Io

This Voyager 2 picture of Io was taken in ultraviolet light on the evening of July 4, 1979, at a range of 4.7 million kilometers (2.9 million miles). The bright spot on the right limb is one of the volcanic eruption plumes first photographed by Voyager 1. The plume is more than 200 kilometers (124 miles) high. The volcano apparently has been erupting since it was observed by Voyager 1 in March. This suggests that the volcanos on Io probably are in continuous eruption.