Bruce Murray Space Image Library
Volcanic plumes on Io
A short-exposure image captures the surface features of the volcanically pock-marked moon, while a longer-exposure image reveals two plume fountains silhouetted against black space. Enhancing the contrast of the longer-exposure image brings out more detail in the plumes, which are from volcanoes named Tvashtar and Prometheus. Two bright conical shapes visible on the terminator (day/night boundary) are unnamed mountains.