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What Is SETI@home?

SETI@home logo The Search for Extra-Terrestrial Intelligence (SETI) has been likened to a search for a needle in a haystack. SETI requires both signal analysis software (to search for needles) and radio telescopes (to find the haystacks). SETI@home falls into the former category. SETI@home is not a SETI League project, thus we cannot answer your technical queries about it. For software downloads or specific help, you'll have to go to the SETI@home website. Nevertheless, this is a project which The SETI League strongly supports.

Launched on 17 May 1999, SETI@home is perhaps the most ambitious application of computer distributed processing ever conceived. The project taps into the idle resources of millions of personal computers around the world, for the analysis of raw SETI data. The SETI League finds the concept highly credible, quite exciting, and are pleased that many of our members have chosen to embrace it.

SETI@home screen shot The basis of SETI@home is as follows: participants download a screensaver-like program from the SETI@home website, as well as a block of raw Project SERENDIP data collected at the Arecibo Radio Observatory in Puerto Rico. That data is be analyzed in the background, harnessing your unused computer power. Your computer sifts through the cosmic noise for patterns of artificial extra-terrestrial origin.

There are a few limitations to the SETI@home concept, none of which detract from its scientific validity. Since the data is not being analyzed in real time, no opportunity exists for signal verification through near-real-time follow-up detection, such as is employed by the SETI Institute's Project Phoenix search. Since SERENDIP operates from but a single antenna at present, coverage will be limited to that 30% of the sky which can be seen from Arecibo. And because it takes six months to complete a scan, only four observations of a given source are likely during SERENDIP's planned two year sky survey. Nevertheless, we consider SETI@home to be an excellent supplement to the Project Argus all-sky survey now being conducted by SETI League members.

After months struggling for funding, SETI@home received sponsorship from The Planetary Society. Additional support came from Paramount Pictures, which provided SETI@home with a publicity tie-in to the December 11, 1998 release of its feature film "Star Trek: Insurrection." Paramount's press release stated, "For the first time in Star Trek history, Planet Earth is invited to help the crew of the U.S.S. Enterprise in a real search to seek out new life and new civilizations."

Recording of data at Arecibo began on 20 October 1998. On 20 November 1998, SETI@home began Beta testing the system with a group of 100 users analyzing real data. SETI League personnel were among the beta test team.

The Unix version of SETI@home was released on 7 April 1999, and the Windows and Macintosh versions were released on 14 May 1999. By May 2000, 2 million participants had downloaded the software, making SETI@home the world's most powerful supercomputer. In eary 2005, the number of participants had grown to over 5 million. By December 2005, the SETI@home classic client was retired, being replaced by new open-surce software running under the Berkeley Open Infrastructure for Networked Computing (BOINC). BOINC and SETI@home may be downloaded now from

Since the small, volunteer SETI@home team cannot possibly provide individual answers to the tens of thousands of email inquiries they continue to receive, interested parties are asked to check the Frequently Asked Questions (FAQ) page on their website.

Key project personnel include David Gedye and David Anderson of Big Science, Dan Werthimer at the University of California, Berkeley, and Professor Woody Sullivan at the University of Washington. Since this is their project, participants need not be SETI League members. (On the other hand, we do hope that many SETI@home participants will also choose to join our membership-supported, nonprofit educational and scientific group. A SETI League membership application may be found here.)

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this page last updated 14 January 2006
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