt.

Magn .. ism is an invi.ibl< force fldd 'hat ~aches ou, in,o ,he ,~« .urrounding a magn ... The magne' ic field of ..... r magn .. , for ins"n« •• 11<2<" " .. ,by me .. 1 obj«" ,uch as ~p<,dip .. Nat"'" aho bcwu an d«"ic f .. ld. an i""i.!lbl< fore< f .. Id w, cc,onds in,o tho 'P"'" arou nd. body' .... ' i, el«:lricallycharge.l. The el«:,ric field of. pw, ic comb rubbeJ "8'i1l<' a nylon ....,.'..-.foT ins"""".can pick up ,n .. U oc"P' of paper.

LiJII' . orcordin! '0 Max_W, equ.tion •• i, a w ... rippling 'hrough ,hese i""ioible w",ellekb, much I~ ..... '" rippling 'hrough ...... ,. In ,I>< <a.« of ....... r .... "'. tho 'hing , .... , <hang .. as ,I>< .... '" p ..... by i, ,I>< I<vtl of , l>< wa .. r. which goes up and down. up .nd d_n. In ,I>< <a.« of ligh'. i, is ,he "~ng'h of,he magnetic and el«:· Ir ic for« fi,1do. wh ich grow .nd d~. g...,.. and die. (Aouolly, "". fidd gr""",..-hil< ,I><OIh..-di<s,.nd via >ttSa. bu"hat', not import.n, h ..... )

Why go in 10 """ gory dotait abo"1 wha, an d«lromap''' ic .... '" is! TI>< an ..... ' i. b«.u«, i, io ncas.sary in orde, '0 underStanJ Ein .. ,in·, quest;"n, Wha, would a ligh' bum look likt if)'Ol.l coulJ ca,ch upwi,h i,!

~Y)'Ol.l O~ driving a car on a highway and)'Ol.l ca,ch up wi,h onolhn" car , .... ling at 100 kilo ....... rS per hour. What dots 'he o,her ca' look like as you come .b",as' of il? Obv;" .... Iy. il appearS .",i",,· ary. If)'Ol.l ",ind d""", l"ur ",ind_. you may ...... be obI< '0 ,hou"o 'he othe' d,iver abo", ,he noi .. of ,he .ngine. In """<1ly ,he .. me .... y. if you coulJ ca,ch up ",i,h .ligh, hn.m. i, ough',o appear ....

'io"",y, like . .. ,irS of ripples fro .. n "" • pond. Howevtt-ancl 'hio i'tl>< key ,hi", no,ic*<! by ,h. 16-l"' .. -oIJ

Ein",in-Ma~II·. equali"", h.", something import.n, '0 say

•

.bout • frozm ~I""romagnttic .... "', ont in whkh lht d«lric and ~< r .. 1Js ... ,w" grow.". ~ but """"in "",,","less I'orever. No

such tho'ng <:Xi<t,! A stationary tkctr<JtnaUldic wavt i. an imJ'O'llibility. Ein •• ein, with hi, pre<ocio\l$ '1un1ion, had put hi, finger on.

par.oJox. Or inron.iSltncy, in !he laws of phy>ics. If )U" ""'''' able ,<> c.,ch up wilh a beam ollight, )'Ou would _. slJliOfW")' .Ioct"' ..... g· n<tic .... "", which i, ; rnpoo$Oihk. Sin« _illl! impauible things ;.., _n. impoosibk,)<>\I cln ntVer calch up with aligh' beaml In other "",nI •• • he thins lh., i. unca,ch.bI....-l,," .hing thl! plays tbe ",Ie ofinf.nil< .~ in our Uni,..~;'light.

FOUNDATION SlONES OF RElATIVllY

The u""atch. bility of light can be PUt . nod ... ,,. ~. Imagine 'lUll the ro.mie or«<! ~mit rnUy i. infinity (though. ol _ou ... , w< now kn_ it ;",,',). And .. y for inll.n«, I mi .. ile i. fired from I fight ... plone ,h.t GIn fly at infini .. . p«<l. I> the ope«! of II>< m;";l. ,.!_u.. to $Om""". '!.mding on th< ground infinity pi"" th< .p<'Nl of thr plontl If it i., the mi<siI.· .. p<tJ ",Io,iv.'o.1>< ground is gmt •• than infu>ity. Hut ,hi, is imp,,..ible .i""" infinity is tho biU~ numbor imagin_ able. Th. "nIy 'hins W, malts ......... is Wllht.ptt"Il oflht mi ... ilt i • • ,ill infinitely fOSl . In OI"'r wnnIs, its.ptt"Il 0.1".....,1 <kptnd on 1'"

.ptt"Il of ilO SOUIT<'-lht >ptt..J "r lht figh'er plan •• I, fOUOWSlh .. in 1'" ~.I Universe, where , ... roItofinfinilt.ptt"Il

i. ploy..! by lh •• p«d of ~ght.'h< .p«d of ~ght dots nOO <kpmd On , ... mOlion of i'''0111"« <il"'r. h·uht umt-.lOO,ooo kilomtt.rs per !t"COI>d---ru> mill .. ""'" fa" 1'" ligh' SOIII"« is ' ...... ling.

Tt.. opood of ~gh", lock al .ltptnd.",. on ,t.. mOlion al ito SOIIret is on. al ,h.,wo pillars on "'hi"" Eins .. in. in his "mirxulou. ,.. . .... of 1905, prouoled 10 build. "_ .nd """,Iu'ion"ry piclU,," al .~ and time-hi. "'pocial- tI>tory "f rrl'livi' Y. Tht " ,h .. "rotequally impo"an,-is 1'" principl. al ~1.'ivi1y.

In ,t.. 17th «n.ury tht &n" ltali.n physicist Galilt<> n"';c.J ,ha. , ... Ia .... of phy>ia .... unaffc.cled by ~I"i", "",.100. In o,htr wonl.,

TII.I>I.ATII OF'PACI! ,,",U T .... " 'heyappnr ,ht ....... , no IN'I<, ""'" fas, )'0" a .. moving rd .. i ... '0 ..,..,..,"" tM. Think r,( ... nding in. f",kl .nd , h"""'ing ~ b.U to.

friftld 10 ..... ' ....... ay. Now imagint you a .. on. moving ,rain in"taJ . nd Ihrowin! Iht 1>0.11 to )'O"r fritnJ, who i .... ..Jing 10 mt1t ..

along tt.< ai<lt. Tht hall in bo,h .,....Ioop< btt.....,n )'0" On • oimilor tra;.c,OI"Y. tn "'her wonlJ, the pa,h ,ht ball follows ' akes "" accounl r,( II>< fact thaI you a .. in a fid.l 01" on • Irain ba""'ing along at. gy llO tilomtt .... per hou,.

In fact, if Ih. window. of tht train a .. blacktd OU" and tht Ir.in ha. , w;h brillianl ,,,,pen,i.,n llul ;1 i, vibr.,i.,n r .... )'0"

... ill bt unabl.,o .. !! from ,h. """ion oflh. ball--<>r any ott.<r obj«, in,id. tht , rain, for Iha, m ... tr-wbtlbtr or nol tht , r.in i. "",ving. For ... ..,n. nobody know •. thtla .... of physics act the

.. m. no mOll .. whalsp«<l )'0" ... " .... ling, .. Iong.s ,hat sp«d «main. ""n"ont.

Whtn Galik<> maJt thu obotrval;"n, ,h. t .... ht h.d in mind ...... II>< Ia ... r,( mOlion thaI g<>wm sum thing:< " II>< Ir.;.clory of ,.nrH)nba.U. flying Ihrough It.< .ir. Eln ... in·, • ...a.:ious loop was 10

.... nd It.< id.a to aU I .... r,( physia. ind"ding tho b ... r,( Oplia 'hat g.,.,..,.n tho bth.,.;.,. r,( lighl. AI;ronling to hi, principl. r,( rtlativity. aU I .... apptar lhe ....... foo- 0 .......... """,ing with "" .... ,"",.pttd .. b,;"'lo tach "' ...... tn. blacktd-out train,in othtr words.)'O" could ""I ttll tvtn from tho .... y light ..... rrlll"Cttd bad and foo-th whtthtr 01" nol,ht train was moving.

lIy ""nlbining tho principk r,( .. lalivity with It.< fact llul tho .pttd of ligh' iot,," ....... irreop«'i ... r,( 'he mo,;"n of ito .. "ret, i, i. p<Wibit '0 deduct .""thor .. lNrk:lble proper'y oflighl. Say )'0\1 ...

Irroding lowanl • -",,,n,, of lighl at high ~. AI whal .pttd d.,.. 'ht ligh, rome ,owanl you? WtlL .. membtr 'htK i. 00 .. peri men, )'0" OIn do to JoI.rmi"" wbt1h.tr il is)'O\l or tht lighl-",ul"« llutu moving (reaU tho blacktd·o,,' train). So an tquUy valid point of v;.w i. '" usu ..... that you ... n .. io""'!' and tht ligh, "'''r« u mov' in, toward you. lIut 1l'nI<I"IIh.tr. tho.ruJ of light Jon not dtptnJ on the.pttd of ito ooolU.I, .'ways kava tht 0001"« at prccioc!y)oo'OOO

kilom<l~rs pt"r s«ond. 5i"", you.", ".1Iion.ary. llIor~to",. III< lighl mu.st .rr;'" .. prt<:i.dy 300,000 IUlo~ pt"r """"d

Gon«q~tncly. 001 only;' III< Spt"t"<l of ~ghl ind<pt"ndnll of Ih~ moti"" of iu _re<, it i .. 1"" ind<pt"ndtnt of t .... m",ion of .nyone

oMn-Yinglh. ~ght. In oth<T word .. tvn}"O .... in III< Uni.,..,,.... 00 mat· 1<, how f .. , they.", moving, olwoys ...... ur .. ",,"cd ylll< sam. Spt"t"<l of ligln_ .lOO.OOO kilorn<ttn pt"r s«ond.

What Ein~in SOt oul 10 .nswer in hi"p«ial theory of ",latiYity wos how. in practic., ...... yo .... can ~nd up ntcuuring pm:i .. ly t .... sam • • ~ fl>r light. It turns out tho", ;. ""ly 0 .... W2f' If "pO« .nd

Ii".. .'" lotolly diff ... tnl from whal ......,ryon. think> thcy " "'.

SH RIN KING SP-,CE. STRETCHYTIME

why do . pK< .nd Ii .... 00"'" inlO things! Wd!. tht .p<td of .nylhinsligllt incluJod--i. til< distanc~ in 'PO«' bOOy ,,,,,,,I. in a g;"'" int<Tvol of lim<. lI.u!tn ..... rommonIy u...t to ",.aw .. JiSWlC< &n<! dodu 10 m<a$Ur< ti",.. ~u..,tly, tho qU<"Slion low an .... f}'<KlC', no

man ... wha, thoir ... 10 of moIi"". mcasu", til< sa",. sp<td of light!-

con be put • ...,. ..... way. Wlw must happ<n tl> '>'Of)'Qn<' ru!tn . nd dodu SO th" . ... h<n thty m<a.<ur< t .... Ji<I."", ~g.ht t"""ls in "g;"'n Ii .... , they .IW;I~ got a sp<td of enctly )00,000 kilornolOrs pt"r """"""1

Tlli .. in a nUl<hdl. i. >p«i>l rdotiv;ly-o "r«ipt"" f<>r ,.11" must happt"n to .poc< &n<! tint • .., lhat .veryone in til< Universe ogree. on

tho op<"<d "flight.

Think of a opa«Ship firing .1 ..... bnm at a pit«of opoet dobri. Ihat h.ppt"IU to b< Hying IowaN it at 0.15 timn th~.p<"<d oflighl. Tho I ..... beam cann", hit tbe debris a t 1.75 tim .. tbe .p«tau .. lhat i. impo<.Siblo; it must hit il at .xacl ly tho sp<ed of

light. Tho ""lywaylhi. con happen io if_<Jbservin! t .... ....",,.

and COIim>ting t .... distara tt.tl tht arriving Iighl tn>ds in a ~ lim<

oil ..... und..-.stimal .. tho rliSlaI>CC <>r o=im", .. t .... ' i",.. In fact. as Einst~in JiM:ov<rn.I. th<-y do both. To OOO1ton. W;llCh·

ing I .... spaceship from outside, moving rukrs .hrink and moving

TI" I>I.A TIl OF"""",.,., U TI>I. •

clocks 101_ down. S~"ron'l'Kts· and ,i"", ".lila' .. ; and ,lI<y <XlII

'rael anJ .lila .. in <:Daly ,II< mann ... no=>aryfo< m..p«<l ofligh' 10 comt oul as JOO,OOO kilomtttn per KCOnd for ~,.,.,e in lht Uni ........ h'.lik some hug. cosmic oon'l'i,ocy. Th¢ oon .... n' thing in OUr Univ .... isn', '1'''''' or Iht Ilow of Ii .... but tll<.pttJ of ~8ht. And .... ')'llling ,be in til< Uni ....... has no choicc bu'k> odj .... t itself to main .. in ~gIJ. in its p""rninrnt pooition.

Space .nd tim. an: boIh relati ... Lrnglhs and ,im. in' ... vak be· com. oignificontly .... ,pt'Il . , sp«do .pplmChing ,h •• pttJ of light. On. person', inttrval of Sl'oce i. not the NJl1' as anom., pt""n"> inlt",.1 0( 'p""'. One ptrSOn'. inltrval of tim. i. not the NJl1t as .no,he, person'. interval of ti"",_

Timt. i, turns QU'. runo 01 Jiffn-tnl ra'" fo, Jiffttmt obot"",... J~nding on bow r ... , Ih.,. are moving "''''~ 10 tacit ",her. And 'ht Ji!oCrtpancy btt ....... lht ,icki"ll 0( m.ir docks g<tl gr"'<r lht .p«<li ... ,II< molion. Th¢ faster)'O\l go, ,II< >lower )'0\1 ""I' It'. a truth that has but! hiJJ.n from \U for IDD$' O(human hi<tory for lht .impl. "".oon that th< >lowing Jown of tim. i> "pp"rrnt only at

.p«ds applmChing tha, of l;gIn. and tll<.pt-td oflight is so tnorm"", ,h .. the Co.",ortl., by compori..,n, m .. at ..... il·. ~ """'" the sky. If m..pted 0( ligIJl hod irultod bttn oruy .m kilomt'ns ptr hou" it woulJ "," h . ... 1-01"," a g.nius like fins,';n 10 JiSCO"o't, t .... ,ruth. T .... tfftcl.or spr.:ill rdativi,y .uch os 'imt J~"iOll and Imgtll COfttraction ,""uld bt glaringly obvious to III< . ..... gt 5·)'«\,-01.1.

M. wi,h tim •. '" wi.h 'p""'. Th. <patill W;1aJ\ct btI-.n any two

boJia i,difft, ... , fo'diff ...... , obot",ers, Jtpnttling on bow f ... ,1Ity .re moving rel .. i ... to tach od .. ,. And m. dioc.-.pan.,. be'-.n ,lI<i' rulero go" greater the r .... , ,he motion."Th¢ r ... ter )'0\1 go, m. IIim·

'To be ............. .,......,. _ ........... ,; .... ...". down for. movi,. _ ...... by . fa<tory. ><II ... T _ INO "(>",1») and .aOO <0'-' th •• p«ol 01

the ...... ;",; _ ...... . 00 the .p«d of 1;"111 ..... p«'iw!y. AI ....... doo< 10 <.

T b«omn """'''''00, and .ime fo, • nl()Yi"" otm ..... , $lows ""'Of< 10 a ... nd.m!

•

m .... )'011 o,.;.aid Einstoin.' On« again. thi' would bt ... If-... idmt if ... Ii"'" <>ur live!. , ...... Iing do>< '" ,ho.p«d of ~gl". !lut livingu ..... do in natu,.", slow I .... , wt annot ..., It.. trulh----ihal sp .... and ,ime ar. shiJ1ing sond, lho un ... rying.p«J ofligh1'''' bco1rock on wh;"h th.t Un; .. "" i. huilt.

(If you think relativity i. hard, take hoan from th. wonl. of Einstrin:"''''' h.rdno thing in tht world to unJor<l.nd is ,nco"", lU'" 1800"', however, the """'" of Israel'. first president, Chaim Wri, .... nn, who, aft.r a" ,. ""Y"S< wilh the g,..l .a.n1i.l in 1921. 5OK!: "Eins',,;" aplain"" his th<-<>ry to "'" <Very .J.y anJ. "" my ..... rMI.I ..... fullycoov;naJ thaI ht undentood i1!")

Can .nylhing ' ...... 1 12m, than li8ht~ 1*11, nothing con cotdl up wilh. bum of Kght. Jjut the pruoibilily ni<ls th.1 lhtrt art 'sul>

a1omic"particl •• d"u Ii .. their live. permanently ' .... veling r .. lCr th.n I~ht. Ph~;ru" caU .ueh hypolhrtical p.Mid .. to<hyot! •. If ta<hyoru exiOl, ~rhap. in 1,," far futuro ..... an find • way 10 <hangelM a!O ms of our bodi .. in.o ,..,hyons and thm b..ck agailL 11><. we 100 ro..J.l ,~l f&>lor ,han ligh,.

On< of ,11< problem. loIi,h ,achyons, howe..,r. is ,ha, from ,11< poi n' of.~ of ""n.in m"';ng ~. body ' ... ..ting f ..... ,h.n ligh, """IJ 'ppt>r ,o bt ' ... ..,~nS bock in ' imtl 'J'h.ttt is. limtrick ,ha, goes lik ,his.:

II 1O<hl tJ<pIom namtd "~igh',

On« """"Inl mud! fa".,. ,loan lil'It. H. Itl 0"' "",.toy. in ~ ,./'>1 ....... ,. IIrrd .. 'w, .... J "" IMp .... ;" ... nig/lll

Anonym"",

'To .,. p«<;..., .totionary _ ...... NO> tho I"",h of. """'i"$ body .hrink by . _, ........ , . INI I _ (" ,<"') ond •• nd «d ofth.

mcw;"g ".,..,. .. " and tho.p«"<l of I"'~ t«p«tiwly. AI. . p«m .... 1\." .. . 1"'''''''"' ill tht: ditf(t"" of n, motion!

TII.I>I.ATII OFSI'ACI! ,,",U T .... •

Tilnt ,ra .. 1 scorn 'M living doylighu 001 of physicm b«ou .. il raiS<> 'M I"'soibilily of po~ ... nlS thaI bJ to logi<o1 ",,",,0'

di<,ioru likt you !Oi", bock in ,;Int and k.illing)OUr vandf01I1«, If

)'Ou kiUe.! your snoof .. .,.,. before'" cooceivtJ )'Our ",.,..,.,.. got>

,h. ''Jurntn'. how could l"u h..., bttn born '0 50 back in ,irn. 10

kill )'Our grandf., ... !"! Some physicUu. howe ..... lhink ,II;" ",me as· Y"1.undi""",,,~ low of physio ;n'...., ..... 10 puvrn' any porad""i.

,"I'hinp from h.p~ning •• nd '" ,ilnt lra .. 1 may be possible.

TIlE MEANI NG OF RELl.TIVITY

aUI whal does rd.,iYi". rn •• n in . nuu·.nd·bolt, ..., .. 1 WeU. JOy i,

.... re possible fo< you 10 'ra .. l,o the ntaml .Ur and bad .. 99.S

ptr«n. of .... op«d ofliSh!. Sin~ Alpha Con •• uri i, aboo, V ligh,. Y"'rS from Eanh. tho"" left on Earth will .... l"u .... urn .fI ... bou' 9

Y" ..... ... urning • brief >101"'= 10 .... 'he sighu. From roor poin, of ~. howe .. r.,'" J .... "". 10 A1ph. Contauri wiU M shrunk by 10 Ii..,.. h« ..... of ",1"iYi'y. Consc<:!lKnl!y. thr round.' rip will ,akt only n;n<'-Itn,h. of • Y".r. or .boII, 11 monW. Say )'Ou deported on )OUr journey on )'Our IWtn'y·firS' binhday. w:ovtJ off from' Ito """". por' by l"ur idrn.ial ,win brot/t.tt. W1t.tn)OU arrilled bKk 00 ..... now 01",.,., 22 Y""rS old. your twin would be )01'

...... lWIy. lit... " • klbtl< flaw;" th "lIla"""," s;"", """ ion io l Ihio ' '' wpoin' I<ad> to the oppooil< oonda,ion th"" bd .... : ttwot tim< ""'" ro. row ,win 1<1 .. , .. to 1"'0. amly. tim< cannot.on oIowIybl.ach of 1"'0. with .... p«. 1<> 011< ot""'. Th. r<OOIu,;"n of thio twin 1".000<. IS ~ io

"'-n." to .... it< tho. J<I'" .~ip ""~Iy .... 10 >lowdown and ....... iu motion" AlrIo. Cent""ri. 1Ica ... of mi, dc«kration. tit<..." poi" .. of ,if" 10IU .~ip """';,,~ or Eorth """"~'" not .. ally «I.ivaI ...

.... "' ....... "" .. bk.

•

H"", """"ld )'O~ ... ry-. t·homt twin makt .. n .. or this .'al. of .ffai .. ! Wdl hot would .. ,urn. ,n., you ~ b«n living in oIow mo

l;"" lhrou~l )OIl' journey. And, our< rnou~h. if;1 wtr<: som,how "" .. ibl. for him to oo..rve)'OU i",iJo your spoeeship. he would ... you moviIl5" if through ,ruck wi,h all \be shipboard clock< crowl_ ing around 10 tim ... 1oW<'!" than n""mal. Your twin will eo<r«Ily _,

tribut •• h;' to II>< I;n>< dilation of rrta.iv;,y. lIut.o you all tl>< dock<

and ...... yllling elK on board will .~.r to be moving" p<rfccdy normal sp«d This i. ,11< INgic of rd.tivity.

Of «>u~, .ho """ ..... piJly)'Ou 'U'o'OitJ to Alpha O:n .. uri .nd Nck., 1M IV"., ... II< Ji<cropancy bt.1<o'ttIl )'Our agt and )'Our l";n" •. Tnvd f .. '....,ugh 000 far ..,,,,,gh ;w;..., .. tho UniverK an.! you will " turn to find thai yow- twin is 1""5 dud and buriN. E",n f".t. and you will find th,U Earlh itself has driN up . nd diN. In facl, if you ,rncbl within. whisk. of the'r«<! of ~gl1 .• ;"'" wouJd 5'> 00 slowly fOr )'<>U Iha! )'011 could walch th. tnli ... future history of the Unl_ 0 .... ra<' you lik<. movi. in { ... ·forw. N."TII< p" .. ibiJity of oi';Ii,,!! II>< fUlur< i, quite a.........,< II> an)'<>'l< woo I .. m. abou, i,

fonl>< first 'i"",; says Russi.n physicist Igor Novikov. W. do rH" Y'" ha~ Iht .bilily II> , .. ""I '" ,I>< ....... ' .... r.nd

Nck ., cI_ '0 tl>< .p«<l of ligln (o .. ,.,n 0.01 pnunt of .h. op«<l

of J;gh'). 1" .... 11,.1 ... , 'im. dib.ion i. <k.«13bIo-ju.s.-in.1>< ""oryday world. upttirn ... 10 h.,., boon urri...t ou' in wh;ch oUr<' accura ••• tomic cJocl<s are .ynchroniud . nd .. paro • ...t, 0 ... boi"8 nown around th.t world on an .irplan< whil. the ",her .toys a. horne.

WMn .h. clocb ar .... uni •• d, .h. ap.rim.n,." find .hot the .round·,M·world clock h .. 1"<gi .. ««1 .ho passage of marginally I ... ,i"", .han ito ... y_ot .bom< munt ... parl. n.. .hort ... ti"", m ..... rot! by th.t mOIling <lock is pr«iocly what i. prtdi<:t...t by Einstein.

TI>t .k>wing of .i"", .ffcoct. aotronauto I",," As N<>oikov p<>ints out in his =011 ... , book, n,. Rim- '" Tom!': -Whon .ho crtw of tho S<wiot Solyu. 'p""" .. at;"n l"<Iurntd to Earl h in 19M! of, ... "rbiti"8 for. Y"" at 8 kilomct .... !«tKHl. th.ty sttppotd into.1>< futu .... by 0 ... huno.lrtJlh ofa socond. -

TI" PUn! OF."""' ..... " T"" •

Tht lime dilalion <if"" is mino.sc,,1e bta ... airpla ..... and .~

<",A ,~ .. only. 'iny fra<lion of I~'~ of ligll\. H""",..,., il is far ,,,,alOr fOr oosmi<-ray ml&Oll" . ubaLomie partid .. cr .. ttd Io/hont <osmie ~ ."perinl . tomic n"d"; from 'P"'" .bm in,o air mol, «uJ<s a' the Il>p of Earlh', almOllph .... ,

Tht key Ihing 10 mow . bo", muo ... is lhollhey h. ", ''''8ially ,horl lim; and, on ""''''SO, d;';nI<8r.tlo, "" d""'r .ft" a mt,.. 1.5 miUion,hs of a oecond Sin" ,hey .. ",.k .I""", Ihrough ,he atmo,phe"' .. mott 'han w,n ptfCml of Ih •• p«J of lighl. 'hi' ......... ,ho •• hey ,houlJ.r,ovd ba",1y OS kilo~rs bd'""o .tlf_d ... "'<lin!Thi' i, nOl far at all Io/ilm it is .... Iiud that COiImic-r.ty ml&Oll' are <",a",J "bou, 11.S kil"mel .... up in 'ho . ir. Eosenli. Uy "" .... ,!,.ref""e .• hould ",ach Ih. ground.

C<>nl ... '1 I" an • • ~,.,i"n .. b.ow~. """'1 "'lu.", me ... "f Eanh', surfaLo is .. ruck by scvnal hundrtd cOllmic . ... y mu"'" cvttr oecond. Somehow. lhese liny ~nicle. ma~e to ,,,,,,,1 2S limes far'hoethan thoy Iuw &n)' righ" ... And i, i, all brc ...... of rela,m,y.

Tht ,ime .. ptriencoJ by • o;pto:Jing muon is not tho .. "", u lho lime "p<ri.,,>eo:J by somt<JlIt on Earth', . " rf .... Think of • ml&Oll U

having an in,,,nal "Iarm clock ,Iu, ,tlis il wllm '0 "",,ay. A, 99.n perunl of th •• p«d of ligh" Ih. clock .Iow. down by a fa<lor of .bout 25. al leu. '0 an obse~ on ,be p"und. C<>1lSt<j""n,Iy, """,ie" ay muon< liv< 2S limes I""ger than thoy """Id if .ta,i"", ar)'-lime enough 10 'ravtl an ,be way ,o,he ground bolO", 'heyJi,· inlogr.olo. COOmic .... y muO'" on ,he r;round 0- their ""y ",is'ence to lime dilat ion.

Wha, Joes ,he wotld look like from a ml&Oll', poinl of vi~ Or

<Ome '0 thinkofi'. from ,he poin' of view of 'M """".faring twin or Ih. atomic clock (lown round th. wotldt wtll from ,he point of v;'-'"

of.n "r lilese. time n""" ptrf""ly normally. Ead> •• fter .U, i . .. .. ion · arr with rn~' 10 iUotlf. Take,he muon. It .. iD Jtcry. aftn- 1.5 mil, lion.h. of • ..."nd. From its poin' of view, however, i, is .. anding .. m and it'. Earth', surface th.., i. appn>aching.t 99.92 pnun' of the

,P«J oflighl. It IherefO"' .... 'he .Ii ... "", i, ho, to ... "'l .... rink by.

•

factor of 2S. tnab~ng;, 10 'taCh {II< gro~nJ CYftl in il< ul1rashon lifo,; ......

Tb.t grat CO<Imic ""'<piracy brtWttn ti .... and <poct work< ",hatever wOy)lOU look 0' il.

WHY RElATIVITY HADTQ BE

TIl< btllJ.ior of ~'" and time a' opwJs approaching 'N' oflighl i. in<lffil Ilium. ~r, i. r.wJ not ""'" b«n I .urpri .. 10 .n)<ln<. Abhough "n, """ryJ'yapori<n<. in na'''''''' 01_ lane h .. tugh .... that on. I'<""n', in'.!ViOI oft; ..... i. analht, ptrSOn', inlnvai of ' i ..... and lru" one ptroon'. inleml of '\*< i, a"."her po....,n'. in,.""tl of '~. Our I>t~tf in both of th .... thiJl&S i. in fOCI tw.d on a rtry

rickty ..... mp!ion. Takt , ;111<. You an 'r<M. ~frtim.,rying futild,. to .!<fi"" it.

Einslrin, IIowCYel", raliud ,h;u Ih. only useful definition i • • practi· cal ono. W. ""' .. ,,'" til< po ... ge of time with ..... m.. 000 docb. EilUl';n too.,{"", said:"Time i. whot. dock ..,.. .... rn.. (Somrti ......

it law. smi"s 'o oWe til< obviousl ) If~. i. going II) ....... ur •• I1< ...... im.mol of .ime be-

h .... n h." ...... 1>. ,b;, i. "Iuivo1m, to .. ying lh.t Ihrir dock, run a' lh< ... me ...... lIuI .. ~ ... kn""", Ihi, n ..... quit. h.pp ..... Your

a1ann dod m.y run a ~ttlt slow. )'lur .... t.:h. ~tll< f.". W. ""'r_

com. th ... problem. by. now .nd tllen. 'l"'chrooi.ing th.m. For in' ''n« • ...., uk 110"""1'1< the rir,ht time .nd. wlltn th<y teU ........

COlTect our " .. tch acconJingly. Or .... listen fot" tilt time signal"pi"," on the- HIIC. HUI in .... ing the- pip ...... rna~. hidden ... umptioot. Tilt ... umptioot i, that it to"'" DO tim. at .11 fOr.n., radio annou"",,_ mtnl to ,,,,,,,1 to our raJio. Coo""lunttly. when we hear the ~

announcer soy it i, 6 a.m .• i. i, 6 .. rn.

A <ignal thaI taks DO time at.U Ir"",l. infinilely f.". Tilt two

.tate .... n' ..... enlirdyequi""lenl. Bu' .. .... know. ,lit ... i. nothing in Our Uni,...,.. ,hat can ,,,,,,,,I ... ith infini'e 'r«d On ,lit other hand. ,lit SJIftd of nodio ..... "'. a fOrm ofligh' i""isibl< 10 ,h .... ked.~

TIl . PUn! OF"""",.,.,u T .... •

i"o hg. com~rN to all hum.n dillances .h ...... 00';0, no dd.y in Ih.ir ... ,..1'0 IU from Ib¢ Ir.nsmi" .... Our as.umption ,n.. t'" radio ",,-,n . ra,..l infini.dy fas'. although fal ... i. 00" bad one in lht cir· cum>lonen. lIu. wn.t hop!'<"". if t'" din.no: from .b¢ . .. n.."i".r U wry I..rgt indct-d! Say . ... Innsm~t ... i. on M ....

\\ .... n Ma .. iu. its do .... , t'" ';gn;ol ukes 5 minute. to Ay across .pa«, '0 Earth. If. ,..hrn .... !.tar , ... annOUnC<'( on Maro .. y it i. 11 a.m., w,'" oor dod:; to 11 a.m., .... will he oetting il to ,b¢ wrong lim<. Th. ""y around Ihi. i • .m.iouoly to lake- in.o account lhe 5· minu,. tim< del.,. .nd. ,..1Im ........ r 11 .. m., ... our clod< 10 6:(l5.

Ewrylhing.of """ .... hingnon knowing lhe lim< il takes for lht .ignallo , .. ,..1 from Earth to Mars. In procti«, ,hu can he don. by bouncing a radio .ignal from Earlh off M ... and pick.ing up lht ",. lurn ';gnal. If i . .. ke. 10 minu, .. for tho round-trip, lhon it mlUt ... kr 5 minuln ' o . ravd From . he .]>ICfihip 10 Earth.

Tho lock of an infini'ely nil "",an. of .. nding ';gn.1J u noc, th.~ .• problem in i~f for synduonizing neryooe·s dod ... It ,an "ill bt don. by bou",ing ~gh' signal. back and forth and ... king inlo accounl lht lim< del.,. .. Tho lrouble i. ,n.,,"i. worlu p<tUc.1y only if ~...,.,n. U "a,iowry with r .. pea to ~ryo ..... 10 •. In , .. lity . • wry<> .... in th.t Uniw ... is moving wi.h rnp«llo tvnyon. doe. And the minu .. )'Ou st.rt bouncing lighl .;g,.alo be1ween...,..,... .... who ar' moving. lhe p«uliar """stancy of ,h •• p«<l of lish' "lrts 10

w""k hame ,..ith common sen ... Say th.", u. opac .. hip lravding helween Earlh.nd Ma .. and

II)' il i. """,iog'" wt Ihal, by com~ri ... n, Eonh and Ma .. app<or stalionary. !magi .... tha" as hefo ... ,)'0\1 send a radio .ignolto M ...... whkh boun"", off" ,he plan ... nd whktJ you t"'n pi<k up back on Ean h. The round-.rip lakes 10 minu' ....... as btfu .... )'Ou drd"", th., t'" oignal.~., M.rs .n .. only 5 minu .... On«, "Pin. if )'Ou pkk up a limt signal from M .... saying il u 11 .. m .• )'Ou will .Jedu"," from Ihe ,ime delay that it i ..... 11y 6:(l5.

