, a Berkeley astronomer and chief scientist of SETI@Home.Werthimer says the thresholds on abnormalities are set intentionally low to hopefully insure that nothing important is overlooked. Because so much data gets returned, not all the signals get a second look from SETI scientists. Instead, says Werthimer, they program a computer to sort through the signals looking for set criteria. One of the most important, he says, is an abnormality that shows up a second or even third time in the same location on different passes by the telescope. Recently a signal that showed up three times was investigated, but turned out to be caused by a glitch at Arecibo. "We've never had a time when we were all jumping up and down," says Werthimer.
If the day comes when an abnormality can not be attributed to noise, a glitch, or any of the other possibilities, it will trigger a set procedure (a link for this "Declaration of Principles" is setiathome.ssl.berkeley.edu/declaration.html ), agreed on by various SETI programs. It includes verification by independent researchers using data from a different telescope, and if the evidence proves credible, systematic notification of numerous government agencies and astronomical organizations prior to a public announcement. One of these is the International Astronomical Union's committee dedicated to the search for extraterrestrial life, dubbed Commission 51. This was due simply to the group's sequential naming practice but it does leads to a humorous, though coincidental, connection to the infamous Area 51 in Nevada.
Werthimer says that the SETI@Home program keeps track of the names associated with returned results, so those people whose computers first detected the real thing would be contacted before the ensuing media tumult. Only then would they know what had happened. With their permission, these people would be given public credit, says Werthimer "Of course, if you're the person who finds it you'll probably become quite famous," he says, "but it's probably going to be another 50 to 100 years, so don't hold your breath."
That is not a problem for Andrew Small, a computer programmer from the UK and an avid SETI@Home volunteer who has donated the equivalent of over five years of computing time to the project. He says the thought of actually discovering an extraterrestrial signal was not the motivation for his involvement. "I felt that I was actually doing something useful, but I think it's really more to eliminate the possibility than anything else," he says. "It would be a complete shock if we actually had a hit."
Seth Shostak, an astronomer with the SETI Institute in Mountain View, California, says the set protocol for a discovery is a good thing. But, he says, in reality the excitement of a find and the numerous people that would be involved in verifying it means that news would likely leak out. "The protocol is framed in a way that would be appropriate in a less chaotic world, but the real world is chaotic," he says. "I don't think that an actual discovery will proceed quite so cleanly." Both Werthimer and Shostak agree that the degree to which a discovery would affect humans would depend on whether we are able to decipher a message. Simply finding a signal would not have a profound effect on our civilization, says Werthimer, because many people already believe there is intelligent life elsewhere. But if we are able to decode information from them, it would be a different story. "They might send their whole library of congress, or the URL to the galactic internet," he says. "Then there is the potential to change civilization in huge ways."
But Werthimer expects that a lot more work will be required before that time comes, if it comes. "The fact that we haven't found ET means we need to be more patient," he says. "There are probably signals out there, but we earthlings are a primitive civilization. It's going to take a while."
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