Saturns Ring System Has Its Own Atmosphere |
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Written by spacetravel.org
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Tuesday, 23 August 2005 22:50 |
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During its close fly-by of Saturns ring system, instruments on the NASA/ESA/ASI Cassini spacecraft showed that the ring system has its own atmosphere, separate from Saturns atmosphere.
The atmosphere around the rings is very similar to the atmosphere around Jupiters moons Europa and Ganymede. It mostly consists of molecular oxygen.
Saturn's rings are mostly made of water ice mixed with smaller amounts of dust and rocky matter. Solar ultraviolet light drives water molecules off the ring particles. The sunlight then splits them into hydrogen and atomic oxygen. While the hydrogen gas is lost to space, the low temperatures cause the atomic oxygen and any remaining water to be frozen back into the ring material, leaving behind a concentration of oxygen molecules on the ring surfaces. It is possible that ion-neutral chemistry causes molecular oxygen to form, but this is not yet understood very well.
Dr. Andrew Coates of the Mullard Space Science Laboratory at University College, London, who is co-investigator for the Cassini Plasma Spectrometer, believes that the ring atmosphere was probably kept in check by gravitational forces and a balance between loss of material from the ring system and a re-supply of material from the ring particles.
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