Oct 18 2004
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(New page: Scientists announced research demonstrating that planets form according to a different process than scientists had previously thought. Comparing recent observations from NASA's [[Spitzer S...)
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Scientists announced research demonstrating that planets form according to a different process than scientists had previously thought. Comparing recent observations from NASA's Spitzer Space Telescope (SST) with data obtained earlier from other satellites, George H. Rieke of the University of Arizona at Tucson had led a team of scientists examining images of the dust clouds surrounding 266 stars of similar size. The prevailing theory of planetary formation held that small rocky planets collide to form larger planets, and the collisions produce a substantial quantity of dust, which steadily fades away over time. However, the team's SST observations had significantly challenged that theory, revealing that some relatively younger stars have no surrounding dust clouds and that older stars tend to have large, bright discs of orbiting dust. The presence of dust clouds around the older stars indicated that planetary collisions continue far after initial planetary formation. The team concluded that planetary formation is a longer and more chaotic process than scientists had previously assumed. (NASA, “Astronomers Discover Planet Building Is Big Mess,” news release 04-347, 18 October 2004; John Noble Wilford, “A New Look at How Planets Are Formed,” New York Times, 19 October 2004.
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