Now consid .... the .pl«'1llip. AMumt th.t .t t'" i ..... n' )'011 ...... 0.1 )'Our radio .ignal,o M ...... it ..,. 01T at its full .peed 10 M . ..... At wn.t

,. ,i",. Jon an OOs<r"" on tilt .pacnhip ,..., lilt raJio sigJW arri~ ., Ma~

Writ from I"" obot ....... '. point of .itw. MarS i. appro.rnin,. so lhe raJio .ignal h .... hom, dis"'.« 10 lravel. aut lhe .p«<l of the

sign.! i. 11>< .. mt for you .nd far ,h. ""'<n'<, OIl lht spocnhip. Allor all, lllal ~ the ''''''ral p= liarily afliglll-it h .. exactly 1 lit .. me.p«<l for <v<ryOnt.

Speed, .. momhtr, i. simply ,h. di"3noo something '''' ... Is in. gi"," ,inlt. So if !he 00 .. , ..... 00 In. spacnhip ..... tht ,..dio signal 1~1 . ohort.r distal!« and "ill ...... urn ,he .. "'" .p«<!. ,he <>b.. "", mu.' m<"aS","' shorltr 'imt 100. In othtt _rd., lilt obs<rvt, <kJ.w:es that tht raJ;" "sui arrives., ~b .. nriitT than you ded""" il dotS. To ,h. obstrvtT, chd.s on MarS lid mort slc>wly. If tI>r at.. .. "'" pickJ up. tim. ,ignal from Mars, saying il is 6 '.m., lht ob... "'" will OOm,,01 il wing •• hart .. lin>< Jtlay and condudt il is, ~ 6:(1), IIOt the 6:05 )'Ou conclud •.

T ho< """ho. i. thallWO oo..r.-.n wno .r. m",;ng rd.,i ... 10.ath

oW, ~r assign th ... ",. .ime to. distant .... nt. n..ir clocb al_ ways .... n 0' .1m .. "" 'P<'f'ds. "''hal is mort, ,hi. cliff.....,,,, is abo<>lu.tly (u...u.n.ntal_no ."",un! of ingenuity i n oynchroniclu can ."" gtt .round it.

SHADOWS OF SPACE-TIM E

Tilt >lowing of Ii"", &ndlh •• hrinking of .pa~ is 1M pTi~!lu, must

M paid 00 Ih .. tveryont in lilt Univ ..... , "" ma"er wit .. Illti' state of motion. measures Iht ...,.,..peed of light. Bullhio only Iht beginning.

s..y Ihtr. u< IWQ .,. .. and a 'P"",,-.uilecl figure io floaling in lilt blad.neos midw.ly 1><1 ........ thtm. Im.gine lh.1t lilt IWQ Sl." explode and,ho O.,.ling figurt 0«. 'hem d<lo""" .imultaneou,Iy-lWQ b~"ding fLa.hes of lighl on ';lho, .iclt of him. Now picl"'" • '1'''''''ship I ..... ling .. enormous.p«cl along lho Ii"" joining ,ho lwo ,,"rs. Th •• pacnhip p ..... by lilt 'f"~ .• ui'ecl figure just .. Ilt S<rt Ih. two

"ars .,.p~. Whal docs lho pilot of tho .p;>eeship ooc?

TIl. I>I.A TIl OF SI'ACI! .,., U T"" '" w"l~ sinct ,he "'ip i, movins IOWaN """ ,tar and a .... y from "'"

o,her, the lighl from lhe .tar ~ i, app","",,;ng will arri"" b..rore tht lish' from ,he .... r i, is rttt<lin~ from. n,., ,wo uplo"" ... wiD tM.-". fore no( appcar .im~l ... n.,.,usIy. Consc<j""ndy, ..... tht """"""' of ,imw,.n"ity i,. asual,y of tht constancy oftht ,PttJ ofliJht. E"",ts

,ha, 0"" obsc ........ SftS .. 'imuit.nw"'.rt not .imul'a""""" '0 .n· Olher ot.s..r...r movin~ with r<spe<"o II>< firS'.

n,., key Ihing h"rt is 'hat the exploding "arS.rt """.raIN by.n in .. ",.1 of Ip>ct. Events 'hat 0"" pcNOn 0<eS ..,p .... ,N byonly .pact. ano,her ~n..,.,. ""I'",..1ttl by'J"« and li_nJ vk" "" .... E""nts """ pn'SOn..,.. "'plra'N only by 'i ..... anoth .. PC""" 0<eS

"""ara'N by ,i"", and ,p>ct. n,., r<iuof ""'')'>'''' m" .... ring ,he same.pt<"ct apl""'rS 10 )'011 .. lim" anJ torn. of ' heir' i .... appcars '0 )'011 ... pact. On. pn'SOn', ;nl«val of spl'" is I noth .. 1"'"",,', ;nttrvai of 'p>ct and tim •. A...! on< ptrton', inl..,..] oflim< i. I notl><r pcNOn .. inltr· .,a] of ,im. and sp>ct. n,., foc, ,ha, >pact .nd ,im< .rt in'trcha"8'" .bl. in Ihi . ..... y ttU. '" torn.,hing remarkabk anJ uncxp«:teJ .bou, .pact Ind ,i ..... M.tnJ.m<ntally. thty art sam. !hing-or at 10 .. , dif·

f......" >id .. oflhe .. "'" coin. n,., p<'rS(In who firSt sow !his--mort dnrly...,n thIn Eins,ein

him..,lf-wa, Einstein'. form .. malhemalics profnsor Hermann Minkowski •• man famoU1 klr <ailing hi. !l.u<i<n' • "lazy oog" who would "" ..... amoun,'0 .nything. (To hi. <I<mll credil, he Iller I .. hi. WO<ds.) "From now "": saiJ Minkowski, -'pact of i,..,1f Ind ,irot of itsdf will sink inlO m ..... hadow. I ...! ""Iy a kind of uni"" be' ...... n 'hem .. ill ,uNi ..... "

Minkowski ""ri".ned Ihi, p«:uliar union of .pac. and ,irot • ,~, i mt: I" uisttnct """Id bt bI.otandy Ohvi<>U1 ' O u. if wt lim! our lives Ira .... linS at clo .. '0 ,he spt<" .p>ct Ind ,i"", fl«l>.

,. Iu Minkows\:.i put it. spKt and Ii ..... a,.. lik< shadows of SPKt

,i"",. Think of. stkk .... ~ded &om .hoe ""i~ng of. room 00 ,h., it can spin around ilS middlt and point in any dir«tion ~kt • "''''I'''' n~". A brighlliglu =1<. "-low of the "kk on on~ .... 11 whil •• «<CInd brighllight ""I<. ,h><l_ of \be obj«! "" an ..Jjoc<nt wIll. W. could. if we wonted, call the oiu of the Jlid;', sNJowon 011< wall il< "Itnsth · .nd !hoe . j ... of its "-low "" th.t ".na wall its .. iJoh. What then happ<1l' as lhe lIick owing. around!

CI ... rly,lhe .j .. ofth. shloo... "" .ad! Willi chlnges. N III< ltnglh V'> ..".IIeT, tt.. wiJth V'> biU .... and vk ......... In {""t. tho length .p~"" to dwlge in10 lht wideh and til< width into d .. Itngth----jus, as if'hor . r< ~u of lhe .. "", thing.

Of COY,,",. thty .'" asp«1< of lh. same thing. Tbt Ltngth and width .r< n'" f"...urn •• u.1 0' all n..y . ruimply ""ifac,. of 'he cli· r«tion from wh;rn we ct.ooo.. 1<> ONa ... the stick. Th< funJ.,,,ntnw thing is the .tick iuelf, which .... can ... simply by ignoring the .hod· OW$ on th< .... 11 and walking up to it It til.mrntal at oil but aro or,ifoe," of our viow

point--ip«:if""Uy. how rOl' ~.'" t",>'ding. !lu, though 'M fund>._ menw,hing i •• ~t-,jm •• this is app.rrn, only {rom a vitwpoin, ,,,,~ling do ... 10 lM'~ oflighl. wIlich of COy", is why i, i. not obvio ... ,o a ny of u' in Our doily Ii,....

Of cou .... 1M Slid-and·.hodow analogy. li~ all an.logi ... i. helpful only up '0 a point. Whcr ... "" lrogth &lid widlh oftM Slick .ro mtirdy "'luivalrot, 'hi' is not qui,. true of ,1'I< ~ aoJ 'he ,ime foe." of 'paa,' ime. Though )'011 can mOV<" in any di",.,ion )'011 like in 'l'aa, .. ~". know>)'OII can ""Iy mOV<" in ...... d;""'Kln in tim •.

The foet thaI .~t-'ime i • .I01id r .. ~tr .nJ .poet aoJ time the mere sho<Iows .... i .... ",,,.,,,1 point. Uke shi pw.-..;keJ mari ...... cli ng_ ing to rocks in • wild .... ' 0 makt ....... <>f ,1'1< world ~ stUch <In-Verattly for 'hings ,h ... ro unch anging. v.~ iJcnlify thing. like Ji"anc< &lid tim •• nJ m ... . Hut Ia'.r. w. Jismvtr ,n.l,h. things .... iden, ifiN .. unchanging'''' unchanging only from our limitN view_

TIl. PUn! OF"""", ,,",U T .... ,.

point Wh.., ... ",id.., ou' p .... p<e.i"" on .11< ""rid ... di.lCOY<'f .h •• o,her 'hingo ... n ....... "''f><C.«l ... tho i""'rian. "'ing •. So il is wi,h '1'"'" and .imt. Whtn ... 0« ,II< world from a hig.h-.pttd vatI\a5t poin" ...... nei. her sp"'" 1>01" .im. bu. til< ... mbo ..,.i,y of 'po«,i"....

1\t:, ... lly, wt .hould 10", ago have gunoeoJ ,ha. 'I'"'" .nd ,ime or. inn"iably .."win& Think of ..... Moon. Who, i. i. IiI« now," Ihi. i",un'! The ."'...,. is ,ho, "'" can ".",r know. All "'" can t""r know is what i, ", .. IiI« 1'1, seconds ago, whkh i. III< limt il uw lig.h, from'M Moon.o Ay aero .. , .... 400.000 lcilom . ..... '0 Earth. N<>w Ihini. 0( .11< Son. Wt anno' know what il i. lilt tith<r, only what i, was like S'I, minu ... ago_ And for the .... r ........ y ... m. Alpha Qnuuri, i. i. "",n _ ..... 1\It ho"".o mal« Jo wilh apietu",

Ihat by 111< 'im. wt 0« i, is . lready 4.1Y"' " ou, 0( date. T .... poinl i. lha •• ollhoug.h """ think of.1It Uni ..... wt ...,

Ihroogh our telescopes .. ai"i", now, ,hi. is a mistaken view. We

can n<vn know whal the Uni ...... i. IiI« a' this in .. an •. The f:orth<r ><1'0$$ op.a we look. , .... farther ba<:k in I;me _ .... If _Io<>k far

enough aero .. '1'""'''' can OC1"ally..., do .. II> th< Hig ~ il .. lf. U.7 billion )'0'" ba<:kin 'im •. Sp"", and 'im. a .. inatricably bound logtlhtr. The Uni ...... wt ... "oul thttt" is not a thing thaI altnd.

in 'I'"'" bu •• thin! that nttnds in sp><~l ime.

The "'a<on ... ha"" btttIl>oodwinktd inlo Ihinki", 0( .pact and lime .... 1" ..... 'hing. i. ,h01ligll 1.1«. so link ,im. to I ... vel hu"""n dis .. ncn tha,,.., raf<1y notiu , .... &lay. Whtn you Of< lalicing wilh someo .... , you..., Ih.m a. ,h'1' ... r<. bmlon.h 0(. second earli ... 8ullhi. inltrval is unl>Oliccablo btatw< i. is .0 million ,im .. obort .. ,han any ....,nt ,hal can .... ptr«'i".,d by , .... human b ... in. It i. ""

wonder lhal w, h ... co"... 10 btlit"" ,ha' tvtrylhi", ... ptr«'i"" .round US ""i", now. 8u' "now" is a r""i,lous """"'''1'1, which ""com .. obviow .. .IOOfI .. ,.., COnltmplalt III< widtr ulli ....... ....tIcK di".ncn ... so g ... t ,ho. il 'akes tig.h. billio.,. 0( Y"a ... o span Ih.m.

The 'pact_ti"... of the Uni ...... can .... though, 0( .. a _I ""p.

All ."""s-from ,II< er .. ,i"" 0(111< Univ..-.. in ,II< 8il1 Banglo your

,.

birth., • p."icul .. 'i ..... and rlaaon Earl~'" laid oul on it, ~ach with it, ~niq~ sp"".,..'ime Ioca,x,n. The map pion,.. is OPF",!,ri ••• btca ..... ,ime, as ,be Hip sid< of .r .... can be .houpl of as an additional .p. tio! Jim.".ion. But lbt mop pictu ... po6<$ ' probl"",. If tv<rythinJ i. Laid ou.t_ pKOrd.intJ ilrno"-I~ i. no morn for the cone"!,,, of past, pr ... m, and futu ........ Ei ... ,.;n .. nlark<d: "For u, phl"ici .... th< di,tinct;"n buww. p .... p.-nl •• nd fulu .. is ,,,,Iy an '[lIuian."

11 i • • pr<1'y comptUing ilIusion •• I>o"8h. _bel ..... th. foct .. main. thlt ,he <»""",1> of past, prnont,anJ futnr< dQ "'" fip"' .. 011 in .pteia! rd"ivi'Y. "n< of Out moll fundamnu.a1 dncriplions of reality. Natu .. . ppn .. nollO nott! 'hom. Why .... do i. 0 ... of ,be 5''''' unsolvtJ mysttrits.

/i .. MC' ANDALL mAT

Til< 'p«iil throry nr rdativi. y JO<'$ more.han profoundly <hanS" our idruof.~ and Ii",., I. <hanll'" our iJ .... bou' • host of orh<r .hingo 100. 111< r<a50n is 'hIt .II,h< lwic quant;,ia of physics.rt fountloJ on .pa« and time. If, .. rd.,ivity t.n ..... . J"« anJ ,i",. ' r< mallnblt. blurring on. into lht olhn- as Iht.pttd of lighl i. a,,"""",htd. lhtn so 100 a .. lht .,.ht, ~ntiti __ momtnlum ond entrgy •• ltclric fidd. and rnognttic fi.1d<. Lilt .pK<' and tim •. which m~rgc inlO lht KOmi ... m..Jium of 'Pac.-limt.ther 100 ... inextricably ti...! togetht, in the inl""" of ke<ping tht.r«J of light constant.

Tal« .ltctricily and magneti.m , 11 turns out that, ju.t .. on~

~...,n', '1'''''' it a"",hn- ptrSOO"'ime. ""~ ",,,,.,n', magnetk field i, on.,.h .. ptrtOn", d«,ric (",Id, EItc,ric and m.gn<1ic (",Ids . .. crucial 10 bolh g ...... to .. , hol m;tk oI«I,kal cum:n" and mot"", thol ,u,n . I«"k cu, .. nt, into motion.. "TIlt: routing armat""'" of nny gcntrOtor.nd ~ mot<>r in lhi, ageof el«1ricily aTe Oleodily prodaiming the t"'th of tht .. lativity thtory to all ",ho ho", <0 .. 10 htor: wrote the phy>iciOl '-"igh ~ag~ in lht t!l4lls. Ilecause .... Ii", in. oIow-

TI" PUn! OF"""", ""U T .... ,.

mocion 1<o'CJrId. "'" art hood"';nl:.<d inlo boli ..... ing Ih.al Oltclrk ond magD<1i< r..lJs h.a,.. "'P'<OI' ",i""""",. lIu, j ... , like 0r_ and ,i"",. Ihty Or' ....... ly dillfftnl focn cl Iht ....... coin. In ... lily Ihtr<, i. only ... mlns ""'ily: ,''' .. tctro .... gD<1k r..k1.

Two olh .. qu.aHlilits that I~rn oul 10 be dillfftnl focn of tht .. nI. coin ... O""'8y.nd '""'"""I urn .' And in Ihi. unlikely con""", ,ion is hidJrn ptTh.ap. thr 11""'«1 .urpriStcl Ma,ivi'y-,h" m .... ;. • form of ""<I1Y. Tho disco.....,. is .nupsul .. ..t in , ... mool f.mo .... • nd 1=1 understood. formula in .U cl "'"'net: E "mt .

'n.r n»m<nlwn "'. body is. ",...,.re ofhow much <Ifon .. l«luiml to IIOp iI. For "'"..,. • • n O~ "oUr ...... tho.~ i, moy bt """""sonly. f<w kiIom<It, .. n "".r. i. for konltr 10 OIop than • Formula' to« <1'1'"'"''' 200 kilo",",,,,,,,,.... hoor. W. "l"1K oiI,iIIlkr .... more momtn1um.

AND THE

WEI6HT OF SUNSHINE

How .. _ ... nw_ ........ " u.· ... os l llWlll me IIIII1!SUC"', _'._11

PIo ...... '""" .......?!II dian', <WI' l_ rIo<r ...... c.,I>o/>:-. --II'. 'M biuc<, ... , of "",~_ <t:aJ~ ;""'linabl .. A..J. <>II.,... i., /war mUt~ .. , r_ II. '" big in fi>ct ,1Ia, irc~ .. ~;gIt ~ "'holt SI~'. Ano! ''''''r ;,', owighi"l 'M """",, ".IF of dU, 0." Sun. Th~Jjgi,aI display h,,, j ... , ct>mt ~ rut QnJ ir'. "'giJltrirtg 2 " J(j' '0 .... ThaI'. 1 foI1owtJ b, 17 u~.(){)() ",ill'm mill., .. mill;"" mill..., '(JIt~ /lUI w.oi. a minu,.,

""",,"ing" wn>ng. Tht Kalt ... ,. ,u.f'<"'<'«ll"'''' n...,. ~"",/wr ,,,,,,,,tdlt .hing abo1<' th""', i" ...s.Jirion I" ,I:.:i. , iu and 10M, ,....-,.'Q"",) /lu, ~wrr _d, .. hen 'M display is ~htd. i, mJd. ~ miUion ",n, Ins ,,,,,,, if dUJ ,he pln'NJId ...... noL 111M,,, going (}fI! s..rrI, 1M Sun ",,',

.... 11, gelling liglt'~, lhe ,...;ght of Q gooJ·siuJ . "pma .. ~ ,i"gI, <ni>nJ!

Ah,""1 it is! Tht Sun is lMing h .. HntIJY, radiating it ;n,o.poet .. • unligbL And ... orgy ;w;,....Jly .... it'" "' ..... hin!.' So tho m".. , un_

'1,m .. jng d", .."d "";!do' hrf< ,Ix way it ;,. uxd in <~q lifo ..

• ynonymo ... with ........ Slri<IIy~ ~I i. «I ........ '" "'" ro"", of v ... ;'y·

~ . ... AN U TII< " 'E>GI IT <Y !iUNstlINl ,. lishttho Sun gi .... QUI. til< light .. it g ..... Mind you.th. Sun i. big .nd .... '"' ollly \lllking .bou, illooingaboul. 1Q·",il/ioft·",il/;"n·",il/;"nlh of. pnant of ilO nw.s por Il<<00.1. Th.af. hardly more than 0.1 por«nl of iI. m . ... in« ilS binh.

",. fa.1 Ih.1 .ntTJy doro indud wri&h OOI'J'ItIhing can bt ...,., vividlyfrom til< btlt.aviorof. com<l. ",. tail of. oomet .Iways poinlS _.,. from It.. Sun jU1l lik<. winJ_k poin .. ~ from tho g.ilhtr.

illl! Slorm: WII.u do III< two haY< in common! Jl.oIh arr boing pwMd by • l"""'"rful wind. In tho.,... of 11>< winJood, if •• wind of air; in

tt...,... of lht~o~ toil .• wind oflisht >Imming "",ward from tho

Sun. ",. windsock is bring hit by . ir mol..:ul .. in thrir ooun,lo .. oril·

liom. It i. this .. 1..,1l ... bombardment th.t i. pu.hing til< fabric .nJ

c.using it to biUowoutward. Tho story is p""'y mudltll< sam< out in J<q> "P'''''. ",. oom<t t.il is bting ball<ml by countl ... tiny por·

tkln of light. It is the m.chi""""8un bombardm<nt of the .. plloto", that is cow.i ng the &lowing cometary g.Ue110 billow:KroSS 'en' of miUiom of kilom ... " of empty .patc.'

1M tho .. is.n important diff ...... '" bet"""" III< windsock bting "ruck by . ir mol..:ul ... nJlht oom<t'"ail bting hit by plloto .... ",. .ir mol..:uln.r< solid , .. i .... of malin-. TI><y thud into the m ... riol of til< windsock lik< tiny buU .... and Ihis is why the windsock """,il ..

But plloto ....... oot so~J mattn-o TI><y .<tually h .... no m .... How

then can they be It.avilll! a .imil .. eff«:l 10 air mol..:ules. which do!

' A <Otnt1 is •• "'" intn-plo"<U'l' • .-b.>!L Bilt., .. of ""'" bod ...... b<li<w-J to ott.i, in th. ~ rr.... beyond the oul,""""" p ......... Oa .. ion· oily. on< is nudvwin~ tail of po.

' '''',uaUy. ""' .. ~ ofa """"t is p_ by. comb"'tion of the I .... from "'" Sun .nd "'" solor wind. "'" million · m~ ... n· hour h", ricane of sub-.tootUc I""~" moody hyd"""," nud ........... .. m"" "'" from the Sun.

,. \Voll. """' thing pholo"" 'tr,airuy do h • ..., is ~""rgy. Think of III<

bt"1n., ... n]iglll Jopo"ts on your .kin wh.on you ",,,bo'h< on • • ~mmn-·. Jay. 'The i"tsap.blt cond ... ion is llul tht tnt1$)' mus, o<luaUy "",jg~ somC1hing.·

Thi'I"""" nut 10 bt • Jim:! <"n.<equtntt of,,,,, unc.lchal>ilily of light. lkcalM III< .p«d of light i, terminally oul of ,oach, no malerial bady <an .... , br ,,",,1 .... 1..! to tl>< sp«<l oflight. no ma'k, '-' liard ;1 i. pwMd. The .p«d of light, r«.I~ plays III< role of infini .. 'peN in our Uni"' ..... JuS! as il would I .... an infinite .mount of .~ to """I ....... body to in fi nite 'I'~ i. wuuiJ uk, an infinite

.mount of < ..... gy '0 p ..... on< to li.ght .p«<!. In ochtr I<o'OI\ls, 1M rnllOn lhal gelling'<> ,he.p«<l of light i, imposoibk i. \>tao .... it

wowd tal< RIO'" tnttJ!f lhan ;. conwnf'll in tht Uni'ottOt. What would hoppen, b.ow~, if you ""'" 10 push. ma .. do .. ,

and clM<r 10 'M sp«d "fligh.! wdL sin", Iht ull i .... t •• ph'<! i. un.,· uinabir, III< body would h .... CO t>«ome hoarder 01><1 hanJ" to plah as you VI i. d_, and d.,...,. to ,II< uhim., •• p«<l.

Ilring hanl to p .... h is til< $am. '" Iuving. big m .... In foct, the ma.. of • boJy i, defined by pr",,;"'ly 'his proptr'r----how hard i, i, .0 p ..... it. A loaded ~frig ... ator which is diff",uh to budge, is said to

h.avt. la'5" m ..... wh"'<a>. ,~'''', which is "..,. '0 budg", is .. id .0 h.avt • sm. 1I m .... I. follows the,.,(oruh.t. if. boJy gelS harder to puoh as i, approaches . he.pted ofli&h'. il mllSl g<l mor< "", .. ivt. In hoC!, if . materi. l body was ...... 10 au.in the.pted of Ught iudf, i, wowd a<qui .... On infinite m ..... whi<h i, )IISI .no""', way of "ring il' . =I .... I;on would uk an infini •• amoonl of m.'5Y. Wh.atevt, way you look I I il. if •• n ;mpoooibilily.

Now. il i, a funJamonloilaw of natu,,, lhal .... 'BY ",n ... ilher be ' .... Ied 0' d .. troytd. only lransformed from on. gu;'" into onOlher.

'Str>:tly op<aI<in[t. tilt thins f>hoton. J'O'O<" is mom<nt...". In oth .. wonk. it tak<o In .Ikon to >lOp tbom. Thi .. fforl is p"",idtd by tho rom<!',

,oiL which r«<>il ........ ok.

~ . ... AN U TII< "'HoG, IT <Y !iUNSI"Nl ,. For inS/.net,<I«.rical .... rgy chlonges in.o ligh. <n<l1Y in I ~sh.bulb;

..,.md on ... sy du.nges in'o ,t.. '''''rgy of motion of a vibra'ing dil' ph",,,.,. in I miaopho .... Wha •.• hen. hapJ><Il"o .M .... '51' pUI inlo pushing. body 'hOI i, moving cl.,..,IO 1M sp«d oflish'! Honlly any

of.M '''''D' an B" inlo in<r<Uing'M body' •• pM.!.i"",. body movingo' cl.,..,,,,.M ,pM.! oflisht i .. lr<aJy 'rov<iing w~hin. wh;,· ktr of.M "I, ;"", ... pM.!limiL

Th< only .hing ,ha. ;nc ...... as.he body is pw.hcd hlnl<' and h .. d<, is its m .... Thi .. IMn, mu .. bo who ... 1I.h< <""'1Y goa. 6u ••

,«.IL ''''''D' can only b< cl>ang<>d from one form in", . no'h .... Th< inescapabl. conclusion, djsccwtr<J by Einstftn, is .I><r<f<>r< .ha. ""' .. ilKlf is I form of <""V. Th< fo,mub for .h. on<IJY \ockt.l up in a chunk of m. U...- of m ........ is ~on by rnhaJ" .h. mos. 1':0""' .... "l",,'ion in .11 of ,donee: Ii. """,, wh ... < is .h. oden,i.u' !I>onh.nd for .M sp«d of Ijglll.

Th< coonectioo bo ......... ""'1y.nd m ... i, perhaps .h. ""'" ,mt. ,bblt of aU 'M ro"""lu.nc .. of [ins'''n·, sp«iaI th<ory of ,m, 'ivitr. And likt 1M ron_,ion b<t~n .pace and Ii.,.., it is. two·

Wily .hing. No. only i. mass I form of <"''1y, b4.t1 """8Y has In

off""iv< m .... Pu, crudely, '~r .... ign. """<thing. Sound <n<'1y.li3h. """y •• I<ctrical <"''1y--any funn of ... ·

<I1Y)'Ou con ,hink of-they.Il"";gh llOOlething. When you WiI,m

up • rot of coITtt. )'Ou odd M ....... <IJY .0 it lIuI M .. ·.".ru .... ish'

som<1hing. Co"""luon'Iy, . cup of colftt .... ighs ,lightly m<>r< whcco hot .han whon cold. Th< ol""' i ... wonl h.,.. is .Iightly. Th< diff .. · onet in weigh' i, far.oo.maU.o moasu,... In flC1, i, i, fl. from obvi· ou.,ha.on<l1Y has I "";gh" which i.of cou .... why i, ,ook ,Itt g.ni .... of Eim .. in 10 fi,., no.ic. il . N .... "h<1 ..... on. form of ..... SY II

la .. ---u..<".'1Y of .unligh,--Jon m-al iu mass whon i. in1<racts wilh a rornt'.

Lish' an p .... h Ibt wi of. rom .. b<-a....., ligh' .norgy .... ish'

som<1hing. J>hoIOm 1>;0 ... an ,ff«'i"" mass by vim .. of 'Mi, .... '51'. Anolbt, I':omili .. form of morgy is ''''''gy of motion. If)'Ou SIC]>

in'o .h. pith of •• pM.!ing ereli .. , you will bo Itfi in no doubt .ha.

,. ouch a IhinB .. is\<.. En«gy of mOlion, lih all olh ... for ..... of .... rgy • .mp.. ..,..,.,hint- So)'<lll ..... igh m"sinon,. ~..n.n you .n: mn_ nin~ Ih.an wlwn J'Oll art .... lkin'"

I. is .... '!Y of mOt;OII that .,..plains why d ... pho'"". of .unlight COo pu>h • co .... 1 'ail An npLon"lion i. n<nltJ bta ..... they o<lll'Uy have no jn'n.,.;,; ........ Iflh<ydid, . fi.r all, t hey """'ILl k unabk 10 ln1 ... 1.1,h"'r-l "flight,. , porN tho, i. forbiJJrn. ' " "II bo.lin wnh mass. Wh., light has in~aJ i. an .lkel; ... ""'_ mass by .irl~ of til< fact thai il has tn<rgy of mocion.

Tho< .... '''''~ of morn of motion .Iso explains why. cup of cofltt i. hn>'i<r ",,,",,, !>olthan .. he! cok!. Heal i.s microscopic me>'ion. The a t"",. in • l;quid or solid jigglt w.,Ut, whil. ,he at""" in • gao fly hith .. and thither. &clast the a,,,,,,, in a cup ofhnl coffff art

jiggling [OSler than the .10m, in •• lor .. ·coId cup. ,hey posot .. mort

tTI<'tJ!Y of motion. GonotqUC"tiy, th< coff« _igh. mo .....

RABB ITS OlTT OF HATS

So much for .... rgy having an "Iu;'olm ' m ..... or wrighing "'''''thing. Tho &,;. that m .... is . form of ""ergy.1so tw profound impli_

cotion .. Sine< nn. rorm of t"orgy can be <0" • ..-,«1 into .nOlher.

~n<!'JY c. n be Ir . ... formed into "ther f",m.<>f <""'IIY . OO • ."n_ vtndy. "th ... r<>r"'" of tntTJY can be chanS....! int" mass_tntrgy.

Tak< the Jan ... P"""""' If m .... ~""'IIY can be ~ <>u1 "r OIhe< form< of "n<rsY. it fo l"- .ha. moss can pop in." aist.nce whe ...

f"rmerly no m ... aisted. Thi. i. <nclly what happe ... in giant ~r-ticlt ocult .. to .... or .tom .maohe .... At CERN. lilt Eu ropean "",t ... for portkl< ph)'>i ... near ~ ........ for in ... nce ...... bo.ornic ponicl.-the building block< of atOms---Mt whirlN .rouOO • • ubt.rrantan

r"""rock and .lammW lOgW>er ot sp«dJ approaching that "r ligh •.

In the violtnt .mashul'o the tmntnoou> mtTJY of motion of the ~r·

tid .. i. C<>~tN into mass-<1ltTJY-11>e massof new ~rlid .. th.t phy>ici.1O w;.h to otu.ly. At the collision poin •• tb.nor partid .. 'PP"'" apparently "ut or nOlhing. IiI« rabbits oul <>f • Nt.

E • ... AN U TII< .,.,HoG' IT <Y SUNS/"NE '" This phtno ..... ""n i. an in"'.n", of ant 'YJl<' of ""orgy changing

in.o muo·onet'8Y.lluI wh., .bors .h.11 h.1pptn! V ... a11.ho 'Bm.

A MIUION TIMES THE DESTltUCT1VE POWEROF DYNAMITE

Think of. pirer of burning c",l. Ika ..... 'he h"". il gives OIl' .... ighs oom<1hing,'ho coal sraJually Iooes nla"'- So if i, ...... poosible '0 o;ollr« and _ith all the proJ.l<l.oftmmin,.......h • .,h.,ho g .... gi>= off. and so ",,~hty wooid 'urn 0\11 '0 wtith Ieos lh.1n.ho origi",,1 lump of ",.1.

Tho .mO\ln' of m .... --nlorgy 'UrnN in.o ht.l.""orgy when "",I burns i. >0 .,.,.nos,obc .... n,i.lly unmeasu .. bIe. N~"hole ... ,h= is. platt in notu", whe",. ,ignificanl m .... io "",.....-.«1 inlo othor

form. of e .. .-gr. It " ... identified by .ho English physicist francis Aston in 1919 while ho wos • .... ighin~" at<>m,. ~l th., .ach of tho 92 .... ,u .... 11y o«urring "<>mH',","i", •

nuclellO mad< from lwo .Ii Slin<1 ."b.110mic p."id<S----4h. prolon .oJ "u'ron.' Sinc. , ho ........ oflhese lWO mld.on ' ....... nti.11y tho ......... h. nudtuS ••• kOSI OS far .. il:l wtigh. i, ",,,, ... n«l. an bt though, of .. bting made from • single building blocl<. Think ofi. OS • !.tgo brick. Hyiliop'n. tho ligh.CSI nude"" i' lhe"fo" made from "". Ltgo brick; u .... nium •• he he •• int. is maok (rom 2J8!.tgo brick&.

Now, tho ... had bern • "''I'i,;''n >in« the btginning of.he 19th ctntu,), ,hal pt,hap' .he Uni",,.... had Sl lrt«l out wi.h ""lyon< kind of atOm---4he .implnl, hydrogtn. Since lh.11 tim •• all.heo.her atom. h.", som.how bern buill up from hydrog .... by lho P""'" of Slick. ing "'S.,her hydrog.n !.tgo brick&. The ... idtnct for ,he iJn, whi<h

' bup<. of rou ..... the """" rommoo iootop< of hyd'OB .... the ""' ..... of wit"'" """oi>" .implrof on< P"""" and no ,,",Irons.

'" hd betn propol<'ll bya London physician .. mal William ~rou! in 1815, was that an "Qm lik. ~lhium appt>"'! II) .... igh on<,ly ,i. Ii""" as much as hydro!"" an .lOm Kk .. carbon exactly 11limts .. much, and 00 <>n.

