Views of the Solar System Welcome to the Planets Mars is similar to Earth in many respects. Its rotation period is just over 24 hours. It is only about 1.5 times further from the Sun.
Clouds occasionally are visible in the atmosphere.
It has polar caps which change in size with season. It is thought to have a metallic core like Earth. This thin atmosphere provides a poor blanket. It is so cold at the poles that CO 2 can solidify. In the Martian summer the CO 2 frost retreats exposing small residual water ice caps.