COMPARE MARS & EARTH
| Mars | Earth | Ratio (Mars/Earth) |
| Mass (1024 kg) | 0.6419 | 5.9736 | 0.107 |
| Volume (1010 km3) | 16.318 | 108.321 | 0.151 |
| Equatorial radius (km) | 3397 | 6378 | 0.533 |
| Polar radius (km) | 3375 | 6356 | 0.531 |
| Mean density (kg/m3) | 3933 | 5520 | 0.713 |
| Surface gravity (m/s2) | 3.69 | 9.78 | 0.377 |
Mars is smaller and, because of its greater distance from the Sun, cooler. It has seasons similar to Earth's because the
tilt of its rotational axis (axial inclination) to the plane of its orbit about the Sun is about the same as Earth's.
Interestingly, unlike Earth the significant eccentricity (elliptical shape) of the martian orbit means that the seasons on
Mars are also affected by varying distance from the Sun. In the case of Earth, because of its almost circular orbit, our
seasons result simply from the tilt of the Earth's rotational axis.
| Seasons | Earth | Mars |
| (Northern Hemisphere)
(in Earth days) | ( in days) |
| Spring | 93 | 171 |
| Summer | 94 | 199 |
| Fall | 89 | 171 |
| Winter | 89 | 146 |
|
