This enhanced-color image of Enceladus byThe ocean beneath the icy shell of Saturn’s moon Enceladus rises nearly to the surface in some places, a new study suggests.
Measurements by NASA’s Cassini spacecraft indicate that as little as 1.2 miles (2 kilometers) of ice may cover the ocean in the moon’s south polar region, according to the study.
Credit: NASA/JPL/Space Science Institute
“This discovery opens new perspectives to investigate the emergence of habitable conditions on the icy moons of the gas giant planets,” Nicolas Altobelli, the European Space Agency’s (ESA) project scientist for the Cassini-Huygens mission, said in a statement. [Photos of Enceladus, Saturn’s Geyser Moon]
“If Enceladus’ underground sea is really as close to the surface as this study indicates, then a future mission to this moon carrying an ice-penetrating radar sounding instrument might be able to detect it,” added Altobelli, who was not involved in the new study.
In 2005, Cassini discovered jets of water ice, organic molecules and other material blasting into space from four large “tiger stripe” fissures near Enceladus’ south pole. Scientists think this stuff is coming from the underground ocean, which is believed to be in contact with Enceladus’ rocky mantle.
Such discoveries have led most astrobiologists to regard Enceladus as one of the solar system’s best bets to host alien life, along with the Jupiter moon Europa (which also harbors an ocean beneath its ice shell).
For the new study, the researchers analyzed observations that Cassini made of a 310-mile-long (500 km) swathe of ground just north of the tiger stripes. The probe made these observations using its radar instrument during a November 2011 flyby of Enceladus. (The mechanics of the flyby prevented measurement of the tiger-stripe area itself, ESA officials said.)
The radar data suggest that temperatures a few meters below the surface in this area are between minus 350 degrees Fahrenheit and minus 370 degrees Fahrenheit (minus 213 to minus 223 degrees Celsius). That’s extremely cold, obviously, but it’s up to 36 degrees Fahrenheit (20 degrees C) warmer than scientists had thought, team members said. NASA’s Cassini spacecraft features the bluish “tiger stripe” fractures near the Saturn moon’s south polar region.