If anyone out there wants to talk, he’s listening. Werthimer is waiting patiently for that telltale blip, the unmistakable signal of an alien civilization reaching out across the universe to make contact. This Search for Extraterrestrial Intelligence, or SETI, may sound like an episode of the X-Files, but its advocates claim that the question “Are we alone?” is a serious and scientific one. “Yes,” says Werthimer, “it used to be considered fringe science, but now people are realizing that it’s definitely worth pursuing, that now we might have a chance of answering that question.” For years SETI has languished in the backwaters of research, but as we enter the new millennium, the search is beginning in earnest.

Berkeley is leading the new drive to find ET, with several initiatives. Last year saw the launch of SETI@home, a project that harnesses the goodwill and spare computing power of nearly two and a half million volunteers on the Internet to analyze radio signals gathered from the far reaches of outer space. This summer, Berkeley astronomers and engineers finally got the go-ahead to build the Hectare Array, the world’s first radio telescope purposely built to search for intelligent life. A collaboration between Berkeley and the non-profit SETI Institute in Mountain View, it will be located alongside the University’s other telescopes at the Hat Creek Observatory near Mount Lassen.

Scientists admit that the search is a long shot, and that it could take a hundred years to complete. They are settling in for the long haul as they prepare to comb every inch of the sky, listening at each point to every possible frequency. It’s a formidable task, so initally they are taking a two-pronged approach. Some SETI scientists focus on just a few stars that are likely candidates, and listen to the signals they put out at every frequency right across the spectrum. Others take a broad sweep of the sky, but listen to a much narrower range of frequencies.

The latter is Werthimer’s preferred approach. He doesn’t know where in the sky to look, but he has a strong hunch that ET will transmit at a frequency somewhere around 1400MHz, close to the “hydrogen line.” Sitting in an especially quiet part of the tranquil microwave band, the natural emission frequency associated with the most abundant element should be a clear landnark for any extraterrestrial scientist. SETI scientists are keeping an eye out for sharp, well-defined spikes poking up out of the noise. While natural cosmic activity produces radio emissions that are spread over a wide band of frequencies, artificial signals of the sort that might be sent by an intelligent civilization ought to be concentrated around a single frequency. In other words, a message from afar will be more of a squeak than a hiss.

Werthimer’s lifelong fascination with SETI began when he was a teenager and read the popular writings of astronomer Carl Sagan, one of the field’s earliest and most vocal advocates. At the time, Werthimer was a member of the Home Brew computer club in Palo Alto, where he and some other kids—Bill Gates, Steve Jobs, and Steve Wozniak—met to dream up new uses for the freshly invented silicon chip. “Unfortunately for me, I said, ‘Maybe we can use these microcomputer chips to do SETI.’ Otherwise I would be a billionaire now!” he jokes.

Today, SETI would be unthinkable without computers that sort through radio signals, scanning millions of frequencies. This is where SETI@home comes in. The principle behind it is simple, yet powerful: to make use of all those PCs that would otherwise sit idle as people answer their phones, make cups of coffee, or take bathroom breaks. When added together, these small segments of donated computer time make SETI@home the world’s largest supercomputer—not to mention the cheapest.

Here’s how it works. Signals received by the Arecibo radio telescope in Puerto Rico are transmitted to Berkeley, where they are broken up into manageable chunks, and then parcelled out over the Internet. When they reach their destination on the volunteer’s home computer, they are analysed by a program that runs quietly as a screensaver. Though small, the program is sophisticated enough to distinguish all manner of artificial signals, not just simple spikes, but also pulsed signals and even modulated radio waves that might carry information—ET’s version of “I Love Lucy,” perhaps, or maybe an intergalactic encyclopedia. “You can put up a screensaver that has flying toasters or goldfish swimming around, but why not do something useful with your computing power?” suggests Werthimer, the project’s chief scientist.

SETI@home complements Werthimer’s other venture, project SERENDIP, Berkeley’s longest-running SETI project. Playfully titled the Search for Extraterrestrial Radio Emissions from Nearby Developed Intelligent Populations, SERENDIP also uses data from the Arecibo telescope. Less sensitive than SETI@home, and capable of less sophisticated searches, SERENDIP listens to a much wider band of frequencies. Using a new “piggy-back” technique to gather date, SETI astronomers can now use the Arecibo telescope throughout the year. “We’ve figured out a way to use these telescopes at the same time as other astronomers,” says Werthimer. “We used to have to compete for time, and were lucky to get a day or two a year; but this is almost as good as having the telescope to ourselves.”

The current SETI revival at Berkeley owes much to the financial support of Silicon Valley’s high-tech community, which stepped in to pull it out of the doldrums. It had reached a low point in 1993, when Nevada Senator Richard Bryan persuaded Congress to cut all funding of SETI research, ridiculing it as “The Giant Martian Chase.” But if the search for alien civilizations was too “out there” for the federal government, it was perfect for a new breed of millionaires, used to high-risk, high-return ventures. In August of this year, Microsoft co-founder Paul Allen offered to fund the Hectare Array—now the “Allen Telescope Array.” That same week, dot-com millionaire Joe Firmage announced a generous donation to SETI@home. “SETI is a long shot. But people who are successful in high-tech fields are somewhat used to long shots,” explains Jack Welch, Ph.D. ’60, of the astronomy department, who holds the world’s first and only SETI chair.