H~. wflcn Aston comporN the rna.«tS of diff.",ntlind. of .'om. m= p~sdy wit" on ;nSlrumftll he invm'N called . """" . p«lrognph, h. diocov.m.! ""m<1hin~ diff .. mt. Lithium in raci weighed • ~ I ... lhln six h)'Jrogtn o,omo; carbon ..... ighed • ~ less,h.n I! h)'l,"8"" "'om .. TIl< bjucs. disc..-pancy ..... ~ lium. tht...,.,.,J ligh~t atom. Sin~. h<~um nudou. wua»<mblal from rour Logo !>ricks. by rights il ""'ulJ .... igh four limes as much as . hyJ"".n alom. In ... oJ, it ...,ig/>t<! 0.8 p<n;er>1 less Illan four byJrngn alom .. It ...... Kkt pul1jn~ four l.kilo""m bap of • .,go, on .... of sales and fir>ding Ih.llhey .... ighed almool I penxnllns ,han 4 kilcJ3ram.1

If.n .lom. hod indtN been ......",bled oul of h)'d""on l IOn> t..go lwic4 OS I'rou, >trnngly ''''~tN. Aston', discoV<r}' rn'<.lal $Om".hing .. ma,kabl. about atom building. l)uring ,"" procns..

sisnifocanl amounl of mass-morgy ...,nl AWOL. M ...... norgy. lik. aU f",ms of """'lIY, con...,. be J .. H"r.,!. II <on

only be dung<d from on< ro,m inlo anotber, u1limolcly lhe 1 ........ 1 fo,m of """rgy-M.Hn<'!y. Con"'lu<mly, if 1 kilogram ofhy.Jro-5cn ...... <on",,"I"! into I kilogr.om of helium. 8 5'.m. of m ... _

energ _uld be ron .... 'I.,! in1<> heoHn<'!y. Amuingly. Ihis i. 0

million tim .. I1IOn' ., .. "u ,h.n would be ~ber.ot£J by huming I ki_ logram of coolt

This fOClor or. million did ...,. go unnoliud by Ulron<>m<n. Fo' millennia. poopl. had ""'oo ... .,! whot krpt the Sun burning. In lhe 51h ""nlu,y lie, the G .... k philosopher Anuogoru----bltss him--had 'p<'01l.aloJ thai the Sun was". ffll · hot boll of iron not much bi~erllu.n Grtta: Lal", in lhe 191h ""Iury. Ih.~. or mal. ph,..i_ d.1J had nalurolly _ootr<d wbe1her lhe Sun was 0 giam lump of mol. I, _ali lu.vt to be lhe """"",, of olilurnp. of mal! 'f1tcy fouOO. how~, Ihal if il was a lump of COIl, il would hurn oul in .boUI

~ . ... AN U TII< "'E>GI IT <Y SUNS/lIN. '" 5.000 mrs. The ,roubl~ is ,h.a"h~ ovid~nu from geology and bioi · "If i> Ih.al Eanh---.tnd by imp!;.;a,i"" ,he $uD-i> .. loa>! a milli""

'imn oidtr. TIlt in"""pable cond",ioo i. 'hat ,he Sun i> drawing "" .n ~ ... r-gy SOUl"« a milHon limes ~ conunlr .. ed Ihan co.l

"I1>< man ,.ho PU"wo .nd lWOlogttMr ..... &I~.h ... Ironotntr

Arlhur Eddingt""."I1>< Sun. he gu.....J ...... powtrN by .tomic. or nadtu ..... nn.1kllbota""" hydrogen. 10 m.ke .1OI1U of 1 be """"d light · e" . helium. In ,be process. mass ...... nn was bring ,umed inlO hea, .nd lighl "'nn. To m.intain 11K Sun". prodigious OU'PUI. 4 miUi""

'OR' of ma .......... IK equivaltnl of a million .I<t>h.n's--..... being de"royotl every >«ond. H= ... 1 .. ,. w.., Ihe ullim.~ sou",. of

.unli3hl.

Tbi> diSCl.lS>i"" COO .... niettliy ski'to Ovt1"lbe maIler of why m.k· ing a htavy alom ou, of. ligh, .'om .""......u so mw:h m ....... ntr-gy

in,o other fOf",' of "'..-gy. A digreshort may help. [magin< rou au walking pa<.t a houor and. slal. &lis from tht

roof and hi" you on the IKa.d. Energy i. ,..I....,J in Ihis ~. For

instan",. lhe ... i> the whad: as ,he sla~ hi .. )"'" btad-sound .... · orgy. Maytx it even knodo you.,....,.. "I1><n Ih<re i, heal "'orgy. [f you

could tntasurt the I<mptt"ll'llrt of the .lal< .nd your head .... ry accu · ralely.)"u would find lhey ~ .... lighlly .... rtntr Ihan btfo ... .

WIKrtdid aU 'hiHn<rVcotnt from! TIK .ns .... r is from gr .. i,y.

GravilY i. a fo"" of a"rae,ion bel~n any lWO mass;"" bod;'~ fn ,hi. C_. Iht V"'ily btt~n Earth and 11K sial< pull. IIKm d .... r

toge,her. Now. wh.al would h.appen if gr .. ily ..... Iwi", as llrong as il is!

CLo.rly.11K slal. would be pullod loward Earth faskr. II would make a bigger noi .. wit .... i, hit. crtal< mort heal. and 10 on. [n ,hort. mor~ '""orgy would be rti • ...:d. W!u, if gravity ....... 10 'imn Slronger!

wtlL ..... n "..,rt .... ..-gywoWd be unLo ... W Now. what if V"vi,y was 10.000 trillion lrillion trillion 'im •• monger! Obviously •• mind·

boggIingly hug. amounl of tntTgy would be "kastJ by ,h. c ..... hing

'" .11't (Ind III< combin. tion of Earth arK! £I1't would bt ligh, ... , Ii ... ,he helium It""')'

But ;"",Ihi.jusl ran,uy! Surtly, ,tit,..;. no foret ,hal i. 10 trillion trillion trillion tim .. "ronger thIn ""vilt. Well, ,I>o<t ... . 00 it

i. opt"'lin~ in .,.ch and <v<ry lHl. of US 0' thi< wry mornm!! 11 is calk<! the nuclear for«, and il is the glut Ih01 hoIolJ (<>sflller 11>< nu

d.; of .'om" Imagine whoal _Id happen if you lOOk 'he nuel"; oltwo light

.Iom •• nd Itl them f.1l1os.,Mr "rod ... ,,,," nucltar force ra,he, lik< ,he 01 ... and Earth r..Uing t",<tt..r unJ"" srav;,y. n.. ""Ui,ion would bt ,,..,mtndously viole"l and an ."",mo" • • mounl of entrgy would be libonted_ mill;,," tim .. mQ,.. .""'!)' ,h, n would II< rt

l.aud by burnin5 the sa"", wrishl of roo!. "'tom building i, nOt ""Iy the sou",. of the Suns ..... rgy. II i,

_Is<> 1M IOU"'. of "'" tn."e' of II>< hrdro&<n bomb. Far ,hal" all H· bomb,do-slom 10gclll<-, hydrog ... nuclti (nor"",II)" , heavy cousin of h)'lrn~m. but tha,', Inool,..,. .,ory) t" make nud.; ofl.dium. 11>< belium nudei u< lighter thon tbe <ombin«! _ight of tbeir hydro_

g<n building blocks. ond ,be mi .. ing "" ...... Pl"' ..... , be 'rtm<ndo ... be. t .""rgr r,( tbe ml<'Io .. firrl>oll. The destructive pow .... r,( a I-mts>''''' hydrogtn bomt.---.bou, 50 ,i",... ~ ...... th.n 'ht 0"" ,hat ok ...... 'N Hiroshima-<:on, •• from ,ho d ... ",,,,ion of litd. mort ,han . kiJovom r,( ""<s. " If ""Iy I had known. I'hou~ h ... bw>mt . w01chntaker! " said Ei".",in, reO ..... ing on hi. mit in ,ho

Jno:loprnnl' of 'he "",ltar bomb.

TOTALOONVERSION OF MASS INTO ENERGY

E""n ,hough EinSlnn downgraded m ..... ,howing ,ha, i, ..... "",rdy 0"" among <oundessothor forms r,( < ....... gr. it i. '1'«;.1 in 0"" w~: It i. ,ho moll mn,,." ' ra'cJ fonn of trttru known. In fOCI. tht tqu"ion E • ....-' trtcapsulu •• ,hi, foct. Tl>t physicisu' symbol {or ,ho sp«d r,( li~h'.~. is a big numbtt_ .lOO million mete .. f'<T S<"COnJ. Squaring i,-muhiplyins i, by i .... lf u""' ... n even bigg<r number. Applying

~ . ... AN U TII< ""HoG, IT <Y !iUNSI"Nl '" ,h. rormula '0 1 kilosram of .... , .. , o.how. tha, i, comai". 9 . 10"

joule> ~ .no<g~ou'" '0 lif' ,ho 'n1i~ popuLa,ion ~ ,ho world into 'Poct'

Of 00II"', '0 gtl,bio kind of .... '!)' ou, ~. kilogram of m." .... i, would bt ~ ' 0 ronvn-, i, <II,irdy in,o ano,h ... rorm ~ <II.

trg),-,ha, i" 10 d"'l'O)'ali ofi .. m .... Tilt nud ... r pro< ..... in ,lit Sun and • hydro~n bomb libtr.t< bardy I pnun' ~ tht .... rgy

locked up in ma' ..... Howe<'''', i, ,urn, ou, ,ha, nature can do for btI, ... ,han lhi"

llLa.ck hoi", ar. rqion. ~ 'p""" wh= 8 .... i'y;, '" "rong , .... , lish' i, .. 1f catino, .... pt'----hnla ,hrir blao:lnHs. TIIty or. tht ",mn.aH' kft bthioo wt.... • m ... i"" Wlr di .... hrinkin! ca,"'rophkally in .... un,illhry li ..... lly winkoul of .. i<l<IIa. '" mall ... swirl. down in'o. blad hok, lik< ........ down" plug holt, i, nibs "soin" i .... lf. h<olinJ ill<l{ '0 inandnttn«. E ... rgy i. unl.uhtd as both Ii"" .nd h •• t. In ,lit .]'<Ci.1 cal< wlltn. blad holt iupinningal ill m •• imum poMibi. rat<. ,ho libtra'N rot'!)' is <qui ... kn, 10 ( J perun, ~ tht m ... oftht ma" ....... irli"!! in. Thi. mnns ,h." pouoo for pound, ,h. in-fall of mo" ... on'o. bl.ack holt i. (3 tim .. ~ .lIkim, at

g ...... 'ing 'no<gylhaH ,bt n""kor P"""""'" I"l"""'ring ,ho Sun or.n H-bomb.

And ,hi. ion', juo"hco'Y. 11>c Un ........ contains object. called qu_ro.. ,he .uperhrigh' m .... ~ _Mrn saini«. E ...... OUr_n

Milky .... ~y g.laxy m.yha .. hod. q ...... r in ill 1>cart in ill wayward you,h 10 billion ~ars .go. Tho puzzling thi,,!! .bout q ...... rS i< 'hat 'hoy 0f,.n pump ou, the ligh' .n<rgy of 100 normal sal .. ics-,ha"o 10 million million .u .......... t>d from a ,iny rqioo "",Ikr 'han ou, 001 ... ,..,,,,,,. AU ,luI <IIorg)' c.nnot btcorning from "'ro; i, ...,uld bt impos.sibk ,o "Iutt"tt 10 million million 'un> in'o.uch a .mall voI-urn. of '1'""'-It can only corne from. gi.n, blad bole ... eking in m.II ... ""rono""'ro.. ,lI<rd"or<, finnly btli.,.. tha, q .......... ro"!.tin ·.u~rm ... iI.~· black ''''In-up to ,0 billion ,imes lhe mass of ,he Sun_ tha, art Slroclily &obbIi", wMlutarS. Hu, ... <11 block holes an

coo",," borcly half of lilt mass of mall.r into o,lIer fonn. of .... rgy.

I. tll<rt a procas t""t con con",," all of th< IN .. into <n ... ~)1 111< on~ is yes. Matter actu.oUy "" ...... in two t~m;tu .... OO .nti_ INn ..... It i. not n<c< P 'y to ........ anything about antiman ... oth .. th.n til< fact that, whon mat~' .nd .ntim;tt~' m..,. til< two destroy, 0, annihibtt tach othtr. with 100 perant ofthti, IN .. -<nnn fLa.h_ ing inslantly into otll<, forms of <n<rgy.

Now. ,,~, Univ ..... for a ,<HOn nobody knows. .p~an to bt m~ alm ... t tntirtly of matlt,. Thi. i. a dttp puult ben .... , wlltn tiny amoun t. of anti man., art madt in til< laboratory, thri' !>Onh i. alwa}'S ""rompanial by an t<juai amount of matlt'. 1Iwo_ t~ i • ..... nti.lly no anliman ... in tht Uni ... !V. if "" want any "" haY. 10

malo: it. It', diffIcult. NO! only do you have to pUI in • lot of tntrgy to mak it-a.< mudt tn<rgy .. )Ou .rtlikly to gt1 out!-but it Itnd. 10 annihHa" as soon as;t In«U ordinary mal1 ... , .., if. difficult 10

o"""mula" a 101 of it. So far oci<ntists ha.., managc<! to coUcd It<o lhan a !>01li""lh of. gram.

N~th<bo. if th< probltm of m.king on,im;o'ter in quontitIft could bt o-ackd. "" """Id ....... at ou, d;.posal tilt """,t ~ul

tn<'lY ""'ret i",",inabit. TIlt probltm with alI.paucraft i. lhal th<y ....... 10 l.k thtir fud .Iong with Il1<m. !lut that futl ""ighs • lot. So rutl i. net<ltd 10 ~ft tht futl into 'I>'a. Til< ;;".ur" Vrod.tI. for in'lana, ""igbtd 3.000 IOns aOO .lIlhol "";ghl-"""'Ily fut~ n<tJtd 10 Ilk t"" m .. to tht .urf"'" of tht Moon and Ttlurn thtm .. fely 10 Eon". Anlimal1" off .... a way oul. A .paucrali """Id rtquirt hanlly any anti"",,1<'1" to !'utI it bta ... antiman .. <on lain. such o Irt"...nJou. omounl of <n<rgy pouOO for pound If"" t"'" manag< 10 travel 10 III< .. ars. "" wiU ho .. 10 kjU~'" ~y lost drop of tntrgy out of m;tttt •. Just as in S.a, T ... k. _ will .... ..,.o !,u;!J ,la,s!.;!" pow

ortd by antimal1 ...

Q

THE FORCE OF GRA V1TY

DOES NOT ExiST

Hi'll WlIIIICII'IIIIO 1111 111m MOl' ~ MIl CAllI fIICIl\I f.\Q

.... 1(IIDI 0IIm. _B, ... _IWIO"" 110< ffloal,,,"",.011 "' ... ,..Io/",Iy "'" ""T. I ....,. ,;~ "" ~ <h.i.;~

"""'0"'" offtc. j" Hmo. s.~ '"' _~" ,,,. ... t "'" If .. _ ",n.".."" '" Jon ""'1m iii> ...... ...,;,;/!" I ...... II>km ./rod. 111;' ,imp/< ,~, <xpffl""'" ........ " Jup ; ... "...,. ........... TIIiI W

...... ,lot."""" of ,tnI"'" Alb." Ei .... l<m

n.." art 1tJ-rt".-oiJ /wi" si"t1'~ 1M, ...."t j" ,/It' 111m. "'''''''1'" j"

Maw'"",,,,,, On. i> an "";"a,,, jn a """'iq'" "' SI_ I~. ,lit "',...,,, .... i" .... "r tht Hitl! 1/""" m'"unml Dn 1M 52rnJ JIM •. Ir'. 8:3O ... m. n.r rom. rll"'''K1l ,Itt «"">;'It dootJ i"'Q ,Itt /0,.,. and go ,/tti. Hf"" ",It W<IJ'~ 0". II",," am>« ,Itt """bit tXf'<''''' " • • ht Irn~...J.JI""r '"""ping """k IIr< OIMT 'pri,," i"", lilt' mourh of"" high •• p.m dt ... · ,"" jl4l /Hfort ,/It'd""" .... ish oku',

Tht """d.""", docl< ""-' tilt' .Int..o. ,pin ."""no! Now if" 5:30 I'm. 0,., 1M 8"",,,d flo« ,iI. sito/"lWiJ'""llwin .,."'s up., 1M big red ;ndiea,« liglll a, jf <"""IS Jo... .. 'M floor>. Wi,,,,, "Ji"g." 1M Joo<. buNI opt" .nd "'" """,ts lin .... il ..... ""n- .. . "n iJ3-,.,...-<I/J brn, !if_ clu'cll;nt" ,ilver zi",,,, ... fra-I

'"

,. If)<>u think this Ktnario is pUA" fantasy. think osoin. I,',an '''''U''t'iIlion, , .. nlN. but it'. on ... " .... ';on oll~ truth. You ,..ally "" "8" mort slc>wly on Iht 5""und floor of. buildin~ than on tht lop floor. I 1'. an di«1 of fjn Olein'.' g ....... I· thwfy of rd., ;vily. Ib¢ rr;II"eworx be cam, up with in 191510 ('" lh, shortcoming. olhi •• pccialthtory

of ... lativity. Thor prob!nn with ,I>< .p«:iol tbro.-y ol r<l .. ivity is ,h ... wdl il i.

sp«iol II ",raleS "'Nt one f'C'rM>n see, wht" Iooking.l lnolhtr person moving'l co,,,'anl .p«d ... \ali ... 1<. 'MIn, ... ""Iing lNI III< moving PO""'" .ppea ... to shrink in tho <li,,,,,,;,,,, "r .hrir mo,ion whilt .Mi, tim. >low. Jawn. df«u thai t.t.:o ..... tytr mort markN

.. thtyoppn»d> 11>0 .p«d of Iigl1. tlu' moI;"n at <on>!a,,' .~ i, of. >try .p«ia1 kind. !\odin in ge"1".1 ch'''lI'' lhtir .pffll with time-for ill5l.nu,aca, accd ..... l<S.w6Y from ,,..!fk Jighuor Ni\SA', .~ u.ultlt olows when it rttnt .... Earth', a"""'ptx....

n.. qu .. I;"" Einslnn therefor< .. , oullO .no ...... afte, he publi;hrd hi. sp«i.aI th.ory of r<lativity in 1905 wu: WI .. , Jo.. """ .,...-. ..... ..,. whm Iooxing at ana.h<or P"""" """,!.rating ~lati ... to t~ml

Til< an ..... r. ""'ich took him f'I>()(f than a d«aJt to obIaitl, w .. con,oi""! in til< "gener.I " , heory of TeI.,i.ily •• rgwb!y til< gre. te .. oon

lribu.i"" .0 scicnct by •• ingie human mind. W"",, Eins,';n .... borke.l on hi, que", ""e problcrn in p.nic\llor

wo,,;ro him: what 10 do about Newton', J..w of gnovi'y, Although i. had stood unchallenged for aim.,.. 250 years. i ....... cle., .0 Eins,ein ,h •• i' ...... fund"rl<n'..uy incompo..ibl. with tI>< >pttial theory of

r<la,jvjly. According to Newton •• ....,. m ... ;'" body 1"8' "" ,""y otl><, massi"" body wilh an attract;'" fmu coU«I gravily. For in· "'"',e. thr~ i •• gravit.tional pull ~ ..... n Earth and each .n.! e ... ry

0 .... of "" i. 1:«1'0 nur fee' glued firmly '0 ,II< ground. There, i,. gntvito'ionol pull between til< Sun . nd Earth. which k«p. Earth

Intpped in orbit around tI>< Sun. Fin",in did nol obj«IIO Ihi' kl ... Hio difficuky was wi,h Ih •• peed of gravity.

Newton ... um«l lhallh. foct<' of gravity acto insLanl ......... Iy,h., is. ,1>0 Sun', gravity reaches OUt acro ... pace 10 Eafth and Earth

'" ( .. Is Ih. lug of WI VOvily withou, .ny dolay. COn""l....,lIy. if the Sun W='Q ""ni,h at ,hi, very "",","",--<Ul unlikly O«I1o,io1-Earth _Wd nOlia lht abltllU of the Sun', gr .. ;ly i"'tan~y and promptly Oy off inlO inl<r>toU.r >p.ct.

A:! inO ...... "" ,h.t .a" ""'" the JUlfbtlwt<"ll tile Sun and Earth in 00 lime., . 11 m"" , .. ..,1 infinitely fasl- i ... lanl . nwu.1ravd . nd infinite .~ . .... co mpl<ldy ~ "ivai ...... H"""".,..,r, >$ El .... '.;n JiM:ov. ",cd. nOlhing--an<llhal "ea-",ily il>Cludes g",vily-an 'ra,-.I f .. ,or ,h.n !ish!. Si"". light likes juS!.,...r tigh t minutes lO 1, .... 1 ~~n .n., Sun and Eanh, it (01., ... ,h.t, if the Sun we« "> vanjoh .u.w.nly. Earth _Id .oo,inut m.rriJy in its orbit for . 1 It .. , rishl on.! • bit minutes btf~ .pmning off to the ......

N.,."",,'s'ocil ... umption ,h.1 5",,,ily ",OdICS nul 0<r0U'~ .1 infini1< ~ i, nol'''' ooly ... ious now in hi.lheoo"yo( gravity. Ht . 1"" .«um<J ,h., 1M foret of 5n1vi1y i. gcr .. nlN by m .... Ein>lein, I>owe ....... , <liscovend Ihal an forms ol en<ll!Y h .... an &«Ii.., m><$, or ~gh $Om<.hing. CO"""l ..... tly •• U form, of m<ry

no' jU$' mau~ry-m~ .. bt $<lUrcn '" V3Yily. Tht challtng. facing Eirul';n ",.,. 111< ... 10'0, 10 incorporalo the

idtos '" Ibt 'p«i.1 theory '" rd.tiyity into. now theory '" ,"'Yily .nd •• llh. sam< lim<. 10 S."tnlitt the .p«iaI th<oo-y '" ... I>li,ily 10 describ< what the workl Ioolcol lib: 10 an . "",It",ttd p¢rson. II was .. h. ronttrnpl.ltd thnt prJ .nl ..... n chall.,,5"" Ihal. ligh tbulh Iii up in Ein ... ;n', lI<ad H ..... lizod, to hi' ,~rpri .. . nd d.lip" , that III< lwo un. _ .. On< .nd the .......

THE ODD THING ABOUT GRAVITY

To undtrsl.nd 111< connection il i. n<c",nry 10 .pprt"Ci. I •• p«oJior

prop¢l"ly '" g",.ily. AD bodieo, irrnp«ti .. '" their moss, 1211 at the ...... "'It. A pn.nul. f..- ;11<1 • ...,.. picr.. up ,p«d j~'1 .. q~id.lr" • person. Thi, bch""ior was fint notictd by tb¢ 17th-«ntury It. li. n sci<nl;'l Galilro. In fOCI. Galilro i.< .. pul .... 10 Iu .. dtrnon<l"' .... the e/ftc1 by uking a light obj«t and a heavy obj«t and dropping tb¢m

.. logClh<r from ,he lop of 111< Inning T ......... of Pi ... Ropot1<1lIy. 1hoy hi. the gl'QUnJ .. the .. m<: .im •.

On Earth ,huff«! i< obscurtJ btau<t objtcl. with. la,# Sur

fac . . ... a .. prtf.",n,i. lly 11..-1 by 'heir p . ... p' through 1he .ir. Nt,...,-thtku,G.lilto', ClIporimcnl an h< carritJ Out in a plattwht ..

lhe .. is no . ir rn;"all« 10 me .. thingo up--lllc Moon. In 19n. ),/""UD 15 rommandtr l);o~ Set>11 JroPrN a harnrn .... anJ • f~th<r 10Selher. Sure .""ugh, they "i1th< luna,"';1 ., exactly lilt ""'t,;""

What is peculiar ,boo, this ph."""",,,,,n i. 1h'lI, ... ually. the Wily

in which. body ~ in rnpon>< 10' fOR;< J<p<...u "" i .. muo. Imagin< a wood", OIoolonJ • Ioad«l rdtigtralor ItInding OIl an kt rink, ........ ,ht ... i, no fric t ion to ",nf,..."hings_ Now i .... gi ... th ..

"""tone push .. lh ... fri!!''''to, and the "ool wilh <xOClly th.t sam<

for« . .",. m>Ol, bc;ng It .. m;wi~ than tM rt(,;g ... "o, .. ill obvj·

ously budgt mo« .... ily and pick up'p«J more ,!uiduy. whalluppens, however, if 111< ",ooland ,h. ",fril!ml1or art "",ed

on by the fmuof 8<2'o';' y1 Say",m..,n< .ip' th<m both off til< roof of • I()."orr building! In .hi. <_ ... G.~ko himodfwould havo p .. _ dic.<d •• 11< ,,001 will no! pick up.p«J f ...... lhan the mrigeralor. [)espi' • • hoir wildly d iff<m>' ""' ...... . ho >1001 .nd.ho .. frig .... ,or

will aced ...... lowonllll< gtound a' txOCtly the .. m. ral •. Now. ptrh. ps ",u .pprtciat. til< un.ral p«uli. rity of gravity."

big m .... xptric ....... a biM"'" """'" of g,",vity than • sm.1l m .... and

'hot (0"'. i, in dir«t pNJ>Oni"" to its m .... SO ,I>< big ""'" """lor-...... aoctly ' ho .. "'" ... 1. OS .h. "".11 m .... 6u. how do<> g .... i.y

.dju" iu.lf.o III< m ... it i, ",.inS on! II .... Ein".in', geniu, 10

... Ii ... thaI it do<> '" in on iDCrNibly .implt ond n .. ural wry---<t wry, furthtrmor., .ha, h .. profound implica.iOll, for our pic,u", of gravity,

THE EQ UIVA LENCE OFGRIo.VIn' AND ACCELERIo.TlON

Sry an ... ....... ut i. in a room OCCtI .... 'ing upward .. 9,8 md .... p ..

I«OIld ptr ><cond. wtoich is .11< aced ..... iOll gravity in,p.",'o fallil18

bod;'" n .. r Earth' .... rf .... Think of tl>< room os • cobin in •• ~

< ... A wh.oo< rockt ~ngi...,. h .. ~ ju>t ... ,t«l firing. Now ... ytl>< "'ro·

ltIut tokH a lu.mm .. and. f .. th ... 1Iold'lMm out from him a, 1M .. ..,. height .bove tl>< flO(), of tl>< cobin, then lot, .I>tm go ';multo·

rIt"OUsly. Wha11l.1PrtJl.1 \\'d~ 1M h.mm .. and katbCT mtd 1M flO(), of COu ...... How thi ..... nt is int~q,...t«l, though, ~petI<b. ..,tirely 00

th. pmiculu vicwpoinL

....... ming th. 'pKC"CI"Ofl i. far .way from tl>< gr .. ily of any big m ..... IiI:., plan . .. , 1M II.1mmor .nd tM katM' ........ ightl .... So if .... i00i< into.ho .p~ from <)U .. i~ wilh "'''''' l:.iOO <If X_roy

vi.ioo ..... '" II>< lwo 00;«1. II.1nging motionl .... How ..... , btcaw< .h. 'I'>«< ... ft i. ><:«I .... t;ng upwan.l, .... '" tho fIoo, of tho cobin

raci"5 up 10 mM 1M h.mmrr and II>< f .. ,hor. WI><n il "run th.m, fuuhtrmo ... , it .lrik .. tl><m oo.h simul •• r>t<>UOly.

Say II>< a.lron;oul """ am ... i. aOO has mlirdy fo'~lm h, is in

a 'I'>«< ... fl. The p<>rthole .. in addilion, .... blacke,J oul '" lher< is nothing to t,1l him who", h.r is. How d".. M intrrprn ,.11.1, ho 0«11

\V.I~ 1M "'",IUU' maintain> tll.1. tlor ham..,., and.1or f,.IM,

h .... fallm undn- gravily. Atkr aIL lI><y havt 00 .... Ih. 0 .... Ihing a h.mme, .nd • f .. IM, .. pori..,,;ng gravity would do--thoy h ....

falltn aliI>< Ame ... 1. 000 hil 1M ground at Ih .... me tim. (ignori"ll

.i , ..... ta"" of""" ... ). "The "''''''''u' is furthtrronvin«d th •• g .... ily is ..... poruihl. for whal I>< has ..,.., by ,I>< (ao:lllI.1l hi' ket appe ..

10 "" glu«l to .Ior floor jU'1 as they would"" if he ...... in a room 00 Earth', surf.,.,. In fao:l. <vrryIhing 1M ... uonaul aperimcn lurns

out to hr iOOi"ingui""'hI~ from what he would aperi..,a if I>< ...... on Earlh', .urf..,.,.

Of <ours<, it muld be • minci.!e"". Ein>t";n, """""" ........ """. vinet<! I>< had 'Iumbled onlO a deq> lruth aboul nalu". Gravily is inde«l indi .. ingui.t.able from """"Iera'ioo, .nd .h ... ...,n (<I' that

could not be simple<. Gravity is ><:«Ie"'lion! This ,uliutiort. whi<h fin ... i" later coiled "tl>< II.1ppinl though. of my lif.: convin«<! him

1II.111ho .... <h for a Ihtory of gravity and roo- a Ihtory l hal dc<cribeJ aculerated rnoIion ...... oo~ and tl>< .. "", .hing.

'"

Ein.,rin d"'alN .M inJiSlingu;sh.bili'y of gr.lvi.y and lea",,,,,iOll 'IU grand principkof pbl"iu. which he <hr;,t~ ,he prinripk of .... ui ... I0""'. Tht priociplt of .... ui ... It"'" r«O~>:tllh., unity i. n<>lliko mho. f<>l'«S. In rac" i, i. no! ....... . , .. I (0"". \\'c ar •• n like It.< .rnnc<ioc .. ,"'''''", in 1M hlackc.l-.ou. <poc«raft. W. do 110. , .. I_ i .. IN. our .urrour.ding"'" accelerating and so h~ '" fi...t ... me othn- way to aploin awqth< (0<1 tha, ri~ ... Ilowd""'nhilland appln fall (rom tree>. Tht only ..... y is 10 invent a fictitious force gravity.

THE FORCE OF GRAVITY DOES NOT EX1STI

Tho ido. that g .... vity iJo fic,;';"u, fo",< may "mnd. lin., far.f<lcht<!. H.,...",.,-, in ochtr ntryday ,.;' .... ,ion .. """ art pttf«tJy barry 10 in_ vetil forces 10 make ...., .. of wt.a. bapP""" to .... Soy you arc • puotng<r in a COr that is racing round a 'harp corn..- in It.< mod. You 'r~.r \(I be flung oo.waN and, 10 ""plain why.)'O\I in ...... ' a foru-<rn.rifugal 10", •. In .... ~ty. t.ow.=, no ouch ("..:. aiM<.

AU mU$i,.. bOOi ... ~ $<' in motion, Iu."". tendenqto k«p ,,,,,,,,ling . , constant .p«J in a " ... igh, line. ' Ikca"", of ,hi. propeny. known as iDoni •• um", ... i nod <>bj«l' imid. ,he cor, induJ ing • pu«nS.r like l"u. con,inue to t .. ",1 in the .lame JirI'C,;"n ,he cor

w .. ' .... '·ding before it ,oonde<l,'" benJ. n.. path IOIIoweol by tho Cor JC>O!" It.owcvtt, i •• curvt. It .It.oultl bt no ,urpriot, then. that l"u finJ your><if jammed up agains, a door. Bu,,'" car door Iw merely rom. ' 0 m<"<1 you in th • .lam. way th.t the floo, <X tho ..:cd.uting 'p;>e«nf' came up to mOfl the hammer anJ fMIIer. ' There i. no fora.

'TIl;, ;, "'" .. 01' 0<0";"'" on Eonh, wh"", fric,"',. "'«CO >ClIO oIow. m"";n~ body. 110w,><" it i. 'r~m' in ..... empty "",,"urn of"' ... .

'I' ;, _th pointin~ out tho,...,.,.,.1ion <100. no< j ... , .... n. dwo"". in .p«d. It ",n .00 ..... n a rn ... ~< ill dir<rtioft. So a ar tra .... l.". around a

~ "oon~ .. ' ...,-io acuI< .... i~

TIl l FOAclOfGlAVlTY 00.. NOT W>f

GM,rifugallOlU is luIown as an ill<rli. llOIu. W< in ..... ' i"o ~Iain our mOli"" 1>« ..... w. choose 10 ign"", ,boo lrulh--th .. our ,urrounJU\i. art moving rtla,ivt '0 u,. Hu'. rt.lly. Our MO,ion is ju.sl • mull of our in,,'ia, our nolu,..}l<nJency 10 ~ m""ing in a " .... i8h'lill<. II was Eins'ein·, 5rtOl in,igh"" rt.ali .. IhOl 5"', i,y too i, on i ..... ,41 foro:. ""Can g .... ';I .. ;"n . nJ in .. ,i. be OJ<mical!"..w Fin".in. '"This qu«,ioo load. Ji....ctly ' " my thro.y ofgr.rvity:

""cording '0 Ei ... ,.in, w. COIIOX" boo for« of gr.rvi'y 1<, <.plain OWO)' ,boo mOlion of .pples faUing from ,rtCS 000 ploll<" circling !he Sun boN;auoe _ ignort ,boo truth-,hat our >urrounJingo.rt "'<;d ....

.. ing rclotivt '0 us. In ... Iily. 'hing. mOvt m.rtly as • rtSull of,h.i, ill<,,4. The folU of V .. i'y Jon _ ""ist!

