An artist's depiction of the possible interior of Saturn's moon Enceladus, with an ocean at its south pole beneath a think sheet of ice.NASA/JPL-CALTECHThe search for extraterrestrial life in the Solar System has been further focused by the confirmation that liquid water exists beneath the icy outer surface of Saturn’s tiny moon, Enceladus. With help from NASA’s Cassini spacecraft, which has been exploring Saturn and its moons since arriving there in 2004, researchers have mapped the gravitational field around the 300-mile-wide moon and found that a body of liquid water covering an area similar to that of Lake Superior lies beneath the ice at its south pole. They published their findings today (April 4) in Science.
“What we’ve done is put forth a strong case for an ocean,” study coauthor David Stevenson, a professor of planetary science at CalTech, told The New York Times.
Stevenson and his colleagues noted that Enceladus’s gravity was weaker at its south pole, likely because of a depression in the underlying rock. But the gravity was somewhat higher than they would expect from an empty depression covered by the moon’s planet-wide ice sheet. “Then you say, ‘A-ha, there must be compensation,’” Stevenson told the Times. “Something more dense under the ice. The natural candidate is water.”
Apparently, the gravitational forces that Enceladus experiences as it orbits Saturn and interacts with a neighboring moon, Dione, create friction and heat that melts some of its icy coat to ...
