If the end of the World War IIsignalled that modern conflictswere going to be dictated byhow well either side controlledthe skies, it was because aerialbombers had performed a piv-otal role in the outcome of thewar. The end of World War I,however, had something else tooffer. Something that wasn’tnecessarily a fallout of the warthat was about to end.

Worst in historyEarly in March 1918, the first

reported case of Spanish influ-enza was recorded. Many be-lieve that it may have beencirculating for years around theworld before going on to be-come a pandemic in 1918. Itspread rapidly in 1918 and theresulting worldwide epidemicclaimed the lives of more peoplethan the World War I, therebymaking it the worst in history.

It started out like any otherflu. Initially called the “threeday fever”, high fever and in-tense chills followed cough andheadache. Soon though, peoplerealised that the Spanish flu wasturning out to be deadly and thesymptoms were also unique.

Victim’s cheeks were markedwith deep brown spots and abloody fluid severely congestedthe lungs. As circulating bloodcould not get oxygenated, their

faces then gradually turnedblue, starting at the ears. Thestruggle for fresh air led to suf-focation and in a matter ofhours ultimately resulted in thevictim’s death.

There is no concrete number,but estimated range falls be-tween 20 to 100 million deathsdue to this flu - one in almostevery 20 people living duringthat age. Almost every countryin the world was affected andeven though the war was notdirectly linked, movement oftroops definitely had a hand inits spread.

While human beings developimmunity towards seasonal flu,there is little or no human im-munity in the case of pandemicflu. What made the Spanish flueven more peculiar was the factthat it affected and proveddeadly among the young andhealthy and not the weak andold - over half the flu deathswere in the 20 to 40 age bracket.One hypothesis is that in an at-tempt to get to the virus, theirimmune system overreacted,thereby destroying their lungs.

Millions perishAfter playing itself out over

time, it subsided… only to re-emerge in a more deadly form.People reportedly dropped deadon the streets and the toll keptmounting. Even though the warstill dominated the news, it was

clear by now that the virus wascreating more havoc.

The flu was nicknamed Span-ish flu as cases were reportedfreely in neutral Spain, unlikeother countries that were min-imising the instances throughtheir wartime censors. The ex-act geographic origin of the dis-ease therefore still remainsunknown.

For more than 80 years afterthe flu disappeared, it contin-ued to be a mystery. It was onlyin the previous decade (October2005) that the entire sequenceof the 1918 flu virus - nowknown as H1N1 - was isolated,decoded and replicated.

It was discovered that H1N1arose from an avian strain, thatis, a virus affecting birds. Fur-ther research suggested that thevirus had developed the abilityto jump to humans, and theswiftness with which theyspread was attributed to the vi-rus’s structure. Bonding effec-tively with human cells andinfecting cells deep within thelungs made them especiallydeadly.

Scientists continue to studythe influenza to this day, as theysearch for solutions to unan-swered questions. Even as a vi-rus mutates, studies like thesewould enable us to be betterprepared to tackle the situation- if confronted with a similaroutbreak.

Virus that shook the worldThe Great War was about to end… but more deaths were to comeA.S.Ganesh

AN EYE FOR AN I

PHOTO: WIKIMEDIA COMMONS

Published by N. Ram at Kasturi Buildings, 859 & 860, Anna Salai, Chennai-600002 and Printed by N. Rajashekar at Plot No. 13-D, Bommasandra-Jigani Link Road, KIADB Industrial Area, Bommasandra, Anekal Taluk, Bengaluru-560099 on behalf of KASTURI & SONS LTD., Chennai-600002. Editor: Malini Parthasarathy (Responsible for selection of news under the PRB Act).

They lurk in dark corners,feed off crumbs, and obeythe commands of humans.Years in the making, and acontender for the most re-volting creation to emergefrom a laboratory, the robo-roach has arrived.

Built by engineers in Tex-as, the robotic insect fuses alive cockroach with a minia-ture computer that is wiredinto the animal’s nervoussystem. At the push of a but-ton, a human operator cancontrol the beast. Or at leastwhich way it scuttles.

Hong Liang, who led theresearch at Texas A&M Uni-versity, said the controlla-ble insect could carry tinyvideo cameras, micro-phones and other sensors.With those on board, itcould gather informationfrom places where humanswould rather not be: col-lapsed buildings, brokensewers, and the kitchens in

student house shares.

How they do itThe U.S. team made

tiny backpacksfor the cock-roachesand stuckthem onwithpaint.Normalglue didnot at-tach to theinsects’waxy backs.Each backpackcontained a com-puter chip that could sendsignals down a pair of finewires into nerves that con-trolled legs on either side ofthe cockroach. With a re-chargeable lithium batteryto power the device, the to-tal weight of the backpackwas less than 3g.

In a series of demonstra-tions, the scientists showedhow they remotely con-

trolled the direction inwhich the cockroach walkedby stimulating nerves on ei-

ther side of its body.When cock-

roaches walk,the three

legs oneach sidemove intimewitheach

other.But the

electricalpulses dis-

rupt this, mak-ing the middle leg

fall out of step with the oth-ers. The result is that a pulseto the left makes the cock-roach turn left, and viceversa.

