READY, SETI, GO: INTRIGUING SIGNAL FROM SPACE BECKONS

Saturday, September 4, 2004

I never quite got around to signing up for the home-computer version of the search for extraterrestrial intelligence, but when I came across a story distributed by the New Scientist news service Wednesday about a possible signal, I was reminded what a hoot it would be to have my computer find the first genuine sign of life elsewhere in the universe. Way cooler than having my name on an asteroid or a comet.

The SETI@home project, which is based at the University of California at Berkeley, takes the enormous amount of data collected by the radio telescope at Arecibo, Puerto Rico, and parcels it out to individual computers for analysis, running in the background when the computer is not fully occupied. Like a screensaver, but useful. It has more than 5 million users, who have contributed more than 2 million years of CPU time over the past six years.

One particular radio signal that the analysis identified as potentially worth a closer look has now been spotted three times, appearing to come from a point in the sky between the constellations Pisces and Aries (and no, I have no idea where that is). Twice it was found by users of the program at home, and once by project researchers.

Well, actually, they were at work. One was in Nuremberg, Germany, and one in Madison, Wis., who said he wonders how his bosses will feel if it turns out the company computers have found aliens. "I might have to explain a little further about just how much I was using" the computers, he told New Scientist.

Dan Wertheimer, the chief scientist for SETI@home, calls it the "most interesting signal" from the program. "We're not jumping up and down," he told the magazine, "but we're continuing to observe it."

The characteristics of the radio signal, the researchers say, don't match any known astronomical object, although that's nothing new. Jocelyn Bell Burnell of the University of Bath in England was the one who in 1967 noticed a peculiar kind of pulsed radio signal that was at first thought to be artificial. It turned out to be from a pulsar, a kind of star whose existence no one had suspected.

Of the new signal, she told New Scientist, "If they can see it four, five or six times it really begins to get exciting."

There are plenty of reasons for skepticism. The signal is weak, it's been observed for less than a minute altogether, and though it's at a plausible frequency, the frequency drifts. In an online article Thursday, Amir Alexander of The Planetary Society (which is as eager as anybody to find a genuine extraterrestrial message) wrote that the reports were highly exaggerated, and that it was extremely improbable that this was a transmission from aliens.

Of course, even if it is a transmission, it may not be intentional. When earthlings started watching television, it was not part of their plan to send a message to the universe just in case anyone was listening. But the message went out anyway.

An earlier New Scientist story reported on a SETI workshop held at Harvard University in August. Frank Drake, former chairman of the board of the SETI Institute in Mountain View, Calif., said that the bright radio-wave bubble caused by television now extends about 50 light years out from the solar system. But, he said, from the point of view of extraterrestrials looking for us, the earth may soon go dark again. More and more, television is delivered in ways that don't leak radio signals into space, through cable or from low-power satellites.

Drake is best known for his work in estimating how many technological civilizations may exist in the galaxy. If a technological civilization shines brightly for only a brief time, perhaps it isn't surprising that we haven't heard from any in the short time we've been listening. He thinks perhaps looking for deliberate beacons may be a better strategy.

We might send them ourselves, also, in the form of high-powered laser beams aimed at nearly stars that for brief periods would outshine the sun.

Other researchers think that "a message in a bottle," a physical object containing data, would be a better way of sending messages, at least if you don't care how long they take to arrive but you do care about how much energy they take. "Once radio signals pass they are gone for ever," Jenny Hogan wrote Wednesday for New Scientist. "So aliens would have to beam signals continuously, or other civilizations might blink and miss them. Physical objects stay where they land."

If, that is, they ever land anywhere; it would be hard to hit a planet from light years away.

The people working on SETI projects hope they'll be around when the Earth gets its first galactic telegram, and so do I. But even if it never happens, I'm glad to know they're out there looking.