Hul .. ai, • minu.e. If.boo """iOll _ .lIrihu.e.o ,boo foro: of 5 .... "· i,y i, a<'1W1y just ,boo mul' ofill<"i. , ,ha, musl meon ,ho, bodi.,li~ Eanh art rn/Iy ju" flyi"3 "'rough 'P"'" at roru'a""p<"«l in ""'igh' linn. Tha"s poten,ly ridiculo usl [O"h i, circli ng,h. Sun 000 not fly. ing in. ", .. igh, lin<. righ,! No, t><tt<Sarily. It all Jepmdoon how you dmnoa>lraigh,lill<.

GRAVllY IS WARPED SPACE

A SI"'igh' lill< is ,boo >horte>1 pa, h betweeo two poin ... This i. "" . .. inly 'nt. on. not piKe of paper. 6u, whOl.houl "" a curvt"J SUr· fao:-for instan«, ,,," ouri"ace of [O"h1 Think of . pl .... Oying I,," ,hon ... mutt heI ....... l.oMon anJ Nn< York. Wha, poth d"... it tak<! To """toll< looking down from 'pac<, i, i, otwioos-a cu"''''' path. Think of. hik .. tr<kking be,,,,,,,n 'wo poinlO in a hilly landscape. Wh., pa,h Jon ,he hikt- ,.l<r? To ",,,,,,,,,.looking down on !he hike, from. IIaJ1 laS< poin, .10 high tha, ,lit undulation. of ,lit lanJ· OOIpc can.",' be ><en. ,he palh of the hikr wigl« bad< anJ forth in

,h. ",,, .. 10<'00'" man ...... C01l'rory 10 ""pee"' io">, 'hen, ,lit shorl.st path bc1 ..... n two

poin" is no, alwaY' a ...... igh'lill<. In foc '. i, i. only a " .... igh.lill< "" • very ,peei.1 kind of surf.." • Oat 011<. On 0 curvtd .urf"", like

Eanh· .. lht ohortest rout. I>cllOttn two points i, liways I curvt. In light <>f th is I"'int. ma,hematicilns Iu,.. gr ...... li.u:<! the <On<q>< <>f I £1rait,ht Ii". to ilKlude CUrvN ourfacn. ~ drfi".. g<o<lHic to be ,he .hort..c pI,h belW<en IWO point. on Iny .urface. nOl ju.>'. nat O~.

Wha, has 011 thi.!<>1 t<> do with gr; .. ity~ The connection, i, turns <>ut, t. ~ht. It t.. dtaract ...... ic pr<>p<nyof ~~ht thlt i, olways taU. lhe shone., routel>clwecn IWO points. Forin'tance, i, take, the ohort.. t path from th .... wo.u. )'011 Ire rtading 10 your eyes.

NQW think bad< to ,he amn .. io.c as'ronlut in his a<celr .. 'ing, bb.cked-<>ut .pocecnft. !!ore.! of ""perimmting with I lum""" and f .. ther, he gets ou, • I ... r an.! places i, on. ""'If on ,heldt·lund waH <>f his ubin, at • hrit,hl of"f J.S mrttn. He lhtn c...,...., 10 tho 'ight-hand wall <>f the cobin and, with. ma,ker pen, draws. rtJ Ii"., also 010 h<it,hl of J.S """us. fin oily, ...... ' r1KIiIullufJU On .... lasa SO that i .. belm "ab. horizontally 1< ..... th. cobin. Wh ... Joe. it .. ,ike , he ,ipn.lund wall!

II .,Indo 1<> r<aSOIl ,Iu" ,inc. ,he as'ronaul has firw ,he bnm horizontally. i, wiU hillht wall euctly on lhe rtJ Ii".. So Jon i, ! The anow ... i. ",,!

Whik tho light i. in flit,h' ..,...,.. the cobin.lhd\oo, of .... space· ".,," i • • lIlhe tim. bring boo'IN by th. ro<kt\ motors. Consojumtly, lhe 800< i. moving .It.adily UPWI.u 10 mtd lhe beom. M the li~hl gets do ... , and d ...... to the right·hand wall, the Roo, gets d ...... ond clo;r, 10 .... lit,hl. Or frorn .... I"'inl of vi.w of ,he " ,,,,"ul, Ih.

light grt. closer Ind dooer '0 ,he 1100,. Clrarly, when the beam hi .. ,he ,ight-hand WIU, it hit. i, below the rtd line. The as,ronaut ~ lhe I;t,hl boom curving " .. dily downw:on.l as il ~ ,he cabin.

NQWlit,hl, rtm<mbor.always tokes lhe ,honest palh boIWttIt two poin,,_ The ,ho"." p;uh on ..,m.thing ,hat is nat i ...... it,h' Ii"., wl>tt ... the short .. 1 path on ..,rn<1hinglhat t.cu,vtd i. 0 cu, ....

What 1 hen .rt .... '0 make of ,he 00 tlutthe ligh, beam follows. <Ut'V<d u-.jtdory acmtS the >pac«nft cobin! Thrr. i. only on< poMibk inltT_

pn:l31ion: Th. space inside tho cabin is in som ....... <Ut'V<d.

N<no,)'OII can 'I)uo th.t this i. just an m .... ion caUoN by tho """'I .... tin! . pa,,"< ... ft. The <",ciol point, how<""., i, ,lut tho "'ro' naut !>as no way of knowing th.t he i. in on occd .... tiJ\jl 'pacta'llft. lk could just ...... 11 bo Gp"ri..,<;in! ! .... ity in a room on Eonlt', .urfo«. Acal .... tion .nd ~ .... ity'''' inJi'tingui<h.bk Thi ... tho principir of "luivalrn«. Wh.tthe np<'1"imon, with tho loser boom is actually dcm<>not .. tin,-nJ th" ,IKMS the ,,,,,,,tnd,,,,,. p<>w<r of tho principlo of "'luivalon«-is .hatlight in.ho presenco of g ... vity follows a curved trlj«1Ory. Or to PUt i, .no,her way. g ..... ity 1><00. the pOlh of ~gh •.

G .... ity I><nd. ~gh, b<co .... 'P""', in Ihr pmrnco or g ..... i'1, is oornd>ow <urvrJ. ln fact, thi, is.n & .... ity turn. "",t.o bto--curvrJ .po«.

Wh., n.o<tJydo .... meon by<UrvN 'P~ I. i, rosy '0 vi .... li .. a curvrJ .<!In.« lilt thr.un"", of Earth. !lut that i. b<co .... illwonly

two direclion .. or dim..,sions-north· ",".h and o .. t· wn!. Spo« is • bit mor< comp~Cl1rd ,Iun tlut. In addit;'", to , It"", 'PO« dil1Kll ' ,iono-nonh. ""uth.nst_wn!, and up-down-t~ is ..... timo di· m..,si0ft---1>UI-fulurr. As Einst';n showN, I>owtvcr, .pac< and time .rr rrolly just 1Sp<'<" of.h.r .. me thing, '" it is ......... ICCU ... t.to .hink of thrr< bri"ll foor ",po«-time" <limo",iono.

Pour-din,.nsional , ,,,,,<-timo i, impoosiblo for US to vi,uali .. • inet .... ~"" in a world of th"",-dimrn,iCKt.il objtclS. Th .. rnnn, th.t tho curva'Ur<, or warp;lg" of foor·dimonoionalopacr· tim. i. doobly impo .. ihl.,o .ioualiz •. lIuI tha,·, wn., , ..... ity io: , ho wa'P.g. off"",.· dim..,sional opo«· ti me.

Por,un31dy ..... can g<I ",m. idea of ""'" this ltV.no. lmaginc I ...." of .n .. tlut .ponds its .."i .. ""jst..,,,,, on the ' ...... dim ... sional .urfoct of I laUI t ... mpo~no. The anto can only .... ""'01 lupp"'" on the .unl« anJ It~ no conupt """auo.""r of ,he .po« .bove .nJ briow tho I ... mpoline-thr thin! Jimrn.sion. Now imagine that you or I- mis<hie""us brinp from thr .hin! Ji .... nsion- put a can"",, · ban on tht , ... mpoline. The .n"disco ..... that whrn thry wander n<Or th. annonball.hrir poth • • r< mysteriously I><n.lowa.u it. 4ui1< ....

.. """ably. thoy upllin thtir motion by saying WIth< cannonball i. OXOT.inga f<>r«"r Itt<><1;.,n 011 ,he ... !'orh. pother ....... co.U tho fo= g,rvi'Y·

H"""' .... , from,he Goo!.lik ... n .. g. point of tho thinl di .... n_

.ion. it ;. clto, II>< .nl> Ort mi't.ktn , 'I1><tt i. "" f,..a aUrae,ing than 10 til< cannonball. Instead, 1M cannonNll1w made I valleylikt de

pm';on in "'" uampoK .... ,.nd this i. "'" no""" the polh. of tlK' onlS art bent , ....... 1'<1 it

finstrin', 8tni ... "'IS to ... Iiu thlt ........ in • rtmarkably simiI.r pooition 1<> ,he an" 1m ,h. trampoline. Tho poth of Eorth .. it lra~k throusJ> spiOC< is c"nu.n~y hr"l ,,,,,,.AI lht Sun, SO much 110 thot tho plan'" I"",," ", .. . n .. r-dmtlar oro;t, \,Juite ,..,...,,,,,bly. we<xplain ..... y this "..,tion by .. ying th.t lh. Sun curl> • foret of .ttraction 011 Earth-the fol'« of va-ily. ~, .... Irt mistaken. If WI! muJd 0« things from !he GaJ·liU rrnptrtiv< or tl>< fourth di_ m'lUion-som~hing that i. II impossible for uolO do as il i. for the .nt, to .... things from thr 'hinl dimmsion-_ would 0« thr", i. no such fOr«. Ins • ...!. II>< Sun Iw <Rot..!. val10ylikr drp~'m in 111< four-<limmsion.1 ",au-tim, in it. vicinity. Ind tht "'...,., ~rth foU.,.".. ........ ci"'ular pith l round it is 1>«1.,.. this is tho shon .. t po .. ibl, poth throuw. tht .... rptJ spoct.

Th,,,, i. no forco of !rlvity. Earth i. m.rely following lho stniw.l .. t posoibl. line thro.,g. . pacc.time. It is 1>«0"", spocc.t ime near lho Sun i. warped lhal thai Ii ... , or gco<Jesk, happcoo. 10 be. n.or· circullr orbit. Mmr.!ing to phy,ici ... RlymonJ Chiao In.!

"dtilln Spdiotopoulos: "In gene .. 1 rtlativity, "" 'grovi1atiollll mit,' niOio. What ..... r>ormilly auociOl, with lht mit, of grlvity on I parlicl. is "<>I I {"''''' at .11: The pa.tido i • • imply t<2Vding l iong tt.. ',lroiy,t<:Sl' possiblt PI th in cu ..... td 'pOC<'-time."

A body lrovding olong tt.. · st .... ightest· poloOoiblt pith through opou.tim. i. in f"'" fo.ll. And, sin"" il is in fltt fall il experiences no gravily. ~"h i. in f"", f.1I .round th, Sun. Co~~ntly, ..... do ""t fctl tht Sun', ""vity on Eorth. The astronouts on It.. lntcrnlliiollli

Spaa Slalion a ... in frtt fall aro~nd Earth. Constq~.ntly, thor do not f.d Earth', ! .... ity!

Gravity ,ri .. ,only whrn a body is prnrnlrd from following its ""lund molion. Ou, ""lu ... 1 motion i. f .... faU low,trd Ih¢ tenler of Eanh. ".. ~round th .... ". u'. ttowc-.ft • ..., w< ful its for<:c on ou, bodies, "'hid> .... inl"'I""I as gra.ily. J,," as untrifugal for<:c i. whal .... fm whtn a cornering.,.,. prn'<'lll1 u' from foUowillfl Ih¢ ""Ium motion in I mli8hl I;n., Ih¢ fora of , ... v;ty i. whal ....., fm whtn ou, .urrounding. prnrnl \1$ from followin! ou, ""Iurill motion alon, a g..,desk.

~rohahly. il srern, unntc .... ,il,. complicalrd 10 .~ ...... i"" bod;., .. moving under Ihei' own i"."ialhrough .... rped.pau-lirne ralher than simply moving und..- Ih. innurnct of a univ<nal foIU of gra.il.I;""'1 'lIri1<1ion. However, lhe two pKlUrn ar. not "'lui",,· lenl. finslrin', i, ,uprrior. For • .Iun. lhe thing thlll i, .... rped is not

m....,ly 'plU bul Ih. 'pau-lim. of 'pecial ,.lalivily. The pi<lu"" Ih.~. au'oml1ically in<orpo"'" lhe p<'CUliar in!<rpt.y brl>oY<n .p.« ."d ti"", ntc .... ry 1o mp lhe .~..J of lip.1 • 'O".I.nl. fin ... i"·, pielu", also prrdict, II<W lhings..

Think "r lhose '"11 "n lhe ' .. mp<>li .... There .... more Wi"" )UU an do ",ilh Ihe main-tal oftbe trampolill< Ihan mtKly dop .... il with I heavy ....... lik. cannonboll. For iml.a""")'>U «Iuld >halo: <HI< romn- up and down. This would au" rippin in Ih. fabric 10 .p ... ...t OUIWltNI >cross lhe I ... mpolin. likt rippl .. on lhe .un"", of.

' Mool propl .... ""'< til .... Iro,,"." orb;,~ u.tII or.~ .... toeea." Ih<ff .. no ~ .. ity in ' r-. '""'-',at the __ kilo""' .. ..,,· '" h<igln of til. [nt""R1tioBa1 Sr- Slatlon, .... ity .. only '''''ut lJ p<tC<Ilt woak<t

til ... on earth', ""f><t_ The ",aI "' ......... '''''''',,,.''' .,..;,;hd ..... til .. they .""<hoi, ~~ .... in fr« f,n just u .. rdy" oomron<;" .. """'to< wI><n ,hr<obI< bt<a4 Th.d;JFrr""" io th:o, til.., """" hit thr ~ound. Why' 1Itc,." """h .. round .nd, .. foot .. they fall ,,,,,,,,n:I 'hr ,~, 'hr • ..-f><t CIoroa _., from thr ... Tl><y, thrfrfo .. , foil Co .. ..,- in • <in:k.

pond. In tit< .. m • .... y. the _ibntion of 0 10"" m ... lil:.c 0 block hoI< out in 'pK" can p""'e rippln in the "f.bri<" of .pace-ti",.. Such g'avilOli""&I ......... ha.,., y<1 to I>e d<t«ttd dim:tly. hut their "xi,,e_ i • • uni~~ p.-..Jicli"" ofEinstein.,heory.

Tht facl that wa ..... can rippl< through .pact-time .u~.'h .. • pace is not tit< "mpty, p .... .,., medium im. gined by N ..... "". In-.. e..!. it is .n octi"" rntdium with ..,&1 prop<rt;'" M. t .... Jon not s.imply puD on .,. her man.,......,.. emp. y .poet, .. N ..... "" im"ined. Man.,. distort. space·.im • . and il i, this di.lOrtN .pace·tim. that in lurn .ff« .. o.her ma"er. A, rohn Wh<d ... put it:"M ... ,oils spo«Ii",. how.o "'arp and "'orped .poet· tim. t.11s ma .. how to IYIO>".-

Th.e di"O rlion of sp>«.'im.ca.....,J by. m .... "" bc.Jy takes ,ime to pmpog.at. to anoth<r ma ... ;II>' .. tho distortion of tho trampolint by . nolht, cannonball takes ,ime to ..... do .It< oornt .. oftlt< trampolint. i!«aul< of thi •. gravi.y-warped .pa«,-.irnt-OC" only oft"r • delay, in ~rft.ct accord with tit< co.mic spct<llimil ott by tlt<.p«d oflighL

TI>< foct tha, .poc.,..,i",. h .. "'",. of ,he '1uoli • .., of. ",&I mt

dium 1iI:.. air or "at.,. has implication. fOr largo bodi .. ULr plant" .nd ".~ When ,hey rota" on 'heir ...... they oc'uolly drag spo«.imt around with tl>nn. NASA has ",. .. urtd Ih. df«l. In .......... frame dragging, wi,h an orbi,ing .poc ... peri",.n, coiled Gravity I'robt II. Fr. .. , .. dragging is tiny in .I>< ..... of Earth but ",,<rWIt<bning

in ,It< ..... of. rapidly spinning blod hole. Such . body s.i" al the <y< of a gmll tocnado of spinning space-.im •. AnJ""ll< fal ling into tit< block hoI< would I>e .. hirlo-d oround wi,h ,h. tornado, which no power in .1>< Uni.,., ... couloJ d<fy.

TIlE RECIPE OF GENERAL RE.l.ATI VITY

Ein".in·, n"",,1 tal< on gravily i. now d .... M·.... for i ........... ..... like lh. Sun-warp ,h •• pac.-lin,. around .h.m. O,her m..... fo, i ........... pian." Ilk Earth_ thm Ay flffly unoothri, own in.,.,i. ,hrough ,he .... rped .pac.,..time. The pa.h. ,hey follow,

called g«><lnks, art C\.r>'N !>tau .. lhtsot art Ih. shorl<S1 pouibl. pa.h, in wo'pod .pac •. Thi> i, i •. Thi, i •• ho g.n.,.1 .h«>,y of rdali.ily.

T\w:J.';I. b.owevt,. i, in lho det. ils. W. know how. mass .... body

li~ a planet m<ron in .... rptJ .pact. It I.W tht .!Iaort .. , ~blo palh. 6uI how prt<:i .. 1y does • mosslik Ih. Sun ..... rp 11>0 spact-li"," .round it! It look Einst.in mDrt th.n • d..,adt t" find "" .. and m. detlils would fill • I.xtbook as blg as. pho .... directory. However, Einst.in·, 'I.rli", po;nl for 1M g..,.ral theory of ",\alivity i. rool dif·

f""I.1O .l'I'rtti .... II i. n<>n' o.hot- than m. prin<iplt of "'Iu;...]""". II.t<CiIl ag.in Iht hamm.r and Iht f.,.lh .... in Ih., blackN-o,,1

'p"""",ft. To tht OO1",nau', .hoy appoortd '0 foil to .ho !loo' unde, 5"';ly. T" .IOrn<'On ...... tcrung Iht "p<rim"" I from ",,!Sido"ht hom",", and ,ht fea,hot- were h.ngin, in m;doir and !hoI tht flo<>< nf Iht c.hin _ occtmli"ll up ..... rd to ",..1 ,h.m. T1S<y ~rt compltt.1y wtighllo ...

Thi> ool<rvOliOll i> of Uy imp<>rtOJlU. A body falling f=1y in ""vity fods no ""vity. lmagin. you ... in an dovotoconJ ""moo ....

cuts 'M cabl •. AJ il f.U" you art "'righ~_ )'nil f ... 1 no gravilY. "Tho bTOOk'hrough cam ..... ddtnly 0 .... J..y," f.instrin WTOt. in

1907. "I _ .inin, on a ch.;, in my l"'1""1 offta in lltrn. Sudd",,1y ,h. ,hough' st'uck me: If. man f.U, f .... ly, he does n.,. f .. l hio own .... i8ht I .... takn abock. Tlti. 'implo thoughl <Xptrime"1 mod< a d«p imp"";"n on me. Thi' led "'" 10 'he ,heory of ""vi,y:

Whol io Iht ,igniflCin<e of . fruly falli", bndy fali", no 5"V·

i'~ W.U, if i. ""porienoes no ",,';I)'-Or 1=lora.ion, "nc< ,ht 'wo or. Iht salt"le---tbtn ito bthavior i> Jescribtd ""li",1y b)' Einstrin',,,,"· dal'h«><r of rtla'i.ity. H ... thtn i, tht cn><w point of oon'ac'- m. all-importanl briJ,e----bttWttn tht sp«ial lheory of .. IOIi.ily and ,h. ,heory of ""vi.y soughl b)' Einstrin.

T\w: obon-... ,ion !hoI . f .... 1y fallin! bndy don not fal ito wriJlhl .nd i> l~fo .. describ<d b)' .ped.l relativity "'U"u 1 """" ..... y to exlend .p«iaI ... Lalivily 10 a bOOy .,.p<rien<in, 5ravity. Think of. fMnd ... nding on Eanh and ..". obviously .xpnie .... i'" gravi,y

,.

pmsi", hi. or hr' fttl 10 ,I>< ground. VOII an ob .. Nt l"ur fritnJ from any point .,r view you lib-from hanging upsi<k down from •

ntatby tift or from an .irpla"" Hying \WI. lIu, one point of vi ..... proviJ ... bit payoff. If you imagine tbingo from • point .,r.;.w ,hat i. in frt't filii. thtn you will be w<ighli<u, ... bjtcll" no ,,"drnl;"", Since you f~l no "",,"'ralion,)'OII are jUSlifiN;n uting the sp«~1 ,!>.orr of rd .. ivity ,<> cl""ribt your frim.!.

But special ,rlat;"i. , .. lales whl! Ih. world looks li~ 10 people moving" "",""nl spnd rei,,; ... 10 uch other and )'Our fri<,nJ i • • <;<dua,;n! upward .. I.,i"" 'Q you. That', 'rut. !lut if)'OU dQ no' mind a 101 oflabori ..... calcul.,ion, you can imagi ... your fri..,d trav,ling at cons",n, .p«<!, • ...,,,,,d, .. y lb¢n a' •• Iightly hi~ oon.,.n,.pted rn, tI>t lI<:Jet second, and so on. II ', noI pnftrt. but r<>u

can appro.im:no l"ur frimd', accdowin" as • series of rapid .t<pO up in .pm.!. f.,,- uch'f'«'l)'Ou .imply ...... r«ia! ttI.,i.ily 10 .<11 you wh.1 is happ<ning 10 ,I> .. pact and 'i ..... of yourfrienJ.

Aero..!i"1 to .pecial,.I.tivity, ,inK oIows Jown tor a moving ob-oervrr. It th<r.ron, foil.,... , ..... tim. !I""" down for your fri<nd ,in«

your fmnd is m<Winl ",Iati ... 10)'0<1. 61.1' ..... i1. Your fri..,d i. movi", ",La,ive '0 you btao ..... hoe or oht i, ",,~ien<in, , .. vity. II fuU.,.,.. ,ha' I!J""vi'r m .... ulow <I""", ,i"....1 Thi' .hauld "'" bt 100 mw:h of. '''rprise. M,er all. if gravi, y i. >imply lhe WlIrp.go or .I"""-li"..... il stond. 10 "' • ..", Ih., if wt or< ""J><ri..,cinSV"vity.ou, .patt and ou, ,i".... mil", W diSl","I<d in 00".... WlIy.

Thoe o,her Ihi", tho. foU.".. from ' hinkin, .bool you, fmnd

".nding '"' Earlh·s surf.a is Ihal if gravily ""'''' Sln>ngtr-say your fmnd ...... ".nding "" • ",..".. ma .. iv. pl."",-hi. or h<r.p«d rd.· .ive'o)'O<l in rr.:~ 1>.U would go. f .... ,quid, ... Aa;ordin,.o.p«i.ol ",La' ivily. Ih. f .... , ...,,,,.,,"" m.,...., Ih. ""'''' Ihoi, 'imo.!l<>wS down.

Coo""!U..,IIy.1ht "n>ngor lhe gravity OOlntOn. i. ""perit""ing •• hoe m"", ,hti, ,i".... .Iows down. Whal Ihis mnn. is thaI if)'O<l ""'k "" .he gfOllnd 0""" of an offi~ building. you .g< m"", sJowly Ih.n you,

rolltajl .... who work on lhe '''1' floo,. Why! 11« • .....,. bring dour 10

'" fal1h,)'OU ""ptrinla a mo", pownful ""U. and tim. 'lows down in

""""g" Sr2>ity. Earth',gravity. hovontt. is ~ry ", .. I<.. Aft ... aU.)Uu an hold your

arm ou, in front of)'>u onJ nOi even the g .... vi.yofthc ~ti'" Earth can ro",. you to drop it. The wc:ox ...... of f.ar1h', gr.Ivity mean. that 'he ditkrenu in ,he flow ra1. of time b<t~n lhe 8"0,,,,<1 . nd 101' fIoon of CV<'n ,I>< ,011<;, building i. n<Hly imp""ibl. '0 mta<u~.

The ~ning .... n<, wi1l. the twin .in ... aging II v .. ,ly .lifT.",." ro'" in tilt;, u;)'Krap<r _,1:.1'10«, i. th«<fo,", • gro .. .".I\8 .... 'ion. Ntv·

rt,heb.. tho<. .n: pla.;n in ,he Un~ with fIr "ronS'" g, .. ity. On, rio« is Ih, ,urf..,., of • whit. Jwuf otlr. wh<rt.ht gr.Ivity is

much >lro"gor ..... n than , ... Sun's. Einstein', theory of !<2\';,y ~. diets th.t time for Ihnt ot>n should ~ 'lishlly slowtr than for ... Tes,ing ,lICIt . p~iClion might ~ ;mpo .. ibk Howe .... '. Utllr' h .. wry col'Mni<n~y provi<kd .. with "d<>cb" on "'" "",f.en of

whi,. ""'orf •. The clocks . .. actually aloms. Atom. ,i"" Out light. ugh. i. aau.ally. wa .. ,hat undula ... up

.nd down like .... "" on w:ot ...... nd .tom, of p ... ,;ew, .Innm,. such .. oodn.m or h)'lrogtn Ii ... out Ii",. !hat is uniq",,'o.1I< ~I<-m""" undub.ing. cl>ol"OCteriSik numbo, of ti ..... ~ 5«Ond. Thnt undula.ioru can be .hou",. cl .. tht.;.:u cl. clock. (In 1ioC!,!ht second i, defined in l«m, of.1I< undul •• ioos of light given out by • p.rticul.r'ypt of •• om. )

How docs .h i. P'~rty of •• oms II<lp US _.II<~"" of ~.i.y on .imrl \~U> with ou, ttI""""pn _can pick up . 1I< li"'t from . , . orn.OI\ whi •• dw.rf •. W. can.h<n comp.~.11< number ofundul.

.ioru p<r KCO/Id cl.1I< Ii",. from, "y, h)'lrogtn on a whil~ dwa,f, with tho< number of undulations PO' oe<ond <>f h)'l"'li"" on Eanh. Whal _ finJ is 'h>t .h.", an r...,..,. undula.ion. PO' 5«Ond in !ht li"'t from • whit~ dwarf_ U",. is ""'~ oJuggi"'_ Time runs oJower!'

'For """nkol ... ""' .. thi .. 1kct ~ known ...... ~ ..... i .. tior>al rrd shift.

'"

W •• ", Kring. dir«t confirm.>.ion of Ein ... in', , .. "",.1 theory of ",La,;';ty.

And thtu ott .IarS known as ntulron ,larS with nn "'0"!l'" gravity ,lui" .ha. of whit. J ...... ,.{" M. mul! of the .. ron! g .... v;ty. limt on ,tit surfaLe ofa nru,ron otOr P"'1If6"" on. and. h.1f limn mOl'< slowly th.n on Earlh.

THE CONS EQ UENC15 O F <iENERAl RElATIVITY

Tim. dila.i.m i, only .,n. of tho ""vd p«<li.;:.ions of fi .... .,;,,', ,ontl'lll.h<ory of rd>livity. Anothtr, .Irudy ,wchtd on, is lht exiSl."'" of , .... i .. 'i,,""1 wavn. W. kn.ow.hey .,i" 1>0< ..... astronom ......... oh<n-vtd p.in of ,urs. wh;rn indud •• t I .... one ntutron star, 1000in~

.... "8Y as they 'piral in IOWOn! _" 0' ...... Thi. puuling 10M of tn-trgy c.n bot ""plainN only if it is btillJ! c.rri«l :nny by ,r.lvita.ional

"'''''' .. Tho< ,aU is now on to M'<C' , .. vi .. ,;""'1 waVd dir«dy. N they

p ... by. thry .houlJ al,..,..,<ly .. meh.oo oqu""u 1iP~. &I"'ri

",.,"IS desisn«l to <kIM thtm lht .. f"", uo. giant "rule,..." many kik>mtt ... long. n.. rult .. or. maokofhght, but.he;d .. i •• implt-lo ddKt lhtdl.nge in Imgt/> of tht rultrs"'l!J'Ivi'.';on.1 ...... ~ rippJ .. ,."

Anollla pmJic' ion <>f Ein.ttin·,IMO<y..I<) fo, p......J 0"', with_

out co''' .... nt. is the bmdingoflight by gnvity. The .. ...,., fo, this bmJiJ\j!. of""" ..... i. tlu, Ii"" must ""gilt . ... the wa,ped t.rr';n of foo'·di .... nsional 'po«-time. Although Newto,,', law of VoIvity p .. -dicts no such elket. it don when combinood with tn. .pecial relativi.,i< ide. tha,.11 forms ofene<gy-indudinJ ligh,_hoY<.n efkctiY< mau. As li"'t pilSSH' mass;"" body Ii\;t th.t Sun. it thtrefort {ttl> the tug of ,'avity .nd is ben, .Iightly from its COUrK_

Of rou ...... pro.1 rtlativity is inrompotible wit h Ncwtoo',I_ of

g,avity. SO 'hi' li"'t·benJiJ\j! prNktion Ius to be toktn with. pinch of salt. In fact. ,he <tJfT«1 thro,~roI rd.tivity-pmlict.,h.t the poth oflight will be bent by twi« .. much.

,.

Thi' <:>, ... roctor of two s<,...... 1<. hislllight ..,me,hi", ."bd • • bou. the prindplt of ~uj ... len~. Ilo<.U tho ~imtnt in whi<;h

tho as,ronaut lim! lht ~ horil:ontally """'" hi' opaccaaft ... d <>OtieN tn.l the beam W;lS be1>, downward. Ika.UK 1~ W;lS no w~ ht could know ht was n04 cxpn-itncing r;ravity in • morn <>n Earth', .urface. it wo. poosible 10 dNucc th. l gravity be ...... the path of light \VdL ,ha. i<.li"I.1K in h<",. You _. it t urns 00' that it "!">"ib'" for the amonay! to 1.11 whether h. is in • rockct or on Emh', ... rfa~.

In til< >cult"";"g rod: .. ,. the forct tho, pins lhot as'ron.ul'o feel to'M n"", pullo him ~niuHy downwanl-wh .... n h. , .. nds in the cabin. On Earth', surfact.~. it matttrs whtrt you .tand booILIK gr;tvity .1_,.. pullo things Iowan! the """In of Eonll. Con· otq..nltly.Wovity pull. in "1'1< dirK!;"" in England but in tilt oppo_ .i~ dim;lion in New Zealand-to tb¢ English, 111< New Ze.lande ..

• r. up<i<k down. an..! via ...... Now, tilt dim:tion <>f the pull of

gravity docs not change 100 much from " ... oklo of. room to 0"",na. ~nhdd$. with "",o.itiv .. roough m<a$Uring i"'trumm .... our "'ronau' ",uld alwa,.. &,«, ~ chang. and ~II WMtOO hr 10",

in a rock! occtlt"' ing ou, in spoco or on Eulh' .... nau. Surdy •• hio in",lida ... tho principl. of "'Iui",I.,,<o and bring>

'he whok «.iiti"" of g." .... 1 rtla,ivi,y ,umbling d""",1 wdL J"u migh,

.hink '" ~ .... to ",ns"\Ie' • thcoryof ! .. vity i, ;,. ",me;"'t only ,h., tht principle of tquivale""" apply in tiny ",Iu",.. of 'poc." and

in c;trtmdy 'iny. 1oc. li...J volum .. of space you can n ..... dttecl chang<"< in tho dUttt;"" of 8rm, y.

What has 'hi' gOl to do wi,h Einstein·,'heory puJiC1ing ,wi"" 'he light dtflt.c,i<>n of N....-ton·.1 Welk we h.a", .. tablish«l,h., tht I ... r ~m will be brn, downward .. il tr~. room on Earth·,

.urfoco .• nd thi' amoun" u'''' OIl' to bo roughly wh., N .... 'oni.n ,,">'ity Pffilicu. Now imagine that ,be tQOm i, in fr~ faIl_y i, Iw bttn Jropptd from on airplant-<lnd ,ho "'ronau' carrin ou' tht .. me c;pori .... nl. In fltt WI ....... robor. , ...... is no , .. vity. So lho

ligh, bo.m should ' ''' .... 1 horizontally aaou ~ tQOm and nOl be brnt al . 11. ~u, nOl all part. or ,ho room art in a porfce, J1ate of fltt

fall. lkaust £ot1h', gravity pull. in on. wr«1ion from ont com ... of the room and from • diff~nt dire<t;"n fo,m the other 00'''''', gravity is not p<rt«1ly "".,,,IN OUt as the room falls through 1M .it, lkaust of ,hi .. who"he .. tronau' . ct""lly .... i. the ligh, beam bent JownwaN by roughly the .. mt am"unt as in tht ,oom on £o"h' •• ur1'au. Tht two tIT"" .. odd ,oge,her,o gi"" ,wi« the light bending prtdic,..! by Newton'. theory of g",vity plu, ' peci.1 ",!atMty.

So if lhe light from. distant .. ar p ...... <Irut 10 tht Sun on its wq ' 0 £o,th, ito traj"",a<y ohould bo< bent .bout twi« .. ,h. rp!y .. N ..... ton would 1» .. predicttd. Such.n eff«t WOIlId aus< tht posi-,ioo of ..... to ,hifi slightly "'I.'i .... 'o o,he, " . ro. Though impas-.iblt to ... in the 5i'" "f daylight, it i, oostrvOblt du"", • tOioi tdips< when the Moon blots OUt,he brigh, so!ardisc. Sudt an <dip .. w .. d"" to ,,"u,on May 29, 1919,.nd tht Engli<lt O<I""'O" It, Arthu, Eddington ,ra>'d«l to,he i.l. nd of ~rincipt off tht ~ of w .. t Afria '0'" it Hi, photograph< ronfinnN , hat ... <ligh, .... indt...J dt11.<t..! by the Sun" g, ... ity by .... ctly the amO<lnt predict..! by the gmtralllttory of ",I .. ivity.

