Volcanic Eruption on Io
NASA's Galileo spacecraft captured this amazing image of an erupting volcano on Jupiter's moon Io as is passed the small moon on February 22, 2000. A number of large volcanic calderas can be seen in this image. The bright orange and yellow spot at the left is an active lava flow that is 37 miles (60 kilometers) long. The dark "L"-shaped dark spot next to it marks the location of an earlier lava flow. The surface of Io is so volcanically active that it is constantly changing. Features that were seen during the earlier Voyager missions were completely different when Galileo arrived.
NASA / JPL / University of Arizona