|MadSci Network: Astronomy|
The Hubble Space Telescope takes occasional; pictures of the outer planets- in the past 7 years it has imaged all of them, showing changes in the clouds circling Neptune, and new volcanos ofn jupiter's moon IO. The principal investiagtions of the outer planets, however, have been carried out since Dec 1995 by the spacecraft Galileo, which was launched in 1989, and has now been in orbit around Jupiter since Dec 1995, at which time it launched also an atmospheric probe into Jupiter's atmosphere, which operated for some 57 minutes before the atmospheric pressure destroyed it. The principal discoveries withthe probe were high winds of several hundred miles per hour, and a lower content of water vapour than expected. Most importantly, howerver, Galileo is on an extended series of flybys of the four galilaen satellites, from which the main news is that Europa, and now Callsto are VERY LIKELY endowed with liquid water oceans beneath a constantly changing surface layer of thin ice, tidally heated by Jupiter's massive pull.The result was a two years extended Galileo mission(GEM), now in progress. This could well be followed within 10 years, by a Europa orbiter, and, later in the new century, a lander; Europa has become the number one candidate for extraterrestrial life, to the presumed astonishment of Mars aficionados! The NASA/ESA spacecraft Cassini, is en route to Saturn with a lander, Huyghens, destined for the large satellite, Titan, whose cloudy atmosphere is thought to conceal an ocean of methane, bordered by waxy cliffs of methane and organic chemical cliffs! The Hubble Space telescope, meanwhile, has obtained the first clear images of Pluto and Charon as a double planet, and has seen lightning bolts in n Saturn's atmosphere of gigantic size. Also, the discovery of a new class of objects, the Centaur s in the Kuiper Belt, are being discovered in the lonely regions beyond Neptune and Pluto- our solar system has nearly doubled in size with the discovery, since 1992, of some 32 of these bodies, ranging from 100-200 kilometres in size. These are 8-9 light hours from Earth
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