Stuff and Substance
Like the Earth, Mars is a terrestrial planet made chiefly of silicates (minerals containing silicon and oxygen), along with metals and a variety of other elements that compose igneous rock. To determine the interior composition of Mars scientists require information on several parameters; these include the planet’s total mass, its size, the moment of inertia and core mass; the latter has not yet been scientifically established. We do know that Mars, like the Earth, has differentiated contents, with a dense central metallic nickel-iron core surrounded by a silicate-rich mantle and overlain by a solid rocky crust. Mars’ mantle is twice as rich in iron as that of Earth, and it also contains a greater proportion of potassium and phosphorus.