Having used up more than a million years of computation time across more than 4 million computers worldwide, the SETI@home data-crunching screensaver that searches through intelligent-looking signals from space, has finally come up with a list of 150 candidate radio sources that deserve a second look.
Three members of the SETI@home team will head to Puerto Rico this month to point the Arecibo radio telescope at up to 150 spots identified as the source of possible signals from intelligent civilizations. SETI@home is a computer program disguised as a screen saver that pops up when a computer is idle and analyzes radio telescope data in search of strong or unusual signals from space. The candidates for re-observation are particularly strong signals or ones that have been observed in the same spot more than once, some of them five or six times. "This is the culmination of more than three years of computing, the largest computation ever done," said UC Berkeley computer scientist David Anderson, director of SETI@home. "It's a milestone for the SETI@home project." SETI@home users should find out the results of the re-observations - what The Planetary Society, the founding and principal sponsor of SETI@home, is billing as the "stellar countdown" - within two to three months. Though excited at the opportunity to re-observe as many as 150 candidate signals, Anderson is cautious about raising people's expectations that they will discover a signal from an extraterrestrial civilization."If there is any possibility at all of finding an extraterrestrial signal, it's probably much less than one percent," he said. UC Berkeley physicist Dan Werthimer, SETI@home chief scientist, isn't getting his hopes up, either. He has conducted a Search for Extraterrestrial Intelligence (SETI) for 24 years - 11 years using Arecibo's 1,000-foot diameter radio dish - and has returned several times to look again at promising locations and frequency ranges to determine if a strong radio signal is more than random noise, a glitch or a passing satellite. He has been disappointed each time. On the other hand, SETI@home has mobilized so much more computing power than has ever before been thrown at signal analysis, that the team has been able to perform much more detailed and complicated computations on the radio data than now possible with Werthimer's ongoing SETI project, called SERENDIP IV (Search for Extraterrestrial Radio Emissions from Nearby Developed Intelligent Populations).