Wired reports that on March 18, the scientists behind SETI@home, the world’s largest distributed computing project, will visit the Arecibo radio telescope in Puerto Rico to re-examine the most promising 100-200 radio signals of the billions they’ve collected since beginning their search for extra-terrestrial intelligence in May 1999. Since that time, SETI@home’s 4 million participants have crunched 1.3 million years in computing time–about 1000 years per day–averaging 52 terraflops (52 trillion floating-point operations per second). The world’s most-powerful non-distributed supercomputer, Japan’s Earth Simulator, clocks in at only 10 terraflops.
According to SETI@home’s October newsletter, the most promising candidate signals must exhibit one of more of the following criteria: (1) its location matches the location of a known star, (2) its location matches the location of a known planet, (3) its barycentric frequency (in which the effects of the Earth’s spin and orbit are removed) is constant across time but cannot be attributed to RFI (Radio Frequency Interference).
So far, every signal that merits closer inspection has proven to be a red herring, so scientists aren’t getting their hopes up. “Occasionally, you find very strong signals and you look more closely, but it turns out to be a satellite or interference,” said SETI@home’s chief scientist Dan Werthimer. “We’re not jumping up and down saying we’ve got to get to the telescope immediately, we’ve just found E.T. These are the best signals that 4 million volunteers have found over the last four years, and we’re going to check up on them.”
Werthimer says that the 1.3 millions years of computing time that they’ve crunched so far is just the beginning. SETI@home has only been searching a narrow 2.5 MHz band among the billions of potential radio bands. “I’ve been doing this for 27 years and I still think we’re just scratching the surface. We’re searching such a small range of frequencies…. We are 20 or 30 years away from a thorough search. It’s like combing a cosmic haystack. We’ve just started poking around the edges.”