It’s been almost 40 years since humans started exploring Mars up close, with landers and rovers on the surface and probes in orbit. And we’ve gained a fair, though still incomplete, picture of what’s happening on Mars. But what’s happening inside Mars remains a mystery.
Studying the insides of a far-away planet is far from a simple proposition. But the European Space Agency’s Mars Express orbiter has started shedding some light on Mars’ inner workings by cleverly looking inside the planet using radio waves.
We don’t know a lot about the interior of Mars, though we do know the planet's core has a radius somewhere between 930 and 1,300 miles, or about half the planet's total radius of about 2,106 miles. Scientists found this core by observing and measuring the way Mars rotates around its axis. A planet’s movements are influenced by the material inside it, and Mars‘s rotation suggests that there’s something dense at its core with less dense layers stacked between it and the Martian surface.