Eddi ngt""'. obotrv;o, ion. rno<k Ein>,ei n'. rtpu,.t;"n .. "t he m.n who p1"O>/«l N ..... ton wrong: 6ut il was not th. tnd of gentraJ ",!at;'ity'. JUC<tsSful prediction>. NewtOO ...... dtmon>'rot«l tllto-rttially that tilt pl ....... orbitt<! the Sun not in circles but in tniP"'" squ..tted circl ... He pl\Wt<!lhat ,hi. was • dire<t COft""luenc. of the bet th., the for-tt of gravity dro"" off in .. ",ngth with. ",,-<:alIt<! in"" ... ·sq"" .. law. In o,her words., whcst you a'" twke .. for away from the Su,," lhe tOree of grov~y i. fOur ,imes as weal:; thltt t im .. IS &roW>}'. it io niM 'imn IS .. uk: .nd so on.

Rel.tivity <It.ng.,. ......-yIhing. For a "''',all fonn.of ..... ,-gr, not ; ... t mus· ... "'!y, g ........ gravi,y. Now gravily i",1f io a fonn of enttgy. Think of. wa,p«! trampo~ne .nd bow much dlSt;' ttlt1"5y 'hat con, . i .... Sin", gravi'y i. a form of ttlt1"5y. the gravity of tht Sun it .. lf ITt.I .. gravity! It', . tiny tffe<t.nd moll of the Sun', gravity

,.

.till coma from iu m .... N .... rlhtlcss., cloM in to III< Sun. "'Mr~ vayity i> "rong. t~ i> ...... n (%I", <:<>n,ribulion (rom g .... ity j t ·

.. If. Gon~"'Rlly. any body orbi, i", lht~ rtd,. grrvilalional.Ufl grel~ than •• p«ted from , .... invOlW >qua" law.

Now_M ,hi. i. the poin,_plantu foU"", dJiptical ,,,bi •• only if .hey "" hting lUF by olOreo obeying an in~ .... ·sq ...... law of for«, Th;' .... &wi",,', di<covtty. R<lativi.y p~;ru tlut til< r""", doe. no. oo.y an invent·sq ..... 1.10'. In fact, ,I>cr. orc <>1M' effects .hal 01", co ... I dtp.nurc from Nc-N,ooi.n gravity. lik< 1M (oclth •• ",yity"kes .imo II> tro".,! """'" '1'"<0, n,. V".o,y , ho' I rnQ'Oilljl

pia"", fcd •• , any momen, .htKfo", <kJ>nlds on il' posilion.' an •• rli .... 'im •• nd. bt<:ou .. oftM .. i, not .Jil'«,W.owaN . he <kaJ ""' . Itr of 'he Sun. The up.hot i,w, planets cln no. followcUip.iai ",tho ,ha, repeal but ra,her .mptkal patlls which gnduaUy chang< thei. or;c,u.,ion in 'poct,'r.lcing oul • """,It.lii« palt"-rL Thi1 is no. "",. ,kelblt far from 'M Sun. The bigs." efT«. i. cIoK in, wlm'< gravity i$ .IIrong ....

Sur •• ...,ugh, ,hen it ",m<thing oJ.! .b<>u, tho orbit of tho in· n<rmoot plant!. M<r<:~ry. For oomt timcfOrt EiIU.oin puhliWd hi, .hoory of S .. vity in 191 S ... tronom .... h.d betn puultd by .ho (o<"h.a. M<A:ury', orbit graJually .rae .. Out • ,,,,,,,,10 p.lI ... n in '1"«. M()5( of this .fk<, u d~ 10 ,ho ! .. vitalionil pull ofVtn\IJ .nd Jupi • ..-" Tho odd thing. ho~" i. w. M ... ""y'. orbit "",uld .!till b< • ...a"SOUt a ro ..... p.II.,n ...... i!V",U,,'MJ Jupi,..- ....... Mot '~.It ua.iny riF«1. Although M.reul')' orbits . ho Sun on« cv<ry 88 Jays.. roo<ItO i"rocN 00. only OftCC .=y J ",i/!i"M,...,r>. l!emarkably, thi' uoxo<tly whot EinSl<in", thwry pralict<d" Uoingg ....... 1 rtla.ivity. ho ""uld uplain <wry Ia .. d ... il of M.rcury", 0"";'" Wi.h ~ 'lIO.ho, ,ucus.sful pr<-<licliOft un<kr iI' bolt •• hor< could bo no doul>l.h •• Ein ... ;n hod discovoral tho <:orr«11h.oory of ! .. vity.'

'Or ........ "",rbbl< thoory fo< lht .im< bt;,,~ .in.« ..... ~ "''';';'1 is _ ,,"","~I to bo th.l ... "",rd on II-""ity.

TilE PEClIUARmES OF GENERAL RELATIVITY

~ ... ..J rtlativity i. a fantUlically dogant th..,ry. Noverm.1no. i, i,

l",m..,Jo .... 1y difficulll0 apply 10 ",.1 .ilualions--for in.to"" •. 10 find lho warpago oI.~ •. lim. caused by a si"'" distribution 01 m ....

Tho", ...... is IN'lhe,hewy i. ratll<rciltular. Man .. ldlup"u-'i .... how to warp. n..n ... rp<tI 'Pac~lim. I.U. rna"", how 10 mO"". Th.

mo"er. which N. jU<1 mo.-N. tells ~ce·'ime how 10 chang. its w''P''S'' And so On. oJ infini'um. Thor ••• kind of chicknt-.nd"'8I!

p" .. oo.- al lilt IInrl of 1M !Mory. Phy£idst.call il nonliMarily. and nonlinu,ity i, • touj!h nu, for!Morists to crack.

0"" maniftstotion 01 nonlin .. rily oI",oJy "",nliontd i. Ih. fOCI ,hat ,r;wi, y i, a sou,"", of ""vity. 1'.'.11. if 8rovity co n malco mort g ...... ily.,N, e"'a g .. vity can n>ok< a 1;ld .... o", g .. vity. and so on. forlU·

notdy. ""vily is so lOuk ,n., Ihi' is nol normally a fUn_or pn>C.fl< and ,II< gr .. ily !"' ... rated by a ...... i ... body i. u ..... 11y .... 11 I><h;wed

u.ually. bUI BOt aIw.,.s. So"", v .. y m"";"" .to .... nd lhoir liva in 0 .p«ta<:ularway. Uou·

oily, Uta, il p,.,..."...J from I><ing crush...! by its <>W1i , ... ity by II>< .tar i, go ..... "ing hoot. Whtn il ,un> oul 01011 po";hle fuels. il .hrink<.. Uoually. lOme OIhor form 01

p ....... ", in .. """,,,,", to m~ a wbitt dwarf 0,. n""lron .to,. "'r<'-do"", ... nor.mho ... Howevor, if t ilt star is .... '1' massi ... and its g ......

ily i, Ynf .. roog. nOlhillfl <an S!"p II>< .torfrom .hrinking down ' 0 a

point. A. far a. physici ... know •• udt st ... ~,e"'lly vanish from e.iS!· .nu. H~.lh.y I ..... ",,,,.,hing bobin.!: '00, g .... vily.

WNI .... . .... I.lkillJ! .boul htr< a", hlacl: holts, porlI.1ps tM moot bi ... rT< of all m. prodiclioru of g ........ 1 relalivity. A blacl: hole is a

"'Ilion of .poet-limt whore gravily i, ..,strong thaI nOl .... n ~ghl can ncar< i' -h<nu its blockn .... And ·"'gion of.poet_Iim." i, lho "p • .,..,i ... ph .... , for 'M mass of tho .tar hu !O ....

H<>w can J'Ou Iu"" gravity without rna ... ! won. u .. ily ari ... nol

JUSt from mass but from all form. of m..-gy. In lho casc of til< blacl:

hoI~. its own gr ... i,y ,,,,a,es mort gravi,y and ,ha, .x'ra gravi ,y crc-. t .. mor< gravity ... .., tb¢ holo r<g."",rates itsdfli'" • m.n holding himstlf in midair by hi. boo, straps. From tho .pact-'im. poin, of vitw •• bIa,k holo i.littrally. 1>010. wt..,,,, .. 0 .... r Ii'" ,ho Sun creot .. a m...., Jimplt in tho "lHo~nding 'patt.tim •.• black hoi. product< o bottomless .... 11 into whklt m.ttcr fan. bu, can lit ...... acap< again.

AI. Nobo.ll'ritt.wi""i~ pbysici<1 S~bnhmanyan Chandra;okhH obstrvoJ:"Tho blad: holes 0( na' u ... a ... ,h. most perfec, macroscopie objects 'h...., .... in ,he un;"",...,"'" only .km..,,, in ,heir

""." ' nleti,,n or< our """"PO' "f .p..,.,.nd ti",. .... lice ...... 0( .heir wtraSlro~ gravi'Y. hI.adr. ""leo rtvtal ,he m,,"

drama'ie .ff« .. 0( g..,or;al rtb,ivity. Surrounding ,b¢m i. 0 .... rf..,., known as an .,...,. ""riwa This mark:! 1M point 0( DO rt1urn roc obj«ts straying too do .. to the blad: hoi., If you "'0Y«t in dt>oc to .h • .,..." hari""" you muM"", .h. hKk 0( ftlur head .in« light fm", behind)Qu would be ben. an 'h .... y around ,he holo beforc r..ching ftlur q'<S. If ftlu muIJ oo"",oow ""'= just o~"id. 1M nrn. hari""'. tim< would now.., <lowly for you th.t you could in.heory .... "h .he ..,tire fu,urt of.he Un;. ...... nash pas! you ~.., a movie in fast. forwan.!!

".., (KI,h • •• i",. ruru for mort .lowIy in 1M stro~ gr ... ily of a blad: hoi. ,han .b.""", .. in .h. Uni"" .... has an intriguing 00 ..... · qu..,a. lmapne you.rt far _If from a black bolt ond you have a friend lingtring ,to.. to it , 1:\<C.a"", of ,h. ntorl:N diff....,cc in ,he flow 0( ,i.". for both 0( you. whi\t you go from Monday .0 friJ..y.

"""I<Tln"'bloc~ hoI.· .... oo;ncd by loon Wh«kr in ,965. 1Itfor< 1965 thtft wtft vtry f<w scitnlili< paron on " .m 00;":"- AIi<rw>rd. Iht fotld aplodtd. The l<rm h .. <Y<I\ .... ttrN ...-ryday lang,,",", P<oplt oft<n ,ok about thing< ru..pp<aringdown. bot<>.otera,;"bI"", hoI<, Th"trnl i .. pt"

k<t a, .. , ... ,.,., of,t.: ;mpot""""" of 11'1';'" ,"" ",h' wor.u 10 do:1<tib< a pt.:OOmtnon in un«. If 'hc-r ~'" • vi¥id piet"r< in pcopk', mi ....... ... rdt ..... ", onract<d 10 ,t.: ."";..n.

yo~' fri<nd P"'V ..... only f,om Monday '0 Thndoy. This man. ,h ... if you wuld fi..J1O .... woy,o .piri. )'>~ ... If """'0 your fri¢..J·, location.. )'>~ coW<! 5" from Friday back 10 Tutsd.1y. y"" could ....... 1 t>;.ck in .i .... 1

11 'unLS o~ •• ha •• hrrt i. in fact 0 .."y '0 .piri. yo...-sdf from on< Ioca,ion 10 onOlher. Eins.C"in',.hwry of ,..1o' i';'y permits.he e.ist.nu of " .... rmhol ... - ,unnd_Kk< shorn:u ... hrough "'.a-1i ..... By entering on< mou.h of '''''h' .... rmbole and .. i.ing a mou.h near yo~' friend, i. wo~ld ind«.! be poosibi.,o AO back in .ime from FriJ.oy '0 TnesJ.oy.

TIlt .rouble ",i.b ...... rnholts i •• hal.hty ..... p oI\u' in on inslan' unltss held open by moU .. ",ith ~uls.iv. gr;wi. y. Nobody kn".,.. whe.her ",<It "notic mo".,.- .. i.u in the Unim-w. Nt>ttlhtl .... . h. u'raorilinory fac. ,..n .. in •• ha, Einstein', theory of va';1)' don not

rule "". the po .... hili'y of tim. ' ...... L There _ a few diffcnnceo, howe .... ', belwtCft ,be kind of..,i ....

lIUdline" permittrJ by srnrra.l ~I .. ivi'y Ind lht I)'P< drocribftl by sci .... " f>CIion wri .. " ~k< H. G. WeU,. For one 'hing. you h;ow 10

'ra .... l. disto ..... bm",h .pact to .ra .... 1 I dis .. ", •• hrough l im •. You cann", limply oit "ill in. 'imelIUdl;nr, pull I Iev...-. ,n..! find your

.. If in I n 6. And o.!<COn..! impo<lIn' Jifkrtncr is 1hl1 you ann'" go t>;.ck to a Ii .... before )'>ur li_ mo<ltine was buil,. So if you .."nt '0

go on a Ji ...... uT .. fori. building 0 lin>< ma<hinr .oday"';U n'" help. y"" ",ill ha .... 'o find one buik and abondoned by .. 1"" ....... lri.l. (or <Ome ""y 'm .. ' din",",ws) 65 miUion years .gol

To ,hwri" •• he poosihili.y of . ime machine. i ..... ry un .. "ling. If ,ime .ra .... 1 is po>Oible, all _" of impossibl. oi,ulliono, or .p..-.~. rai .. their ugly heaJo. TIlt """, f.mou> is the g"",Jfllher pa ... JM in which. m.n gors had in ,im< and shoot. hi. grandfa,hrr befor. he concr; .... ,he man', """h .... TIlt problem is, if he shoot< his vandfillhrr. how can he net be born 10 go bad in 'i .... and do ,he dirly d«.!!1

F.mbarra ... ing qur<.iono like this haw prompted 1he Engli'h physicist Slephen Hawking to propose.he Chronolot!y prol<c.ion

cooj«tu, •. Basically, if. j .... t a fancy nomo for an outright han on tim. t .. ",,1. A«ONi"3 to Hawking, ..,..... u_~·unk""wn law of physics m .... t int.,,,,,,,. to p, ... ..,t tim. t .. ""L l-k h .. no cast· iron .,..;d..,,,,, of .w:h • low but .imply ask&: · Wboor • • r< 11>0 touri.t> from tho fu.urrl"

Ein,,"in hirnsolf d;.J ""t bd~ that tim. ,.. .. 1 was po"';bI.,do.pit< "'" fact that hi< throry of ~ ..... ity p~i<1<J i •. He .... wronJ. howoY<r, about'''''' ",boor p~iction. of hi. tl>oory. H. did nO( ho· Ii .... that black hoi .. ....,.. possibl., and today "'. haY< ""ml"'l~ng .,..;dm"" that .hoy .. i<L And 1>0 did "", bool~ w ..... hi, .11«>'1 .... tryi", to toU him about tho origin of tho Uni..... th., it hogan in a Big !J.ang.

THE ULTIMATE RABBIT

Our OFA HAT

H(III .. lIIIUID,..,.,..' u.",I\(,,~ om 11I$Il . ...... III"M\ ... .. A __ 1]..1 RIM nMS AM

... w/O.",oIo/Jit is p,.!W DU' of. top ,..,. 8«._ ;, ;, "" .... ..-Iy

"''1'' ,./Jbi, .• It< rridr ... f>i,.,." of,.. ...

111.,. Q" high.,tdJ gI""". Akr<ly b, ,,,,allint" Lwb "" ~ Im-. you am "runt· 1M", I" _ .. U lcirrJ, '" lilli, "",,,,all, inv"ibk ro ,b. h""" .. ,, ~_ y"" Ide 1M'" """Uk .... " roId, .111".,. "igll' "ltd ,tart twiJ· J1i"l.

711< fi ... ' thinl J'O" >« is 1M sky in u/lmvio/". light I'umptd , .. " b,

"~,, ",,,<h /wll" 'M" t/w s.. ... So .... f"", i/;", .... " IIa .. ",niJh,J, and so ............ 0 ..... """" swum in .. view, ,h",OMltd in min, nt/!.'"";"'. Tht

"''''' "'iki"l fou,,," tf 1M .t,. ""-w" i. ,It. ........ as il ww for .". ""btl . .". sl" I,,, "",,,I, hl""l

You twidJk.",.

NQw ", ..... _;n8 X.",,.. high.~"J' hgh • ....dialN b'l'" ""'"d II> h"nJrtdI of Iho .... ""I. of dtg,.... ... ilswi,,. J.o .... MIl> 'Mlic ob;t<ts IiI>! />I,d Itoh 0>1 ... <>gain, ,"" _$I ",iling/t"'u",,,,,1ot >I.', if ,ha, i, is ""',,,, bMd.

You ""idJk back'M Oilier ""',. ,'ppi", h""t Ih,.,ugh uk",";" .. , Ii,", "nd ",iblt ligh' I" irr/mm) ligh •. ,i....., 0'" b, obj«tJ mud. ",/Ja

'''''It ,Itt S~~" ~ IItt sky is pt~ by SI,II", ... b....-",. '" 'to

,.

TI" ULTIMAT .... INT OUTOf. " .. T '" "'III, bOf'll ,,,., art >/i/J .W4lhtJ in .himmt,ing pl4ctnlll1 ga< and

hlOQ'N m1 gian" in 'hei' Jo",h 'h ....... 1I"'.u.pi'~ ,he fitrt ,ha,,1t< ok, is /il b, It _ ~"..141;"" b{ ,,,,rs, ill "",It "rikin8 IhinS _in. lhe

"'_./1 is "",sri, b/ad:. y"" ,widdl~ "". N_ "'~ art uti"8 mi<""",,_ht l:ind afligh'

wstd ~ """'"'. mobil< "",,_ and m~ """ .... II", wmnhing oJ.l i, hal'/I<ni..g. 11r< ,*yi' l'"i"g brigh,,,. Nfj, j,," bi,. <fi_1I <fi,!

y"" ,,,I;e off ,/to g/4ssn, ",b "...r.,... lind pw Ih .... 1>0,,* en. 0", ""'hing "'" ""'ng<d. N_ 1M ... holt '*y. from hori""" ,~ /oori""". is glowing It "nifi"'''. f><arir whi,,, Ya" twiddl, ,"I1Mr. b", ,/to '*y jim gtll b,.;ghU, "nd brighl". 11r< ,../wIt <f'p4U _ la ht gI_i>r8. II~ /il, ".,i"g in.id, a gianlligh'b~lb.

Arc 'M gla<on malfune';"ning! No.1My "" _,kin~ r<rl"<-<tly. Wh., )'Ou ... Sfting i. 'M cumie NdgrounJ radiation. tM .. lie of 'M fi...bal l in whim rhr Unn..rw waS born 1) .7 billion ~.,., ago. [nerd· iNy. it "ill ~ ......... ry p"'0 of ..,aco. ~r .. tIy "",I.J by 1M a·

pan.ion of ,h. Univ.n • .., 'hat i, no'" app"" .. low·.norn micro"';"', ... ,he< thon visiblo ligh •. lIdie .... i, ,>r ""t. tM """,,1<: badground rodiation "",,unlS for an '!loni.hing 99 pnunl or rhr light in today'. Universt. h is incon1rovtl1ibl. prool"thol,h. Universe bq;.n in • titanic oploo;"n-rhr Big l!an~.

The cownie background radiation wu disc.........J in 1965. ~Ut tho , .. Iiution lhallh~ ha.l t.t..n a Big Blngac, uUy amo .... lia. [n

fact. tM fon, "Of' WUl.km by Ein".in.

mE UlllMATE SCIENCE

Ei ..... in·. th.eory of gnviry---W.< g ..... ral theory of .. lotivit)""""-'k.

scribn how""''1 chunk of malin- pulls on tvtty atM' chunkof mal· ,or. The biggest co[lection of mal~ we know ofi.th. Un;,.. ..... No .... ' on. to .... y .way from lh • .. oily big problems in scion«. Ein<'oin in 19 [6 appliC'd hi. 1h<o'1 of sravity to 111< who" of c .. ation. In doing

,. so h •• r .. IN cosmology-lhe ullimOl< ",i<cnce-which deals wilh lhe ori~in, """lut;<>n, an.! ukim.,. fat • .,r 1hot Un;" .... .

AllOOugh Iht KIt .. hthind Ein ... in',thtoryor , ... i11 Ort dtctp-lively ,imple, lb¢ mathematical . pp.,..'''' i. nol. Working <>II' """,111 bow" parlku.brJiotrihul ian "r m.U .. warp' .pau-lim< i. very hord indeW. l! was nOl until 1962. for instonce-almou holf. century "fie, Eim,rin publi>hrd hi. p'na.i .htarr of ,,,.,wily-that New

Z .. !Jnd phytic:iSl Roy Ktr' "!cUlliN lhe di'lOrtioo of .pa~li ..... "us«! by • ",>lillie, spinning. black I>ole.

Figuring out bow II>< whol< Un~ warp. >I""'''''';mt would ha .. btm impo .. ibI. without m.king.., .... 'implifying ..... mrlions .bout how ilO m,mer is .prnJ throughout .po«_ fin ... ;n .... um«l th.t it m.kts no iliff.,..,,,,,", whtrt in tIM: Uni ...... on o""rver h.p~ru 10 he. In .,Ih.,. words, h< assumed ,h. tt'" Uni ....... "'" the "\I"C gm .. pr<IJ><r\in ... herr.....- )'OI1",..1ooI1«1on<l, from wh<~r)'Uu Ort JoalN, illooks roughly lh ... ,.,. in .... ry <li",..,.I00.

M.ronomial oborrvations ,,;nu 1916 h ... actu.ally .hown ""'" ..,urn",i"", to "" ..... U foundo:J. n.. Un .... rw. building block$-which EinSl.in.nd ... oryon. d .. "",,. una .... ,.. of., ,II< lim ....... ,. gal .. ;.,., ",,'1 is4nd. of .tars IiI<.: "ur own Milky Way. And m<><l.,.n Itkswpn d" ind«.l.how IlI<m 10 I>t SQlIIOrt<d p"uy tvn\1y around lho Un ........ .., lho vi.,.. (rom on. pluy i, mud> tho .. m ... tho y;"'" from any 0100.

Ein.loin', conclusion. aft •• applying hi' thoory to III< Uni .. rw .. a whol., was llul iu "",",II .poc .... lim. mUSt lot wup<J, Warp«!

'p;>a·lim., how .... r, causes malter 10 m<w<, Thi' ;' Ihe anlral man· Ira of gm .... 1 rrialivity, Conoe.qu<nlly, III< Un;. ..... could nol po .. i· bly I>t .tiU. Th" di.ma~ Ein,,,in. Like Now,,,,, I>tf" .. him, h. ftrVtnlly I>di~ III< Uni ...... lo b< .talic. il.< conSlilu.nl bodi<snow k_n ,,, I>t p!uin 5"'pondod .... ntially mOIi"nless in tho ....

Ana,i< un' ....... wasappoalingboau .. ;' ,.main<o.l tho,.",~for alliin><. n....., was "" n<nl'" add"", stidy q .... tio .. aooul who,..

TI" UIIIMATl ... INT OUTO •• HAT ,.

'ho lJniv ..... COm< from 0' "'MrO i, "'as going. I' haJ no !><ginning. It haJ no onol. Tho moon tho lJni ........ .".,.. ,he "'y;' wu "' .. b<:<:ou .. 'hat wu ,he "'ry i, had al ... ys b«n.

"'corJing 10 Newton. for ,he UniverO< '0 b< m.,ic.""" coodi,i"" haJ '0 b< sa,i.<fi«l: rn.Uo, had lOu' .... d inf",i,dy in all dirrdions. In

such. noveronoling coonlOS. <ach body has just as many bodi .. "" ",,<,.id •• ""Ui,,!! i, "" .... y..;!h ,heir ~vi'y. •• on tho ,,!,pali" oi.k.

puBing i"he oth<r ... y. Uk .... bring pulltd by '''''' ~ually strong 'ug·o(· ... , ' nm .. i, ,he .. f ... o ,.....,3in. motionl ....

How ........ ac<;ording ' 0 Iii ..... in .. 'hcory of gravity. ,he Un~

wu fini ... no, idfinit<. n.«po«-'irn< ,u,....J t...:k"" i,odf---the fou,-dim .... oional ~uiV2len' 0( ,he \WO.dim .... oionol .urfo« of. hO>Ju:. . baU. In such. Uniw,.. the ~vi" 'ion.I'u~-of .... or i.<., no poin,

pc-rkc,1y balon«<!. lk<:ou .. <v<ry body Ifi .. '0 pull .very o,be, body ,oward it. the Uni .... ,.. .h,inks uncon,roIl.bly.

To .. /vag. ,he ioJ .. 0( • Slatic lJni .... ,... EiIlSl'''' had to .. ..,n 10 mutia,ill,!l hi.< d.gant ,heory. H. ad.kJ. my ........... foru of ro<mic r"puision. ",hKh pU$hcJ .p.n ,he ob;«:I, in ,he Uni .... ,... H. hy.

pothesiud ,ha, i, had. ,isnif.an ' olke, only on bodi .. ,ha, """ • .... ormously fa, .pan. ""puining why;, haJ no' b«n not;.;eJ W<n in Ear,h', neighborhood. By pr<cisdycount<racting ,he [0",,0( gr .. -

i,y ,ho' ..... perpe'ually trying '0 drag bodies 109", ...... ,he cosmic r"pw.ion kept the Uni"",*, [o~r .... ic.

TIlE EXPANDING UNIVERSE

liin .. oin·, ;n"inct.,um«l ou,lO be "'rong.ln 19211. Ed";n Hubble-

,h. Am<ricon ."ronom<' r .. pon,ibl. for .Ii,.;o ... ,ing ,h .. ,h.

lJni ........ ·• builclill,!l blocks ...... gal .. ~nnounctd. d .. matic n ..... di"OV<ry. Tho galui .. ""'''' flying .pan from .. ch o,h<r lilu: pioc<S of cosmic ...... pnd. For from being " .. ic. the UniverO< .... srowill,!l in siu. As soon as Ei ... tein I .. ,ned of Hubble. discov<ry of ,be a· pondill,!l uni ......... he .. nouncru hi.< co...."i, nepul<ion. calling i, the

,. biggoSi blund ... he <"'tt mad< in hi. ~f~.' Ein.t.in", my,'orio", rtpuis;" f.,= oould ~ h . ... kepI.he plui .. lu.nging mOlionlno in .~ ..... Arthur fAiJil\j!'lH'I poinlt<1 ou, in 19JO, a u alic COIImoI i. in ......... tly uns •• ble, lik a knife b. bno:d on it> point n.. n .. rest nudg ....... W b< <IIlKIgh 10 "" i1 expanding or cont,"";nS-

Oth .... .lid no1 malo, the .. me min.lIt .. Ein~jn. In 1922 the RU$Si.n phyoici$l Al ..... nJ, FriMmann .ppli..! Ein.,<;n', , ..... ry of

gravity to lhe Univ ..... ar><! "' .... cclly concludN thai it m .. ' tither b< contracting or expanding. FiY< ,.. ... laler the.am< conclusion was rnd...J in~domly by ,II< Il<Igi.n Cath.o!;'; pn... Gft)'pH""ri t.t ..... u,., .

.... k>hn Wh«ltr has .. it!: "Ei",.";n', dncrip,;"n of , .... vity as curalurt or 'pack.tim. IN &rte1l1 10 thaI grN'''' of all predictio",: Th< Uni ....... ;, .. If is in IOO,ion," It i. j"",", th.1 Einstein hi ..... lf miMtJ til< _gt in hi< OWn throry.

TH E BI G BANG UNIVERSE

Sine< Iht Un ....... is .. ~nJing. on. conclus.ion is il>CSCop. hI<: il mlU' It.,.. to..... .m.U .. in tho pas,.1Iy imagining ,he ",,,,,,,ion ,un ·

.ing t..ck .... n1. lil< . movit in ~ •• stronomns d<JuuJ that 13.7 billion yo . .. • go oil of e,nl;"n was ",'I=«.l into lhe liniesl of tiny ""l~ ...... Tht l....,n of Ihe IYU<iinJ p in;" i. wi the URi",,... though oM, has nOl o,.t<J fOR"". There was • !><g,nning 10 I'me." "' .. ~ 1l.7 billion y .. u .go. all ",.n ... <n<,!y. lpa<~ .• n.ltim< fOUnlOin<J inlO ""i.l.na in • litlnic •• plooion-lhe 8ig ilan8-

n.. CO<II1", opansion lurns 001 to obc-y a ",markably simple low: E",ry plaxy i. rushing oway from thc Milky Way with • • p«<l Ihal i. in Jir«1 proporlion 10 it.< Ji<tanct. So a pluy Ihal i. Iwict ..

's.. 101, IIbrld Mot<"" Goo"" G&mow (New York. 197U~ in wtUdI the I~thor writ« of Ein .. .u.:'11< ..."OrUd [to _ I Ib .. the introdlO<llon of the

ooomoI~ ' .. m __ the bilrlt<tt blgnd ... It<..-.:r ma<Ir in hi> ~k"

TI" UITIMATl .... NT OUTO •• HAT ,.

f. r oway ... oo,htr is ...ading ,,,,i« as fas" 0 ... 10 'imn as f. r oway 10 ,i",.. as f .. " and,., 011. This ",Ia'ion. known as Hubble', law. 'urns ou, to bt unavoidlhle in.ny uniYn>< ,ha'g""'" in stu while co."inuing'O look I ...... me from .... '1 pLuy.

' '''"'i .... altw;,h rai,ins in it If you could .hrink in ,itt.nd ,il Oil . ny raisin, ,he vi"", wiU always bt ,he .. me. Furthtrmon:, ifthe eak< is pu, in an ""'n and ap • ...t., or n..s, flO' ooly will )<Iu _ &II 'he o,h ... raisin. n:cedo (rom you bu')<Iu will_,hem rtce<Io wi,h .p«do in di..." proportion '0 ,heir di".n« from you. It rna"'" not .,.U wha, .. i,in}'<lu ,il on. lbe ~ ",iD.1w2ys bt , he .. me. (lbe taci, ""umplion bt", i. ,h .. i, is . hig ak<, I<l lha, l"u an: .Iw.ys f.r from ,he eJgd G.Jaxi .. in an apanoling un~ ar. like rai.ins in • ruinga ke.

It IOllows ,ha" jus, i>o<alM .... see .11 ,he galaxi .. l1ying oway from us, ..... houkl fIO' ..... me 'h.' .... ar. at ,he «'Tl1CT0( ,he Un;, ...... and 'hat ,he l:IOg 6ang h. pptned in OIIr _mie backyard, W .... .... ' 0 bt in.ny galaxy DIM than ,he Milky Way. _ woukl _ the .. m< 'hing_U ,he o'M p1ui .. o..ing from us. The l:IOg 6ang did 110' haPJl<'n here, or ~ ,here. or a ' any 0'" poin' in , he Uni ....... I, happerieJ in all placn ,imulla""'usLy. " In ,he univerK, 110 «n'.r or circumftrcnce ""im. bu, 'he CftI '''' is tvt,y .... "tre; .. id the l6thcen,ury plrilooop .... r Giordano Uruno.

lbe Hig ll.ing ;.. hil 0(. rni1l1OmtT. h w" ,_Uy unlike any

explosion wilh ",hich we .n: famili ... When a "id of dynamite det<>· ... ,n. for inslanc<,;' aplo.ln ou'ward from. IocaIiuJ poinl.nd ,h. d.bris ""ponds inlo p.-.c;isting .""",. The Hig ll.ing did 001 hap· peri I,a singJe poin ' and ,here was roo p""",isling voidl E"'rylhing.pace. lime, "'e<g)'. and nu.1I........,.m< in'o bring in ,he lIig Hang .nd began expanding ....... )"'"...., II once.

THE HOT BtG BANG

Whnrcvtt you "'In.., .. I<lmrthing inlo, .mall..- volume-for in· " anc., a ir into a bkyde pump-i' get. hoI. The Hig ll.ing was , ........

,. f"r<' hoI Hig Ilang. Tht first p"rson 10 , .. Ii,., 'hi' was tl>t t.rI<ninionAmorian ph)'>icis1 G<-<>rS< Garnow. In,he first few m"",,,,,,, a~ .. It.. 6i~ II<I"S> he ,,_ned. Ih" Uni~ .... ""'. rtminiKtnt of 1M bl;".ringly hoi fireball of. nud ... ~Ios;on.'

lIul wbtttas tI>< h .. 1 and ~sht of. """Itar firrl:o.lI diM;patt int" lhe almoophcre.., lh.l, hoors or da,.. afle. ,h. aplOilion, they ar. all gon •• 'his was not Ir"" of II>< hn, anollight of.t... lIig 1Io"l! r,,,,ball. Since the Un;~ ... , by definitioo. is oU IheR is, lhert ..... simply nowh<rt for it I" go. n...".fl<rglow" of the Big Bang "'as in"ead boul..! up in It.. Un~ (""OW" Thi, ..,.. ... it ohoultl.till he . round today. nOl .. ~isiblt lighl~incc il would ha>'t bttn grt.~y cooItd by 1M apo-nsi"" 0111>0 Uni ....... ';n", .h.ollig lI. ng-but as mio'owa ....... n invi.iN. ro.-m of Ii".,! m. ..... ttri<tic of wry c<>ld tx:..Iin.'

