Tuesday, January 09, 2007

Searching a 100 million stars for something like us

A pair of astrophysicists want to divert a new radio telescope to identify radio-emitting civilizations:
Eavesdropping on the Universe

...The MWA-LFD is a radio telescope designed to detect and characterize highly redshifted 21-centimeter emission from hydrogen molecules in the early universe. Its key scientific goal is to create a three-dimensional map of ionized "bubbles" that formed as the first quasars and galaxies flooded space with ultraviolet light billions of years ago. ...

.... Loeb and Zaldarriaga calculate that by staring at the sky for a month, the MWA-LFD could detect Earth-like radio signals from a distance of up to 30 light-years, which would encompass approximately 1,000 stars. More powerful broadcasts could be detected to even greater distances. Future observatories like the Square Kilometer Array could detect Earth-like broadcasts from 10 times farther away, which would encompass 100 million stars.
I't's hard to get too excited about surveillance of 1000 stars. It seems unlikely that civilizations would radio-emit like us for long, the odds of catching a 100 year slice of radio emission in the 3 billion year slice of a habitable planet is pretty low. A hundred million stars though ... That would be about the right order of magnitude. So maybe in forty years ...

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