Io: A Unique World in our Solar System

Jupiter’s moon Io is the most volcanically active world in our Solar System. Eruptions on Io sustain its atmosphere, feed the Jovian magnetosphere, and contaminate neighboring moons. This unique volcanic and tectonic activity is powered by tidal heating, caused by its gravitational interactions with Jupiter and other moons. The silicate crust of Io is coated with sulfur compounds, and its interior—one that is exceptional for an outer-planet moon—is composed of a metallic core and a silicate mantle that may host a magma ocean. Such spectacular large-scale volcanism and high heat flow provide insights into the processes that shaped all terrestrial bodies. Future exploration of Io would answer key questions and herald a new era of discoveries about the evolution of terrestrial planets and moons within our Solar System and beyond.