astronomy 100 tuesday, thursday 2:30 - 3:45 pm tom burbine...
TRANSCRIPT
Ast
rono
my
100
Tue
sday
, Thu
rsda
y 2:
30 -
3:45
pm
Tom
Bur
bine
tbur
bine
@m
thol
yoke
.edu
ww
w.x
anga
.com
/ast
rono
my1
00
Scor
es
•Th
e hi
ghes
t sco
re in
the
clas
s cur
rent
ly is
a 9
7%•
The
low
est s
core
in th
e cl
ass c
urre
ntly
is a
33%
•(A
ssum
ing
thei
r tes
t gra
des r
emai
n th
e sa
me
for
the
rest
of t
he c
lass
and
act
ually
cal
cula
ting
thei
r H
W a
nd P
RS
scor
es)
Cla
ss A
vera
ge•
The
exam
ave
rage
for t
he c
lass
is 7
2.2%
.•
If I
assu
me
ever
ybod
y ge
ts 1
00%
for H
W a
nd
PRS
scor
es a
nd th
at th
is e
xam
ave
rage
doe
s not
ch
ange
for t
he re
mai
ning
test
s:•
Cla
ss a
vera
ge =
80%
x 7
2.2%
+ 2
0% x
100
%•
Cla
ss a
vera
ge =
77.
8%•
Afte
r all
the
exam
s, th
is c
lass
ave
rage
shou
ld ri
se
to a
bove
80%
Sche
dule
•To
day
(Qua
sars
, Dar
k M
atte
r)•
Thur
sday
(end
and
beg
inni
ng o
f the
uni
vers
e)•
May
3 (D
oes L
ife E
xist
Els
ewhe
re in
the
Uni
vers
e)•
May
5 (R
evie
w)
•M
ay 1
0 (E
xam
4)
•M
ay 1
2 (E
xam
5) (
optio
nal)
•M
ay 2
0 (F
inal
)(op
tiona
l)
Exam
4
•K
now
the
clas
s not
es•
Kno
w a
ll th
e de
finiti
ons o
n th
e w
ebsi
te•
Kno
w th
e Su
mm
ary
of K
ey C
once
pts a
t the
end
of
eve
ry c
hapt
er
Exam
5 a
nd F
inal
•K
now
the
clas
s not
es•
Kno
w h
ow to
do
ever
y qu
estio
n on
the
1st4
exam
s•
Kno
w th
e Su
mm
ary
of K
ey C
once
pts a
t the
end
of
eve
ry c
hapt
er
OW
L as
sign
men
t (D
ue T
hurs
day)
•Th
ere
is b
e an
OW
Las
sign
men
t due
on
Thur
sday
A
pril
28
at 1
1:59
pm
.•
Ther
e ar
e 15
que
stio
ns a
nd a
per
fect
scor
e w
ill
give
you
2 h
omew
ork
poin
ts.
Hom
ewor
k A
ssig
nmen
t(D
ue b
y M
ay 3
)•
Mak
e up
a te
st q
uest
ion
for n
ext t
est
•M
ultip
le C
hoic
e•
A-E
pos
sibl
e an
swer
s•
1 po
int f
or h
andi
ng it
in•
1 po
int f
or m
e us
ing
it on
test
•Th
e qu
estio
n ne
eds t
o be
on
mat
eria
l tha
t will
be
on th
e 4t
h ex
am
Hom
ewor
k A
ssig
nmen
t(D
ue b
y M
ay 5
)
•I h
ave
plac
ed 4
0 te
rms o
n th
e w
ebsi
te•
You
get
0.1
of a
HW
poi
nt fo
r eac
h of
thes
e yo
u de
fine
and
hand
in to
me
•D
efin
ition
s nee
d to
be
hand
-writ
ten
or h
and-
type
d•
A lo
t of t
hese
def
initi
ons w
ill b
e on
nex
t tes
t
•D
rake
Equ
atio
n•
Dar
k En
ergy
•Tu
lly-F
ishe
r Rel
atio
n•
ALH
8400
1•
Cep
heid
Var
iabl
e•
Whi
te D
war
f•
Joce
lyn
Bel
l•
Vik
ing
Mis
sion
•H
ubbl
e’s L
aw•
SETI
•B
ig B
ang
•C
OB
E•
Stan
dard
Can
dle
•Q
uasa
r•
Plan
ck T
ime
•In
flatio
n in
the
Early
Uni
vers
e•
Olb
er’s
Para
dox
•C
osm
ic M
icro
wav
e B
ackg
roun
d•
Isot
ope
•B
aryo
n
•Pe
rciv
al L
owel
l•
Red
shift
•D
ark
Mat
ter
•M
AC
HO
•C
ritic
al D
ensi
ty•
Rad
io G
alax
y•
Mai
n Se
quen
ce F
ittin
g•
Cos
mol
ogic
al H
oriz
on•
Whi
te D
war
f Sup
erno
va•
Inte
rste
llar M
ediu
m•
Supe
rclu
ster
•W
IMPS
•Pu
lsar
•H
abita
ble
Zone
•M
aund
er M
inim
um•
Con
vect
ion
Zone
•R
adia
tion
Zone
•H
ubbl
e’s C
onst
ant
•St
arbu
rst G
alax
y•
Euro
pa
Ast
rono
my
Hel
p D
esk
•Th
ere
is a
n A
stro
nom
y H
elp
Des
k in
Has
brou
ck
205.
