This video segment adapted from NOVA examines the discovery of active volcanism on Io, one of Jupiter’s innermost moons, and its implications for astrobiology. Volcanologist Ashley Davies describes why Io’s surface is not frozen as would be expected of a smaller moon that is far from the Sun. Instead, Io’s surface is covered by lava flows generated by up to 300 active volcanoes. Davies explains how forces related to Jupiter’s massive gravitational pull on Io have created so much friction inside Io that its core is molten like Earth’s, providing what could be a source of energy for life. The video features real satellite imagery as well as simulations.

This video is available in both English and Spanish audio, along with corresponding closed captions.