Jupiter’s largest moon, Ganymede, is an icy world that astronomers believe hides a liquid ocean beneath its surface. That fractured surface, which jumbles old and new features together, has long hinted at a complex history astronomers have sought to understand. Now, a new study to be published in print November 15 in Icarus shows that Ganymede has undergone periods of tectonic processes much like those seen on Earth, bringing to light some of the moon’s tumultuous past.