| Mean distance from Sun: | 1.52 Astronomical Units 228,000,000 km |
|---|---|
| Diameter: | 6,800 km |
| Mass: | 0.53 Earths |
| Density: | 3.9 grams per cubic centimeter |
| Surface temperature: | 72 F to -271 F |
| Orbital period: | 686 days |
| Rotational period: | 24 hours, 37 minutes |
Mars appears reddish in our sky, even to the naked eye. This is caused by the rich content of rust (iron oxide) in the top soil. In the Martian springtime the surface of the planet changes color due to seasonal winds covering and uncovering darker surfaces of reddish dust. Mars has two small moons - Phobos is the larger and zips around Mars in only 7 1/2 hours. Deimos, the smaller moon, takes 30 hours to orbit.