Wednesday, March 16, 2005

Cassini probe detects Enceladus atmosphere

LOS ANGELES, California (Reuters) -- The space probe Cassini discovered a significant atmosphere around Saturn's moon Enceladus during two recent passes close by, the Jet Propulsion Laboratory said on Wednesday.
Scientists speculate the atmosphere comes from volcanoes, geysers or some other kind of sub-surface activity, JPL said in a statement.
"These new results from Cassini may be the first evidence of gases originating either from the surface or possibly from the interior of Enceladus," said Dr. Michele Dougherty, principal investigator for the Cassini magnetometer and professor at Imperial College in London.
Cassini made passes on February 17 and March 9 and discovered the atmosphere using a magnetometer, which discovered a magnetic field on the moon.
Because gravity is weak on Enceladus, a continuous source is needed to maintain the atmosphere, JPL said. The 310-mile-wide (500-km-wide) moon is icy and considered the most reflective object in the solar system, bouncing back about 90 percent of the sunlight that hits it.
Titan, another moon of Saturn, also has a substantial atmosphere. The European probe Huygens, which went to Saturn piggy-back on Cassini, landed on Titan in January.
Cassini-Huygens is a joint venture of NASA, the European Space Agency and the Italian Space Agency. Scientists at JPL designed, developed and built Cassini.

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