Geoscience Reference
In-Depth Information
From Sun
to
(
10
6
km)
d
4,880 km
Atmospheric gases %:
3.30 · 10
23
kg
m
H
2
,
He, Ne.
5,427 kg m
-3
r
p
Core
Mariner 10 1974-75.
Highly eccentric orbit.
Extreme surface
temperature variations.
500-600 km outer silicate
“crust.” Partially molten
Fe core: weak magnetic field
3.701 m
2
s
-1
g
L
d
58.6 days
L
y
88 days
l
e
0
t
s
167
°
C (-170 to 430)
57.9
2 · 10
-6
atm
p
s
Mercury
Atmospheric gases %:
CO
2
96%, N
2
3.4,
H
2
O 0.14.
H
2
SO
4
clouds
d
12,100 km
4.87 · 10
24
kg
m
Radar mapped by
Magellan.
Low orbital eccentricity.
“Runaway” greenhouse
atmosphere.
Spectacular extinct
volcanoes and rift valleys.
Some active hot spots.
Convecting molten
mantle. No magnetic
field
Core
5,204 kg m
-3
r
p
8.87 m
2
s
-1
g
108.2
L
d
243 days (retrograde)
Venus
L
y
225 days
l
e
2
°
t
s
420-485
°
C (“runaway”
greenhouse)
p
s
c
.90 atm
Magellan radar imaging
Atmospheric gases %:
Our moon
N
2
78.1%, O
2
21.0,
Ar 0.9, CO
2
0.03.
d
12,756 km
Densest planet in solar
system. Strong magnetic
field. Molten Fe outer
core. Convecting silicate
mantle drives plate
tectonics in lithosphere.
71% water covered, but
oceans less known than
Venus. Surface life.
Oxygen-rich
atmosphere. Soil
5.98 · 10
24
kg
m
5,515 kg m
-3
r
p
9.81 m
2
s
-1
g
149.6
L
d
1 earth day
Earth
L
y
365 days
Core
I
e
23
°
26´
t
s
15
°
C (greenhouse)
p
s
1 atm
Atmospheric gases %:
d
6,794 km
CO
2
95.3, N
2
2.7, Ar 1.6,
O
2
0.13. High orbital ellipticity.
Long rifts, extinct volcanic forms.
Southern half cratered. Molten
mantle, no active plate tectonics.
No surface water today but
runoff earlier in history.
Oxidative aqueous rock
weathering. Perennial polar
water-ice caps. Wind blown dust
6.42 · 10
23
kg
m
3,933 kg m
-3
r
p
Core
3.69 m
2
s
-1
(Fe + S core)
g
L
d
1.03 earth day
228.0
L
y
687 days
Mars
I
e
24
°
t
s
-55
°
C (no greenhouse)
p
s
0.006 atm (strong wind)
Fig. 1.1
Comparative planetology.
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