New research suggests Europa may have had (and perhaps still has) seafloor volcanoes.
Source: NASA/JPL-Caltech/Michael Carroll
Published: September 8, 2021

This illustration depicts scientists' findings about what the interior of Jupiter's moon Europa may look like: an iron core, surrounded by a rocky mantle believed to be in direct contact with a vast, internal ocean. New research and computer modeling show that volcanic activity may have occurred on the seafloor of Jupiter's moon Europa in the recent past – and may still be happening. The new work shows how internal heat produced by tides—warping of Europa's shape as it changes distance from Jupiter during its orbit—could partially melt its rocky layer, a process that could feed volcanoes on the ocean floor. The recent modeling of how this internal heat is produced and transferred is the most detailed and thorough examination of the effect this heating has on the moon.