Far from perfectThe system is far from

perfect. In tests when ro-botic roaches were held onlittle leashes, the insectscould be steered about 70%

of the time. But when theinsects were left to roamfree, the remote controlworked only 60% of thetime. To make them turncould take a jabs of the but-ton.

Ethical issuesSethu Vijayakumar, di-

rector of the Institute of

Perception, Action and Be-haviour at the University ofEdinburgh, has reservationsabout the work though. “Asmuch as the technology isinteresting, there are a lot ofethical issues before we godown that line, even withcockroaches,” he said. — ©Guardian Newspapers Limited,2015

Ian Sample

The robo-roach has arrivedTexas engineers have attached aminiature computer to the nervoussystem of live cockroaches to gathervideo information in places such asbroken sewers

The scientists showed how they remotely controlled thedirection in which the cockroach walked by stimulatingnerves on either side of its body. When cockroacheswalk, the three legs on each side move in time witheach other. But the electrical pulses disrupt this,making the middle leg fall out of step with the others.The result is that a pulse to the left makes thecockroach turn left, and vice versa.

CMYK

BG-BG

SCIENCE & TECHWord of the dayEmbroil (Verb): bring into a state of confusion or disorderUsed in a sentence: India’s Daughter documentary has been embroiled ina rowSuggested by Sandeep Dwivedi. Your turn! Pick a word from today’s TheHindu in School, the meaning of which you do not know and send it to us atschool@thehindu.co.in (Subject: Word of the day)

Black holes are among the mostfascinating objects in the Uni-verse. How would a journey to-wards a black hole look like?

The escape velocityWhen you throw a ball up in

the air, it always falls back downto the ground because of theEarth's gravitational attraction.If you throw the ball harder, itwill get higher but will still falldown afterwards. The ball can'teasily escape the Earth's gravity!

If you could throw the ball atan extremely high speed though,it would escape the Earth's grav-itational attraction and contin-ue its journey into outer space.The velocity required for that iscalled the escape velocity, and itis about 11 kilometers per sec-ond at the surface of the Earth.This is the speed space rocketshave to reach in order to liber-ate themselves from the Earth'sgravitational influence, and itrequires a lot of energy. Haveyou ever seen how impressiverocket launches look?

If the Earth was more mas-sive, its gravitational attractionwould be stronger, your ballwouldn't go as high as usual, andit would require more energy tosend something into outerspace: the escape velocity wouldbe higher and hence more diffi-cult to reach. For extremelymassive objects, the escape ve-locity could even be impossibleto reach!

A black hole is an object whichis so massive and so compactthat its escape velocity is greaterthan the speed of light: as noth-ing can move faster than thespeed of light, nothing can getout of a black hole. Even light.Any light emitted inside theblack hole is dragged back by itsstrong gravitational attractionand thus never reaches observ-

ers situated outside. A black holelooks black because there is sim-ply no light coming out of it.

A journey into a black holeA black hole is like a huge

maelstrom that attracts the sur-rounding matter, so moving to-

wards it would be a bit likeswimming towards a huge wa-terfall. Gravity would pull youtowards the black hole as thewater flow would towards thefall. If you are far away, you canstill swim back and get away. Butas you get nearer, the current

gets faster and faster, up to apoint where there is no turningback anymore: you are doomedto fall with the flow. For a blackhole, this point of no return iscalled the event horizon and thisis where the escape velocity isequal to the speed of light. Butalthough crossing the event ho-rizon of a black hole would marka turning point in your life, asyou wouldn't be able to travelback anymore nor communicatewith the outside world, youwouldn't necessarily notice any-thing special on the moment asyou would still seem to fall to-wards an endless black pit.

But what is exactly inside ablack hole? There are manyspeculations about it, but nodecisive answers yet: as no lightever comes out, we can't see any-thing beyond the event horizon.Are black holes gateways to dif-ferent places or even differentuniverses? Is all their mass con-centrated in a single point inspace? Or are they just extremeastrophysical objects denserthan neutron stars? All of theseare open questions, as we stilllack a unified model to describethe inside of black holes.

Nevertheless, it is possible toobserve how gravity affects starsand gas around them, and this ishow we know they do exist.There is notably a supermassiveblack hole at the center of ourMilky Way, as in most other gal-axies. It is named Sagittarius A*(to be pronounced “SagittariusA-star”) and should weigh asmuch as four million suns. As ina whirlpool, stars orbit extreme-ly fast around it, in an irresist-ible cosmic dance!

(Jonathan Freundlich is aPhD student at the Paris Observ-atory, in France, working on starformation and galaxy evolution.He can be reached atjonathan.freundlich@obspm.fr)

An irresistible attractionThere is something fascinating about Black holes. Perhaps it is their strong gravitational pull and elusiveness Jonathan Freundlich

IN THE DARK A computer generated image of a black holeshowing the visual distortions it would cause if you were toapproach it. CREDIT: ALAIN RIAZUELO, IAP/UPMC/CNRS.

