Saturn's Moon Dione May Have Once Had Subsurface Ocean

Posted on June 2, 2013

Saturn Moon Dione


Saturn's moon Dione may have once been home to a subsurface ocean. Scientists found evidence that Dione may have been active in the past after studying close-up images of Janiculum Dorsa, a 500-mile-long (800-kilometer long) mountain on the moon. NASA astronomers also say Dione could still be active. The scientists say Cassini's magnetometer detected a faint particle stream coming from the moon and images have shown evidence for a possible liquid or slushy layer under its rock-hard ice crust.

Bonnie Buratti of NASA's Jet Propulsion Laboratory in Pasadena, Calif., who leads the Cassini science team that studies icy satellites, said in a statement, "A picture is emerging that suggests Dione could be a fossil of the wondrous activity Cassini discovered spraying from Saturn's geyser moon Enceladus or perhaps a weaker copycat Enceladus. There may turn out to be many more active worlds with water out there than we previously thought."

Map showing topography of Janiculum Dorsa


This image above shows the topography of Janiculum Dorsa created using data obtain by Cassini. Color denotes elevation, with red as the highest area and blue as the lowest.

Noah Hammond, based at Brown University, is the lead author of a paper about the mountain published in Icarus. Hammond says, "The bending of the crust under Janiculum Dorsa suggests the icy crust was warm, and the best way to get that heat is if Dione had a subsurface ocean when the ridge formed."

Photo: NASA/JPL/Space Science Institute(1st)/NASA/JPL-Caltech/SSI/Brown (2nd)