On Earth, quakes are caused by the motion of the tectonic plates. Quakes also happen on the Moon and Mars without them, and Chris is curious to find out how they occur as well as to listen to one of these outer-world quakes. 

Listen on Apple Podcast or on your favourite podcast player through Anchor.

Main image Credit: An artist illustration of the InSight lander on Mars. InSight, short for Interior Exploration using Seismic Investigations, Geodesy and Heat Transport, is designed to give the Red Planet its first thorough checkup since it formed 4.5 billion years ago. NASA/JPL-Caltech