Earth might be the only world in the solar system with complex life, but it certainly isn’t the only world that has experienced volcanism. Thanks to interplanetary missions, scientists have discovered that Mercury, Venus, the Moon, Mars, Io, Enceladus, and maybe Titan have experienced volcanic activity. Io and Enceladus are active right now. But volcanism on these other worlds takes on a wide variety of forms, from the maria on the Moon to the towering shield volcanoes on Mars to the strange cryovolcanoes of the outer solar system. In this 14-minute interview, planetary scientist Rosaly Lopes of the Jet Propulsion Laboratory describes the volcanism of these other worlds, and speculates about the volcanic activity that might exist on planets and moons orbiting other stars. Lopes is the author of Where the Hot Stuff Is, the cover story of the July 2011 issue of Sky & Telescope.