Seth Shostak, a researcher at the SETI Institute in Mountain View, CA, and a collaborator and friend of many of the researchers at BSRC, likens SETI to the proverbial search for a needle in a haystack. “How long it’s going to take you to find a needle only depends on how big is the haystack, how many needles are in there, and how fast are you going through the hay. For SETI, we know how fast we are searching the sky, and how big the haystack is, in this case, just our Galaxy. We don’t know what the third component is, namely how many needles are in there – how many societies are broadcasting in our direction. But if you just look at a range of possibilities – maybe it’s a few thousand, maybe it’s a few million – you can predict how long it’s going to take to find them, and that turns out to be a couple of decades if you’re lucky.”

In the meantime, though, there’s a lot of hay to go through, and that’s where SETI@home plays a key role. The mundane task of sorting through the cosmic static in search of the elusive signal from an intelligent civilization is one that’s very well suited to a large network of computers. Each SETI@home volunteer runs a copy of the program that downloads a small “work unit” of data from the central server in Berkeley, searches it for several classes of signals that are thought to be much more likely to arise artificially than from natural astrophysical processes, and then uploads the results back to the central database.