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New Findings on Early Solar System by Alexander and Ciesla |
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Wednesday, 25 June 2008 |
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Table: Science.
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New research on the composition of chondrules by Conel Alexander and former postdoctoral fellow Fred Ciesla, now at the University of Chicago, suggests that the dust clouds from which Earth and the inner planets formed were much denser than previously thought. The key to their conclusion, reported in the 20 June issue of Science, is higher-than-expected sodium content of chondrules from the Semarkona chondrite that fell in India in 1940.
Chondrules are thought to have formed by the heating of dust in the early solar system—a heat that would also be expected to deplete them of volatile chemical elements, such as sodium. “Chondrules formed as molten droplets produced by what was probably one of the most energetic processes that operated in the early solar system,” Alexander noted in a CIW press release, “You would expect all the sodium to evaporate and be lost from the chondrules under such conditions; instead, the sodium was retained. The chondrules stayed as effectively closed systems throughout the heating and melting.” The group determined that in order for the molten droplets that formed the chodrules to retain the levels of sodium observed, the initial dust cloud must have been far denser than previously supposed.
For more information, see the CIW Press Release.
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