Optical astronomers scan the sky for signs of life.
The search for extraterrestrial intelligence (SETI) will ramp up in coming months as two dedicated facilities come online — one to look, the other to listen.
A team led by physicist Paul Horowitz of Harvard University will begin scanning the skies this week for flashes of light from alien civilizations. Most SETI searches have been at radio wavelengths, but theorists surmise that extraterrestrials might also shine laser beacons visible from a few thousand light years away.
This will be the first optical SETI project to scan the entire sky, or at least all that can be seen from the Oak Ridge Observatory in Harvard, Massachusetts, where a 180-centimetre telescope has been installed. The $50,000 instrument was paid for by the Planetary Society, a grassroots group of space enthusiasts, and will record flashes briefer than a nanosecond. No known natural process causes such flashes. The all-sky search requires 200 nights of clear viewing, and is expected to take several years.
Meanwhile, at the Hat Creek Radio Observatory in northern California, the first ten dishes of the privately funded Allen Telescope Array are due to be demonstrated later this month, says Peter Backus, observing programmes manager at the SETI Institute in Mountain View, California. With money from Microsoft alumni Paul Allen and Nathan Myhrvold, the institute, working with Berkeley, is building an array of 350 six-metre radio dishes dedicated to SETI. The entire array will eavesdrop on nearly a million stars for hints of intelligence.
Managers hope to have 42 antennas working by July. The first scan will be of a narrow swathe of the Milky Way's centre.
Font: Nature vol 440, 853 (13 April 2006)
