NASA's Cassini identifies oxygen atmosphere on Saturn moon

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Monday, 05 March 2012 15:15

March 5, 2012

Researchers said recently that they had detected oxygen in the Solar System, prompting a spirited discourse over whether there could be life contained outside of Earth.

NASA said that its Cassini spacecraft identified an oxygen atmosphere on Dione, one of Saturn's moons. Scientists from the space agency noted that human beings would not be able to survive on the moon's surface – its atmosphere is 5 trillion times less dense than the air at Earth's surface – but they said the findings are significant.

Cassini detected an ultrathin layer of oxygen ions on Dione, a deposit whose oxygen concentration was approximately equivalent to conditions about 300 miles above Earth. Space.com reports that on Dione there is just one oxygen ion for every 0.67 cubic inches of space. Researchers conceded that although the figure is slight, it is still substantial enough to qualify as an atmosphere.

The BBC reports that researchers contended Cassini's latest findings bolstered their belief that moons orbiting gas giants such as Saturn could hold critical substances necessary for sustaining life. The scientists, who published their results in Geophysical Research Letters, said that Dione does not have liquid water. However, they said other moons of both Jupiter and Saturn could potentially be home to liquid water.

"Some of the other moons have liquid oceans and so it is worth looking more closely at them for signs of life," University College London professor and study co-author Andrew Coates said. "These are fascinating places to look for signs of life."

Scientists currently believe that Enceladus, one of Dione's sister moons, could house a liquid ocean, albeit one hidden beneath its icy surface. Researchers also reckon that three of Jupiter's moons, Europa, Ganymede and Callisto, could similarly contain liquid oceans.

Scientists are continuing to lobby officials from both NASA and the European Space Agency to develop spacecraft capable of traveling to such sites. Researchers supporting such initiatives said that such projects would enable them to more effectively and efficiently determine whether the moons could harbor life. Nevertheless, amid sweeping budget cuts to both agencies, it would be difficult to allocate the necessary funding for such projects, experts say.

Dione is one of Saturn's smaller moons, measuring only 698 miles in width. It orbits Saturn once every 2.7 days at roughly 234,000 miles, which is nearly equal to the distance between Earth and its moon, according to NASA scientists.

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