Diameter: 6,794 km

Density: ~ 3.9 g/cc (if you assume a sphere

* I stole these numbers from my husband’s calculations!

As I understood, Mars, like the Earth, has different layers- core, mantle, crust, and atmosphere. They use a feature called the “moment of inertia factor” to describe the sizes of these layers.

Have you seen those beautiful pictures of Mars taken by the space crafts and the rovers? It’s real fun to visit the Mars page of NASA.