Languages
Pages
Legal
Mar
18,
200
5A
stro
nom
y 21
0 Sp
ring
200
5
Ast
rono
my
210
Sect
ion
1–M
WF
150
0-15
5013
4 A
stro
nom
y B
uild
ing
Thi
s C
lass
(L
ectu
re 2
5):
Deb
ris
Nex
t Cla
ss:
Bir
th o
f th
e So
lar
Syst
em
Mus
ic: A
my
Hit
the
Atm
osph
ere
–C
ount
ing
Cro
ws
2ndH
our
Exa
m in
2 w
eeks
!
Mar
18,
200
5A
stro
nom
y 21
0 Sp
ring
200
5
Out
line
•Pl
uto–
Plan
et o
r L
arge
st K
uipe
r B
elt O
bjec
t?
•L
ife
in o
ur S
olar
Sys
tem
?
•C
omet
s–Y
ou D
irty
Ice
ball
•A
ster
oids
–Sp
acec
raft
haz
ard?
•M
eter
oids
–w
atch
you
r he
ad
Mar
18,
200
5A
stro
nom
y 21
0 Sp
ring
200
5
No
luna
r la
ndsc
ape,
no
Mar
tian
dese
rt c
anco
mpa
re to
the
terr
ifyin
g so
litud
e of
Plu
to.
Pat
rick
Moo
re a
nd D
avid
A. H
ardy
Cha
lleng
e of
the
Sta
rs(1
972)
Mar
18,
200
5A
stro
nom
y 21
0 Sp
ring
200
5
Cly
de T
omba
ugh
(190
6 –
1997
)
The
Dis
cove
ry o
f P
luto
•A
stro
nom
ers
calc
ulat
ed th
at th
ere
mus
t be
anot
her
body
per
turb
ing
the
orbi
ts o
f U
ranu
s an
d N
eptu
ne•
Perc
ival
Low
ell c
alcu
late
d th
at
“Pla
net X
” m
ust h
ave
a m
ass
7 tim
es
that
of
the
Ear
th•
Cly
de T
omba
ugh
was
hir
ed to
look
fo
r it
•In
193
0, h
e fo
und
a pl
anet
•In
hon
or o
f L
owel
l, it
was
nam
ed
Plut
o (P
.L.)
Mar
18,
200
5A
stro
nom
y 21
0 Sp
ring
200
5
For
tuna
te M
ista
ke
•It
turn
ed o
ut th
at
Plut
o w
as n
ot
Low
ell’
s “P
lane
t X”
•Pl
uto
has
only
0.
2% th
e m
ass
of
Ear
th, n
ot 7
tim
es
the
mas
s•
Too
sm
all t
o in
flue
nce
Ura
nus
& N
eptu
ne’s
orb
its•
Mod
ern
obse
rvat
ions
and
cal
cula
tions
sho
w n
o “P
lane
t X”
need
ed to
pre
dict
thei
r or
bits
Mar
18,
200
5A
stro
nom
y 21
0 Sp
ring
200
5
Rad
ius
0.19
Ear
thSu
rfac
e gr
avity
0.04
Ear
thM
ass
0.00
2 Ea
rth
Aver
age
Dis
tanc
e fr
om S
un39
.5 A
UTi
lt of
Rot
atio
n Ax
is12
2 de
gree
sO
rbit
ecce
ntric
ity0.
249
Year
248.
6 Ea
rth
year
sSo
lar
day
6.39
Ear
th d
ays
(bac
kwar
ds)
Ear
th -
Plu
to C
ompa
riso
n
Mar
18,
200
5A
stro
nom
y 21
0 Sp
ring
200
5
How
Doe
s P
luto
Mea
sure
Up?
Mar
18,
200
5A
stro
nom
y 21
0 Sp
ring
200
5
Plu
to’s
Orb
it
•H
ighl
y ec
cent
ric
•H
ighl
y in
clin
ed
with
re
spec
t to
the
othe
r pl
anet
s•
From
197
9-19
99,
Plut
o w
as c
lose
r to
the
Sun
than
Nep
tune
!•
Nev
er w
ill c
ollid
e be
caus
e of
3:2
res
onan
ce w
ith N
eptu
ne
Mar
18,
200
5A
stro
nom
y 21
0 Sp
ring
200
5
Plu
to’s
Sur
face
•N
o sp
acec
raft
has
ev
er v
isite
d Pl
uto
•O
ur b
est v
iew
of
Plut
o co
mes
fro
m
Hub
ble
•C
over
ed in
nitr
ogen
, m
etha
ne, a
nd c
arbo
n m
onox
ide
ice
•C
urre
nt s
urfa
ce te
mpe
ratu
re -
abou
t 40
K (
-230
C,
-390
F)!