Gamow did not beliow il would be po .... bk 10 di'tinguish this microw .... ofl<l1lLow (mm other ...... ra< of light in ta..lay's Uni...,,... Howev<1", I>t was mutaken. As hi' ..... rch Sluden,. "'Iph Alphcr and Robrn H<nnan ",altuJ. tl>< ,die h.nt of th< lIig liang would haY. ''''' unique kat"'" th.t woulJ m.kr it ,tanJ QUI ... "t. bo<a_ it ",m. from lht Big B.ng, arKIlht Big Bang I>apptntJ .\'Cf}""'h<~ oimultan"""'Iy, the light ,hQuld bt ",ming <q.wly from <very di"",_ Ii"" in lht .!ky. And,KCOnd. ito .<p«lrum--lhe ""'y Ih. bri5hln ... Qf ,he light "'. ngod with the light' ..... ry-w<mld bt .ho, of. "black body.- 11'. no. """"""y IQ kn<>w what. black body i .. only .hol a block body .p«trum i •• uniqu."C,ngtrprin':

AI.hQugh Alphe, .nd Horman pmlictcJ .he ni"m~ of ,he af_

,erglow ofthelliJ! Bo",- the coomk microw .... background radio,ion---in 19411, it was 00' Jj"""",tJ until 19M and lhen tOtally by

'n>< lIi"lIon,. ....... m<d 0,.' he- E>W ish .. t «>nO ...... Fr<d 1 (0)'\< ~"nn,. • BBC rod .. ~"", ..... in t949. Th<~I<01 irony is th .. lIoyk. to the- <II)" he diN, ...... , bcli<v«I in "'" B. Bon~

' Ar>d of ""'s<><trons. which pow« mlcrowo .. owns ............ , t .......

min .....

TI" UITIMATl .... NT OUTO •• HAT

,,"idm'. Amo I'tntias .nd Robtrl WHson,Iwo yoong .. ,toOIOmtrS., Ildl Lobs 01 Hohndol in Now Iet"o<y. wen: lUing. horn_.h.pttl mk!"O.... .,., anlm". formerly usN forcommunkaling with Ttl.:",. Iht firSt mool.rn communkaliOll' .. ,.Uil., ~n lhey pkkd up a myst.rio.,.

hi ... of microw, .. "",,.,k" coming ..... ...ally from tv<rrdill'Clion in Iht .ky. o..-.r th. foUowing mOlllh. as ,hey puuJed over ,II< .ignal, ,hey

... rio",1y thoughl,ha, i, migh' he roJio ".,k from ncarby N ..... York

City, .. ""''I' her k n uclca, 'e" " or e-ven pi""",, dropping> coo,i"g I ht in,erior of Ihtir mkrowa .. horn. In f"", ,My hoJ made Ihe 1'00.1

impor .. nt CO>Dlolop:ol di~ sin« HLtbbl. iQund ,hal ,he Uni_ .,.,,.. ..... aponding. The .fl<rglowof cr .. 6on ..... ]><>'V<I"ful n'idtnc<

Ihot our Univ ..... had ind«J !..gun in • hot, d ..... ,''''- lIig lI.ng_nd hoJ betn g~ing in.iu and cooIing ... IT oinct.

~w .nd Wilson did n'" "'eep' Iht lIig IJong origin of 'heir m~'eriou .... ti< fOr . ,It."IWO ~an. Nt.,.,rthtlns. for 'htdi«ovttr

of Iheofltrglow o f C''''iOll, ,hty carried off th. 1m Nobel Priu for ,-lht CO>Dl k b..ckpound ...no,ion i> ,he <>Ido .. "fo .. ~· in {R<Ilion.

II comes 10 '" Jir«tly from the lIig IJong. carrying wi,h i, precious informa' ion .bou"he ... 1< of lhe Un;"",.. in its infanq •• 1".,., 13.7 billion years ",0. Th, coomk background i •• lso ,ht coklffi,hing in

nalul"<--Ollly 2.7 Jog ..... . bo.,., absolu' ... ro, Iht Iowesl possible

'rmrr" ,ur< (_270 .ltgI'''' Crlsius).

lht co.mic background raJialion i. ",ulOlly 0 ... of'M mo.l "riking f .. ,u .... of WI' Uni_. When _look up .. ' M nigh, o1y.

its most obvious fto'u", i.,h .. it is mostly b~k. Iiow<-v<r, if wI' ores _'" .. ",i,i.,., 10 mk""""". lighl .. IMr lhan vioiblr lighl ..... "",-,1.1 or< ",rn<thing.-err Jifl'rrm'. Far f!"Om bring black. lhe rnli« oky.

from horizon 10 horizon. "",-,IJ be ",""il<. ~I:.e 'M insideof ali8h,bulb.

E.-en billions of yea .. afier'M tven" 011 of '1''''' i, "i1l81o"";ng softly wi.h rdic htot of .he lIig Bang firrball.

In f.oc l,tv<ry" .ugo!"Cube-.i ..... "'8ion of empty.p;><:t con .. ins)OO

photo .... of tht ooomic b>Ckground rO<!i..tion. Nit>t1y,nin. p .... II' of . 1I1M pho,on. in 111< Uni_ a", .iN up in iI, wilh a m«< I rr=nt

,. in .... rutht The ",.."ie Nckground radialion i.,ruly ubiquilO<lL If you tun. )'I>U'lV ~"""n .... ,., .... I ~nl of.he ",now" on ,he scrttn is the rdi< SI'lic of 1M IIiJ liang.

DARKN'£SSATNIGHT

Til< fact .Iu. 1M Univttw t..san in a Hig Bang aplain1am,,1In sua! ",y5l<'1- ",hy Ih. nighl sky i. dark. The German •• Ironom.r l<>han ..... Koplor.in 1610. ..... 'I>ofi .... 10 'taU"" 'hi ....... puzzk.

T hink of. romo of ~gu1.arly .p>e«l pi ... lr<n going on rOl . ..... If you ron into 1M rom, in a slI ... ighllin<. ooontr or 101.,. you would bump into. 1=. Simi4rly. if the Univtn< is fiUe<! wi,h .. gularly .~ ,tars and 5"" on r.".."..,.. your pu win alight"". " . r no m.;III., wbkh di=tion you look oul fro<n Earlh. So",. of It.- >tars will'" disWlI and faint. ~r. tlxTt will bot m,,,. dtllant .Iii,.. lh.n nearby ones. In fKl_nd this i. ,he crucial p<>inl- Ih< number of SlarS will in<rn.1e in such. way that j, =nly rompm.sa .... for ."-'ir r.in' ....... In ",ho, wonls. 1M ........ . , ..... in Ji ... nce from

Earlh will , oo,riool' jlLSl as much light in loW 0$'1'1< ""es twice as far o""y, ,bitt tim ....... y. [<;KI' ,i..,.. ..... y. and '" on. When ~11 the li3ht .m"i,,!!" Earth is.Jdtd ~p.1he rtlWt .om therd"OK bt on inlini~ ~moont of light!

Thi. is d<orly JIOrumo;al SIO" .... nOl pointlikr:!hey .... 'iny <Ii,,", So nearby"'" biOI o~t "'",. of the light of Il)(>K di".n"Ia" ju<t as n<orby pin~ lrus bI",d "~I ""'''' di<l.nt pin< 'I<'d.II~1 ~ ... n .. Icing ,hi. effect into KCOUnt, the conclusion ........ inesca~bl< 'hot ,he ",,,i .... ky sho~1d bt "p.peud" with <10,.. with no &OP' in bt' .... IL F.r from being dork .t nigh" the nigh' .ky oho:;..tld be .. bright .. the "'rfact of. typical ".r. A Iypical ,lar i •• mI dwarf ...... glowing like. dying ember. ~u.ot1y, ,he oI<y .. mi..might sho~1d bt ~n~ blood rtd. The pu>'" "fwhy it isn·t was pop~l1rittd in ,he early 19th century by the ~r"",n OO1ronornC1" Heinrich Olbers ond i. known .. OIbt,,' paradox in his 1>0..."..

The way 00' of OIbers' ~rodo>; i. the .... liution that the tlni-

,. "',.. has noI in foct niSiN fort"" blat wu born in a Hi, ~ng. Sina ,he ~'flr ~..,.t iQn. , ..... has boon only 13.7 biU"", )'O~ .. for tho lir,hl '" di'tant st.rs 1<1 .. ach .... SJarits we 0«

.. ~ tb.ooc ,hat a .. near .no~gh thot their light hu,aken I .... th. n 13.7 billion rurS to 5<1 to us. Mrut ofth< 'luS,nd piu:irS in the Uni· ........... $0 far awoy tllal their light will take mo ... th. n n.7 billi"" l""" t" "'arh .... Tilt Ky" al,'- objoe,. i ... ill on it. woy \0 Earth.

n.. .. foro, the Imin .. ...,., ,he .k,. a, night is d;uk i. lhal lilt lish! from most of 'Mobjtcu in III< Un;. ..... Iw )'<110 moch w.. ["" .inee ,h • .J.WJ1 "c human history •• he {oct ,hot.he Uni ...... had. tqinning has Iottn .... ring ... in 1M fOct in ,bt duk ..... of lilt nil!ht .ky. 1* ...... simply t..01l,,,., .. upi<! 10 , .. Ii .. it.

or COur"" if we "",,1<1 .... it .noll1<T billion y ..... , "'" ,""uJd..., .t. rs and ploxi .. $0 fa' away 1Nl their light h .. t.ken 14.7 bill;"" l"'''' In 11"1 htK. The qu .... ion ."",dor •• riln ol ... hclhtT. if .... K~ many triDions of ynrs in the futu ... when tilt liyn from many more " ... and gala:.in Iu.J ,;"'" 10 '<ach us. tl>< oky a t night woulJ ... raI. The an.-, 'u,", 0\1'10 I>< no. 11>< rnooninB of KrpIeT ond 0 11>< .. i, ba><d on on i1>COn't'C ...... mp.~M •• l>. .. ~'" kll'o",r. In foct . • vtn .he longnl·IM:<l.,. .. will U$ up .ll,hei, ~I and bu,n "," ofirr obou.lOO !>illion y ..... Thi. i.long I><forc mough li&f\' ha. orrivrd o. Ear1h.o make ,he ,k)'~.

DARK MAlTER

Th. Big Bang h .. mo"""", "planotory pow<1". N""'r1h ...... i. h .. ..no", probI..,u. For on. i. i. dilftc\lI •• o undrrsland wile", galaxi .. like our Milky Woy como from.

11>< firrball of.ho Hig Hang ..... 0 mile of parlicles of matter ond ligh •. Th, mo11 .. would M'" off«1<d ,he li&f\l. Fo' inOlO""", if ,he matt., h..J curdIN into dump •.• hi. """,1<1 bt ctfI«1<d in .ho ofttr· glow of.ho t:liB Bong- il would no' bt uniform allover ,ho oky1O<loy hul would bt h<i&f\'<r in '''",'1< plao:n than Mh ..... 11>< fact that tht . f'..-glow i. rvtn.ll.roun<l.ho sky mean"M' ma11er in.ho fire""!1

,. of Ih. Big Bang m .... ' h .... b«n '1'1' .. <1 about ""rrmdy .moolhly. Hut ... know that it oould n.o' be 'l'read wmpleldy • ....,.,.hly. Aft .. 011. today', UnivtrK i. dumpy. with &>Iui .. of ,larS ond d ... ' .... of

gal .. ;", and !reat void. ol empty sp~ in beI ..... n. ", some point. lh<",for<. lh. rna!!« in lht UIIi",,,,, mu" "" ... 50n< from b<in~ . mooIh If di,. ributNt hrooghoul .pa« to be; ng elu mpr. And the >lart or thi< P"""" .haul.! t.. vi<ibl. in ,I>< OOiImi< background radi.,i"".

Sur< ~OII8 h, in 19'11., """Y .Iight • .,ia,;oo, in the brig)lIn ... of 111< oflcrglo« of til< Big Hang ....... Ji",,,,,,m1 by NASA', Cosmic lb<q;rounJ EIIp\orff SOld i." COilE. n.... roomk rippln--<> ... ol lh. Kimliru in""l.-N ,... mort pictut<'S<Ju< in Iil.<ning thotm to ",h. fa<. of God"-"<>wtd thot. ~Ut )00.000 y .. ,uft.,. ,ho Ilig lI.ng. some paruoflht UniYtttCw ..... few thou .. nJ,luof. pttCtnl <It"", ,h.n.,.hers. SO .... how, lbtse hartly ""tic .. bl. clump. of m,nor'h< "oct<I," of .. ructur_had 10 VOW to form lh. grtat dus"", of galaxies we 5« in !<>Uy', lIni ....... Ilutlh<,. i • • problem.

Clum ",of"",,, .. ""'" to boroorn. biWr dum", h<a _ of r;rnit)'. lI .. iaJly. if. u!!iO" Iu$ $lightly"", .. m.ona than • n<ighboring

"sian, il' . lronBtr g".-ily will ~n ..... ihal il will "eal )'tI mo .. malla from its neighbor.I~" OS , ... rkher Btl richer and the I""" S" poo .... , I'" Jorun- rrgions allho Un ;.. ........ ill , ,, ""'r Jonser until. ....,nl""lIy. I"'y b«oo,. ,he pI .. i ...... S« around us ' <><lay. n,. problrm tho lheorists nOlicrd was ' hal 1l.7 billion ""aro .... nol enough l ime (or gravily 10 mak I ...... ,.,. pI .. i .. ou, of lhe liny dump. of malltr orrn by ,he CO BE .. "lli". The only woy they rou Id do il was if ,he .. was mlldt mo", mall .. in Ihe Uni .. !W IMn was tiN up in .ioiblr "aro.

Actually. , ......... "rong ,vid,n« fQr mi .. ing mall .. d.,... 10 home. Spiro] galuirs IiI« our own Milky Woy arr lilr gianl whirl

pools of ........ only their .... ro 'urn ou' to he whirling aboullheir crnl<ro rar too f.st. By ri,hu.1hcy .hould Ily off inlo inlt!plaC1h: .p~ iusl os )'O~ would be Aung off • mrrry"!<,"round 1It;r, .o" ,.on, had .pun "'" fost. The alroorJinary apl ..... ' i"" that ' ho world·' ... tronomero h.", come up wilh is that galax;" lik, our Milky"",y

TI" ULTIMAT ..... NT ou.-O .. " .. T '" actually conl.in aboUI 10 limts as muell ""'" .. as i, vi,ibI, in ,lars. Thq ""II lho i""i>iblo m,",e duk rna" ... Nobody know. whO! il ;,.. How ..... , tht exIra gravily oi 1M dark mati .. hollis 1M ,larS in Ih,ir

.".bi .. and SlOp. lhem m,m flying off in'o inlorplac'ic '1'0«. If 1M Uni>n-st as . whole conl.i .... 10 limn as mudt dark m'''te

as oNina.,. ma"", lho"'ra gravity is ;Uil ... ough 10 Iuen lho dump.o oi ma".,. _n byCOIlE in'o ,o.J.y'. g>W:y du"'rS in tht B.7 biUion r<arS,i_ Ih. tin;.. .... wa. horn. ".., 8ig 80ng piclu", is .. ved· n.. prier is 1M oddition of. lot of dark m."or, who .. id ... tily nobody k~_U, alm"". nobody. In ,ho _N. of ~las Adams in MOI.I, H4rmk"'"For along poriod of lim< lhor< was much 'J><"Culation and con, .......... y about whor< tho ..,-callttl'mi.,ing nu"",' of Ih, Uniw ... h><l goIttn 10. AU CW<T Ih, GaI .. y lho .a.nce Jtparl. m ..... of .11 1M nujor uniw,..;I;.. ........ acquiring mo", and .!abo. ral. "'Iuipm.nllo prot.. and .. arch tht hurts of dist.n. galui .... nd Ih.n III< wry """, .. and III< ..... y «lin of Ih. wbol< tlftiw ... , bul wh.n owntualJy i . .... trICUd down i. ,ur....! out in faa to bt 011 tht "ulf whKh tht "'luiI'm ... ' Iu.d b«n podtJ in! "

INFlATI ON

Th. fact Ihat ,h ... and.aN Uig I!o.ng piclu", dotS no' provkJ. e""ugh lim. foc m'"'' '0 dump in'o goluin i. not tht only rrobltm wilh Ih. ",nario. n..", i, . nothn-, O'1uably more .. rio .... 0 .... It coo· C<'rn.1 tht smoothn ... of Ihe <o<mic bocqround rat!i..UoIL

Things ",och Ih ... m< I ..... p<ralu'" wh.n h . .. lrawl, from a hot body 10. cold body. For i ... lana, if )'011 PUI )Our cold hand on. ho' wattr bonlt. ht.t will now from ,ho bonk until )'Our hand

·""'WIIly. thtr.;.!housh' to bt bttwom 6....J 7 ,im .... mud! dart< mall ... otdinory mall,"" Thi, .. Otau"' ..... .,. >«OWl' rot only . ..... I>olf tho on! ino'l' .... , ..... TIlt ... , wh dI "..,. bt U'I ,bt fonn of dim PI do .....

bet""", 'h.~ ... ia. h .. "'" )'<I ...... idmtifO<d.

'"

.. odin 1M samt lnnp."nur •. Tho cosmic bockground radio Ii"" i. buicoUy.I1 ... "" sam. ,.mp""u"" This mear .. , .... t, .. ,he •• rly Un;" ..... 8"'" in .iM. and..,,,,. hits lagsN bthind olht .. in Itm

p¢ralur., h .. ,.lways BowN into them from 0 w;o,m..- bit, "'luoli,i1\8 It.< Innrt .. l" ....

n.. problem .. ise. if l"U imagine th. expansion oft,," Uni ....... T"nni"l: badw:ml ~k<. movie in rnr .... AI "'" time thot til< rosrn;"

Nckground radio,ion 1 •• 1 had any contoet with m.n.r~bo"l JOO))OO )'t" .... aft ... 1M 8ig Ilang--bil< of tho Unil'tlS< that today .rt un oppo';,. oi"'" of th. .. ky ..... too far ap.rt {"" heat to I10w (rom onc to lht oth<T. n.. maximum.p«J it could H"", i.lh<.p«d of ligh., and the JOO,OOO yt""'" the Un;. ..... h..d b«n in nist."",.".,.. 'imply 1101 long tno"!lh. So how i. it 1 .... 1 1M crumic background

" .. ii.tion i, the sam< temperaturt ~rywheK ''''''"I-Phy.;':i" ..... v. <Omt up with an CJ[trac",lina'Y an'''''''. Hut

could h ..... tloweJ back aO>d forth throughoul1he Uni ..... , "'luilil-ing lht ~mp .... 'u",.only if th.<urly UniV<Tkwa' m ..... $mal!., .lun our bockwud.runnin~ mo.~ woulol imply. If .. gions ~ mud.

cloot. IOSw..r than "'p<d.,t lht~ would ha", b«n pl<nly of l im. for ..... 10 flow from hot to oold rqions and «I""li .. ,''' ~ml"""_ lu~. Bul if lht Uniwn-r,.... mudl small<r .. rlin- on. it mu:" h:lv< pUI "" a big .pun of powth 10 F' 10 i\$ presonl .i .. .

Accordi n5 10 lht Ih<-orr of inO .. ;"n. Ih. Uni"' .... "i nfLal«l" cl ur_ ing ;1$ firsc o;>HI -..-.:000 of .. i"mc., ull<l<rso ing a phcnom..,aU y vioIml ",po"""" Wh., d...,... lht apt",i"" was. preuli., prop<rly of lilt vocuum of empty .poet, allhough Iha", "m hazy 10 pIoysicim. Tilt poinl is Ih.al lbore,.... Ihis enormously rosl expln.ion. which vorr quickly ... n out of "urn, a.-.l t"'n lilt m"", ..,J.,. ",pon';"n Ihal ..... 0« loday lOOk 0 ....... If lilt normal Big Bang upan.i"" is lik.nod 10 ,''' o:q>lo>;"n of. "id< of dynamite, innation can be lilcen«l 10. nw:l .... xplMi<>n."T1lt ,u .-.lard Big BIng Ihto'l'''YS nothing aboul what b.ng«l. why il banged or whol happened befo~ il ~..J.' .. ys infLalion pionttr Alan Guth. Infl.ni"" i, .,1 .... an .1_ ~m~ 10 ><Idrn .. uch queslions.

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i. that, ..... n """" oil tht monor in til<- Univtrv-Yi.ibl~ manor ond J.o,k II\lItt~r-.. ..wed up. it .moun" to only obout 0 th in.! of til<ential m .... lnfl.ation. it would ......... i. 0 lIO",t.,tor. IWll th.t'. how it ~until • K .... tional dis«m:ry WO$ moJo in 1m.

DARK ENERGY

Two teams wert <>boerYing "oupern<wu"-aploding OI . ........ n d~ lant galaxi ... 0.. t ... m WIO 1«1 by Arnone.n Soul PorlnlUttor .nd tiltht, by Austroli.n, Nick Sun~ff.Dd B,ian Schmidt. Supe'l\OV2S .rt "'plod;ng .ta ... Ih.t oft .... OUI .... in. lhtir I"",nl galaJey .nd to can ~ ... n .. ,,,,.t <li'lances I>ul inl<> the Univ ...... n.. kioo the tWl) ttom. of .. I,.,nom .... wort Iooling .t wtrt known • • Type 10 ,upe" no;was. They hi"" the p"'perty Ihlt, when they d.IOnOIt, III<-y alwoys shint with the .. 11'1< rtak lumino<ily. So if,..,.. _ Ollt that is foinltr

thon 1110111<-" you know it i. fa"her away. What the .. tronom ... sow. ~, wOO that tho< 0 ..... that _'"

futhe, .way ""'''' &intor than theyaupll tl> ~. tokinK into ""COUnt Ihtir di.tan~ from wlh. 111< only way to aploin wh.t thty we",

~n! wlOthlt the UniverK', ~n";on hoJ speeded up oi"". the ,I.ro "'ploded. p .... hing IMm farther.way Ihln ap«led and makillj! them oppeo' fain It,.

11 ..... bomb ..... 11 dropped into the wo,lI of sci<nu. 111< toit for« off«lillj! tM g.b.inought to ~ thei, mutu al Srlyit.tio",,1 pull. Thlt <hauId b. braking the <"I'.",ion. not .peedi"!! it up.

The only thillj! thaI could be """itroti"g thi,,!!' WO$ 'I'"'" it>df. Cootrory to .nap«t.tions,;t could not be cntpty. It m .... t cont.in tom. kind I>f "",in! stuff unkn<>WR to .d ... ~ "J.ork .nt'gr" -thlt "' .. """ing I kind of «10m;': rtpukion on 1M Univtrst, count."", 8,;wity ond d'MnS the g. lni .. opo".

P~ioto .'" totolly It ... when i, comn to und .... tanding dar • • norgy. Thei, bes, ,heory--<juantum mecbonict-prtdiet •• n .nergy "",,,iltn! with empty '1'''''' 'hit is I foU"""<'<l by 12l,..rotS bil!l!tr th. n I'<rlmullt' ob .. ......J1 Nobellau .. at< SI.""n Weinbe'll hlO <It.

TI' . u u ...... n .... NTOUTO •• IIAT ,.

ocribN ,hi ... "Iht _,.., foilu", of an <>r<J<r-<>f-..... gnilud ... ,imo" in , ... hi,,"'Y"( ",i."""."

Ll<spil< , his .mb.rr ... ", .. ". Iht dark ..,orn t... at Ins, on< &.irobk oo~u.nc •. K=I1,h .. ina .. ;"n C«juireo ,h. tlni"" ... '0 h."" ,h. critical m ... bu"h .. all thr m''''r in Iht Uni ....... ad.b up 10 ""Iy abou, a 'hiN of , ... a i,ia.l mass. W.U , 11 form. ,,( .n<rgy ... Fim,';n .l;.m,..m/. hovu MIl"<ctM m .... AnJ ,ho, i IX ludn thr .l.rk

mn-gy. In fOCI. i, ,urns ou"o account for abou"w<>-,hir.ls of , ... critical mass, so ,ho,,'" tlni"" ... h .. ruClly , ... critia l m..........-juu wh .. is pm/ie",d by infbtion.

A1tllough nobo.ly knows wh .. , ... dark .... rgy is, "". poosibili,y is th., i, i • ....,..iolr<l with t'" "",ul.M fo",."( .... pty '1'0« proprurd by Ej,,,,';n. In sci..,,,,. i, ... ms. IU 'hing. btsin Ind rnd wi,h

Ein".in. Hi. bigs'" mi".kr ml y )'<t ,urn out '0 be hi. bigs .. , .ucc ....

II is ""'th """"ng. however. ,ha, t '" ~ig ~.ng, for all it>.",-c--. is .till ba$icolly • .l<scription ofhow aur tlni ....... has noI~ from I , uprnlrrlS<' .... pn-bot .. . .. to its p~nt ...... with pi .. ;..., ....... . nd pl'M'L flow i,oll began isstiD ohrouJrd in m)'ltrry.

TOTIiESINGtiLARITY AND BEYOND

I ..... gin<' ... "'pansion of .... Uni ....... running bock .... rd "&oin like I .....,...;. in """' .... As t'" Uni ........ hfink« lown '0 I sprd, its ml" .. ron'rnt btmrntS""'" ""'''' oomprnstd . nd ......- 110" ... In fa<!. ,her. is no limi' '0 this process. A, the instant t'" Uni ...... ' ... paNion brgln----t'" momat, of it> bi"h--it ..... infinitely dntl< and infinitrly IIoL Physkiot. <aU , ... point when """, .. hing &k~ to in_ finity I .inguLari'Y. According ' 0 Iht .. ondonl III! B.ng p;cturr. Iht tlni ...... wu ,hrrrfo", born in. >ingularity.

",. ",her pLact whrrt Fin ... in'. theory of S ...... ity pm/icu I sin·

gularity ;" at , ....... " of . black hole. In this cos< ,h. matt .. of. caWtrophiaJly shrinking . tu <vmtuaUy b«am .. 'omprrs<eJ into zero voIum. and ,h.rm.", brcomcs infinitrly de .... and infinitely hoi.

"iliad hole .. " "' someone onco said. " .. e ... here God divkltJ by

.e'o." A 'in~uloril y is I 11O.uo .. e. Wl><n .... <11 a mo">1"' ...... "ily POP'

up in • Ihwry of ph)'>i"". il i, ~1Iing UJ Ihot tl>< lheory-in Ihis cast.

Ein"",,', Ihto,yof J",vily-i, foully. W ...... OIrrtching it btyond Ihe domain whm: it has anything .. nsible 10 oay aboUI II>< world, This is nt>! ,urproi,,!!. Gt ... noI ,dal;'i,y is a throry of II>< .. ry Iarg<'. [n ilS

,"rliesl'tages. howevtr, 11>< Un i ............. mllltr Ihan an alom. And II>< lheory 0{ II>< atomic r .. lm i, quanlum theory.

N",mally. thm: i, no """,lap beh.~'n lhoot two ,.,.,...,.ing monu_ menlS 0{ Z(Uh-ctnlury physico. H~, Il><y come inlo conHicl II

11><a" ofbbcl< hoi .. . nd 0111>< birth ofll>< Uni ...... lf wu ... "... goin~ 10 undttoland how tht Uniwru cam< inlo bring. w<: art Soin~

10 ho .. 10 find a b,,, ... dnaip';on 0{ ..... lily lhon E;nsl"n'"heory 0{

5, .. ily. w.. n«<l a quanlum Ihwry 0{ gravily.

"The w.l:; of findi,,!! ""'h I lheory i. formi<llble bea\llt of Ih, fundam.n .. 1 incomp.tibi~lybnw«on 11' ..... 01 rtlalivityano.! quanlum lhwry. Goo .... 1 .... t.livilYo like.wry Ihtory 0{ phy$iQ; btfOrt il. i, a rtcipo fOr prtJicting tht fuIU ..... If I plan., is 1>< .. now, in I day'. Ii"",

il will hao." mO'o'«l 0 .. ' 11>< .... by following Ihis p.,h. All th..., Ihingo I .. prtJictable wilh [00 porctnl «ruin!),. Qulnlum Ihtory. how

''''. is. "",ipo f", p.-..licling probabilili, •. If on . lOm i. Oyi"8 through ' ",c<, all w<: can prtdiCl i. il< probable finol ro.ili"". il< probable pOlh. Quanlum lheory Ih,refo ... und ... mi .... ,I>< .. ry foun

dalion 'IOn" 0{ gmtnol ",I.'ivily.

Cu .... mlly. phy$iciolS .... uyi"8 10 di..,.,..,. II>< ,Iu.ive quantum Ihwry of gravity by I number of roul ... UndoubltJly. II>< on< se'ling Ih, moot publicilY i .... ~uing Il><ory. which vi .... ,I>< funda_ mental buildinJ! blocks of man ... nol as poinclil:.e ",,,ides bul as

'A<t ..... y. th ... is •• obd< d",indi"" be......., tho .;"gubriti., .. tho h .. n of • bU<I< h.oI< ,nd ,.., S;, Bon~, "., f". ........ . ,;ng.U.ority i" .in><.nod tllr 'on,. I .i""",.,.;1)' in '1*'<.

TI'.uu ...... n .... NTOUTO •• IIAT '"

III,,,,'iny pi...:es of ".tting." Th • .,rin8~ur><rron"'n'''''N mass""Of!)·--,,;on vibra,. jUSllike • violin "rin8- and ""dt di>lin<' .ibr.,ion "mo.,k" corruponds '0 a fundam""tal partido such as .n .1«'ron 0 ... plw>lon.

Wh., tui'e< .trin~ th_im i. ,h., some form of ~r.vi'y.I,hough no' n«...arily g.n.ral ~I.'i_i'y-i. au,oma'ically con ,.inN wi'hin "ri~ ' hrory. On. sligh' compli<ation ;. tha, tbt .. riJIIS of string ,htory _ibralt in I I o.o.Umc-nsional world. which ...... ns ,her. h.", '0 oxi.,.n addi,ion.l.ilI spact di ..... nsion.'oo .mall tor ""0 haw no'icodAnothtr prot>l<m i"ha, "ring theory i"",,1vu such ho,.. r""oo ... ly complicatcJ ma,hematics tha, i, has so far p1"O'o'N im]>OS-,ib!t '0 m;tke • p~iction wi,h i, tha, Cln b< .... td agains' ~ality.

No on< know. how drut or how far ..... y .... '" '0 po<S<SOing a quan,um 'htory of g"'vi' Y. tlu' wi,hou, it,lI<~ i. no hop< of traveling tholt las, ton,alizing ... p. bad '0 ,II< bQ;inning of ,h. Uni",...,.

How ...... """. of ,h. 'hinv ,h .. mUS! h.ppert along ,h. roIIt< . ..

d .. r. Think of,he""p"",",n of,he Uni......, in ~ ag.in. A, Ii ...

,h. Uni"' ..... will.hrink 11,11< Am< "' .. in .1l diI"<'C'ion .. Thi. is he"""It tbt Uni......, i, p"'''y mud! ,II< .. m. in all d;r«'ioll$. lIu, />""1 mud! ,II, "'m';' not ,h ... me as """II, ,II. "' ...... Undoub,Nly. ther" will b< oIigb'ly mort galuito in On< diI"<'C,ion 'han ano'her. In ,II< tarly stagtS of ,II< contraction this imbalOJlCC will h.w no "",i",oblt tff«1. However. aslhe Un;.., .... shrinks down 10....., ""I" ...... ouch m." .. iIT<l!wui'i .. will btC"'M <wr mo .. m.gnifi<d. So whm tbt body .hrinlu to uro vol"m<.lhe fi ... 1 M'gcoof,1I< coIlapte will he wildly chaotic. G"'yi'y~ .... rpN sp."'-'im~will vary wildly <Itpertding on ,h. di=tion m,m which ,lit .ingw..ri. y io approach.td by an in-falling body.

Very doot '0 lilt Jingubrily. Ih ..... ."..g. oI .poC<-'i ..... will b<com. so .ioI .... ' and chaotic ,h., .p"", .nd 'i ..... will actually .h ...... ,plitting into myri.ad dropl .... Cono:plO like "be{o"," and ".fi .. " now I .... aU m •• ning. So '00 do CO"""plS like "dim,""," and "diI"<'C,iOll: An imp<1l<,,,,bI. f"ll bloclu ,h. vitw ahtad. It shr<>U<IJ ,h. mysterious

domain of quantum S .. Yi!y. wh<r<- no thtory )'C1 .~;m !o oct as our gui<k.

Bu! Jttp in !hal f"8 I~!I>< aJUwtT1 to sci<nC~>' mOil! PrflOing quntio"" WI><~ di.l !I>< Uni ...... corn. from! .... 'hy.Hd il bursl inlO bring in a Big Bang lJ.7 billion ,..,.n .go! Wlul. if anything. ni<k<l befo~ II>< Big II;on~

TI>< tioTvrnl hop< i. ,lut. who" .. IHI,.., m'fLiI~ 10 ",..., .0-g~h<r our lho:ory of ,I>< verys.mall wilh our Ihwry of ,I>< ... ry Ia'l!" ,.., will rdld !I>< an ....... to these question .. Th<n,.., will co ..... fau to

ra.:. with.he ... him ... qU .. lion: How rouk! ",,,,., hing ha"" rome

from ROthing!"1t i< onough to hold a .Il"". in )'OUr lund; wrol<

1,,"lOin G .... rdtr in Sopn;,-, IlbrU . ....". univerK woulJ h~ ~n

tquaUy incomp"'hm~blt if it had only con.;..«1 of . hat on< .IllHlt

,I>< !oil< of an o .. ng •. "The qunlion would be ju.ll H imprn .... blt: Wh<r<- Jid ,hi • .IllHlt oorn~ from!"

