Mars is the red planet, a cold desert world with a thin atmosphere, the largest volcano in the Solar System and clear signs that water once flowed on its surface.
At a glance
| radius | 3,390 km (0.532 × Earth) |
|---|---|
| distance from the Sun | 1.52 AU (228 million km) |
| sunlight takes | 12.7 minutes |
| one orbit | 687 days |
| orbit eccentricity | 0.093 |
| reflects | 25% of the sunlight it gets |
Read off the piece’s own catalogue, the same values it draws with.
About Mars
Mars is a rocky planet smaller than Earth, its colour coming from iron oxide, rust, in the dust that covers it. Its atmosphere of carbon dioxide is so thin that liquid water cannot last on the surface today. Yet the ground is carved with dry river valleys, deltas and old lake beds, and orbiters and rovers have found minerals that form only in water: Mars was once wetter, and probably warmer.
The planet holds the largest volcano known, Olympus Mons, and a canyon system, Valles Marineris, that would stretch across a continent on Earth. Its polar caps hold water ice under a seasonal frost of frozen carbon dioxide, and at times dust storms grow until they veil the whole planet. Rovers including Curiosity and Perseverance are still driving across its surface and studying its rocks.
Mars has two small moons, Phobos and Deimos. From Earth it appears as a reddish point that brightens strongly when the two planets pass closest on the same side of the Sun.
What you see in the piece
Mars is drawn with its real surface map, its reds and dark plains lit only by the sunlight it reflects. Close by, you can find Phobos hugging it in a tight, fast orbit; from any other star neither can be seen.
Questions
Why is Mars red?
Its surface dust is rich in iron oxide, essentially rust, which reflects red light more strongly than blue.
Was there water on Mars?
Yes. Dry river valleys, deltas, lake beds and minerals that only form in water show that liquid water once flowed on Mars. Today its water is locked in ice at the poles and underground.