A Water Ocean On Enceladus

Scientists have discovered that icy-surfaced Enceladus, a small moon of Saturn, appears to have a regional ocean of subsurface liquid water at its south pole (Science 2014, DOI: 10.1126/science.1250551). Enceladus may be joining a growing list of solar system bodies—Mars, Jupiter’s moon Europa, and Saturn’s moon Titan—that have or have had liquid water and are or were potentially hospitable for life. Luciano Iess of Italy’s Sapienza University of Rome and colleagues base their conclusion on gravity observations from NASA’s Cassini spacecraft, which show there is more mass at the moon’s south pole than is indicated by what they see at the surface. Water, which is denser than the ice at Enceladus’s surface, would fit the bill. Space scientists have suspected that Enceladus has a liquid subsurface ocean since the mid-2000s, when Cassini observed jets of water spouting from fractures in the moon’s surface.