The Cassini spacecraft of NASA along with the Deep Space Network have found evidence that Saturn's moon Enceladus has a supply of underground liquid water; adding evidence to the theory that the moon may have supported microbial life.
In 2005, Cassini found ice and water vapor coming out from the vents of Enceladus' South Pole. This led the researchers to theorize that there might be an underground supply of liquid water below the moon's surface. This study provides the first data on Enceladus' interior.
"The way we deduce gravity variations is a concept in physics called the Doppler Effect, the same principle used with a speed-measuring radar gun," coauthor of the paper and member of the NASA's Jet Propulsion Laboratory (JPL) in Pasadena, Calif., Sami Asmar stated in a press release.
Asmar further explained that as the spacecraft flied around Enceladus, its speed is affected by the moon's gravitational field. Changes in the velocity, measured by radio signals, allow the scientists to measure Enceladus' gravitational force.
The measurements showed that a large ocean, measuring around 10-kilometer deep is present just below a sheet of ice 30 to 40 kilometers thick. This subterranean ocean further supports the theory that the moon may have supported extraterrestrial microbial life. In July 2004, when Cassini reached Saturn, Enceladus was not yet included in the celestial bodies, in our solar system that have the capabilities to support life.
"This then provides one possible story to explain why water is gushing out of these fractures we see at the south pole," David Stevenson of the California Institute of Technology, Pasadena, one of the paper's co-authors, said in a press release.
The spacecraft has been visiting Enceladus for 19 times and it also did three flybys to measure the moon's trajectory. Changes in the spacecraft's speed were also instrumental in detecting other features of the moon such as mountains and other land bodies.
This study was published in the April 3 issue of Science.
