MENTION the search for extraterrestrial intelligence and you can be sure of a mixed reaction.
The cynic will argue that we have better things to do with our time that look for little green men who probably do not exist. A SETI enthusiast will counter that the prize is too profound for us not to try. The discovery of aliens could revolutionise our understanding of evolution and religion. (It might even finally help us to answer the question 鈥渨hat is life?鈥� see 鈥淭he mysteries of life鈥�). The pragmatist will argue that the aliens are so far away that for us to pick up anything at all they would have to transmit directly at us, at the very time when we are looking at them, so the chances of success are slim indeed. An optimist will say that while it may be a long shot, it might just work.
So how should we regard the news that the vast radio dish at Arecibo in Puerto Rico has found a signal that defies conventional explanation 鈥� not once but three times (see 鈥淣ot long ago, in a galaxy far away鈥︹��)? One thing is certain: it is too early to say that ET is calling. All we know for sure is that the signal does not fit the profile of any known astronomical object. We have not watched it long enough to know if it is anything other than random noise, and there is still a faint possibility that it is an artefact of the Arecibo dish itself. Of course, it may eventually join that other great SETI celebrity, the 鈥淲ow鈥� signal of 1977, as an intractable mystery. Another possibility is that the signal could be from a previously unknown kind of astronomical object: that would not be as exciting as extraterrestrial life, but still fascinating.
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Whatever the anomalous signal turns out to be, finding it is a significant achievement. Astronomer Paul Horowitz of Harvard University says that only two or three other events in the past 30 years have piqued his curiosity as much. There is also a group of people who will be particularly eager for more information. The signal was spotted by the SETI@home project, which exploits free time on the home and office computers of more than 5 million volunteers to analyse recordings from Arecibo. This is the first noteworthy discovery in the six-year history of SETI@home and may turn out to be the best 鈥� certainly the most public 鈥� advertisement yet for the value of distributed computing.
One of the most frequent reasons given by people who participate in SETI@home is a desire to join in science鈥檚 quest to advance human understanding. Today, people can use their computer鈥檚 free time not only to search for aliens but also to design drugs, calculate protein structures and detect gravity waves. This latest discovery can only increase the number who want to take part. For this reason if no other, the discovery is a welcome development.