Upload
others
View
2
Download
0
Embed Size (px)
Citation preview
“Ura
nus
& N
eptu
ne, T
he Ic
e G
iant
s”
Wha
t We
Will
Lea
rn T
oday
•H
ow &
Whe
n w
ere
Ura
nus
& N
eptu
ne
disc
over
ed?
•H
ow a
re th
e in
terio
rs a
nd w
eath
er o
n th
ese
plan
ets?
•W
hy is
Nep
tune
as
“war
m”
as U
ranu
s?•
Wha
t are
thei
r m
oons
and
rin
gs li
ke?
•W
hat i
s sp
ecia
l abo
ut T
riton
, Nep
tune
’s
moo
n?•
How
are
thes
e w
orld
s un
ique
in th
e S
S?
Pro
pert
yU
ranu
sN
eptu
ne
Sem
i-maj
orax
is19
.2 A
U30
.1 A
U
Siz
e (r
adiu
s)4.
0 R
Ear
th3.
9 R
Ear
th
Mas
s14
.5 M
Ear
th17
.1 M
Ear
th
Ave
rage
den
sity
1.32
g/c
c1.
64 g
/cc
Com
posi
tion
H, H
e, H
-com
poun
dsH
, He,
H-c
ompo
unds
Clo
ud-t
op T
emp
60K
60 K
Moo
ns>
27
> 1
3
Orb
italp
erio
d84
year
s16
5 ye
ars
Rot
atio
n pe
riod
*-1
7.3
hour
s16
hou
rs
Axi
s til
t97
.9o
29.6
o
Orb
ital i
nclin
atio
n0.
77o
1.77
o
Orb
ital e
ccen
tric
ity0.
046
0.01
0
Pla
net D
etai
ls
Ret
rogr
ade
Mos
t ext
rem
e
As
“war
m”
as U
ranu
s!
* M
easu
red
base
d on
rot
atio
n of
mag
netic
fiel
d lin
es
Sm
alle
st J
ovia
n
Ura
nus
& N
eptu
ne’s
Dis
cove
ry•
Firs
t pla
nets
dis
cove
red
usin
g a
tele
scop
e•
Ura
nus
disc
over
ed in
178
1 by
Will
iam
&
Car
olin
e H
ersc
hel
–A
lthou
gh fa
intly
vis
ible
to n
aked
-eye
, doe
s no
t “w
ande
r” a
s m
uch
due
to it
s lo
ng 8
4 ye
ar o
rbit
–D
isco
vere
d du
ring
a su
rvey
of t
he s
kies
•C
aref
ul o
bser
vatio
ns o
f Ura
nus
show
s de
viat
ion
in p
ath
vs. N
ewto
n’s
law
s•
Ada
ms
& L
ever
rier
inde
pend
ently
pre
dict
ed
influ
ence
on
Ura
nus
from
an
unse
en e
ight
h pl
anet
•N
eptu
ne d
isco
vere
d in
184
6 by
Gal
le b
ased
on
Leve
rrie
r’spr
edic
tion
of it
s po
sitio
n!
For
mat
ion
of U
ranu
s &
Nep
tune
•S
imila
r to
Jup
iter
and
Sat
urn,
cor
e of
abo
ut 1
0 M
Ear
thfo
rmed
from
hyd
roge
n co
mpo
unds
•A
ccre
ted
muc
h sm
alle
r at
mos
pher
e–
Orb
it ar
ound
the
Sun
is m
uch
bigg
er–
Acc
retio
n sl
ower
as
a re
sult
–S
olar
win
d bl
ew a
way
gas
into
inte
rste
llar
spac
e–
Sto
pped
pla
net f
orm
atio
n, le
avin
g U
ranu
s an
d N
eptu
ne le
ss m
assi
ve
Inte
rior
of U
ranu
s &
Nep
tune
Fig
11.
5
•N
o liq
uid
or m
etal
lic h
ydro
gen
–N
ot e
noug
h pr
essu
re
•R
ock
& m
etal
cor
e–
Larg
er th
an J
upite
r &
Sat
urn
as it
is n
ot w
eigh
ed d
own
by a
larg
e at
mos
pher
e
•H
ydro
gen
com
poun
d la
yer
–D
iffer
entia
ted
over
roc
k &
met
al c
ore
unlik
e Ju
pite
r &
Sat
urn
•G
aseo
us h
ydro
gen
•V
isib
le c
loud
s•
Ura
nus
–C
oole
d of
f and
dul
l (as
exp
ecte
d)
•N
eptu
ne–
Inte
rnal
hea
t sou
rce!
–P
erha
ps d
ue to
ong
oing
con
trac
tion
•Li
ke w
hich
oth
er p
lane
t?
Atm
osph
ere
& W
eath
er•
~ 8
4% H
, 14%
He,
2%
CH
4
•M
etha
ne c
onde
nses
into
“s
now
flak
es”
less
than
100
km
bel
ow th
e cl
oud
tops
–G
ives
the
blue
col
or
–M
etha
ne g
as a
bove
abs
orbs
re
d lig
ht
–M
etha
ne c
loud
s re
flect
blu
e lig
ht
•W
hy is
Nep
tune
blu
er?
