Wednesday, December 11, 2013

Sounds kind of improbable to me...

Life possible in the early Universe 

Aliens might have existed during the Universe’s infancy. A set of calculations suggests that liquid water — a pre­requisite for life — could have formed on rocky planets just 15 million years after the Big Bang.

Abraham Loeb, an astrophysicist at Harvard University in Cambridge, Massachusetts, has realized that in the early Universe, the energy required to keep water liquid could have come from the cosmic microwave background, the afterglow of the Big Bang, rather than from host stars. Today, the temperature of this relic radiation is just 2.7 kelvin, but at an age of around 15 million years it would have kept the entire Universe at a balmy 300 kelvin, says Loeb, who posted his calculations to the arXiv preprint server this month (http://arxiv.org/abs/1312.0613).

Loeb says that rocky planets could have existed at that time, in pockets of the Universe where matter was exceptionally dense, leading to the formation of massive, short-lived stars that would have enriched these pockets in the heavier elements needed to make planets. He suggests that there would have been a habitable epoch of 2 million or 3 million years during which all rocky planets would have been able to maintain liquid water, regardless of their distance from a star. “The whole Universe was once an incubator for life,” he says.
 But as one critic says further down in the article:
Christopher Jarzynski, a biophysicist at the University of Maryland, College Park, is not convinced that life could exist in a uniformly warm Universe. Life on Earth depends thermo­dynamically not only on the heat source of the Sun, but also on the cold cosmic microwave background, which provides a heat sink, he notes. “Life feeds off this,” he says. And Alexander Vilenkin, a cosmologist at Tufts University in Medford, Massachusetts, says that a few million years is too short a time to produce intelligent life.
 Anyway, if true, and aliens did evolve then, it certainly sets up well the idea that our alien overlords (like the ones in 2001 A Space Odyssey) are very old indeed. 

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