Signs of Life Sought in 164 Radio Signals Culled From Space
After cocking their technological ears to the cosmos more than 30 trillion times over the past year and recording 110 million radio signals, the operators of the world’s largest search for extraterrestrial intelligence said Tuesday they have found 164 signals worthy of further investigation.
However, Stuart Bowyer, principal investigator of the UC Berkeley project, said that “if experience is any guide, they will all turn out to be nothing” when he and his colleagues track down the source of the signals.
“These are not extraterrestrial signals, most likely,” cautioned Chuck Donnelly, a computer software engineer for the project, called the Search for Extraterrestrial Radio Emissions from Nearby Developed Intelligent Populations and known by its acronym SERENDIP. “But they stick out from the background noise and we need to check them out.”
Finding “candidate” signals is not unique to this project, which uses the 1,000-foot-wide radio telescope at Arecibo, Puerto Rico. Earlier incarnations of SERENDIP at smaller telescopes and similar projects sponsored by the National Aeronautics and Space Administration and others all sweep the sky for radio signals and go back later to study the strongest signals.
“It usually turns out to be a satellite or a passing airplane or someone turning on their dishwasher that emitted a brief radio signal,” said Donnelly. In the past, UC Berkeley researchers said they traced promising signals back to their own equipment or to nearby airports.
But the possibility exists that some alien civilization could be spewing out radio, television and radar signals as voluminously as earthlings, and that those signals could be detected here.
“We don’t think the Earth is particularly unusual,” said Dan Werthimer, an electrical engineer on the project. “We think the universe is teeming with life.”
Not all life would be intelligent, he added, but some may well be clever enough to generate radio signals strong enough to reach Earth--just as some terrestrial signals have “leaked” into space and become available to any aliens able and willing to listen.
“ ‘I Love Lucy’ and ‘The Ed Sullivan Show’ were broadcast 40 years ago,” Werthimer said. “Those television signals have already gone past 5,000 stars.”
Extraterrestrial beings, if they are out there and listening, are unlikely to be watching terrestrial television. TV signals are not very strong and early signals were particularly weak, so the outer limit of “The Outer Limits” is relatively short--50 light years.
The Berkeley team said that in the first year of looking, they have been able to cover 86% of the sky visible from Puerto Rico. That is equal to about 28% of the entire sky, they said.
Their search so far has concentrated on a relatively narrow frequency band focused on the 4.2 million channels used most often on Earth. Next year, they intend to install computers that can analyze more than 134 million channels.
