3. Jupiter's Moon, Callisto
4. Jupiter's Moon, Callisto
3. Jupiter's Moon, Callisto

3. Jupiter's Moon, Callisto

Courtesy of NASA/JPL

http://photojournal.jpl.nasa.gov/catalog/PIA02277


This picture of a multi-ring basin on Jupiter's icy moon Callisto is similar to the large circular impact basins that dominate the surface of the Earth's Moon and planet Mercury. The inner parts of these basins are generally surrounded by radially ejecta and several mountainous ring structures that are thought to have formed during the impact event. The ring structures on the Moon and Mercury have been likened to ripples produced on a pond by a rock striking the water. The great number of rings observed around this basin on Callisto is consistent with its low density layer below the surface. Examination of close-up images suggest that there could be an ocean of liquid water beneath this icy surface.