Mar
18,
200
5A
stro
nom
y 21
0 Sp
ring
200
5
Plu
to’s
Atm
osph
ere
•O
bser
ved
whe
n Pl
uto
occu
lts
back
grou
nd s
tars
•C
onsi
sts
mos
tly o
f ni
trog
en
(90%
) an
d ca
rbon
mon
oxid
e–
Sim
ilar
to T
rito
n
•A
s Pl
uto
gets
far
ther
fro
m
the
Sun,
atm
osph
ere
may
“f
reez
e ou
t” a
roun
d 20
20
Mar
18,
200
5A
stro
nom
y 21
0 Sp
ring
200
5
Plu
to’s
Moo
n, C
haro
n•
In 1
977,
Plu
to w
as
foun
d to
hav
e a
moo
n•
Lar
gest
moo
n re
lativ
e to
hos
t pla
net
–A
bout
120
0 km
acr
oss
–A
bout
12%
Plu
to’s
mas
s
•Su
rfac
e co
vere
d in
w
ater
ice
•B
oth
rota
te s
ynch
rono
usly
–Pl
uto
and
Cha
ron
each
kee
p th
e sa
me
face
poi
nted
tow
ards
the
othe
r
Mar
18,
200
5A
stro
nom
y 21
0 Sp
ring
200
5
Plu
to’s
Moo
n, C
haro
n
•In
197
7, P
luto
was
fo
und
to h
ave
a m
oon
•L
arge
st m
oon
rela
tive
to h
ost p
lane
t•
Abo
ut 1
200
km a
cros
s–
Abo
ut 1
2% P
luto
’s m
ass
•Su
rfac
e co
vere
d in
w
ater
ice
•B
oth
rota
te s
ynch
rono
usly
–Pl
uto
and
Cha
ron
each
kee
p th
e sa
me
face
poi
nted
tow
ards
the
othe
r
Mar
18,
200
5A
stro
nom
y 21
0 Sp
ring
200
5
Inte
rior
s &
Com
posi
tion
•Pl
uto
is s
imila
r in
den
sity
and
si
ze to
Nep
tune
’s
moo
n T
rito
n•
Lik
ely
a si
mila
r co
mpo
sitio
n, a
ro
ck/ic
e m
ix
(60/
40)
•R
ocky
cor
e, s
urro
unde
d by
wat
er-i
ce m
antle
•Si
nce
it is
sm
alle
r, C
haro
nis
pro
babl
y no
t dif
fere
ntia
ted
Mar
18,
200
5A
stro
nom
y 21
0 Sp
ring
200
5
Cu
rren
tly
pla
nn
ed f
or
lau
nch
in 2
006
htt
p:/
/plu
to.jh
uap
l.ed
u
New
Hor
izon
s
Mar
18,
200
5A
stro
nom
y 21
0 Sp
ring
200
5
Lif
e in
our
Sol
ar S
yste
m
Con
clus
ions
•N
o co
nclu
sive
evi
denc
e ex
ists
for
life
in o
ur s
olar
sy
stem
bes
ides
on
Ear
th
•B
ut, p
ossi
bilit
ies
exis
t for
life
–V
enus
may
hav
e lif
e in
the
clou
ds th
at m
igra
ted
whe
n po
ssib
le o
cean
s bo
iled
away
.
Mar
18,
200
5A
stro
nom
y 21
0 Sp
ring
200
5
Lif
e on
Ven
us?
•Su
rfac
e is
far
too
hot
–If
lead
is li
quid
, thi
nk o
f w
hat h
eat w
ould
do
to
com
plex
org
anic
pol
ymer
s
–N
o co
oler
pol
ar r
egio
ns e
xist
•H
eat i
s un
ifor
m!
•B
ut, h
igh
in th
e cl
ouds
it s
houl
d be
co
oler
?!
–M
aybe
life
can
stil
l exi
st in
the
clou
ds?
Mar
18,
200
5A
stro
nom
y 21
0 Sp
ring
200
5
Ven
us C
hem
ical
Dis
equi
libri
um
•A
t 50
km u
p, th
e te
mpe
ratu
re is
not
too
hot a
nd
the
pres
sure
is 1
atm
osph
ere.
•H
igh
clou
ds in
the
atm
osph
ere
cont
ain
chem
ical
s th
at h
int a
t the
pre
senc
e of
som
e ki
nd o
f bi
olog
ical
act
ivity
.
•H
ydro
gen
sulf
ide
and
sulf
ur d
ioxi
de -
two
gase
s th
at r
eact
with
eac
h ot
her–
exis
ts in
the
clou
ds.
•So
met
hing
is p
roba
bly
prod
ucin
g th
em.
•H
ardl
y an
y ca
rbon
mon
oxid
e. S
o so
met
hing
is
perh
aps
rem
ovin
g th
e ga
s.
http
://w
ww
.man
son-
valle
y.de
/fot
ogal
erie
/man
son/
imag
es/a
css
/acs
s_32
.jpg
Mar
18,
200
5A
stro
nom
y 21
0 Sp
ring
200
5
Lif
e on
Ven
us?
•O
ne p
ossi
bilit
y is
that
mic
robe
s liv
ing
in th
e cl
ouds
cou
ld
be c
ombi
ning
sul
fur
diox
ide
with
car
bon
mon
oxid
e an
d po
ssib
ly h
ydro
gen
sulp
hide
or
carb
onyl
sul
phid
e in
a
met
abol
ism
sim
ilar
to th
at o
f so
me
earl
y te
rres
tria
l m
icro
orga
nism
s.
