Volcanism on Io, a moon of Jupiter, produces lava flows, volcanic pits, and plumes of sulfur and sulfur dioxide hundreds of kilometres high. This volcanic activity was discovered in 1979 by Voyager 1 imaging scientists. Observations of Io by passing spacecraft (the Voyagers, Galileo, Cassini, and New Horizons) and Earth-based astronomers have revealed more than 150 active...
