
In “Are We Alone In the Universe? New Analysis Says Maybe” (LiveScience, 25 July 2011) Natalie Wolchover reports
Scientists engaged in the search for extraterrestrial intelligence (SETI) work under the assumption that there is, in fact, intelligent life out there to be found. A new analysis may crush their optimism.
Hey, Wolchover, have faith! they’ve been breathing optimism for decades. It’s all they’ve got and it’s all they know.
Their optimism relies on one factor in particular: In the equation, the probability of life arising on suitably habitable planets (ones with water, rocky surfaces and atmospheres) is almost always taken to be 100 percent. As the reasoning goes, the same fundamental laws apply to the entire universe, and because those laws engendered the genesis of life on Earth – and relatively early in its history at that – they must readily spawn life elsewhere, too. As the Russian astrobiologist Andrei Finkelstein put it at a recent SETI press conference, “the genesis of life is as inevitable as the formation of atoms.”
But in a new paper published on arXiv.org, astrophysicist David Spiegel at Princeton University and physicist Edwin Turner at the University of Tokyo argue that this thinking is dead wrong. Using a statistical method called Bayesian reasoning, they argue that the life here on Earth could be common, or it could be extremely rare – there’s no reason to prefer one conclusion over the other. With their new analysis, Spiegel and Turner say they have erased the one Drake factor scientists felt confident about and replaced it with a question mark.
No one in here but us chickens then … ?
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