4. Jupiter's Moon, Io

4. Jupiter's Moon, Io

Courtesy of NASA/JPL/University of Arizona

http://photojournal.jpl.nasa.gov/catalog/PIA02550


An active volcanic eruption on Jupiter's moon Io was captured in this image taken on February 22, 2000 by NASA's Galileo spacecraft. White and orange areas on the left side of the picture show newly erupted hot lava. The two small bright spots are sites where molten rock is exposed to the surface at the toes of lava flows. The larger orange and yellow ribbon is a cooling lava flow that is more than 60 kilometers (37 miles) long. The orange, yellow, and white areas show temperature variations, orange being the coolest and white the hottest material. Dark deposits surrounding the active lava flows were not there during a November 1999 flyby of Io.
The lava on Io is much hotter than lava produced on Earth. Io is considered to the be the most volcanic body in the Solar System because of the amount of heat that is produced by its volcanoes.
This image is about 250 km (155 miles) across.