March 2, 2012
Cassini Detects Oxygen On Saturn’s Moon Dione
Researchers report this week in the journal Geophysical Research Letters that NASA's Cassini spacecraft has detected oxygen on one of Saturn's moons.
They said their finding increases the likelihood of finding the ingredients for life on one of the moons orbiting gas giants.The ice moon, Dione, has no liquid water and does not have the proper conditions to support life, Andrew Coates of the University College London said. However, he said that it is possible that other moons of Jupiter and Saturn do.
"Some of the other moons have liquid oceans and so it is worth looking more closely at them for signs of life," Coates told BBC.
Instruments on board the Cassini spacecraft detected a thin layer of oxygen around the moon about two years ago.
The discovery suggests there is a process at work around Saturn and Jupiter in which oxygen is released from their icy moons.
The researchers said that it seems that highly charged particles from the planet's powerful radiation belts split the water in the ice into hydrogen and oxygen.
“Dione's exosphere is very thin - compared to Earth's atmosphere the density is about a million billionth," Dr Geraint Jones ov UCL Mullard Space Science Laboratory and co-author of the paper, said in a press release. "The exciting thing is that there is oxygen - and the oxygen may be being recycled via the surface."
Another Saturn moon, Enceladus, is thought to contain a liquid ocean below its surface, as well as Jupiter's Europa, Callisto and Ganymede.
“It now looks like oxygen production is a universal process wherever an icy moon is bathed in a strong trapped radiation and plasma environment," Coates said in a press release.
“Energetic particles hit the icy surface, the hydrogen is lost and molecular oxygen remains as an exosphere. We now know that this happens at Saturn's moons as well as Jupiter's - and it may well occur in extrasolar planetary systems too.”
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