Gravity maps of Enceladus reveal liquid water ocean beneath satellite’s south pole
JPL-Caltech/Space Science Institute, NASA
Scuba divers take note: an underground ocean awaits on a moon of Saturn. Astronomers have, for the first time, measured the depth and extent of a subsurface sea on the ice-covered moon Enceladus. The findings shore up the notion that an underground reservoir feeds the moon’s ice geysers and raise questions about Enceladus’ habitability.
For a long time, astronomers thought the 500-kilometer-wide Enceladus was an unchanging, dead world. But the Cassini spacecraft, which arrived in 2004, found an active moon. Geysers shoot particles of salty water ice through fissures that dot the southern hemisphere. The fissures expand and contract in rhythm with the tides of Saturn (SN Online: 7/31/13). Heat wells up from the moon’s interior through the cracks. Putting these characteristics together, many astronomers suspected that a sea of liquid water lurked beneath the ice. But