Washington, Mar 3 (): NASA’s Cassini spacecraft detected oxygen around one of Saturn’s icy moons, Dione. An international team, led by Los Alamos National Laboratory, says it has discovered molecular oxygen ions in the upper-most atmosphere of Dione, one of the 62 known moons orbiting Saturn, thanks to NASA’s Cassini spacecraft, the ‘Geophysical Research Letters’ journal reported.
The international mission made the discovery using combined data from the Cassini Plasma Spectrometer (CAPS), which includes a sensor designed and built at the University College London’s (UCL) Mullard Space Science Laboratory.
According to co-author Andrew Coates of University College London, Dione has no liquid water and so does not have the conditions to support life. But 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,” Prof Coates said.
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.
As Dione orbits Saturn every 2.7 days, Dione is bombarded by charged particles (ions) emanating from Saturn’s very strong magnetosphere. These ions slam into the surface of Dione, displacing molecular oxygen ions into Dione’s thin atmosphere through a process called sputtering.
“It now looks like oxygen production is a universal process wherever an icy moon is bathed in a strong trapped-radiation and plasma environment,” said Andrew Coates from UCL. “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 extra solar planetary systems, too.”
This most recent discovery will no doubt give a boost to scientists lobbying for sending missions to the gas giant’s satellites to search for alien life as, like the presence of liquid water, the presence oxygen could support microscopic life forms on other, more habitable moons.