Moon of Jupiter has a surprising icey atmosphere
18 March 2005
by Richard Conan-Davies
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While Cassini was flying by the Saturnian moon Enceladus, the magnetic sensors on board noticed that the magnetic field around this moon was bent a little. The only explanation is that there is an atmosphere on this moon. The moon is a bit too small to hold the atmosphere for very long and so it seems that the atmosphere is being regenerated or replenished. It is thought that perhaps ice volcanic activity may be responsible for this atmosphere because they detected ionised water molecules around the moon. Professor Michele Dougherty, of Imperial College London and lead investigator for the Cassini magnetometer mission explained that "It was a complete surprise to find these signals at Enceladus. These new results from Cassini may be the first evidence of gases originating either from the surface or possibly from the interior of Enceladus," Previous fly-bys in 1981 by Voyager space probe did not show any signs of an atmosphere. About 500 kilometres in diameter Enceladus shows some of the most interesting surfaces of all the icy satellites for example it is the most reflective object in the solar system, reflecting almost 90 percent of the sunlight that hits it. It could make a great place for skiing. |
 This artist concept shows the detection of an atmosphere on Saturn's icy moon Enceladus. The Cassini magnetometer instrument is designed to measure the magnitude and direction of the magnetic fields of Saturn and its moons. During Cassini's two close flybys of Enceladus - Feb. 17 and March 9 - the instrument detected a bending of the magnetic field around Enceladus. Image: PPARC |
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