•G
iven
that
the
tem
pera
ture
on
Ven
us w
as o
nce
muc
h co
oler
, the
re m
ay o
nce
have
bee
n oc
eans
on
the
plan
et. L
ife
coul
d ha
ve s
tart
ed th
ere
and
retr
eate
d to
sta
ble
nich
es o
nce
the
runa
way
gre
enho
use
effe
ct b
egan
.
•M
aybe
a m
issi
on to
sco
op u
p so
me
atm
osph
ere?
Mar
18,
200
5A
stro
nom
y 21
0 Sp
ring
200
5
Lif
e in
our
Sol
ar S
yste
m
Con
clus
ions
•N
o co
nclu
sive
evi
denc
e ex
ists
for
life
in o
ur s
olar
sy
stem
bes
ides
on
Ear
th
•B
ut, p
ossi
bilit
ies
exis
t for
life
–V
enus
may
hav
e lif
e in
the
clou
ds th
at m
igra
ted
whe
n po
ssib
le o
cean
s bo
iled
away
.
–M
ars
may
hav
e so
me
mic
robi
al h
isto
ry li
nked
to w
ater
, an
d pe
rhap
s so
me
subs
urfa
ce li
fe.
Mar
18,
200
5A
stro
nom
y 21
0 Sp
ring
200
5
Mar
tian
Mic
robe
s?
•M
icro
scop
ic s
hape
s th
at
rese
mbl
e li
ving
and
fos
sil
bact
eria
on
Ear
th–
nano
bact
eria
. Pe
rhap
s w
e ha
ve m
eet o
ur f
irst
ET
?•
With
new
evi
denc
e of
onc
e liq
uid
wat
er, w
e ca
n fu
rthe
r sp
ecul
ate
wha
t hap
pene
d w
hen
the
plan
et’s
atm
osph
ere
disa
ppea
red,
per
haps
life
m
oved
to th
e su
bsur
face
. G
oing
und
ergr
ound
.
Mar
18,
200
5A
stro
nom
y 21
0 Sp
ring
200
5
Lif
e in
our
Sol
ar S
yste
m
Con
clus
ions
•N
o co
nclu
sive
evi
denc
e ex
ists
for
life
in o
ur s
olar
sy
stem
bes
ides
on
Ear
th
•B
ut, p
ossi
bilit
ies
exis
t for
life
–V
enus
may
hav
e lif
e in
the
clou
ds th
at m
igra
ted
whe
n po
ssib
le o
cean
s bo
iled
away
.
–M
ars
may
hav
e so
me
mic
robi
al h
isto
ry li
nked
to w
ater
, an
d pe
rhap
s so
me
subs
urfa
ce li
fe.
–Ju
pite
r’s
atm
osph
ere
is r
ich
in p
re-b
ioti
c m
olec
ules
.
Mar
18,
200
5A
stro
nom
y 21
0 Sp
ring
200
5
Flo
atin
g L
ife
•M
aybe
sim
ilar
to w
hale
s–m
ixtu
re b
etw
een
jelly
fish
an
d bi
rds?
•B
ig b
ags
of h
yrdr
ogen
gas
feed
ing
on s
mal
ler
mic
robe
s.
•O
f co
urse
, thi
s is
all
spec
ulat
ive,
and
ther
e is
no
way
to d
etec
t suc
h lif
e.
http
://w
ww
.epi
logu
e.ne
t/cg
i/da
taba
se/a
rt/l
ist.p
l?ga
ller
y=31
26
Mar
18,
200
5A
stro
nom
y 21
0 Sp
ring
200
5
Lif
e in
our
Sol
ar S
yste
m
Con
clus
ions
•N
o co
nclu
sive
evi
denc
e ex
ists
for
life
in o
ur s
olar
sy
stem
bes
ides
on
Ear
th
•B
ut, p
ossi
bilit
ies
exis
t for
life
–V
enus
may
hav
e lif
e in
the
clou
ds th
at m
igra
ted
whe
n po
ssib
le o
cean
s bo
iled
away
.
–M
ars
may
hav
e so
me
mic
robi
al h
isto
ry li
nked
to w
ater
, an
d pe
rhap
s so
me
subs
urfa
ce li
fe.
–Ju
pite
r’s
atm
osph
ere
is r
ich
in p
re-b
ioti
c m
olec
ules
.
–E
urop
a’s
sub-
crus
talo
cean
s m
ay h
arbo
r lif
e, e
ven
fish
-lik
e lif
e.
Mar
18,
200
5A
stro
nom
y 21
0 Sp
ring
200
5
Io•
Inne
rmos
t Gal
ilean
moo
n –
the
“piz
za m
oon”
•T
he m
ost v
olca
nica
lly a
ctiv
e bo
dy in
the
sola
r sy
stem
.•
Voy
ager
1 d
isco
vere
d pr
esen
ce o
f vo
lcan
oes
•In
tern
al h
eatin
g by
Jup
iter’
s tid
es•
Atm
osph
eric
gas
es r
ippe
d of
f by
Jup
iter’
s m
agne
tic f
ield
–io
n to
rus
Pill
anP
ater
aer
uptio
nB
efor
e &
afte
r
Mar
18,
200
5A
stro
nom
y 21
0 Sp
ring
200
5
Eur
opa
•Pe
rhap
s lik
e Io
, Eur
opa
is a
lso
heat
ed f
rom
w
ithi
n?•
Lik
ely
that
ther
e is
liqu
id w
ater
bel
ow th
e ic
e su
rfac
e.•
Lif
e co
uld
exis
t bel
ow th
e su
rfac
e ic
e be
low
th
e su
rfac
e, a
roun
d hy
drot
herm
al v
ents
.•
Ear
ly li
fe o
n E
arth
, may
hav
e fo
rmed
ar
ound
suc
h ve
nts.
