21 January 2010

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Thursday 21 January 2010


20 January 2010

Image of the day




22 January 2010



This day in space history

On 21 January 1908, Bengt Strömgren was born in Copenhagen, Denmark. Strömgren did important research in stellar structure in the 1930s, but he is best known for his theory of the ionised gas clouds around hot stars. He found relations between the gas density, the luminosity of the star, and the size of the "Strömgren sphere" of ionised hydrogen around it.

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December 2009
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January 2010
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February 2010
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March 2010
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