SPL RF Mar 2018

Diagram showing the interior of the terrestrial planet Mars. The outermost layer is the crust, which is about 30 miles (50 km) deep on average - quite thick compared to Earth's. The convecting mantle, immediately below the crust, is a thick shell of silicate rocks. Lastly there is a substantial core which occupies up to 52 per cent of the planet's radius. Like the Earth's it's probably made up mostly of nickel-iron with about 17 percent sulfur