•W
e do
n’t h
ow th
ick
the
ice
is y
et.
•Fu
ture
mis
sion
s, w
ill h
ave
to
em
ploy
sm
ash
and
dive
spa
cecr
aft.
Mar
18,
200
5A
stro
nom
y 21
0 Sp
ring
200
5
Lif
e in
our
Sol
ar S
yste
m
Con
clus
ions
•N
o co
nclu
sive
evi
denc
e ex
ists
for
life
in o
ur s
olar
sy
stem
bes
ides
on
Ear
th
•B
ut, p
ossi
bilit
ies
exis
t for
life
–V
enus
may
hav
e lif
e in
the
clou
ds th
at m
igra
ted
whe
n po
ssib
le o
cean
s bo
iled
away
.
–M
ars
may
hav
e so
me
mic
robi
al h
isto
ry li
nked
to w
ater
, an
d pe
rhap
s so
me
subs
urfa
ce li
fe.
–Ju
pite
r’s
atm
osph
ere
is r
ich
in p
re-b
ioti
c m
olec
ules
.
–E
urop
a’s
sub-
crus
talo
cean
s m
ay h
arbo
r lif
e, e
ven
fish
-lik
e lif
e.
–T
itan
is v
ery
inte
rest
ing
•T
hick
atm
osph
ere
•R
educ
ing
chem
istr
y
Mar
18,
200
5A
stro
nom
y 21
0 Sp
ring
200
5
Tita
n
Tita
n’s
atm
osph
ere
•L
iqui
d/ic
e hy
droc
arbo
ns?
•O
rgan
ic c
ompo
unds
–li
fe?
•Pr
obab
ly n
ot –
too
cold
: 95
K•
May
be
a “d
eep
free
ze”
of th
e ch
emic
al
com
posi
tion
of a
ncie
nt E
arth
•C
ould
ther
e be
a “
fish
” sw
imm
ing
in li
quid
m
etha
ne?
Mar
18,
200
5A
stro
nom
y 21
0 Sp
ring
200
5
No
Inte
llige
nt L
ife
•W
e m
ight
fin
d ev
iden
ce o
f so
me
sort
of
life
in o
ur
Sola
r Sy
stem
in th
e ne
xt d
ecad
e, b
ut v
ery
unlik
ely
to f
ind
com
plex
ity n
eede
d fo
r in
telli
gent
and
co
mm
unic
ativ
e lif
e.
•A
ppar
ently
in o
ur s
yste
m, E
arth
’s c
ondi
tions
are
ne
cess
ary.
•O
ther
pla
nets
may
hav
e m
icro
bial
for
ms
of li
fe,
and
may
beco
mpl
ex f
ish-
like
orga
nism
s, b
ut w
e do
n’t e
xpec
t com
mun
icat
ive
bein
gs.
Mar
18,
200
5A
stro
nom
y 21
0 Sp
ring
200
5
How
to s
earc
h fo
r lif
e?
•H
ow d
o w
e se
arch
for
life
in o
ur S
olar
Sys
tem
and
be
yond
?•
Wha
t tes
t will
indi
cate
life
exc
lusi
vely
?•
Is is
cle
ar th
at f
utur
e m
issi
ons
need
to la
nd a
s ne
ar a
s po
ssib
le to
site
s of
sub
surf
ace
wat
er o
r ot
her
solv
ents
.•
Wha
t if
the
life
is s
till i
n th
e pr
otol
ife
stag
e? C
an w
e de
tect
that
?•
The
bou
ndar
y be
twee
n ch
emic
al a
nd b
iolo
gica
l pro
cess
es
is d
iffi
cult
to d
istin
guis
h.
Mar
18,
200
5A
stro
nom
y 21
0 Sp
ring
200
5
Dec
isio
n T
rees
–Se
arch
for
Lif
e
•W
ait f
or it
to c
ome
to u
s vi
a m
eteo
rite
s or
com
ets.
•R
obot
ic o
ne-w
ay in
vest
igat
ions
–M
ars
rove
rs.
•Fe
tch
and
retu
rn w
ith s
ampl
es.
http
://w
ww
.ibib
lio.
org/
wm
/pai
nt/a
uth/
frie
dric
h/tr
ee.jp
g
Mar
18,
200
5A
stro
nom
y 21
0 Sp
ring
200
5
Pro
blem
s
•In
the
last
2 c
ases
, we
have
the
prob
lem
of
cont
amin
atio
n by
E
arth
life
.
•O
rgan
ism
s ca
n liv
e in
Mar
s-lik
e co
nditi
ons
on E
arth
.
