Ice geysers off the south pole of Saturn's moon Enceladus potentially hint at an underground ocean. In three flybys, the Cassini space probe detected a plume of ice and dust shooting thousands of kilometers high above the cracked, buckling crust. Most of the plume falls back down as snow to gild plains already littered with house-size ice boulders. The rest escapes the moon's gravity apparently to later make up Saturn's blue outermost E ring, some 300,000 kilometers wide. Like Yellowstone's Old Faithful, Enceladus's geysers are powered largely by deep-down heat, researchers believe. The heat within the moon that must be setting off the geysers may result from shifting, glacierlike tectonic plates and tidal forces. Such movement suggests that a liquid ocean might lie 10 meters or less below the icy surface. It might even be capable of supporting life, scientists speculate in the March 10 Science.
This article was originally published with the title "Cold Faithful" in Scientific American 294, 5, 29 (May 2006)