Portrait of Io

Jupiter's volcanic moon Io

Here’s a beautiful high-resolution portrait of Io by Jason Perry, assembled from Galileo images taken in 1999 and posted to The Gish Bar Times, his website dedicated to Jupiter’s volcanic moon. Check out the link for a labeled version of the image as well as details on how it was created.

Slightly larger than our Moon, Io is the innermost of Jupiter’s four largest “Galilean” moons (the others being Europa, Ganymede and Callisto) and is unique in that it is covered in constantly-erupting volcanic vents and depressions, seen above as dark spots surrounded by areas of ejected material. With over 400 known volcanoes, Io is the most geologically active world in our solar system other than our own planet.