•If
som
e E
arth
life
sur
vive
s th
e sp
ace
jour
ney,
it c
ould
col
oniz
e M
ars,
pos
sibl
y de
stro
y an
y M
artia
n lif
e. T
hink
of
Kud
zu.
•C
urre
nt m
issi
ons
mus
t be
ster
ilize
d.ht
tp://
ww
w.h
ope.
edu/
acad
emic
/bio
logy
/fac
ulty
/eva
ns/i
mag
es/A
ngio
sper
ms/
Cor
eEud
icot
s/E
uros
idsI
/Fab
acea
e/K
udzu
.JP
G
Mar
18,
200
5A
stro
nom
y 21
0 Sp
ring
200
5
Bio
mar
kers
: H
ow to
look
for
ext
raso
lar
life.
•W
e ne
ed to
dec
ide
how
to s
earc
h fo
r bi
omar
kers
or
chem
ical
si
gnat
ures
of
life.
•O
n E
arth
, met
hane
and
oxy
gen
are
indi
cato
rs.
The
y no
rmal
ly
reac
t. S
omet
hing
is k
eepi
ng it
ou
t of
equi
libri
um.
Sort
of
like
Ven
us d
iseq
uilib
rium
.
•T
he G
alile
o sp
acec
raft
on
its w
ay
out t
o Ju
pite
r, tu
rned
and
look
ed
at th
e E
arth
.
•D
id it
det
ect l
ife?
Mar
18,
200
5A
stro
nom
y 21
0 Sp
ring
200
5
Bio
mar
kers
: L
ooki
ng a
t Ear
th.
•St
rong
“re
d ed
ge”
from
ref
lect
ed li
ght.
Abs
orpt
ion
from
ph
otos
ynth
esis
.•
Stro
ng O
2. K
eepi
ng o
xyge
n ri
ch a
tmos
pher
e re
quir
es s
ome
proc
ess.
It s
houl
d sl
owly
com
bine
with
roc
ks.
•St
rong
met
hane
. Sho
uld
oxid
ize.
Rep
leni
shed
by
life.
•St
rang
e ra
dio
emis
sion
s th
at c
ould
be
inte
llige
nt li
fe.
•R
ecen
tly, r
esea
rche
rs h
ave
look
ed a
t the
Ear
thsh
ine
from
the
moo
n.•
The
y ag
ree
with
Gal
ileo
resu
lt.
The
re is
life
on
Ear
th.
–W
ater
–O
xyge
n–
Ten
tativ
e de
tect
ion
of “
red
edge
”
http
://e
pod.
usra
.edu
/arc
hive
/epo
dvie
wer
.php
3?oi
d=56
256
Mar
18,
200
5A
stro
nom
y 21
0 Sp
ring
200
5
Bey
ond
Plu
to –
The
Kui
per
Bel
t
•A
“re
serv
oir”
of
icy
bodi
es b
eyon
d Pl
uto
•Pr
opos
ed to
exp
lain
sh
ort-
peri
od c
omet
s
•T
he f
irst
Kui
per
Bel
t O
bjec
t (K
BO
) w
as
dete
cted
in 1
992
•T
ypic
al s
izes
10
-50
km, v
ery
fain
t–
Smal
l one
s ar
e po
tent
ial c
omet
s
–A
few
are
larg
e, h
undr
eds
of k
m a
cros
s
Mar
18,
200
5A
stro
nom
y 21
0 Sp
ring
200
5
Qua
oar
& S
edna
•C
urre
ntly
the
larg
est k
now
n K
BO
s•
Prob
ably
si
mil
ar in
co
mpo
sitio
n to
Cha
ron
•Su
rfac
e te
mpe
ratu
res
arou
nd 3
0 K
(-2
40 C
)!
Mar
18,
200
5A
stro
nom
y 21
0 Sp
ring
200
5
Dis
cove
ry im
ages
Qua
oar
•O
rbita
l dis
tanc
e ~
42 A
U
•A
bout
50%
the
diam
eter
of
Plu
to
Mar
18,
200
5A
stro
nom
y 21
0 Sp
ring
200
5
Sedn
a
•A
bout
75%
the
diam
eter
of
Plut
o
•C
urre
ntly
at 6
7 A
U f
rom
the
Sun
•O
rbit
take
s it
over
90
0 A
U a
way
•10
,500
yr
orbi
t
Mar
18,
200
5A
stro
nom
y 21
0 Sp
ring
200
5
Plu
to, P
lane
t or
KB
O?
•Pl
anet
?–
Odd
pla
net:
all
othe
r ou
ter
plan
ets
are
gian
ts–
Ver
yec
cent
ric
orbi
t–
Orb
it hi
ghly
tilte
d w
ith r
espe
ct to
the
othe
r pl
anet
s
•K
uipe
r B
elt O
bjec
t?–
Lar
ger
than
oth
er K
BO
s(b
ut c
lose
in s
ize
to Q
uaoa
r&
Sed
na)
–H
as a
n at
mos
pher
e (l
ike
Tri
ton)
•B
ecau
se o
f si
ze &
clo
sene
ss to
the
Sun
–T
ypic
al K
BO
com
posi
tion
(icy
-roc
k m
ix)
–O
rbit
typi
cal f
or a
KB
O
•M
any
KB
Os
are
also
in r
eson
ance
with
Nep
tune
Mar
18,
200
5A
stro
nom
y 21
0 Sp
ring
200
5
Pla
net?
