Terrestrial Planetary Characteristics
Mercury
- closest planet to Sun
- no atmosphere
- heavily cratered (like Moon)
- high surface temperature (large range)
- solar constant = 3566 Watts/m2
- only Mariner 10 took photos during flyby
- large iron core
| Surface temp (K) |
Surface temp (C) |
Gas Pressure (bars) |
Gas |
Percent |
| 713 |
440 |
2 x 10-15 |
He |
42 |
|
|
|
N |
42 |
|
|
|
O |
15 |
|
|
|
H |
1 |
Fact Sheet
Venus
- 2nd closest to Sun, 6th largest
- very circular orbit (low eccentricity)
- slow rotation (243 earth days = 1 Venusian day)
- Earth's sister planet
- similar size as Earth
- similar densities, chemical composition as Earth
- Atmospheric pressure = 90X Earth
- sulfuric acid clouds, which obscure view of Venus
- probably had large amounts of water that boiled away
- no magnetic field
- no satellites
- solar constant = 2660 Watts/m2
- high temperature (457 C), runaway greenhouse effect
| Surface temp (K) |
Surface temp (C) |
Gas Pressure (bars) |
Gas |
Percent |
| 730 |
457 |
90 |
CO2 |
96.4 |
|
|
|
N2 |
3.4 |
|
|
|
SO2 |
0.015 |
|
|
|
H2O |
0.010 |
|
|
|
Ar |
0.007 |
Fact Sheet
Earth
| Surface temp (K) |
Surface temp (C) |
Gas Pressure (bars) |
Gas |
Percent |
| 288 |
15 |
1.013 |
N2 |
78.804 |
|
|
|
O2 |
20.946 |
|
|
|
Ar |
0.934 |
|
|
|
H2O |
variable |
Description
Fact Sheet
Moon
Comparison with Earth:
- Both are same distance from Sun, therfore both have the
same solar constant
- Earth has an atmosphere
- Moon has a neglible atmosphere
- Mean temperature of Moon = -16 C
- Mean temperature of Earth = +15 C
- Therefore, Earth's atmosphere keeps the Earth 31 C warmer
than it would be without an atmsophere
- Greenhouse gases in Earth's atmosphere (water vapor,
carbon dioxide, methane, nitrous oxide)
| Surface temp (K) |
Surface temp (C) |
Gas Pressure (bars) |
Gas |
Percent |
| 257 |
-16 |
2 x 10-14 |
Ne |
40 |
|
|
|
Ar |
40 |
|
|
|
He |
20 |
Description
Fact Sheet
Mars
- 4th planet from Sun, 7th largest
- The Red Planet
- Orbit is significantly elliptical
- Mean temp = -55 C (Range -123 to +22 C)
- Erosional features indicate presence of liquid water
in early history (4 billion years ago)
- Very thin atmosphere (1% of Earth)
- Permanent ice cap on both poles
- No magnetic field
- 2 moons (Phobos, Deimos)
- Mars Pathfinder
Mission
- Life
on Mars?
| Surface temp (K) |
Surface temp (C) |
Gas Pressure (bars) |
Gas |
Percent |
| 218 |
-55 |
0.007 |
CO2 |
95.7 |
|
|
|
N2 |
2.7 |
|
|
|
Ar |
1.6 |
Fact Sheet
