San Antonio (TX) - Saturn's moon Enceladus may have an ocean of water, kept liquid by ammonia, say scientists.
Writing in Nature, a team led by William Lewis of the Southwest Research Institute in San Antonio, Texas say that ammonia could keep underground oceans from freezing despite temperatures of -148 degrees.
The Cassini spacecraft spotted plumes of gas emanating from fractures in the moon's surface during a flyby of Enceladus during its mission in 2005. Now, Lewis' team reckons ammonia and other compounds in the plumes act as antifreeze, keeping water liquid beneath an icy crust. The plumes escape the moon's gravity and become part of Saturn's 'E' ring.
"We conclude, from the overall composition of the material, that the plume derives from both a liquid reservoir as well as from degassing, volatile-charged ice," says Lewis.
"The measurements reported here, together with observations of sodium salts in E-ring particles and the gas velocities in the plumes, provide compelling evidence that a liquid water reservoir exists - or recently existed - in the interior."