Und
efin
ed!
•W
e ha
ve n
ode
fini
tion
of
a pl
anet
!–
Its
like
art:
We
know
on
e w
hen
we
see
it
•If
Plu
to is
a
plan
et, w
hy n
otSe
dna
or Q
uaoa
r?
Mar
18,
200
5A
stro
nom
y 21
0 Sp
ring
200
5
Way
s of
Def
inin
g a
Pla
net
1.H
isto
rica
l–
Just
the
orig
inal
nin
e!
2.H
isto
rica
l Plu
s–
Any
thin
g bi
gger
than
Plu
to
–…
and
not s
omet
hing
’s m
oon!
3.G
ravi
tatio
nally
Rou
nd–
Big
eno
ugh
that
its
grav
ity m
akes
it r
ound
4.Po
pula
tion
Cla
ssif
icat
ion
–Is
olat
ed b
odie
s vs
. mem
bers
of
larg
e po
pula
tions
Mar
18,
200
5A
stro
nom
y 21
0 Sp
ring
200
5
Cla
ss Q
uest
ion
Plut
o. I
s it
a pl
anet
, or
is it
a K
uipe
r B
elt O
bjec
t?
How
do
you
thin
k Pl
uto
shou
ld b
e cl
assi
fied
?
Dis
cuss
this
with
you
r cl
assm
ates
and
wri
te d
own
your
gro
up’s
con
clus
ion.
Mar
18,
200
5A
stro
nom
y 21
0 Sp
ring
200
5
Com
ets
•A
ppar
ition
s th
at a
ppea
r lik
e gh
ostly
fir
ebal
ls f
roze
n in
the
sky
•In
anc
ient
tim
es, t
he a
ppea
ranc
e of
a c
omet
was
oft
en c
onsi
dere
d a
harb
inge
r of
doo
m•
Iron
ical
ly, l
ife
on E
arth
may
ha
ve b
een
impo
ssib
le w
ithou
t th
em•
Als
o co
met
s an
d m
eteo
roid
s ar
e th
e ol
dest
ori
gina
l sol
ar s
yste
m
mat
eria
l! L
eft o
ver
build
ing
mat
eria
ls.
Mar
18,
200
5A
stro
nom
y 21
0 Sp
ring
200
5
Wha
t is
a C
omet
?
•D
irty
iceb
ergs
in
spa
ce–
10-5
0 km
ac
ross
•C
ompo
sed
mos
tly o
f w
ater
ic
e (b
ut a
lso
CO
2
and
CH
4), w
ith
som
e so
lid d
ust,
rock
&
met
al–
Dar
k su
rfac
es!
•V
ery
ellip
tical
orb
its ⇒
vary
ing
r im
plie
s va
ryin
g T
•W
hen
one
appr
oach
es th
e Su
n, s
unlig
ht s
ublim
ates
M
ar 1
8, 2
005
Ast
rono
my
210
Spri
ng 2
005
Com
ets
Cha
ngin
g r
impl
ies
a ch
ange
in T
Mar
18,
200
5A
stro
nom
y 21
0 Sp
ring
200
5
Com
ets
•C
oma
–Su
nlig
ht e
vapo
rate
s co
met
su
rfac
e–
Form
s a
clou
d of
gas
& d
ust
arou
nd th
e nu
cleu
s
•T
ails
–G
as is
ioni
zed
by th
e su
n’s
UV
lig
ht
–G
as &
dus
t pus
hed
away
by
the
sola
r w
ind
Mar
18,
200
5A
stro
nom
y 21
0 Sp
ring
200
5
Whe
re D
o C
omet
s L
urk?
Mar
18,
200
5A
stro
nom
y 21
0 Sp
ring
200
5
Whe
re D
o C
omet
s L
urk?
•T
he v
ast m
ajor
ity li
ve f
ar o
ut in
the
Sola
r Sy
stem
, bey
ond
the
plan
ets
•Sh
ort p
erio
d co
met
s: K
uipe
r B
elt (
aka
tran
s-N
eptu
nian
)–
Orb
ital p
erio
ds o
f hu
ndre
ds o
f ye
ars
–A
roun
d an
d be
yond
the
orbi
t of
Plut
o (3
0-50
0 A
U),
pr
obab
ly f
orm
ed th
ere.
–N
ow a
bout
240
ish
the
size
of
10%
Plu
to
•L
ong-
peri
od c
omet
s: O
ort C
loud
–E
dge
of S
un's
gra
vita
tiona
l inf
luen
ce
–O
ut to
50,
000
AU
–Pe
riod
s >
105
yrs
–Pr
obab
ly d
id n
ot f
orm
ther
e. E
ject
ed b
odie
s by
Jov
ians
.
