This was
your sky.

Galileo Views Io Eruption

Io's surface is very active, with geyser-like eruptions from volcanoes. Both Voyager spacecraft saw these plumes in 1979, and Galileo's camera spotted them again in 1996. The blue plume, magnified in the inset, rises 60 miles above the surface from Ra Patera, a large shield volcano. Its blue color comes from condensing and freezing sulfur dioxide gas.