<P> The composition of Mars covers the branch of the geology of Mars that describes the make - up of the planet Mars . </P> <P> Also like Earth, Mars is a differentiated planet, meaning that it has a central core made up of metallic iron and nickel surrounded by a less dense, silicate mantle and crust . The planet's distinctive red colour is due to the oxidation of iron on its surface . </P> <P> Much of what we know about the elemental composition of Mars comes from orbiting spacecraft and landers . (See Exploration of Mars for list .) Most of these spacecraft carry spectrometers and other instruments to measure the surface composition of Mars by either remote sensing from orbit or in situ analyses on the surface . We also have many actual samples of Mars in the form of meteorites that have made their way to Earth . Martian meteorites (often called SNC's, for Shergottites, Nakhlites, and Chassignites--the groups of meteorites first shown to have a martian origin) provide data on the chemical composition of Mars' crust and interior that would not otherwise be available except through a sample return mission . </P>

What is the core of mars made of
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