–U
ranu
s ha
s sm
og-li
ke la
yer
due
to it
s ex
trem
e se
ason
s
–S
catte
rs b
lue
light
bef
ore
reac
hing
clo
uds
Fig
11.
7
Win
ds &
Wea
ther
•U
ranu
s–
Voy
ager
2 s
aw n
o ba
nds
or c
loud
s in
19
86–
Sub
sequ
ent H
ST
and
AO
obs
erva
tions
re
veal
sto
rms
brew
ing
–P
erha
ps d
ue to
cha
ngin
g se
ason
s N
H
seei
ng S
unlig
ht a
fter
42 y
ears
!
•N
eptu
ne–
Ban
ded
atm
osph
ere
with
sto
rms
and
clou
ds–
Gre
at D
ark
Spo
t •
Last
ed o
nly
abou
t 6 y
ears
Fig
11.
11 c
, Kec
k IR
imag
e
Fig
11.
11 d
Mag
netic
Fie
lds
•M
oder
ate
size
d m
agne
tosp
here
des
pite
wea
k fie
ld–
Liqu
id c
ore
of m
etal
s an
d hy
drog
en c
ompo
unds
gen
erat
e m
agne
tic fi
eld
–W
eake
r sol
ar w
ind
pres
sure
al
low
s m
oder
ate
size
d m
agne
tosp
here
•B
oth
mag
netic
axe
s ar
e ve
ry
tilte
d w
ith r
espe
ct to
rot
atio
n ax
es–
Don
’t kn
ow w
hy
Fig
11.
13
Ura
nus’
Med
ium
Siz
ed M
oons
•A
ll na
med
afte
r S
hake
spea
re's
cha
ract
ers
•M
ade
mai
nly
of ic
es (
wat
er, m
etha
ne, a
mm
onia
)•
Voy
ager
flyb
y ga
ve u
s in
form
atio
n an
d ra
ised
qu
estio
ns–
Arie
l & U
mbr
iela
re v
irtua
l tw
ins,
but
onl
y A
riel s
how
s ev
iden
ce o
f vol
cani
sm &
tect
onic
s–
Tita
nia
& O
bero
n ar
e al
so s
imila
r si
ze, b
ut o
nly
Tita
nia
show
s ge
olog
ical
act
ivity
•M
irand
a, th
e sm
alle
st,
show
s
man
y te
cton
ic fe
atur
es a
nd
rela
tivel
y fe
w c
rate
rs–
Per
haps
due
to p
ast t
idal
hea
ting
Fig
11.
28
Nep
tune
’s C
aptu
red
Moo
ns•
Man
y re
trog
rade
orb
its, h
igh
incl
inat
ions
–C
aptu
red
aste
roid
s
•T
riton
is th
e la
rges
t cap
ture
d ob
ject
in th
e S
olar
S
yste
m–
Col
dest
wor
ld in
the
sola
r sy
stem
(hi
gh a
lbed
o)–
Onc
e or
bite
d th
e S
un
as a
KB
O–
Larg
er th
an P
luto
–R
etro
grad
e or
bit
–S
pira
ling
into
Nep
tune
–W
ill c
ross
Roc
he L
imit
in
abou
t 100
mill
ion
year
s–
Evi
denc
e of
pas
t geo
logi
cal a
ctiv
ity•
Pas
t ecc
entr
ic o
rbit
caus
ed ti
dal h
eatin
g
Fig
11.
29
Rin
gs
•U
ranu
s’ r
ings
are
tipp
ed
over
–P
hoto
from
HS
T in
IR
•N
eptu
ne r
ings
pic
ture
was
ta
ken
by V
oyag
er
Fig
11.
34
Uni
que
Fea
ture
s of
Ura
nus
•F
irst S
S p
lane
t to
be d
isco
vere
d w
ith a
tele
scop
e–
Far
thes
t nak
ed e
ye p
lane
t, bu
t not
rec
ogni
zed
as a
pl
anet
•T
he m
ost t
ilted
pla
net
–M
oon
and
rings
are
like
bul
ls-e
ye f
rom
the
Sun
/Ear
th–
Mos
t ext
rem
e se
ason
s–
42 y
ears
of d
ay a
nd 4
2 ye
ars
of n
ight
!
•T
he o
nly
gas
gian
t to
have
no
inte
rnal
hea
t so
urce
Uni
que
Fea
ture
s of
Nep
tune
•A
s w
arm
as
Ura
nus
desp
ite g
reat
er d
ista
nce
from
the
Sun
–In
tern
al h
eat s
ourc
e
•La
rges
t cap
ture
d m
oon
–R
etro
grad
e or
bit
•M
any
moo
ns w
ith w
acky
orb
its–
Cap
ture
d K
BO
s
•T
riton
is c
olde
st w
orld
in th
e S
olar
Sys
tem
–35
K, -
238
o C, -
396
o F
•S
mal
lest
gas
gia
nt p
lane
t
Voy
ager
Mov
ies