Nasa’s InSight lander reveals internal structure of Mars

Nasa’s InSight lander has revealed the depth of Mars’s crust and the size of its central core by using data from dozens of marsquakes captured since the probe landed in 2018.

The Seismic Experiment for Interior Structure (SEIS) is a domeshaped instrument that can pick up seismic events thousands of kilometres away. It has recorded 733 distinct marsquakes.

Analysis shows that the Martian crust is between 20km and 37km thick. Below this is the mantle, which extends about 1,500km down to the Martian core, which has been revealed to be 3,660km across. A key finding is that the Martian core is still molten; most scientists had assumed it would be solid.