May 16, 1994: The giant gaseous planet Jupiter and its moon Io are featured in this Hubble telescope picture.
One of Io's many volcanoes, Pele, appears as a dark spot surrounded by an irregular orange oval on the lower part of the moon. The orange material has been ejected from the volcano and spread over a huge area. Though the volcano was first discovered by the Voyager spacecraft, the distinctive orange color of the volcanic deposits is a new discovery.
Credit: John Spencer, Lowell Observatory; NASA