GLOSSARY

ABSOUTfE ZERO Low", .. mr< .. t~ ... ".'nabl •. AJ . boJy i. cooled, it. OIom. """" mo~.1Id mol'< sluggishly. At .b"'lu' • ....." Nluivalrnt to -273.15 on thr Cd .......... k th.ry «-'$<' to """" .lto_ g<lMr. (Actually •• hi. i. nOi tn,i .. ty ,rut ,i""e 1M H.ismbtrg .. "«ru inl)' principle prod .. ",", residuol ji11'" ~n .. ob",lul< .. ..,.}

ACCRETION \)IS K CU-,hoped disk of in_.wirlin, ma<1o' ,h., farm •• round. ,trong """Itt of ","vity .uch as. block hole. Since sr.ovi.y wta~ns with Jisunu from its OOUrtt. mall<, in tM out .. portion of tho disk orbits mort .Iowly than in the innet portion. Fri<'Km b<1W<'m r<gi<>1l$ w~ "..'1<r i$ , rawlinJ.t Jiff.rrn • • ~

he.,. til< dis\:. to millionsof d<srces. Quasars ... thought to """ their p..,.!igio .. brigll1ne>O II> (o"""" .. ,1y hoc ao:;miQn Ji!b ,a'rounding

-,ur<rmassi..," black 1>01 ...

ALPHA CEr..'TAURJ The l>Cam' .t.r oY:S' ''''' 10 ,lit 5un. II ron.ist. of

,h,.., .urs . nod is 4.3 ligll1·Y .... Ji,tant.

ALPHA [)ECAY TI, •• p~ting Out of. hij;h •• pouJ alpha partido by. larg<. un". bl. nud .... in on .!tempt to tum n .. 1f inlo aligblCr,£lablo

"~ ... '"

,.

ALPHA PARTICLE A bound .ta •• of '''''' prolan. Ind two nout",... ....,,'i.Uy. htlium nucl...-,h., "",Jo:.. out "ran unst.ble Dud ..... durinS radioacti~ Ilpha dtay.

A/','THROP IC PRINCIPLE 11>c HIt. th., 1M Viii"""" is II>< .... y it i. b«a .... , if it .... 00', we would 00' bo 1Ier. to 001;"" n. In <lIh .. _~,ht fo<l of our o j"mc< i. on important s<;'n,ilic oo...rv.t;"".

A1','TIMATIER 'krm lOr I Iarg. ""cumulation of antiparticles. Anl;"""""" an'inru,,,,,, .. and pooitroru OIn in &.:, <om< .",.,1Ier to ...u.., Inti-a loms. And ,Mr. is nothing in principle to rule 0<1, lht

"" .. ibili,y of .nlist . ... , .. !liplan .... Q< . n.Hift. 0". oI,ht !rn'",' nI)'SItri .. 01 rhyoico i. why..., ."""or 'n ~vt in a Uni ...... made !Oldy of m.nt, wllm the law, of ph)'>ia KerrlIO pmlict • prfllj' mud! SOl SO mis of rn.t1<, and .. timon tr.

A t..'TII'A RT1CLE E ~ry ,ub.."",i< partido has an a.uo<iota! .n ti .,..,_ lido with oppo,ilr prQP<'fti<t. ouch .. tlr<:lrical chaTP'o For irutuxt •

• 11< nog.al;.t!y chargal .k<:'ron is ,,,,inoN with. "".;,;.-.Iy <horg«! antip;utidtlmown OS tht pooi.ron. Whtn I p." kIt • ..J its an'ip;"'''

,idt mttI. they .Id f -oottuct, or · annih il>,.; in a lLa.h of hiJIh-r""5Y

ligh'. 0' gamma raj'S>

AroM Th. building block of ~Il oormal m.ner. An .1Om consi ... of • nud .... orbi,ed by • dou..! of d<'<t ....... n.c I""iti .... d\'''J< of ,he nud .... is .",ctly Nl.nced by ,he nogat;"" c harg. of ,h •• lectron •. A n "om is .bout one ]I}-million,h of ~ millimeter aero ...

AroMIC ENERGY s.., Nuclc .. E""5Y.

AroMIC NUCLEUS The 'ight d",,., of vrot0n< and neutron. ( • • ingl. proton in ,he caoe of hydrog ... ) a"h. cm,er of . n alOm. n.c nud .... con tain< n>On' than 99.9 r<rttnl of ' lx ma.« of an ~'om.

'" BIG BANG Til< lilanic ~xplo<ion in ",hich III< Un;...., .... i, thought to h.~ ~ born 13.7 bill;.,n )'00" 'S'" -&"I.,.;"n" is "",,,,,11y • milll<HntT "net til< 6iS ll.ang h.ppmtd rwrywhtrt at once and 1Mr" w .. no r_xi>ting void into wh"", tile Uni~ ......... pleJ. Spau, ,i_, and """'l!Y all am. into btiT13 in II>< 6ig &IIg.

BIG liANG THEORY Th< idr. ilial "'" Un~ btgan in a ,up<'r'

den .. , .upt.hoc Sll" 1).7 billion years ogo and h .. bt<n expanding and cooling ....... il>Ct.

BIG CRUNCH If th.tt. is enough mlU" in 111< Un;. ...... it. gra~ily will ono .loy h.h and rev ..... the Uni ...... ', "p;m,ion so ,ha, i,

.hrinks .I""", 10 • lIig G-unch. This is • .IO!"t of milT'" ;""'ge or lht Big lI.ng.

BLACK BODY A bOOy INI ab<otbs all ,he heal tho, r,n, on il. The hu, i. u.a....! among"'" .. om. in s""h • way ,h., th< hr., ""li"ion it Ii,," out uU$ noa<<<mnl ol what the body i. maJ. ofbu, ~oo. ooI<1yon i ... tempt .. I"", and t.as. ,horaetor; .. " 01><1 "..ity """sni..bl. form. The .ta ... rt 'pl'"",;m,'" bt..d bodies.

BLACK HOLE The grossly W;I~ .poce-time lor, bcbind whon. musivt boJy'. SrlIV;' Y CO""" i. ,<> shrink down 10' roinl. Nothing. nol "" ... lighl, <an eocap<-h<n« a black ho~'. blackn .... The Un;.......... pp" .... 10 ronlain" 1< .. 1 two Jistincl 'rPd of black hole.t.llar-Aud black holn that form",""",, ..... ry m ....... st .... <an "" long..- 8 ....... '. inlornal h .. , to "",n,..-bal.nc. ,lit gravi,y trying '0 <rush 'Mrn .nJ · .upormaooi ..... • block hoi ... MO!l ",wi .. 'p~r '0 h ....... . "po",..... ...... black hoI< in thoir h ... rt. The)' "HJ!C' (rom mil-lions of tim .. tho mass of tho Sun in our Milky W~ to billio ... of ooI.r ........... in ,lit pownful'luosars.

BOSE-EINSTEIN CQNDENSATlOl-l Ph .... om .... "" in whi.:h.u tilt microscopic ~"id .. in a body wdd .... ly crowd into tho .. m •• tato.

'"

Til< p."idts mull be, booon, and Ih, ~mpt""'~"" m .. ' g"' .... lIy b< ~ low. Helium "om .. for illS\ll""<. cruwJ in'" lhoe .. "", .. at. be-1ow-271 J.~ CCI<i ..... ,uming ~quid hdium int<l •• upnfluid.

IIOSON A microocopic partido with inltgtr spin-th,t is. 0 units. I uni" 2 units, and ... on. lIy vifl~ of lMi, .pin., such p.mid .. are hugrly 8 .... &',iau .. puticip •• inM in call«ti ... b<h .. ior tho. !raJ. '" l ........ upnfluids, and sup<rwnduclOr$.

IIQYLE'S LAW The o~lk>n that the v,,!umo r,(.! .. i. i~y proportional!" ~. p"' ..... ft'----{hiol i.>doublin~ III< mOIl' famous inslano: i. of polk" grains zigugging through wa'''' as they .r< "'p"'.<dIy IUt by WoO'" mol«w... 11>< phrnom<fl()n. Jt..:owrN by bolani" JtOO..r, llrown in [827.00 .riumphantly explainal by

Einslrin in 1905. was powtrful proof of tht <::<iI'''''' O[oloms.

CAUSALITY The KI .. thai. ca"", .1 .... ,.. p...udts an df«t. C.usal;ly i, • mlU:h .. d ... ,i.hed prindpk in physiC!. Ho~r, quantum """nts such .. tht <kay of .'om. apmr I" b< .fTtct. with no J'Tior CIU><.

CHANLlKASEt;; HAR LIMIT Thc 1111'" posoible ma .. fo, 1 whit< <I", .. f. h .!tr.nd. on a '10'" ch.micll composi,ion, bu, for 1 whit< dwarf mad. of II<lium it i. about 44 pon;en' mo ... m"';,..

,han ,II< Sun. For • olar bigger ,han lhi" III< d<C1roo <lcg..,cracy p ..... ur. in.ide is in .... £r .. denl to p ...... o, S .. vity from ,rushinS til<

.larfoI1hn-.

CHARGE·COUI'LED DEVICE (CCD) Sup.ro<n.itiw.I«' ronic

ligh' <1<1«:101" 'h' an .. p."" cl .... 'o 100 po .. ..,1 oflhoo l;g,l,hat

,. ralls on iL 5;'>« photographic plain .. gin ... m.rt I I'<"",nl, CC!)s

allow. ,oJ....,!'" to perf.". .... os ....,II ... tt""""!,,, with 100 times tho lit,l>t-<XIIJ«ting .......

CHEMICAL !!ONlJ Tho "put" tho, Slick< .to"" lOSetha- 10 mal<

molocul ...

CHRONOLOGY ~ROTECTION CONJECTURE ~ miclurt,hal

timo ,ra ... 1 i. impo .. ibk No one h3. yet ma".god 10 pro ... it~ in fact. ,he law> of ph),>;", 'p~r 10 ~mit ,ilm ,,..vd-bu, ph,..; . • ;.co such OS Sltphftl H .... k.in! l'ftII.in co.winaJ ,h., oomt ... -~

unilis<ov<red law of n.ture forbids tim. modlin ...

ClASSlo.L PHYSICS Nonq"""lum physics. In eIl«t,all ph)'>i'" be· f,... 1900 when ,I>< G<rm.n phy.ici<l Mu Planck fin ' pr<>p<>stJ thai morgy might "'"'" in discm. dlunlu, or Guon, •. EI ... ,';n wos the fir$! to ,uliu ,ha, ,hi; iJ ...... ",ally incompatibl< with aU ph)'>;'" , .... , t....l Jon. b<for<,

CLOSED nME-UKECURVE (eTC) ~!ion of opo<c-timt.., Jr." m.';cauy .... ,ptd thalli",. loops backon ;, .. 1£ in much , ... sam. "'''Y tho, oP"'" loop. I>ooc;k on itself on an a'hletkotrod:. II ere, in common parlanC<'. i •• Ii"", mKhin •. II i. p<rrnitt«i 10 <Xi" by tht CUr_ ron! );OW> of p/lysics..

COM ET Small icy body-u.>uoUy me~ kilome!e .. acrou-!ho! "'. biu • star. Most com. U orbit the Sun beyond the ou!ermoll p);oneu

in an . normou.> <loud mown a •• heQor. OouJ. Lik ISkroids,~om<10 or< builJ<n' rubbl< loft ~ from , he form •• ion of!he pl.".u.

COMI'TON EffECT The m:oil of an d«lron ... heIl <xpoMJ to

higl -en"'1Y light JUS! .. if!he el«troo i • • tiny billian! NIl struck by onothtr tiny biUi.rJ baiL Tht efftrt i. 0 gr.ophi< d,"n ..... ' '''tion !h.,

light i. ul!imately mode of tiny buUetlike ~"ides, or pilot ......

CO~DUCTOR A mal .. iallhrough which an el«1ricaJ cumnl can ,-CO~SERVAnON ~W Law.,(physkJ lhai .. pr.....,. Iht flCI Ih .. a

q ..... nl ilyan """", changt. For iml.net. Ihe "", .. "",lion of el'l<T3Y .Iyt<l, only convtrled fTOm One form 10 aMI""'. For aompl •. tho <hemical _rgy of pe_

lroleum can be COO ..... I«I inlo lhe en"'l!Y.,( moIion of a Clf.

CO~SERVAnON OF ENERGY Prin<iple Ih., en"'l!Yan n .... be creat<J or destroyed. ooly COO ..... I«I from one rorm 10 onoth.n".

COOPER PAIR Two .1«1ron. wilh op[>OOile .pin WI p. ir up in som. mmls al .. I ... "",1y low IttnperaIU .... Cooper pai,." unlilcc indi

viduol d«lron •. aJT bosom. GonO<q""nlly. th.ty can.rowd into the

.. m. 'lal<, moving t<>geth.r in Iodst<p I"rough lhe melal Ulcc an irlnistible armyoo the move. The el«<rical CUrren' in such a "super_

COndW:lor"Can run for ........

COPERNICAN PRINCIPLE The idea ,ha t'~ is ",,'h ing spedal

.bout OW" po<ilion in Ih, UnivtlY. in eithor .poet or time. Thi' is a

g ... ...:ti>N ,..,..ioo 01 Clp ..... ic .... '. re<:ognilion ' hot Earl" is not in a sp«iol ""sition .1 tI>t cenln of lhe sol .. systern bul is jUt . nother planet d ... ling ,he Sun.

COSMIC BACKGIlOUNlIll.AlIlAnON The .... florsl""'· of tile IIiJ! II.1ng fireball. Incralibly, it "ill permeates all of .paor I ) .J billion Y"a .. ah.,. tI>t ..... nt .• tepid micr<>wa .... ....J .. tion <:<>rrnponding to a lemperaturt of -170 d,grra Celsius.

COSMIC RAYS High.,peed atomic n",lei. rnrutly proton •. from

s~. Low-.nergy ones com. frorn ,be Sun; high-energy 0 .... prob

ably co"", from supernovas. The origin of uh .. -h~h-eI'l<T3Y .""mi. rays, panides rnillio ... of limes mor. energetic Iltan anything ~ can

,.

",rr""tly prodUCt on Ea"h, is ...... of tilt 8""01 un",]vt'd puuJes of ... """,my_

COSMOLOGY 1M ultima,. "'~. The science who ...... bjea mal, .. is 1M ,,"pn •• ",Iution. on.! fate of Ih • ..,lif< Uni~rS<.

COSMOS Aoothtr """< galnin an.! sp«ding up lilt .. pans;oo <>fIt.. tlni ........ Nobody t.... mud> "f.d". wha' it is.

u"RI( MATT ER Mauer in lhe Uni", ... th., give. oul no light As·

lronom"" know il .xi.to btc.u ... 1>< 8 .... ;'Y of tht invisible Sluff bmd. lilt ~Ihs of .loibl. ,lars and galuics u,hey fly through sp.~, Th .... is brtwttn 6.00 7 tim .. .. m""h .!ark matt., in.1I< Uni ....... .. onlinary, lip.t~min;ng m.ona. n.. idrntiry of 1M Jark malt ......

Ih' oolSlandi", problom 0( astronomy.

V[COHf.RENCE Tho .....mani.." thai JtSlroys 'he wrinl qu.anlurn ""'\If< of . bool~ thai, for inn .. """ it appears ]O<a]i..,J rother ,h.n in many ilifftr.n, placn .imullanco",ly. L>tmba<nct OO<ur1 if 'he oul>iok work! 5<1<10 "koow' aboullM body. The knowledge may ht taUn a .... y br' ,ing\< photon of ligh, or an air mol«ul~ ,h.,

bounces off ,he body_ Sina big bodies lill< <abln .... con'inually muck by p/Iol<>lU and air mokcuiesand can",,' rC'l"lUin i..,lalN from 'hoir , urTOUOdi ngo r""long. ili<y I.,... 'heir abilily 10 he i n many p 10"" al ona in a fanla<1ically shor11Um----far [00 ,hort tor u' 10 ""'iu. DEGENERACY PRESSURE Tht tw-in·a-ba.·lil<c prt:<.<urt <:urtN

by eltclron. "lu«ud inlo a .,.,all volume of sp;1«." conS«.juena of lh. H.ixnbaJ ur.: .... inly principl~. il a ..... btcau .. a microoaJpi<

,. Jnr'icl. """"" location is known '.,.y....,jj """""",';Iy has • 1111< unco .... inty in its velocity. n.. J"!i ....... "'" pr ... u .. of .Ita..,... p .. -_IS whil' J""rf. from .hrinking unJ<r 'htir "",n vavi1y. WMrns ,he dog ... .....,. prnw .. of n~I"'ns 00.. 'ht .. me thing for neutro"

,"~

lJENSITY 11K ma.oor In objKt dividrtl by its vo]um<.Air h ... low

oknsilr. and iroo has . high d .... ily.

[)IMENSIQN An in<ltpn>.knt ill,,,,,,;,,,, in '1''''' ..... ;'''''. The famili ..

""'rid around ... Iw Ih,« .pact di ........ ion. (ltlt -rig/n. for .... rdwckw; ... l, up-down) and on. of lime (p .. t_fu lure ), Sapo .. "ing th.tO<y lniui~ lh< Uni ...... 10 """ six <>.1 r.I sp>« J i_miD ..... ",..,. diff ... ....tic.Uy r""" , .... 0' .... ' dimensioru beau .. I~ .rc roIl~ up vtry.maO.

lJOUIlLE SLIT EX~ERlMu..'T up<rimmt in which p.,tid .... r<

shot., • $O'ffn with."", d""dy . poeM, p ... :alld ,Ii" out in it. On til. far sid, of 1M scrttn, 1M f'1r1id .. ming\<o or "inlorf,re,," with <:ach "thor .<> p",.!u", • ,ho"""",,,i .. ;'; "int.""",,,, pa".rn" on I >«OM IICrttn. The biurrt thing i. lh.t lht p.ILrrn forms ........ if !he partid ... • '" >hot at ,he ,Ii" " ... 0' • lime, wilh long PI" OO ..... n-in other worn... when the~;. no possibility of . hnn mingling wilh ",ch othe,-. This "01111, cl.i....J l!.ich. N Fe),.",,"n, highligh.ed , he ·",n, ... 1 mys,ery. or q\UJl,urn 'hrory.

ELECTI!.IC CHAI!.GE II prop~")' or microscopic pa"icl .. 'ha. oom .. in 'wo ~p<>ti'iw and ... p'i ..... floc'''' ..... fur in",,,,,,. art)' •• 'p'i"" charge and P"""'" • poU.i"" char, •. P.r.idn .. ilh ,he .. m. charg. "'I"'1...,h o,her, wbil'l"'r,icb wi,b unlikt cha,!!" aUrocI.

ELECTRIC CURRENT II riva or chargtJ pulicld.. u'ually d«_ ,rono, ,hal can Oow 'hrough • cond""OI".

'"

ELECTRIC FIELll Th. fi.IJ of foret ,h., .urround. an ,1«1ric du",

Etf.cTROMt.GNETIC FOltCE o...o£,ho four fundamenlil fol't<'J of ... ,u ..... It i< """",,";bk lOr gluiI15 l"Stlhn- aU , .... ,lin,,}, "",tlcr. including!'" alOm. in our bodi .. and 111< "0".,. in the ,..,..;b bMnth Our ifft.

ELECTROMAGNETIC WAVE II ...... thaI '<>Mim of an ,"",ric f~J th .. p<,iodically grows.oJ .Ii .. , al' ...... . i"g with. m.S"".k ftd.! d"'l"'riodiaUy JinanJ"....... An tl«lromag.nt1ic ...... iI sm.... t<J by . vib,..,;ng d«l"" ""'~ anJ ' ...... Is through .po« at tho .pttd of ~5hl.

ELECTRON Ntg.tivtly ""''lied oubo tomic p.rtick typicoilly found orb;ling 1M nude .. of an .'om, As fa, as anyone an ~1~;1 i •• truly .k"",ntory partid<o inapabl. of bring oubdivid<d

ELEMENT A ,ub,'anct thaI canno1M r«lU«<! any fur,h .. by d>omi<.1 ""'an>. All """',flr. g;v.n d...,.nt p<>SS<SO ,he oarn. num· btl- of prolons in lh<ir nucltus. For ;n<l''''''. all .'om. of hyJrosm h ..... one pr<llon, aU O1om, of chlorine h ..... 17, and so .,.,.

ENEIlGY II q""nlilythal iul"",,! impoosibk 10 ddine! u,ergy can n." .. " b. .",. ted or In,roy<J. only oonV<rtcJ from ""~ rorm to an· other. "''''''''8 tbe many {amili .. forms au heat enOlllY, enOlllY of motion, tlectrial energy. and sou"", "'OIlly.

ENTANGLEMENT Tho inttrmingling of two or Il"H)K microscopic pa.,icln.., thot ,bey \0", ,I,.;r ind;";du.ali'y and in many _yo be· hart ... oinr,l..,nti,y.

,. EVE/liT HORIZON Th< on~-"'.y "membrane" Ih.! .urround •• black hok Anything ,h.a. f.U, thro"th-wheth.or rna".,.". [ipt

ean " ...... 5<1 Ou' as.in.

EXOTIC MATTER Hypoth<ti.:al matter with "'Pulo;"" 1I"'''';ly.

EXI'ANLllNG UNIVERSE T~ n ... ing or ,I>< &a1uin frOnl .. cll

olher in the . ftcrnwh or the l:IiJ! Sang.

FERMION A micr""'''pk p.rtkk wi,h half.in108'" 'pin_,hat i .. 'I, unit. 'I, unit •. 'J, "niu., and.lO on. By •• nut oflMir .pin. ouch ,,"rtides ohun.ach .,.her. n",;, unsociability is the " ,U,>n d"'l atoms ni .... nd lht ground 1><".,.,11 Our {ttl i • ..,Iid.

FRAME DRAGGING 'fbc JraWng around of spa«_,im< by. ""...

oj ... mlaling body. The eff«t is very small- thougll poI<nlially me.ouru.lr-in tl>< vicinity of Earth h't",,,,,,,,,, n<at. fO$,.,<>I.i,;ng black bolo. Such. block hoi. ,i" at 'M .,.. or • lO,nado of whirling

'~- li""'.

FUNllAMENTAL FORCE One of lht rour basic foras that ... 1><li~ 10 un.,1erli •• U phe1>om<1>a. Tht {ou, furta .rr 1he gravi,ation.! fara, el«lromasn<1ic mItt. <lrong foru, an.! weak fora. 'IlIt mOIlJ! suspicion omoos ph)"iici ... i. Ihal lhese to,o:. a ... aclually mt,dy fo«u of •• ingl. ,ul""kllu. In f><t. opnim .... u h.~ alr .. Jy shown'M tltc, romagr>t1ic anJ ~ak ("""",,, be Jifforenl .W .. of ,htsamtcoin.

FUNllAMENTAL PARTICLE 0". of 1ht N<ic huilJing blocks of all "",n.,. o..rrmtly, physicists bdi.~ tht« .... si~ diff=m q .... rks.nd .Ue iliff .... n' I""" .... making a ,,,,.1 "f I 21ruly fund.." .... tal par,id ... TIlt hop<: is ,hal ,lit quo'iol will lu'" ou' to be m=1y ,liIr .... nl faces of,hot kp.o ....

,. FUSION s.., Nud .. , Fusion.

GAlAXY 0". of Iht builJinj block< of tht Univtrst. G.lui .. arc great isl. nds of ... ... Ourown i.land, the Milky W.y. i. spiral in ""~ .nd ",nl.in • • bout .!OO,OOO million .\uS.

GAS CollKl;on of "on" th.t Ily about Ihmu", .poe. Iii;" ..... &mI

oftinybtes.

GENERAL TH EORY OF RfU,.nVIIT Ein,,';n', thoory of sravil)'

th.t thow. gt;Ivity '" bt nothing mo~ th.n III< .... ~. of .~time. n.. ,heo<y inoorpo"'" .......... 1 Kltas thot w= nol incorpo""N in N~on·. thtory nr gravity. 0..., was . hal nothing. no' nm gravity, can ' ..... 1 r., .. .,. than light Ano' ........... , h. , . 11 for"" of ... • "1lY ha"" rna .. and "'.~..,., "'to of S,"vil y. Among olha things. "'" IhC'Ol"y prtdicled bJad holes, the •• ~r.din8 Uni ....... , and that gravity would bo.nd .11< J>lth of light.

GEOUESIC Tht ,ho"ts' path bc1 ...... n tWO poinlS in Io';IrpN. or <u,..,..d •• poc<,

GKAVlTATIONAL FOIKE The ",.01." of the four (un..Lament.1 foren of ""' u ..... Gravity i. 'I'Pra. im.,dy cltoeribtd by Ncw\",,-, uni· ve ... II . ... of gravity bu, more aa:u .. ~ly described by Einstein', .hrory of povi,y-tht sm.....! throo-y of ..... "ivily. Gmtnol r<'i:nivity bRab down ot the .ingularity at the hea., of a block hole and the .ingularity at the birth of lhe lJnwers<. !'hyoid ... ore currently look· in, fQr a booner deocrip. ion "r vavity. 111< th«>ry, alroady Jubb<J ~uanlum ,ravily. will «plain g"I'ity in ttrm. Gr . he """""8" of par· tid .. <allod vavit""".

G ItAVIT A no NIIL LIGHT liEN]) J SG Tho boond in g of the traic<IGty of ~&Iu tlu. p ..... by. mIMi ... body. Ilea"", the .p.ct in tho vicino

,. ily of such. body is ",.rpeJ lik< ... U..,.. tilt ~gh! has no choice but !O

, ... ~hl""g a ",mod po.th.

GRAVITAT10N,o\L REI) SHIFT 11>< 10 .. of .... rsr .. light climbs out of th.t van.,. in <1'..,.,.,;",< .,..,und. mU<ivt alt<li.1 bOOr. 5i"" ,he "color" ofligh. is ~lalN to ilS .... rgy. with ...J ligh, having I ... <TK'TJ!Y than blue Kgh •• a!l ronornrr> taUt of light t..;ng , iliA..! to til< red end of 111< sp«lrum or"rN·shifted:

GRAVITATIONAL WAVE A riprlo sp~aJin8 oul through "',«lim<. G .... ital"'.w ,...,... .r. 5'l'tratN by violtnt mol;"". of "",so, . ""h as lho m,rgo' ofblad holes. 1Iea.,... they . .. _ak, ,hey ...... n<>l bt<-n d.'«IN dir«tly y<1.

GRAVIIT ShG,nit.tional ""ICt.

HALF· L1FE Tht ,im< it ,u.s h.Jfll>< nudri in a ""'i"""jv< $ampl. 10 di,inl<g"'" Aft .. """ half_lifr.1ulf th.t .lOm! wiU boo [<It; .fi., two

half-li ...... . 'lila,''''; ,f't, 11>....,_ an eighth. and so on. Half-li ..... can vary f""" ,he m._ op1i(.s«ooo to many billi.,... of,..aro.

HEISENllfJlG UNCERTAINTY "lUNa PLE II principle of quon_ tum thMry that !btu art ",irS of quanti!; .. ",ell ... pulido.', loe.-1;00 aoo "I'ttJ that clnnO( "mullalltOusly be known with absolute preci1iolL lbt un«rU.inty principk put> a limit <>n '-' wdlth. prod""t of suell. poirof quantities can be known. In practiu, this m ..... that if the ,p«d of a partide is known pr«i .. ly. il is imp"", ible to have any idea where tho ponid. io. Con~ ... Iy, if the l""otion i. known with =lainly. lhe parlido', >p«d i. unknown, lIy limiling wh .. we can know. lhe H.i....,be'll u"" ..... in'y principle impo ... "funi"""'" <>n n"ur<, If we look ''''' dowly . .,...rything blurS lik •• new"",~r picture dis.solving into n,.. n;ngl ... dot ..

'" HELIUM S«ond li8hl ... ,Innml in nalu", Ind lh, oolron.10 h."" b«n di~ "II the Sun btfo ... it was J;""""retl on Earth. He· lium i. th.t SKOnd moll common dane .. t in 1M Un;... ...... rl.,. hydro, ... , oc<oun1ing for .bout 10 pen:<n1 of .1I.coms.

HOIUZON The Uni ........ has a horizon much lik the horizon dllu surround<. 'hip .,~ .. ~ relSOn for ,t.. Uni_', horizon i. ,h •• lightlw. fin;~.peed and the Un;"", ... has betn in aiOlena foronly • fini'e limo. Thi. moan. thaI ..... ooIy .... objects wIIo .. light has had ti"... to ... d . OJ ,in« the lIiS liang. n,. """' ..... bl< un~ i. t~ •. fore Iik. bubblt ",nlOrN OIl Eanh. ",jlh II>< horiwn being II>< sur

f"", of lhe bubble. f.....,. day 1he Uni ........ ge .. "lJet (by" ... d.y), '" t>tty .loy I"" horjIO" <:JCpW' outward and n ... Ihin5' btcomt .i,_ ible, ju>lliu >hip. coming O\'ef ,he boriw" .1 .. a.

HOIUZON Plt08LEM The probltm that r .. ·nungparu of dl' Un;"' ... that could nn<'T h.,.. Ix<n in """ta<! with _h oth<r . .wn in til. lIiS !Ian,. h~ aim"", iJ..,ticai propalir> "",h a$ Jrn,.;,y onJ lrmp<ralu ... T«hnically. 11><1""' .. always boyond each othtt', hori:roo. n.. thwry ItQGEN Tho liShln! .ltmenl in "'UU"." h)'Jrot!", atom coo· .;;" or. sinslt proton orbited by • oinsk .I«tr<>n. Clo .. 10 90 1"".

ctn, or.1I atom. in III< Uni~ ....... hydrot!tn atom •.

HYL>ItQGEN BURNING Til< r\llK," of hydrog", in.o hdium "". companit-<l by III< libtrolion or l.,g. ~u.n~lin of nuclt., binding '"..-gy. This is .11< power ..,"'u of.1I< Sun ,00 ",.,. ........

HYL>/lOST"T1C Et.JUILlIIM1UM Tho ,UI. in which lh. g ... " ... . lio ... 1 rOret Irying 10 au'" • star i. paftrt/y balancN by.1It r""", or ilO hot gas ptuhing OU1W3.u.

IN ERTlA Tht u,ndmcy for I ",... .... bo.Jy. on« sel in molion. 10 k<q> on l1IQYing"1 con ... nt opted in ..... ight Ii ... in unworp«l o~ and alMg a g<'O<lot,ic in WOrpN <poc<. NoboJy knows lilt origin of inc,,4.

IN EItTIAL FOItCE A fo", ..... invenl 10 aplain a m<>lion Ihat iJ ac,uolly due 10 nothing mOf< than in<1'l4. A good aomple iJ «nlrifu_ gallO",<. Thtre iJ no OIICh fore< Hinging ... O,tlWON in a Clr 1'OIInding a sharp corn .... We a", simply conlinuing 10 moYC' in IOlrlighllin< b«ausc of our i ... ,,;;' •• nd ,lit interior of the car. b=o .... it iJ 11IQY

in8 alMg. curved palh. inlrrcq>1S ....

INFU.TlON. THEORY OF 1..It. 1iu.1 in Ih. fIr .. splil-.I«O<td of ilS crea,ion Ih. Uni ...... underwen,. fan ..... ically fa ... """nsion. In. sense. infLalion puttde.l the con",nlional Hi!! Bong aplosion. If lilt Big B.ng iJ likc-ned '0 lilt .xplosion of . grenade, infLalion was Uk< .1It .. plosion of on H·bomb.lnA •• ion C.n "'~ 10m< problom. with ,lit Big BOIlJ! thtwy .uch OS tilt horiz.on problem.

IN FRAREI) Typ< of invisible light that iJ gi ... n out by w.rm bodi ...

INTERFERENCE Tht .bilily of lwo w ..... p .... ng Ihrough nch othtr 10 rninglt. ",inforcing wh...., liltir ptak< coi ncidt and canctling whm: II>< p<au of on. coincid. wilh ,lit lrouglu of In<>llltr.

INTERFEItE.NCE PATIEItN Pa".,." of lighl and dark >!ripes ,hal 'P,,",'" on a scr«n iIlumin","" by lighl from lwo IOII!US. Tht pal,""' iJd ... to the lighl from tho two IOU"" ",inforcing.' "'"'" placeo on IIIt.!attn and canctli", 01 <>IiItr placn..

INTERSTF.Lu.R ME[)]UM Tht ttnl1Oll' 80s and d"" Aoaling bt_ ' ..... n lilt .. . ro. In l ilt vicinily of lilt Sun Ihi. gas comprise • • bou, 0 ... h)'lrogm alom in .. ery J cubic u ntimelrn., m.lci", il a _uum far bet, ... Ihan anything ochicvable on Earth.

'" lNTERSTELU.R SPACE ",.~ ~Wffn lhtuars.

lOS An .1om or molKulr tlu.l has t>t<n 'lrippal of 0 .... Or mor~ of ilS orbit in! ~le<lrons and.., has . .... 1 po>ilive olo:<:lrk.1 rh.'!"_

ISOTOPE 0 ... poos;bk form of an .Ie .... nt t.o.opa are di"ingui.h· .bl. by , h~T diff .. ing nI ....... For in.[.nc<. chlorine 00",.. in

,"" ,I3bJe iSOlopes. with. mas< of J5 011<1 J1. The m ... Jiffemlct is Jilt 10. differing number of IIt,Umns in their nuclei. For in.tana,

dtlori ... -15 «I"lllin. 18 Bal''''''' onJ <hlori~·}7 mntain, 2(1 n.u_ trons. (1klIh contl;n lilt .. mt numbor or proloou-l7~inct this Jourmi .... the id..."ity ofan .1em<1l'.)