•
It is
ope
n M
onda
y th
roug
h Th
ursd
ay fr
om 7
-9
pm.
Hub
ble’
s Con
stan
t
•v
= d
x H
o
•d
= v/
Ho
•d
= di
stan
ce th
e ga
laxy
is fr
om y
ou•
v =
velo
city
the
gala
xy is
mov
ing
away
from
us
Exam
ple
•A
gal
axy
is m
ovin
g aw
ay fr
om u
s at a
spee
d of
6,
000
km/s
•H
ow fa
r is i
t aw
ay fr
om u
s?•
Ho =
71 k
m/s
/meg
apar
sec
•d
= v/
Ho
•d
= (6
,000
km
/s)/(
71 k
m/s
/meg
apar
sec)
•D
= 8
4.5
meg
apar
secs
Act
ive
Gal
actic
Nuc
lei
•A
ctiv
e G
alac
tic N
ucle
i are
the
unus
ually
brig
ht
cent
ers f
ound
in so
me
gala
xies
M87
Ellip
tical
Gal
axy
Qua
sars
•Q
uasa
rs a
re th
e br
ight
est a
ctiv
e ga
lact
ic n
ucle
i•
Emit
imm
ense
am
ount
s of r
adia
tion
•So
me
are
brig
hter
than
1,0
00 M
ilky
Way
s
Qua
sars
•Lo
ok li
ke st
ars
•B
ut h
ave
huge
reds
hifts
Rad
io G
alax
ies
•A
gal
axy
that
em
its u
nusu
ally
larg
e qu
antit
ies o
f ra
dio
wav
es
•Th
ough
t to
cont
ain
an a
ctiv
e ga
lact
ic n
ucle
i
Pow
er
•A
ctiv
e G
alac
tic N
ucle
i, Q
uasa
rs, a
nd R
adio
G
alax
ies a
re th
ough
t to
be p
ower
ed b
y su
perm
assi
vebl
ack
hole
s•
They
can
exc
eed
1 bi
llion
sola
r mas
ses
Ener
gy
•En
ergy
from
the
blac
k ho
les c
omes
from
its
grav
ity•
Gra
vity
con
verts
pot
entia
l int
o ki
netic
•C
ollis
ions
con
vert
kine
tic in
to th
erm
al e
nerg
y•
Phot
ons c
arry
this
ther
mal
ene
rgy
away
Ver
y Ef
ficie
nt
•E=
mc2
•10
-40%
of t
he e
nerg
y of
the
accr
etin
g m
ater
ial i
s re
leas
ed a
s rad
iatio
n be
fore
the
mat
ter c
ross
es th
e ev
ent h
oriz
on•
Mor
e ef
ficie
nt th
an fu
sion
, whi
ch tu
rns l
ess t
han
1% o
f the
mas
s of t
he m
ater
ial i
nto
ener
gy
Dar
k M
atte
r
•M
atte
r we
infe
r to
exis
t fro
m it
s gra
vita
tiona
l af
fect
s but
from
wha
t we
dete
ct n
o lig
ht•
Dar
k m
atte
r dom
inat
es th
e m
ass o
f the
Uni
vers
e
Rot
atio
n cu
rve
Plot
show
ing
orbi
tal v
eloc
ities
Of g
as a
nd st
ars
Milk
y W
ay G
alax
y
•Th
e m
ass o
f dar
k m
atte
r may
be
10 ti
mes
the
mas
s of v
isib
le m
atte
r•
Vis
ible
mat
ter i
s sta
rs
Spira
l Gal
axie
s
Why
is D
ark
Mat
ter I
mpo
rtant
?
