History of SETI

SETI, the Search for Extraterrestrial Intelligence, began early in the Space Age. Only two years after the launch of Sputnik, two physicists at Cornell University, Philip Morrison and Giuseppe Cocconi, published an article in the journal Nature in which they noted the relative ease with which radio messages could be sent between the stars. This led to the remarkable suggestion that it might be possible to detect the presence of extraterrestrial civilizations using radio telescopes.

The two physicists also proposed that one part of the electromagnetic spectrum - the so-called microwave region - was particularly effective for communication across space. Not only is this the naturally quietest part of the band, but it also boasts several natural emission lines that would be studied by radio astronomers of any advanced society. It seemed to make sense to suggest that cosmic phone calls would be made in at microwaves.

At the same time, Frank Drake - a young radio astronomer working in West Virginia - independently fashioned an experiment to search for signals from extraterrestrial intelligence. On April 8, 1960, he aimed a 26-meter radio telescope at the National Radio Astronomy Observatory in Green Bank at two nearby stars. Sweeping his single-channel receiver up and down the microwave band, Drake spent several weeks listening for extraterrestrial signals. Known as Project Ozma, this was the first modern SETI search.

Since then there have been more than 98 SETI projects around the world, some quite short and others spanning many years. In the 1970s, NASA became interested in the prospect of a SETI program and in 1988 finally began work on making that happen. Observations began in 1992 on the 500th anniversary of Columbus' arrival in the New World. One year after observations began, the US Congress cancelled the program.

The SETI Institute in California, which was organized in 1984 to facilitate scientific research and educational programs related to life in the universe, managed to find private funding to continue at least part of the NASA SETI Program. The Institute's search of nearby star systems is known as Project Phoenix. The first Phoenix observations - 2,600 hours over almost six months - took place at the 64-meter Parkes radio telescope in New South Wales, Australia.

Project Phoenix observed for a total of 100 days over a five and a half year period at the world's largest radio telescope, the 305 meter Arecibo dish in Puerto Rico.  The Search System(TSS) simultaneously monitored 58 million radio channels. It equaled Frank Drake's Project Ozma in a fraction of a second, and was a hundred trillion times more effective than the experiment of 40 years ago.

Other long-term SETI projects are underway. Among these is Project SERENDIP operated by the University of California, Berkeley at the Arecibo telescope. A second major project is conducted in Australia by an independent group, the SETI Australia Centre at the University of Western Sydney. The Australians have bought the SERENDIP technology to run their own 58 million-channel experiment on the Parkes radio telescope.  The popular screensaver/distributed computing software project known as SETI@home, run by UC Berkeley, has brought SETI to millions.

In the meantime the SETI Institute has been focussing on the future. In a joint project with UC Berkeley, it is building a SETI-dedicated array of telescopes that will equal a 100-meter radio telescope, the Allen Telescope Array. It is the forerunner of other larger radio astronomy arrays planned for later in the decade. It is possible that as telescope and SETI technology advance it may be possible to detect intelligence not by directed message but by the same kind of 'noise' we accidentally broadcast to the cosmos via radio, television and radar signals. SETI truly is a long-term project.