Mar
18,
200
5A
stro
nom
y 21
0 Sp
ring
200
5
Fal
ling
Into
the
Sola
r Sy
stem
•O
ccas
iona
lly, c
omet
orb
its
get “
pert
urbe
d” b
y pa
ssin
g st
ars
•T
hey
fall
into
the
inne
r So
lar
Syst
em o
n hi
ghly
elli
ptic
al
orbi
ts
•In
tera
ctio
ns w
ith p
lane
ts c
an
shor
ten
thei
r or
bits
Mar
18,
200
5A
stro
nom
y 21
0 Sp
ring
200
5
Lif
e &
Dea
th o
f a
Com
et•
Eve
n co
met
s on
sho
rten
ed o
rbits
liv
e m
ostly
in th
e ou
ter
sola
r sy
stem
•E
very
orb
it, th
ey lo
se
1% o
f th
eir
mas
ses
to s
olar
ev
apor
atio
n–
Hal
ley’
s C
omet
will
onl
y la
st a
bout
56
00 m
ore
year
s
•W
hen
they
bec
ome
too
smal
l, th
ey
brea
k ap
art
Mar
18,
200
5A
stro
nom
y 21
0 Sp
ring
200
5
Lif
e &
Dea
th o
f a
Com
et
Mar
18,
200
5A
stro
nom
y 21
0 Sp
ring
200
5
Dee
p Im
pact
http
://r
eals
erve
r1.jp
l.nas
a.go
v:80
80/r
amge
n/V
ideo
-NA
SA
1st-
Pesr
son-
Yeo
man
s-A
VC
2005
-016
.rm
Dee
p Im
pact
Mar
18,
200
5A
stro
nom
y 21
0 Sp
ring
200
5
Dis
cove
ry o
f th
e A
ster
oids
•In
180
1, G
iuse
ppe
Piaz
zino
ticed
an
unch
arte
d “s
tar”
th
at s
hift
ed p
ositi
on a
mon
g th
e st
ars
over
sev
eral
nig
hts
•C
ould
it b
e an
othe
r pl
anet
?–
Its
orbi
t was
bet
wee
n M
ars
and
Jupi
ter
–V
ery
dim
, so
it m
ust b
e sm
all
–T
oo s
mal
l to
be a
pla
net
•It
was
an
aste
roid
, a “
min
or p
lane
t”
Mar
18,
200
5A
stro
nom
y 21
0 Sp
ring
200
5
Ast
eroi
ds
•Sm
all s
izes
–L
arge
st –
Cer
es: 9
40 k
m a
cros
s–
Onl
y 3
mor
e th
an 3
00 k
m–
Abo
ut 2
40 b
igge
r th
an 1
00 k
m–
Mill
ions
und
er
1 km
•C
ompo
sitio
n–
Roc
ks (
silic
ates
) an
d ir
on/n
icke
l
Ida
and
Dac
tyl f
rom
Gal
ileo
55 k
m
Mar
18,
200
5A
stro
nom
y 21
0 Sp
ring
200
5
The
Ast
eroi
d B
elt
•M
ost a
ster
oids
are
fo
und
betw
een
2 to
3.5
AU
–B
etw
een
Mar
s &
Ju
pite
r
–R
egio
n is
cal
led
the
Ast
eroi
d B
elt
–N
earl
y ci
rcul
ar o
rbits
Mar
18,
200
5A
stro
nom
y 21
0 Sp
ring
200
5
The
pos
sibi
lity
of s
ucce
ssfu
lly
navi
gatin
g an
ast
eroi
d fi
eld…
•A
ctua
lly, N
ASA
ha
s se
nt m
any
spac
e pr
obes
in
to a
nd th
roug
h th
e A
ster
oid
Bel
t•
Unl
ike
in S
tar
War
s, th
e A
ster
oid
Bel
t is
not t
hat c
row
ded
•A
vera
ge s
epar
atio
n be
twee
n si
zabl
e as
tero
ids
is 1
0 m
illio
n km
!
Mar
18,
200
5A
stro
nom
y 21
0 Sp
ring
200
5
Des
troy
ed…
by
the
Em
pire
•A
re th
e as
tero
ids
a de
stro
yed
plan
et?
No
–C
ombi
ned,
the
aste
roid
s ha
ve a
mas
s ab
out 0
.1%
th
at o
f th
e E
arth
–L
ess
than
10%
that
of
our
Moo
n
•T
he a
ster
oids
mig
ht b
e a
fail
edpl
anet
–Ju
pite
r’s
grav
ity k
ept t
he a
ster
oids
fro
m c
oale
scin
g in
to
a pl
anet
–Ju
pite
r pr
obab
ly e
ject
ed m
any
aste
roid
s fr
om th
e So
lar
Syst
em
Mar
18,
200
5A
stro
nom
y 21
0 Sp
ring
200
5
Apo
llos
and
Tro
jans
•So
me
aste
roid
s ar
e on
orb
its th
at c
ross
E
arth
’s o
rbit
–C
alle
d A
pollo
ast
eroi
ds–
At l
east
169
0 ar
e kn
own
–In
197
2, o
ne s
kipp
ed
off
the
Ear
th’s
at
mos
pher
e
•O
ther
ast
eroi
ds s
hare
Ju
pite
r’s
orbi
t!–
Cal
led
Tro
jan
aste
roid
s–
Lea
d an
d tr
ail J
upite
r ar
ound
the
Sun
Mar
18,
200
5A
stro
nom
y 21
0 Sp
ring
200
5
Lan
ding
on
Ero
s
•In
200
1, N
ASA
land
ed a
sp
acec
raft
on
the
aste
roid
Ero
s
•H
eavi
ly c
rate
red
surf
ace
•B
ould
ers
buri
ed in
the
rego
lith
•A
ncie
nt –
4.6
billi
on y
ears
old
Mar
18,
200
5A
stro
nom
y 21
0 Sp
ring
200
5
Ast
eroi
ds -
Ear
ly S
olar
Sys
tem
L
efto
vers
•T
he a
ster
oids
wer
e to
o sm
all t
o ha
ve m
uch
inte
rnal
hea
t –
No
diff
eren
tiatio
n
–N
o ge
olog
ic a
ctiv
ity
–T
he s
ame
as w
hen
they
for
med
4.