•Th
e U
nive
rse
is b
elie
ved
to p
roce
ed a
long
two
path
s•
It m
ay c
ontin
ue to
exp
and
fore
ver
•O
r it m
ay st
op e
xpan
ding
and
col
laps
e•
Its fa
te is
dep
ende
nt o
n th
e de
nsity
of m
atte
r
Ellip
tical
Gal
axie
s
•Th
e or
bits
of s
tars
in e
llipt
ical
gal
axie
s are
di
sorg
aniz
ed
Ellip
tical
Gal
axie
s
•Si
nce
som
e st
ars a
re m
ovin
g to
war
ds u
s and
som
e ar
e m
ovin
g aw
ay fr
om u
s•
Spec
tral l
ines
are
bro
aden
ed
Ellip
tical
Gal
axie
s
•V
eloc
ities
of s
tars
stay
rela
tivel
y co
nsta
nt a
s you
m
ove
from
gal
actic
cen
ter
•El
liptic
alsc
onta
in d
ark
mat
ter
How
ever
•W
e ca
n’t d
eter
min
e th
e am
ount
of d
ark
mat
ter i
n an
elli
ptic
al g
alax
y•
Bec
ause
we
can’
t mea
sure
thei
r mas
ses a
s far
fr
om th
eir c
ente
rs
Mas
s-to
-Lig
ht R
atio
•Y
ou c
an c
ompa
re th
e m
easu
red
mas
s to
the
lum
inos
ity o
f a g
alax
y
Milk
y W
ay
•M
ilky
Way
con
tain
s 90
billi
on so
lar m
asse
s of
mat
eria
l with
in th
e Su
n’s o
rbit
•Lu
min
osity
of M
ilky
Way
at t
his o
rbit
is 1
5 bi
llion
sola
r lum
inos
ities
•M
ass-
to-L
ight
ratio
of o
ur G
alax
y at
this
orb
it is
6
sola
r mas
ses p
er so
lar l
umin
ositi
es
This
tells
us t
hat …
•Th
e va
lue
of 6
sola
r mas
ses p
er so
lar l
umin
osity
te
lls u
s tha
t mos
t of t
he m
atte
r is d
imm
er th
an th
e Su
n ou
t to
the
Sun’
s orb
it•
Mas
s-to
-Lig
ht ra
tio o
f our
Sun
is 1
sola
r mas
s per
so
lar l
umin
osity
•So
mos
t mat
ter i
s dim
mer
than
the
Sun
For s
ome
..
•Fo
r som
e ga
laxi
es, t
hey
have
mas
s-to
-ligh
t rat
ios
of 5
0 so
lar m
asse
s to
sola
r lum
inos
ity•
This
is to
o hi
gh to
be
acco
unte
d fo
r by
star
s alo
ne
Fritz
Zw
icky
(189
8-19
74)
•W
as a
mon
g th
e fir
st to
sugg
est t
hat t
here
is a
re
latio
nshi
p be
twee
n su
pern
ovae
and
neu
tron
star
s•
Sugg
este
d in
the
1930
s tha
t dar
k m
atte
r was
fo
und
in G
alac
tic C
lust
ers
Clu
ster
•C
lust
er is
a c
olle
ctio
n of
gal
axie
s (th
at c
an
num
ber d
ozen
s to
thou
sand
s) th
at a
re
grav
itatio
nally
bou
nd
Zwic
ky
•B
y ca
lcul
atin
g th
e sp
eed
of g
alax
ies a
s the
rota
te
arou
nd in
a c
lust
er•
He
foun
d th
at g
alax
ies i
n th
e cl
uste
rs h
ad h
uge
mas
s-to
-ligh
t rat
ios
Type
s of D
ark
Mat
ter
•M
AC
HO
s•
WIM
PS
MA
CH
Os
•M
assi
ve C
ompa
ct H
alo
Obj
ects
•In
clud
es–
Bro
wn
Dw
arfs
–fa
iled
star
s –
Fain
t red
star
s–
Jupi
ter-
size
d ob
ject
s
WIM
Ps
•W
eakl
y in
tera
ctin
g m
assi
ve p
artic
les
–N
o el
ectri
cal c
harg
e–
Do
not e
mit
elec
trom
agne
tic ra
diat
ion
–H
ave
mas
s so
do in
tera
ct so
me
with
mat
ter
Neu
trino
s
•D
ark
mat
ter i
n ga
laxi
es c
an’t
be n
eutri
nos b
ecau
se
neut
rinos
esc
ape
from
gal
axie
s with
eno
rmou
s sp
eeds
WIM
PS
•H
ave
to h
ave
mas
ses l
arge
r tha
n ne
utrin
os•
Hav
e no
t bee
n di
scov
ered
yet
Que
stio
ns