Io's Largest Volcano, Loki, Erupts Every 500 Days. Any Day Now, It'll Erupt Again.

Jupiter’s moon Io is in stark contrast to the other three Galilean moons. While Callisto, Ganymede, and Europa all appear to have subsurface oceans, Io is a volcanic world, covered with more than 400 active volcanoes. In fact, Io is the most volcanically active body in the Solar System. Io’s largest volcano is named Loki, …