Water Vapor May Surround Enceladus |
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Written by spacetravel.org
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Saturday, 07 May 2005 00:03 |
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An atmosphere that may contain water vapor has been discovered around Enceladus, one of Saturns moons. NASAs Cassini spacecraft detected the atmosphere during flybys of Enceladus on February 17 and March 19, 2005, when it sensed that magnetospheric plasma was being slowed and deflected by something in the moons vicinity. Cassini also detected magnetic field oscillations caused by the presence of ionized molecules. Scientists have concluded that these molecules are most likely water, based on the frequency of the oscillations.
It has been suggested that eruptions from ice volcanoes or geysers on the surface may be causing water vapor to collect in the atmosphere. Such eruptions may also explain Enceladus high albedo. Enceladus, with a 90 percent albedo, is the most reflective object in the solar system.
The only other moon of Saturn known to have an atmosphere is Titan. Unlike Titan, which is large enough to maintain an atmosphere even more dense than Earths, Enceladus is only 500 kilometers in diameter and could not hold onto an atmosphere very long without frequent geologic activity, such as eruptions, to replenish it.
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