Artist's impression of the interior of Mars
Artist's impression of the interior of Mars
With a diameter of about 6800 kilometres, Mars is only half as large as Earth. Its internal structure is not well known. With the gephyisical InSight lander planned for 2016/17, NASA expects to gain new insights into the structure and thermal evolution of the planet. Mars has, much like all rocky planets, a shell structure. The relatively small, hot iron core is surrounded by a presumably largely solidified shell of iron-rich, siliceous rocks. There is evidence that Mars, in its early history had magnetic field (probably a weak one).