6 bi
llion
yea
rs a
go
•Fo
ssils
of
the
earl
y so
lar
syst
em!
Mar
18,
200
5A
stro
nom
y 21
0 Sp
ring
200
5
Met
eors
•W
hen
you
see
a “s
hoot
ing
star
”,
that
is a
met
eor
–A
pie
ce o
f so
lar
syst
em d
ebri
s (a
m
eteo
roid
) in
tera
ctin
g w
ith o
ur
atm
osph
ere
•M
ost “
burn
up”
or
disi
nteg
rate
in
the
uppe
r at
mos
pher
e, b
ut s
ome
do
surv
ive
fall
–T
hese
are
met
eori
tes
•C
ompo
sitio
n: r
ock,
som
e m
etal
s
Mar
18,
200
5A
stro
nom
y 21
0 Sp
ring
200
5
S. N
umaz
awa
Met
eor
Show
ers
•M
eteo
rs h
it E
arth
all
the
time
•In
the
earl
y m
orni
ng, y
ou c
an
typi
cally
see
abo
ut 3
per
hou
r•
Seve
ral t
imes
a y
ear,
the
rate
in
crea
ses
–M
aybe
mor
e th
an a
met
eor
per
min
ute
–C
alle
d m
eteo
r sh
ower
s
•Se
em to
ori
gina
te f
rom
a
sing
le p
oint
in th
e sk
y
Mar
18,
200
5A
stro
nom
y 21
0 Sp
ring
200
5
Met
eor
Show
ers
•W
hen
a co
met
ent
ers
the
inne
r So
lar
Syst
em, i
t lea
ves
a tr
ail o
f du
st•
Whe
n E
arth
pas
ses
thro
ugh
this
dus
t, w
e ge
t a m
eteo
r sh
ower
•M
eteo
r sh
ower
s do
n’t
typi
cally
pro
duce
met
eori
tes
–It
s al
l dus
t, no
t roc
ks
Mar
18,
200
5A
stro
nom
y 21
0 Sp
ring
200
5
Pee
kski
ll F
ireb
all
(Oct
ober
9, 1
992)
Mar
18,
200
5A
stro
nom
y 21
0 Sp
ring
200
5
Typ
es o
f M
eteo
rite
s
•94
% o
f m
eteo
rite
s ar
e st
ony
–M
ade
of s
ilica
tes,
ha
rd to
dis
tingu
ish
from
Ear
th r
ocks
•5%
are
iron
s–
Iron
-nic
kel c
ryst
als
•1%
sto
ny-i
rons
–Si
licat
es w
ith ir
on in
clus
ions
Mar
18,
200
5A
stro
nom
y 21
0 Sp
ring
200
5
Met
eori
tes
are
Anc
ient
•M
eteo
rite
s ar
e th
e ol
dest
ob
ject
s in
the
Sola
r Sy
stem
•R
emna
nts
of th
e So
lar
Syst
em’s
for
mat
ion
•T
he o
ldes
t are
car
bona
ceou
s ch
ondr
ites
(a ty
pe o
f st
one)
–A
bund
ant i
n ca
rbon
and
wat
er–
Con
tain
am
ino
acid
s -
build
ing
bloc
ks o
f lif
e!–
4.56
bill
ion
year
s ol
d
•So
me
have
dia
mon
ds p
rodu
ced
by in
ters
tella
r sh
ock
wav
es!
Car
bona
ceou
s ch
ondr
ite
Mar
18,
200
5A
stro
nom
y 21
0 Sp
ring
200
5
Met
eori
te O
bser
ving
•T
he U
ofI
has
a sm
all m
eteo
rite
col
lect
ion
in th
e N
atur
al H
isto
ry B
uild
ing
•A
ctiv
ities
:–
Cou
nt th
e nu
mbe
rs o
f ea
ch ty
pe o
f m
eteo
rite
, com
pare
to
the
frac
tions
that
exi
st in
spa
ce–
Why
do
we
know
whe
n m
ost o
f th
e st
ony
met
eori
tes
fell,
but
not
the
iron
one
s?–
Vis
it a
web
-site
, lea
rn a
bout
how
to id
entif
y m
eteo
rite
s
•E
xtra
Cre
dit R
epor
t: D
ue A
pril
8th, w
orth
1/3
a
hom
ewor
k.
Top Related