Mars contains surprise layer of molten rock

In the interior of Mars, a layer of molten rock envelops the liquid-metal core, which is smaller than previously thought. Scientists discovered the unique layer by analysing the seismic energy that vibrated through the planet after a meteorite impact. The seismic waves’ speed depends on the types of material that they are travelling through. The molten-rock layer might be left over from a magma ocean that once covered the planet.