The Interior of Mars

Abstract

Despite knowing a considerable amount about the surface of Mars, relatively little is known about the interior with any degree of certainty. This is largely a function of the very limited geophysical and geochemical data that is available. What is known is the mean density which is 3930 kg m^-3, and the mass which is only about one-tenth that of the Earth. When the density value is corrected for the effect of self-compression in Mars’ gravity field, the figure is seen to be smaller (3730kgm^-3) than that for either Venus or the Earth. This density deficit traditionally has been explained in one of two ways: either Mars always contained less iron than the Earth (Urey, 1952), or the total amount of iron was roughly the same for all the terrestrial planets (bar Mercury) and the carbonaceous chondrites, but on Mars it was in a more oxidized state (Ringwood, 1966).