Welch collaborates with the SETI Institute on Project Phoenix, which focuses very closely on a thousand nearby stars. When the Allen Telescope Array comes online in 2004, Welch hopes that number will go up to at least 100,000. His own interest in SETI was piqued in the late 1960s, when his research team discovered water in the interstellar medium; it only grew when, later, hundreds of organic compounds were found wafting through space. “All this low-level stuff that you need to make life is just floating around out there,” says Welch, who is convinced that life must be ubiquitous throughout the universe.

Evidence like this has persuaded other astronomers of SETI’s worth. Berkeley professor of astronomy and physics Chris McKee, Ph.D. ’70, recently co-authored a report to Congress making research recommendations for astronomy and astrophysics. The report gave special mention to the Allen telescope, reflecting the seriousness with which the astronomical community now takes SETI, says McKee. “There’s a small chance of success, but most astronomers regard the possibility of intelligent life elsewhere in the galaxy as very real,” he says.

It was not always so. Until relatively recently, most scientists considered life to be very fussy, cropping up only when conditions were just so. But organisms have since been found living in deep-sea vents miles below the ocean’s surface, at temperatures above the boiling point, in the frozen Antarctic, and even miles underground. “Life is a lot more robust than we thought,” concludes Werthimer.

And, up until five years ago, the idea that planets like ours orbited stars like our Sun was just educated guesswork. But once astronomers perfected their techniques for detecting planets in far-off solar systems, they began to find them everywhere. To date, over 50 of these planets have been catalogued, many found by Berkeley’s own planet-hunting team, led by astronomer Geoff Marcy. Judging from the numbers so far, Marcy estimates that there may be as many as 12 billion solar systems in our galaxy, which leads him to conclude that there must also be vast numbers of Earth-like planets, very hospitable to life. “There’s no question that there are oceans and lakes out there, no question that the universe is teeming with life,” claims Marcy.

All this evidence now points to the very strong possibility that we are not alone, but it may be presumptious to suppose that life elsewhere developed as it did here on Earth. Intelligent life might be just a quirk of nature peculiar to our own small corner of the galaxy, says Cliff Pickover, a researcher at IBM and author of The Science of Aliens. “The most successful creatures on Earth are the dumb and clumsy rats and beetles. Evolution doesn’t necessarily select for intelligence,” he says. Even if intelligent species do pop up from time to time on other planets, he goes on, they might be incapable of developing technologies of their own. It takes a high degree of manual dexterity to build radio transmitters, and the chances that another species would be both sufficiently intelligent and sufficiently dextrous are very slim. Even on our own planet, few species have developed much of either trait. “Those that have acquired a little of one—smart dolphins, say, or dextrous spiders—have acquired none of the other. And the only other species to acquire a little of both—chimpanzees—has been rather unsuccessful,” notes Pickover.

But with 200 billion stars in our galaxy, and even more galaxies in the universe, SETI scientists still like their odds. Not only do they fully expect there to be other technologically advanced civilizations, they also believe that some sort of common language of mathematics or science will make communication possible. “I suspect that intelligent life will discover the same mathematics and the same laws of physics. Those are universal,” says Werthimer.

This may be wishful thinking, cautions Berkeley anthropologist Alan Dundes. He argues that science and technology are cultural products, particular to the present time and place—aliens are no more likely to share our science than they are to speak English. “People assume that what they do is the norm, and that everybody else is weird. That’s called ethnocentrism,” Dundes maintains. Doug Vakoch, a social scientist at the SETI Institute who works on the design of messages that might be understood by creatures of alien civilizations, concurs with Dundes. “One of the issues that needs much more widespread recognition in the SETI community is that there’s a big distinction between the universality of physical reality and the cultural contingency of our particular models of reality,” says Vakoch. But he still believes that the search is worthwhile.

“If SETI succeeds, it would be incredibly valuable. It would be an extension of our making contact with other cultures here on Earth, and it would broaden our understanding of the universe,” says Vakoch. Carl Sagan, writing back in 1978, expressed a similar sentiment: “SETI is the search for a generally acceptable cosmic context for the human species. In the deepest sense, the search for extraterrestrial intelligence is a search for ourselves.”

This is what keeps researchers like Welch and Werthimer going. They live for the day when the first contact is made, but they also know they must be prepared for the possibility that the result of their search will be silence. “Either way it’s profound. If we find out that we are alone, then we’re just incredibly special, and we had better take super-good care of this planet,” says Werthimer. “Or we might find that the universe is teeming with life and that we’re an emerging civilization among hundreds of thousands of civilizations that have all been talking to each other for millions of years. That’s profound, too."

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