links for 2010-12-02
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Scientists working at NASA will shortly hold a press conference to announce the discovery of life in an arsenic-rich lake in Yosemite National Park, in the United States. The bacteria, found in the bed of Mono Lake, are believed to exist as a second form of life — using arsenic in cells in place of the phosphorous found in most living cells.
That suggests that they've developed entirely independently from our life, implying that if life has evolved twice on Earth, then it's far more likely to have evolved off Earth too — especially as it's believed by astronomers that among stars similar to the Sun, as many as one in four could have small rocky planets like Earth, at least some of which would occupy the same "goldilocks zone" that Earth exists in — neither too hot, nor too cold, for life to emerge.