JOULE ",. ",ndanl ... ientifoc unit of OfIt!'8Y. The en<l1Y of m ... i"" of. pitchc.l burlJaIl is .bout LO joul .. , th. d'l<mic.1 _Tn pmviJtJ by • ';IlII< oliet of brood is abo"1 100.000 joul .. , aOO II>< d«nical m"1lY of. lip,.ning Ji«:horg< is about 10 billion JOYI<$.

IAMBOA !'OINT Temptralurt btlow which liquid ht~um begins to turn in'". "'peril";.!.

U.SEIl Jliht OOU= in which the g~rio\l$ nature of pholonobooons--«>nl« ,n the font. 5p«ifocal.ly. II>< """" phocoTl< the .... r. passing Ihm"'" a n .. l.ri.1 1M gr.al<r tho proMt>;lity that <>Iher al· on" will.rnil othrn with the .lam' pro~i ... Tho mwl i< In avo· lar.che of photons .n lra ... lin8 in locbl<f'.

UGHT.CONSTANCY OF n.. ~uli.rity tn.t in QU' Uni ........ tho .p«d or lishl in trnply .~« i< .I .... yo tho .lam., irrtsptCli ... or tho .p«d of th • ..,.."'. of li!bt or of anyon< ob .. rving tho light. This i< on. or I"", co'I'ItrSlo ..... or Ein.trin', spocial thtory or relativily, tho other bting tho principle of ,..I .. i.ily.

'" UGHT,SPEIDOF Th< COiImic .p«'Illimil-.JOO.OOO kilom~ .... per -, LIGHT I:IENIJING Sec Grovi'a1i""i1light l!ending.

LIGHT· YEAIl Convenient un;, for op .... ing di.u""", in the lIni· n ...... It i •• imply "'" di,,"noC< ,hat li~l "...,1, in on< J'<'ar in • vacuum, which tum. out to be 'J.46 trillion kilome{ .....

LORENTZ COr.. ... RAcr[O~ Tho <on"oc,iQn of. OOJy "",ving rtlat;'. 10 an "01> ........ : Tht~...,. stn III< body .hrink in I"" <li=,;oo of ilS m".iOlL Th< off«. is "'li keabl. ooly wh.en .hot body i, moving dos< to lh .. rttd of ~g.1 wilh .np«ll0 Ill< oboe,m-.

LUMINOSITY 11>< tOtal amoun' of ~sll1 pumr«! in", 'Poe< urn second by • cda,iol body such as • S1.r.

MAGNETIC HELl) Thrfiold offoru that surrounJu mas-.

MANY WORLDS The i.ln tlut quantum thwry <I"",.;.,... ..... ry

thing, nol .imply the microscopic world of alom. and thtit conSliluemS. 5i"", quantum !h<Or)' permits . n atom to he in two places at "net, this m .... _ an thltl I.bl. unN in two pl><n.l ooa, M_

cording 10 ,h. M.ny Wo,ldJ ideo, howe...,., the mind of the perso" obKTving II>< ubi. <pli .. inlO ................ !lul p<rttiva til< w,k to bt in ono piau and ."",her tlul pt, .. ;' .. i"0 be in ,,,,,,her. The lwo mi1l<1s"';01 in "poral. reo~li ... or universes.

MASS II mnsurr oflh •• moun' of mailer in a boJy. M ... ;. lilt moSi <oncenlraied form of energy. II .mgle gram <oniain. thoe pm.

amount of ..... '!!' as 100.000 Ion. of ",nomi" .

MAXWEll·S EQUATIONS OF f.LECfROMAGNITISM The hanJ· ful of ele80nt «Iuation .. wriu.n down by Jam .. a...k Ma..-II in

1868. l!>al nn~y ,umm.ri,., all okcl ric.1 .nd m.g ...... ic p/l<no""' .... n.. «I""IiQ", rnnl l!>al ~ghl i>.n d«Irom. gn ... ic wa~.

MILKY W/'o.Y Our pI .. y.

MOLECULE Colleclion of . Ionl' gl..N l",elM by eleclrom. gnelic f"",<s.On. no"" CI~<an Knk ,.ilh it5df and "'ho.r 01"""'0 maU • huge nUnlho., of nloI=l<» fo, Ihi> , .. ,on, dlemi ... dMJe mol"""'os inlo "orgo nic"-Ihose Nsed on carbon-.nd " inorganic "

them'.

MOMENTUM n.. mo .... ntum of a body i, . ...... u .. ofhow m""h

rifort i> rt\]uirrd lO"OP iL for in.tan<t. an oil tan ..... "<11 Ihough il may be going at only. few kilome ..... an hour, i. far har<.le< to .. op

than. Formub I ~. <ar J oing 200 kilomncn ]><T bour. n.. oil I. n .... i, lOW 10 hove more mnm<nlum.

MOMHITUM. CONSERY!o.T10N OF ~rinripl. th., mom<ntum can ... ~, ho. cre.tal or dntl"n)'N.

MUtTlYERSE Ilypolh<tical <1Ila ,#m<1l1 of Iht co.mo. in which our Uni ....... turn. out to be one . mong an enorm""" number of orpanolt and di<tin<l univnvs. Mool univtrtCS.rt dud and uninltT·

e"ing. Only in a liny .uboel do tho. lOWl of phyoico p~. the .."tT· genee of .ta ..... pion .... and lif •.

MUON Shot1-livtd sub.tomic partide l!>al btha .... like. lin")' vtr

.ion of the elec'ron.

NE(JT1UNO N .... traJ .Liba,,,,,,ic particlr wi,h • ~'1' ,,,,,,II mas.s thot

l..ntls "''1' <~ 10 Ihe <pt<"<l of light. Ntulrinoo hanlly ntr in • .....,1

will. ""'11tT. H ....... ~', when c reated in hug. nurrol>tTo. they can blow • ".r .p.rt .. in • • uptrn<ML

NEUTRON On. or tho t"'o main building bloclu or tl>< .tomic nucl<U!l.t tl>< ",nt.r"r "om~ Neuu, .... h ........ n.i.Uy.1>< .. me ...... as protoru but arty no .l«IriclIl chorg". Th.y are unotabl.out.iJ. of . nucleus , 00 di.integ .... te in about 10 minu ....

NEUTRON STAR An .. thot ha. shrunk unJa it. own g .... vity to ouch an ""tm' that _ "r iu mo •• rial Iuo brtn rompms-N into nC"lltrons.1'ypkally, ou.dt a .t .. i. only lO to)(l kilo .... t .... acrooo. A

. ugar cub< of ncutroo .... Sluff """,Id wrigh as much as tl>< onti .. human ~.

NEWTON'S UNIVERM.L LAW Of GAAVfIY The i<k • • ha. , 11 bod

in pull on .. cIt OIMT ICrntS ' p"'" wi.h a fore. that dcptnd< on tho product"r th<ir iOOivid",1 ........ and tl>< in ....... sq",re of .h<ir di"on'" .part. In OIM word!. if tl>< Ji't.n'" betw.-<n tho bodi .. i. doubled, tl>< fore< becom •• four times ~.kct; if it is tripled, nine .iJ1X$ wuur, ... .1 10 on. New.on·, .heory al V",ity is perf«tiy ~ for owry.J.oy .ppli,"';on~ bu. 'urns ou' '0 be an 'ppl"OIIimatiOfl. Einstrin provided an impro....."..,t in tl>< general theoryof ",\ol;'i.y.

NONLOCALfIY The spooky ability of objKts , ubftd 10 ~u.ntum 'heory to COIl.inU.lo "know" about each OIher'utateown whm sep.rated by . la'll" di,l.n« .

NUCLEAR ENERGY The.uns ellnllY ",I<OMJ when 0'"' . tomic nud<U!l change> into anOll><r atOO"lic nucIeuo..

NUCLEAR FUSION The ~Iding loge.hrr of lWO light nuclei '0 mau a hr.v;'" nucleu .. a proc<~um in tl>< co« of .h. Sun ,ince it' by' pl"<><lllCt i .. unHgh1.

m

NUCLEAR REACTION Any pro« .. ,h., con'Orl. on~ Iyp. of .,,,,,,ie nucleus into ."",her typo "r . t"",;.; 0""1 .....

NUCLEON Umb .. 14 ,erm used for 1'''>'''''' ' 00 ntu'''''''' the two

building bl""b of th.t olomic nud .....

NUCLEUS s..., Atomic Nw:I ... J.

PAI01CLf ACCELERATOR Gi.nl machine. of,m in lh. slup< of. cin;ular ,,, ...... <1<, in which ,n"",,,,,,,, p;>n;d ... ", accd ... ,...! 10

high sp«d and smasMd in''''ach OIhtr. In such "'l~.i"".,h< .... rgy of "",.i"" of.hot p."id .. bow ........... ilobl.,0 .",.,. r.ew po.rtid .. .

I'M0 1CLE PHYSICS The que" to diKO'o'O!" the fundamental building block< and funJamtntai ro.a. of n.tUr<.

PAULI f.)(CWSION PRINCIPLE Tht prohibition on 'wo micro· K<Jpiq>a"idn (f .... mion .) oharing ,he .. m. qWlD,um ""0. T!.. rauJi

ad ... ion .top. d«lrons. which .'" f ... mio ..... from piling on top of tach ",her '00, <:<>nSttJ""ntiy, """I. ;", the ""iSl''''''' of Jiffi: .. n, .,. """ .nd of lh. ""itly of 1M world .round us.

I'HarocELL A practical dtvitt thaI "1'10;10 the photod" " ic d· feet The inl<l'ruplion of an .k<:lrk cu,mol wl>tn • body bre.ks the

light!..am f.l~n8 on. rndal is...ro '0 con,roI .., .... thin_fo, in· ".nc~, an automatic door at the ~nt ... n« '0 a ."~'m .. ktt.

PHaroElECfRIC EFFECf Tht~i«'ion of ~lo<t..,... from ,he ... ,. fact of a metal by photon. "riling the moul.

PHaroN ""r1id.ofli~t.

PHYSICS, U.WS Of Ttl< ful>lamnl1allaw> that occht<, .. ,. ,tI< tot· ham of ttl< Uni ........

"Uo.NCI: ENERGY Th. suptrhi&h tntlly at which gm'ity btroma ",mparable in st~ngth tQ the .,ther funJamentol f<>«es.,f n.tur •.

PUo.NCI: LENGTH n..fanWtiaUy tinylength SC2k at whkh g ..... -ity btroma ",mparabl< in .tr.ngth tQ the othn- funJa",..,tol foTUll

of ... ture. n.. Pland Imph is . trillion trill;"" t;meum.lI..- t"'n an . ' Om. It "'fUSl"'"ill.o "'" 1'I."d e",,'!Y. SmoJl di ... n«-<.r< <yn_

onymous with hi&h energie. bta .... of the .... ve n.tu~ of m.ner.

PUo.SMA An elt<triully ,h.rgrJ p • .,f;.,,,, . nd el""ro",.

I'OSITRON A •• ip.nicle of.he oI«.ron.

PRECESSION Of THE PElllHEliON Of MERCURY n.. facllhat ,he orbi, of Me",ury. the pland ,~t to the Sun. don not follow •

.... ightforward elliptical orbil but ralher an elliptical oobil wt.o.< nNr<"$1 point • .,.he Sun grad....J1y _ ...... nd the Sun. _.,iting in ,he plan .. tracing ., .... r-"elil<o p.l1em. n.. aplanation is 'hot the gra'ity of the St.an "".knt. with distanc. from the St.an mort oI<>wIy th. n in lhe ...... ofNtwton ian gravity, which uniquely predi<1' .llipti",1 orbit .. It "".I<on> mort 'lowly 1>«0 ..... in the Ein"nni.n pietu",. gm'ity i, .. lf i •• >our« of mo~ v""ity.

PRINCIPLE OF EI.1UIVALENCE Th< id .. I"'1 gravily and accelera,ion are indistingui.hable.

PROTON One of the lwo m.in building bk>d:.s of the nud ..... Pro

'0'" c.rry. """'tive el""rical charge. «[ ... 1.00 "I'p<JOi', to th •• of .1«lton ..

PU!.V.1l It rapidly m!:lling neutron star thot ....... ps .n interut beam of radio .... ves around the sky much likt a lighlho .....

'" \.lVANTUM Th< .moUn, chunk in.o "'hid! ",mmi", can bt .I; . .;J.,.J. Photons, for i ...... "" •• • ~ q~ .. .,r tht 01«'''''''"8'''';'; f.,ld.

l,JUANTUM COMPllTER A mKhin. ,h. , • • ploi" ,I>t fact that ~uanlurn sy:sttm .... ell ... ""m. can ... in many Jiffttrnl suItS at oou 10carry out manyalcul.,;.,ns at oou. The best quantum computtn <an ""'nipulatHmly. hanJful of bin;ory digits. or bits. bu. in principle such comput .... could m_ivelr outperform co,,,,,,ntio ... 1 compute ...

\.lUANnJM ELECTII.Ol)YNAMICS 1'b.tory ol how ~gll1 interacts with "",ner. n.. theo<y aplain • • Im.,., ~erylhin8 .bout tho =ry. <I.,.,.",-Jd. from why tht 8rGund ben ... ,h OUr fttl is solid to bow. I .... ' worko, from ,he chtmislry of mnabo!i..., to ,he operat;"" of

"'"'put .....

l.lUANTUM INO[STINGU1SHAH1UIT 11K in.bi~tyl0JUtingui;h bft~n two quantum """to. Thro< ",.,. b< indi,' inguiohabl., for

inslan",. beca...., .hty in'oI ... idrn'iaIl"'t1id .. or oimply boca .... the ..... n .. are 110' <>b .. ", •• 1. Th< cruci.1 thing. how ........ is ,h .. tho probability W;I"" iWOCi.t«l with indi<lill5uisb.able ...... 110 inlnftK. Thi, I .. d, to . 11 mann ... of'luncum phenomena.

lJUANTUM NUM6£1t A number chac .pecifies a micl'OKOpic prop. <Tty ,hac 00 ..... in chunk< such .. "'" <pin Or orbiul .... "C' of an ol«,ron.

lJUANTUM PItQUAIlIUIT ~ ch. "",. I,. p.oo.bili,y. ,,( a micro· ""'Ilic .""nt Although naturt prohibit. US (rom In<>wing thing. wich ~r,.inly. it no""rthel ... pormiu u' t" kn<>w th. pr"babili'i .. wich urtainty.

lJUANTUM SUPERf'QSInQN Si.wltion in which. q .... ntW'<l ob· ject .uch .. an alom;, in m<lI'O than .,... 0131. at a limo. It might. for

,.

inSlanct. bt in many ploas simuh3neoo~y. II i. 1M inl~raclion. or "interfe .. "",; bttwttn lh¢ inJiviJu.al,Ia'e> in ,he .up«JlOOi .;.,n ,hot

i. ,h. b .... of all qu;lnlum .orird ...... 1)«""" .. "", prtVtnl> ouch inl~tion .n.! ,ht .. fo;n <lesi"'l" Gu .ntum boh.avior.

QUANTUM TliEOItY Usoonli.lly, the IlI<o,y of the microocopic world of"tomi.nd tIKi, coM,;,umt<. n.o.. who f .. or.h< Many

WorkJs interr,.u'ion btlie"" il also describes the large-sale ""rid.

QUAt>.WM TUNNELING ",. "ppuentiy miraculo ... obi!i'yof mi_

croscopic porticl<s 10 neal'" tlIrir pri""" .. For irulanct, an alpha particl, can tun...,lthrough ,ho born.. pennin! it in the nucl ..... tho tquivaltnt of . hl8h jumpn- jumpin8 a .-metn-.hi3h ... 11. Thnndin~ i, )'<, another ""n'"'l~"'" of the wavelike t h.""' .... of microocopic putid ...

\J1JAt-."fUM UNPREDlCfAH1LlIT Thr unprnl;eubility ofmi<ro_pi( I"',,;d ... lh<i' b.h.,.ior i, unpuJic .. bl< ~n in prin<iplo. Conlrast ,hi. wilh d .. unpr<diclat.ility of • coin co... II is unprNict.blo only in p<aet;';'. In principle, if_ knew tho sluJ>tofthe coin, It.. force eurttd on ii, 1M air cu" .. n!> arouOO i •. aOO.IO on. we could

preolktthe oo'come.

QUANTUM VACUUM The quan,um pktu~ of ~mp'Y .p;>Ct. For from <rnpty. i. 1ft, .... with ul.",·.t.o...·~m.l micn>«opic panid .. that ar< permin<d by.he HC'i,.nbcrg unctn.inty pri,.ciple to blink

into ~xist.nct aOO blink oot again.

QUASAR A gal .. y tha. dni ..... moot of its .nrrgy from maU.,. htOttd to milli"". of <kg...,. OJ it .witt. into. «n,tal!"n, blod hole. Qua

.. n can 5"" .... 1< os much ~sh' os. hunJrnJ non,...1 gal .. i .. from . volume """,lie, than ,he ""lor .y>tem, making 'hem ,he most ~rful objrcts in the UnivttK.

'" \.lUB1T A quantum bit, or biR;l'Y digiL WII<r~a< a normal bit an ""Iy repr ... m a '0' or. "I,". qubit <on .. ;" in a superp<>OiliOll of tht tWO .t.,es, '<prfltnling • '0' anJ a "I" simu.h.n«>u.sly. Ikca"",

"'inp <>f qubits can ~prn<'f\t. 1.'1" numbor of numbc .. Jim"l. t.l\tOu.Iy.!My an bt used ,<> cln. 10'1;< nUmMT "r ",kul_Iion. ,imultanto"'ly.

RADIOACTIVE DECAY Tho di.in~gration of "nSlObl. lleary IInmic nud'; jnlO liglutr, Sloblt, atomic: nuel';. Tho process i. 1<'

""",.,..nio.! by ,II< ,miss;"" of tithot- alpha p;>nid ... bot> p."kI ... or 8"m ..... 1'lI)'O.

RAlllOACflvrrv Proptrty of atom. th at UndCT!O ,.dioarl;"" decay.

IlALlIUM Highly un'tablt. or radio;w:li .... , .I<mtnl Jisco ... ud by Mar~Curi<in 1898.

R~TlVITY. GE1·.:ERAL THEORY Of EinOltin', gtn< .. liwion of h i •• p«.i.1 th«>rr "r ,e1otivit y. G¢ .... r:al robt wily rdat .. whot one per-son ..... wh", looking a' .nolhtr pnoon accd'''l1ing ,..Ialiv. 10 I t..m. Ikca ... """'I .... lion .1><1 gr~ity a .. indi,,; ngui,hable-lht prine; pl. nf <'quival<ntt-gtn<ra1 roialivily ;. also alhrory "r 5, .. ily.

RELUIVITY, PRINCIPLE Of Til< oMcrvotion that ..u ,IIoking ot o"",thtr person moving.t """ , "ont 'reed reI.,i", to thtm, It rtvnJ .. among othtr things. ""'t tht moving penon appta ... to .hrink in til< dil'«lion of their moti"" whil. tll<ir tin>< slows down, tfft.cts ""'t btmn>< • ....- mo", .nnW .. 'h<yapproach tll< .p«d of light.

'" SCANNING TUNNEUNG MICROSCOPE (STM) A <kvia that

drop an ul' ... fin.,....Jk """"" ,he sure. .. 0/. nu. • .,.;.1 000 OOfI""n, lht up -.nJ-<down mocion of tht .......u. inll> an im.gt of tht .comic

bnrlscapt of the surOO.

SCHRO[)It-:GEIl EQUATION EqlUtion that go,,",ns the way in whid. the probilility W~. or lOR. funLtion. d«<ribing. .. y . pa,_ tido, <ha"8" with time.

SIM ULTAN EIlY n,. iJ .. th.t ~<n" .ha. 'pp"or to harP'<"" ,he .. me tim. for ont ptrson .!hould '~"10 happtn 01 tht ... me 'i ..... for ""eryon. in It.. Uni..,..... SpW. l ....... tivity ohows that thi, iJ .. i, m;'t.ktn.

SINGUU.RJTY Locati"" wlKK 11>< fabric or .p~tim. ruplurn and.., an001 be undenlOOd by Einstein', tbeory of ' .... ity, II>< genor.oI .h.oryor ~I .. ivi'y. Th.~ was. lingulari'r-' point """'~qun.

,iti ... uch .. '""P<'f.tur • • kyrod:. .. ...J to infinity--<o' ,he bq;inning

of ,II< Uni"' ..... 'Th<~ is 01.., <NIt in , he 'tn1" of ''''ry black hoi •.

SOU.R SYSTEM The Sun and its f.mily 01 pl ......... moon., com.to.

and "' ... , ..... md rubbk.

SPACE-TIM E In the gt .... ri1 theory of ~l.tivity. 'paa and 1;"", are ....,., to lit .-n1uUf the sam. thing. l1xy ar< ",.".fo", tr •• tal as • single entity~·time. It is tho ""''Page of spo""-time that turns out to bo gm-ity.

SPECTRAL UNE Atom. and moltcults aboom and 8i ... out light .t chHoct ... istk "", ... length .. If tboy ."",now ~ light th.n thoy emit, 1M r...wt is. clark liM in 1M 'r«!rum of. cdntial objtcL Con_ vusdy. if thoy<mit more than thoy swallow, the rauh is . brightli ....

,. SPECTRUM TIl< "'Paralion of lig/n inlo it< con.,itu<n, " .. inOOw"

oo.~

SPIN <)ua"I;ly with no ~ryrlay .nolo!. Loosely JP~.king •• ub· "<>m;< p.rtid« with spin bth ... " .. if \hey Or< tiny .pinning top. (only they or. nOi 'pinning" . 111).

STAN A gionl ball of gas thai rtpl<ni,h .. lhe hoea, ~ I.,.., lO .poa by mean. of nuclear • ...rgy 8." .... 1<'11 in il' cor<.

S'TRlNGTltEORY SttSup .... 'ringThtory.

STRONG NUCLEAR fORCE Th< ~rful ohM.nn!O fora ,hal

hoIdJ p,..,.o ... and ... "''''''' IOSfl .... ' in an atomic nucleu~

SUBATOMIC PARTIClE 1\ particle wnaller than on au>m. ouch as an <I«tron or. I><Utron.

SUN Th<nea'.'Ular.

SUPERCONDUCTOR A m.ltriallh.I, wlltn "",IN to u1lra)"", tomptl<lturn,conoJucu an .Ie<tncal cUrTenl for..... ,hat is, with no ,<si't.net. This ability i< <OnntClffl with. ch.n.¥ in the condu<liI15 p."idn (rom r .. mion. 10 boso .... Sp«if>eally •• Joel"' .... (f ... mions) poir up t" form eo..""" pai .. (bosom).

SUPEJlFLUJl) II fluid thai, bcIow. critical lmIp .... ,ur<. develop> bi",,« propt";" .",h .. the .bility to A"", uphill and "'U~H Ihrough impo .. ibly .moll hoi ... Th< btsl ",ampl. is lKJuid hdium. which bt<;o"""" a .u~rfluid below a tem~r .. u", of 2.17 d.S ..... abo"" aMoi ul. Hm. s... paflu iJ ".... its wri.-..bl ... 10 quanl um Ihtory and I'" r""llhal htlium .Ioms.rt booons.

,. SUPERNOVA II cataclysmic .,.plooion of. musi ... u ... II "'1'<"'n.,.... "",y. f<>r a ""'r1 lime. QU,ohine an .nti~ galaxy of tOO billion orJi ... ,y.tars. 11 ;. 1ho..u., to I ..... bthin<i a hiEhly comprnotd

nm''''" "ar.

SUPEI<STIUSG THEORY Tht«y which poolula'" d"" the funda· men ... 1 ;ngm!;"'U of the UnivtTst.r< .iny .trinp of rnantr. The SIring' vibr"e in a sp~lime of 10 di .... ruioo .. The groa, pI)<>ff of ,hi. ide. i.llIa, it may b< abl, to unite. o, · unH,.." quantum Ih«>,y

.od Ibt g ...... lth<ory of ",t.'ivity.

TACHYON H)'l'Q,he1ic.1 por.icl.,h .. I....,. ;\Slik pt"'manently , ..... -

,ling f .. 1eT tlu.n li&ht.

Tfl.EI'ORTAnQN The <!tv., uu of mt.anJitment to pin down ttl< .""'" $\:". of. microscopic ~rlid •• in .~renl .;olation of what i. pt"rmin.,J by ,IK li<i<m!..qj un<er .. inty principL.. 11Ii ..... bln tl>< infonnotion _n>truct 11>0 ,ta .. of thr parlid< In b< stnl to .... ""', •• il •.

TEMPERATURE The Jogltt <>fOOtn ... of. body. RrI"N to !he en<'IY of mOl;"" of tho p.rlkln ,h. 1 oornpooc it

THERMOVYNAMICS. SEroN U LAW OF Thedecr«lh. ,mtropy

cannot nn d<'<n' .... This i. "luivalrnt '0 oayilljj th.t h .. , Con I>n'<r

flow from 0 cold body 10 0Il0l body.

TIME IJllATION ~.Iowingdown oftim. for on oboot~ "",,"_ ins do"" 10 1M.p«<l of ~sht or "p<rirncinS "rootg grayity.

TIME MACHINE SttCt.o.t.i Ti"",·Likt CUrY<'o

,. TIME TRAVEL 'Ira"",l into lI>t pastor fUlu~in III< cas< ol in. futur<, .t • ",,~ 0( more ,han I )'Oar p<'I" )'n"

TIM E TJt,\V EL P"RAOOX N.,......,,.;col.i' ... 'ion l""llim~ lr .. vd oppars 10 pmnil. TI>t most f.mow is II>< ~f.tha-p~ox in ",hi<h oomcone goes bod in time and >hoot, tim, gl<lndfalMr befOR he <o,"'.~ th<ir n><>th<r. How then ro..JJ tlxy ha.., b.m born 10 ~

bock in time and ",mmillh. I CI!

TOTAL ECLWSEOFlliE SUN TI>t«>v .... go .,rthrSun by.htdis< oftht Moon whtn 1M Moon m<WtS bt{~ lhtSun and Earth.

TWIN PARAOOX Tht porod"" WI."", whtn .IOm«H'IC ,,,,,,,I. a, ~ 10 light .pct<lIO Alph. Cenuuri .nd b<lck who<tlm, twin stay •

• , horn •. Ao:mrJi"l; k> !ptciaJ rdnivily. th. 'pa<c-' r1.vding ,,.in "I!« I .... How""..-, from .".,.her point of v;cw, il i. Earth ,luu r«NN from tM 'p.a. ,,,,,,,,ling twin . t do« to tll<'rrnl of1;gh, . 00 'Me_ r.,... II>< .. .,. •• '.~'win who 0SI$I<$,. ",. porada. is ,,,,,,1wJ by , ... lizi", thai III< ,"" ,i,,,,,,i,,,,, art 00' <quivaltnl. Til< .~

."vding twin mu .. undo"" .<I"""k"",;"n . ntI an ",,<d ... ,;"n at tho turnaround a, Alph. em lauri. and acultra,iol'lS rt<juire 8'ntnll '" lati.ily 001 .pe<i.oJ r<lativity.

ULTRAVIOLET Type of invi.ible lighl IhOi i.!i,..n oul by .... y hoc bo.!;" which i. mp<>nsibk for . unburn.

UNCEJlTAI~'TY PRINC IPLE 5« Hti""nbtrg lJ roct,1Iinly Principk.

UNIFICATION Tht idt. thai alatrrmC"ly high ~ncrgy th.t four fun · o!am..,\2l fol"«O of natu ........ on~. united in •• ingl~ thoo .. tical f .... m.....".k.

UNIVERSE AU .nc.., i •. Thi. in naibk term on"" ......J for whal .... now call tM solar .ystem. La.er, i. was ......J for what .... call tM Milky

,. Way. Now;t i. u!e<l for tho sum 10ul of alIlh. gala. ies.of wIIich lht,. 'PI"'H 10 be .bo", I 0 billion within lht oboorv:abl. Uni"" .....

UNIVElI.SE, EXP"NS10N OF Tho neting of'ho pl .. i .. from_ach

other in tI>< .fI"muth of tht IliJ 6.ng.

UNIVERSE. OBSERVABLE All Wt ,an .I« ",,' 10 ,I>< Un;"' .....

""rizon.

URANIUM Tht .... vie>t n"u",Uy <><Olmng .lomtnL

VIIt11JAL PAIIT1Q..E l'ortid. that"". n ... ing ""islt"""" popping in to being and popping ou1 Ig>in "",,ruing 10 the conllrain l im· po..,.J by the H.i .... bt" un«<\ainer principle.

VISCOSITY The in~r",,1 {rielion of . liquid. Trtad. Iw hi8h vi.

coli'Y .nd WlI1<r Iu< low v;.roo.i'y.

WAVE FUNCTIO:-: II m.thtmalial <nli1y Chal conllins a1llh., i. kllOW2bl • • bo",. qWlntum 'lbj«:t ... d> .. In l\Om. Tht ~ func_

lion chang .. in limt "",,nling'" lht SdlrGdingor ....... ,ion.

WAVELENGTH The cli ... "", for ..... "" 10 go through I romplel. osc;11;o1;oo <yd •.

WAVE·PARTICl..E l)UAUTY The ability of . subatom ic pl nick 10 bdl .... as. Iocaliud billi ... d b.all·likt particle or I spr .. d...:.ul ......

WEAK NUCLEAR fORCE Tho KCOnJ kit"" t xptritnud by pr<>-'0"" and neut..,... in .o .. ""';.: oucl ..... , ... .,. ..... bein! the "roO! nucla, foret. The ...,ak nudtar [0«< "n ron .... ". """,ron in'o. p,.,.oo .nd so u involvW in bota ,Jc;;oy.

'"

WHITE l)WARF II .'ar thai has Nn ou, of fu<l .nd ,h"ll1"vity has oornp""sed un,il i, ;,. .bo<u 1~ 'w: of Eonh. II whi~ Jw:orf i, oup

patIN ~.inst furthtT Ulrinkagt by tlKt."" ~.., .... q prflSur •. II .uga' cubt "r whit. dworf mat.rial_igb • • lx.,u .. much ... family Car.

WORMHOLE II tunnd throu~h spo«.'i"", tha, COnnteU widtly

.~ccd "'gions and so provhl .. a .oortc\ll.

X·RAYS II higb •• ~ fo<mQflight.

FuRTHER READIN6

ATOMS ANDQUAt.TtIM THEORY

V""mum, A Gu;J'I" ,It< ""pI~ by Jim AJ· Khalil; (Y*iJ""r.1d lie Nicolson. London_ ZOOJ).

Tami~l ,,,.. AlOm, by Haru Christian "",n llaty<r (PmSuin. LondlKl.

I'J'l.4J. MiwAA "''''cAi"", anll rh< Mulrj"""." by Ju~.n 8rown (Link Brown.

New York. 2000). Th< Magic fur"""" by Mar<u$ a.own (Odoni Uni=$ity p~ Nnv

York. 2(01).

Th< Falmnrf Rnilily. by David l)"u,,,,h (Ponguin, London. 1997).

Thirtr Y"II1 Tha, Shook I'll,..", by Georg. Gam"", (LJov<r, N .... York. 19R5).

n. Gtr.ot /'IIrsi<ists from "",Uk<> '" lii","i.., by Georg. Ga....". (1)0. vtt,N<w York,I9S8 ).

1ltt I'b> Q\<oIMum Uni ....... , by Tony Hoy ar><! l'auid Wallen, 2nd ..Ji t ion (Co mbridg< Uninrli ty p"", Cambridge. [ngland,

""". 1M Fry"""," uau,~ "" PIIpia. a1i,.J by Rob<rI t..ipl1"" ... L

(Addison ·Wollt)'o Ntw York, 198\1).

'"

,. R£l.AT1V1TY AND COSMOLOGY

Afr"l/q", <1 0...,;"", by M"", ... O>own (Univ=i'y xien<:e !J<>oI<o. Sau.sali' G, caKro,nia, 1994).

11.. UnMr>t Ntxt Door, by Morn&.< ChowtI (Oxford Uniwnily ",..,.., N ..... York, 2(02).

eo<moiov. by Ed .... 'd Ham""n (C:ombriJg< Uniwni,y I'r"" Com·

bridge, England, 1991 J. TN ~i .... , tfTi_. by Igor No.,.;kov (Cambridge Vni",,"i'y J>,..,..,

Cambridge. EngJanJ, 1\198 ),

Ei""...-", U!"'Y. by Julion Schwing<r (Sri<ntif", Amrriun Libncy,

N ..... Vorr..I986). Th. 1'~";NlI Uni ........ by Fron k Sh (Vniveni 'y Sti,n"" IIook.,

Saouali,o, California. 1982).

INDEX

A _ ...... 'U, .. ,.'" ... opI« . .... '''''''~ I"'.~ond, IlIl-lU

Ado .... ' ..... p 'I. 1)1 ... ........ -..of .... , .... ~117_ '" V.rtr<lkrt~ 1)0-1 ) 1

<p<6aI1"""rof ........ ,. 9', 9S

• AIIm. \'\body. 1(16

AIph.o 1"""* dra~9.).1

dtfin ...... 9 _ from nudtw,"'., ..... l "'.n ....... od;'" m.1I 'unnd .... . l-I<

,oJpMr. ~>Iph, 146 .-...-... III ""tinun",I' .. 1I6 """".AI .... S! .u.o... Fr_" Ill. III Addn_._,O A ........... 6-7

'"

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