● The contracting core of a very big star canbecome a black hole during its explosion as asupernova, but our Sun will never turn into ablack hole because it is far from massive enough.

● Gravity around a black hole is so strong it wouldstretch you and tear you apart as you get closer.

● A black hole disrupts the structure of space-timeitself, which would cause unusual visualdistortions when you approach it.

● Time flows differently near the event horizon ofa black hole: you would age much slower therethan on Earth, and a few minutes spent therecould mean years on Earth if you come back.

ASTROPHYSICAL SERIES

 A NASA spacecraft namedDawn is making space ex-ploration history. It is thefirst spacecraft to orbit twodifferent solar systemtargets. 

Plenty of spacecraft haveflown by two or more plane-ts or moons during theirmissions. But orbitingsomething is a lot harder.The spacecraft has to putitself into “reverse” usingits thrusters and lots of fuelin order to be captured bythe gravity of a planet andgo into orbit. Otherwise, itwould just fly right on by.And to leave orbit, it wouldhave to pull itself out of thegravitational field usingeven more fuel, like haul-ing itself up out of a deephole.   

You can’t really put that

much rocket fuel on aspacecraft. It would be tooheavy and expensive tolaunch. But Dawn worksvery differently. Dawn useselectricity to propel itself.Its ion propulsion technol-ogy shoots charged atoms,called ions, out of a smallengine at super high speed.The electrical energycomes from solar panelsand the atoms are from agas called xenon.  

This technology has al-lowed Dawn to make itshistoric journey to the aste-roid belt, first orbiting andstudying the asteroid Vesta,then leaving that orbit,travelling another 900 mil-lion miles and going intoorbit around dwarf planetCeres. Dawn is also the firstspacecraft to visit a dwarfplanet. The ion engine hasenabled Dawn to spiral into

the “gravity well” of onebody, spiral back out, andhave enough fuel left to goand do it all over again (al-though Dawn will not beleaving Ceres orbit).  

Ion propulsion usesmuch less fuel than othermeans of space travel hu-mans have tried. Therefore,the spacecraft is lightenough to launch, but stillhas the power to make bigchanges to its course. Theonly real drawback is that itcan’t accelerate very fast. Infact, it would take fourwhole days for Dawn to gofrom 0 to 60 miles perhour! 

But once it gets going, itreally gets going! By keep-ing these ion-powered en-gines thrusting for a longtime, Dawn can do thingsno other craft has done!

A two-for-one space firstAlex H. Kasprak

These two views of Ceres were seenby NASA's Dawn spacecraft on February12,2015, from a distance of about 52,000 milesas the dwarf planet rotated. CREDIT: NASA/JPL-CALTECH/UCLA/MPS/DLR/IDA.  

Visit NASA’s Space Place to learn more about ionthrusters at http://spaceplace.nasa.gov/ion-balloons.  Learn more about the Dawn mission at http://dawn.jpl.nasa.gov/

PARIS: One of Thomas Edi-son's little-known ambi-tions was to build a deviceto hear the voices of thedead, according to a nearlylost chapter of the inven-tor's memoirs which is be-ing republished in Francethis week.

The American, who de-veloped the phonographwanted to create a sort of"spirit phone" that record-ed the utterances of de-parted souls.

Edison (1847-1931) de-tailed his efforts and theywere published posthu-mously in 1948 as the finalchapter of his "Diary andSundry Observations".

The chapter shows howEdison tried in late 1870 tofind a basis for his "spiritphone" invention by ampli-fying the sound from hisphonographs, the precur-sor of gramophones and re-cord players.

He even made a pactwith an engineer working

with him, William WalterDinwiddie, that the firstwho died would "would tryto send a message to thesurvivor from beyond,"Baudouin said.

Edison believed not onlythat ghosts existed but alsothat they were verytalkative.

He "imagined being ableto record the voice of an-other being, to be able tomake audible that whichisn't -- the voice of thedead", Badouin said. AFP

WHAT IF WE COULD TALK TO THE DEAD One ofThomas Edison's little-known ambitions was tobuild a device to hear the voices of the dead,according to a nearly lost chapter of the inventor'smemoirs which is being republished in France.PHOTO: AFP

Edison's 'lost' idea: aspirit phone

The book talksabout how Edisontried in late 1870to find a basis forhis "spirit phone"invention byamplifying thesound from hisphonographs, theprecursor ofgramophones andrecord players.

Liberate: free/ release

Doomed: destined

Speculation: assumption

Irresistible: appealing

Haul: dragging

Scuttle:to cut or open a hole

Memoir: An account ofthe personal experiencesof an author

Pandemic: diseaseprevalent over the world

Mutate: change in form

GLOSSARY

THE HINDU IN SCHOOL I MONDAY I MARCH 9 I 2015

3

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