Table 1 Basic information for the terrestrial planets
| Â | Mercury | Venus | Earth | Mars |
|---|---|---|---|---|
Semi-major axis (AU) | 0.39 | 0.72 | 1.00 | 1.52 |
Radius (km) | 2439 | 6052 | 6378 | 3394 |
Gravity (m/s2) | 3.70 | 8.87 | 9.78 | 3.69 |
Density (g/cm3) | 5.43 | 5.20 | 5.51 | 3.93 |
Surface temperature (K) | 440 | 730 | 280 | 220 |
Crustal thickness (km) | 35 | 15 | 7 | 50 |