Highly Sensitive New Allen Telescope
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The universe seems determined to maintain radio silence, so
SETI astronomers involved in the search for extraterrestrial
intelligence are broadening their hunt and looking for light
signals directed at Earth. This method has been tried before
but previous experiments have been plagued by false alarms.
?This is perhaps the most sensitive optical Seti search yet
undertaken,? says Frank Drake, chairman of the board of the
privately funded, non-profit Seti Institute. Drake, who in 1960
conducted the first modern hunt for evidence of
extraterrestrial intelligence, is usually associated with radio
Seti, an approach in which large antennas are connected to
specialized, multi-million channel receivers. ?This is different,?
he says. ?We are looking for very brief but powerful pulses of
laser light from other planetary systems, rather than the
steady whine of a radio transmitter.? They have already
examined about 300 individual star systems, as well as a few
star clusters.
Light detection has the disadvantage of only being able to
detect a signal deliberately targeted at Earth, but it is less
susceptible than radio to terrestrial interference. The new
system uses a trio of light detectors and was designed and
built by researchers at the University of California. Other
systems have used fewer detectors and have consequently
suffered from frequent false alarms.
Another optical Seti project, a collaboration between
Princeton and Harvard Universities, is working on installing a
light detector, while the optical Seti project at Columbus,
Ohio, already operates such a system.
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