First Contact (25 page)

The wind was picking up and gusting hard again as I came across one of the numerous antennas named for accomplished donors. This one was
named jointly after Jack Welch—not the former chairman of General Electric and business seer, but the famous radio astronomer—and his wife, Jill Tarter. It was a serendipitous but appropriate introduction to the story of how this unlikely, faraway field in the Lassen National Forest came to host 42 radio antennas and may someday have 300 more—all of which would be listening for messages and signals that alien civilizations just might be sending our way.

Jill Tarter, as all SETI enthusiasts know, is a founder, and now the matriarch, of the SETI Institute. A passionate visionary of extraterrestrial intelligence, she became a rather high-profile cultural figure after release of the 1997 movie
Contact
, which was based in part on her life. (Jodie Foster played her in the movie, which regrettably did justice neither to the subject nor to the individual, although Tarter says it worked miracles in terms of fund-raising.) An engineer and astrophysicist by training, Tarter has an endowed chair at the SETI Institute, located in the high-end Silicon Valley town of Mountain View, and just across Route 101 from NASA's Ames Research Center, which once was involved in SETI work as well. Jack Welch may not be quite as well-known in popular culture, but in the world of astronomy he is a giant, too: the first to find water vapor and organic formaldehyde in distant space, discoveries that rewrote the textbooks about the makeup of interstellar space. He led the radio astronomy lab at the University of California, Berkeley, for twenty-four years, and since 1998 has had an endowed chair as well, the Watson and Marilyn Alberts Chair in the Search for Extraterrestrial Intelligence, in the astronomy department at Berkeley. It was the first such chair, and remains the only one of its kind. Given their highly specialized skills and unusual interests, Tarter and Welch were destined to meet. They not only met but they both eventually divorced and re-married.

Each is a forceful personality on his or her own; together they are a power duo that can make things happen. In the late 1990s, SETI and Berkeley formed a partnership to build the array, and in 2004 construction began at Hat Creek, thanks to an initial $11.5 million donation from Microsoft
cofounder and billionaire Paul G. Allen. Pleased by what he saw, Allen later put in another $13.6 million, and the initial forty-two-dish array was dedicated and began work in 2007. While the telescopes would fulfill the decades-old SETI dream of having cutting-edge equipment that was dedicated to its goals, it would simultaneously provide equally cutting-edge technology for the Berkeley radio telescope program, which researches more traditional and incrementally revealed subjects such as how galaxies form, the nature and properties of dark matter (ubiquitous in the universe but known only by its gravitational pull), and the nature and workings of black holes. Under Welch's leadership, the array is also drawing a cosmological map of the presence of hydrogen in the universe.

Hat Creek represents quite a coming of age for SETI, which long struggled for telescope time, funds, and respectability from the federal government, and ultimately secured none in substantial or dependable form. The giggle factor was just too high. During the 1970s and '80s SETI was funded to a limited extent by NASA, and in the early 1990s was finally embraced and awarded funds for a more sophisticated program. But that dream ended quickly in 1993 after Senator Richard Bryan, Democrat of Nevada, made zeroing out SETI into a personal priority. “The Great Martian Chase may finally come to an end,” he said as he closed in on his goal. “As of today millions have been spent and we have yet to bag a single little green fellow. Not a single Martian has said take me to your leader, and not a single flying saucer has applied for FAA approval.”

The odds remain long that Hat Creek and other SETI efforts will make contact with distant civilizations, but what the scientists are doing is far from the caricature presented by the senator from Nevada. The former senator would be dismayed to know that not only has SETI attracted millions from savvy high-tech entrepreneurs and scientists, but the Institute is again eligible to compete for NASA funds after its program was deemed to be scientifically sophisticated and sound. The forty-two dishes are unusual not only because of their SETI mission, but because they're also a cutting-edge design and generally seen as the future of radio astronomy.

The United States already has one huge radio astronomy dish at Arecibo, Puerto Rico, which is a thousand feet across and can pick up radio signals from 100 million light-years away. For years it was the primary site for SETI work, though listening time was limited. A much-used “giant eye” with real star power—it has served, after all, as a backdrop to movies ranging from
Contact
to the James Bond film
GoldenEye
and an
X-Files
episode called “Little Green Men”—it nonetheless belongs to the past and is struggling to hold on to the limited National Science Foundation funding that it receives. Not only would it be prohibitively expensive now to build an Arecibo, but it would be seriously behind the technological curve. Welch in particular pioneered the notion that many smaller dishes hooked up together would have the same power and sensitivity as a big dish, and would do it at a much lower cost. Hat Creek is the prime example of that change in approach and vision, and its receiving dish is actually as large as the distance between the most distant antennas. At 350 antennas, the Hat Creek dish would be, in effect, a kilometer in diameter.

Space technology aside, Hat Creek also gives the SETI enterprise a permanent and easily expandable home. Over the next two dozen years, the Allen Telescope Array as currently configured will gather a thousand times more information from distant star systems than has been collected in the past forty-five years. The data will also be far more precise and will come from fainter, more distant stars. Perhaps most important, the dishes produce a detailed image of a broad expanse of the radio sky at any given moment. This is how Seth Shostak, SETI's lead astronomer, put it: “Let's say you're looking for elephants in Africa. If you have one guy with binoculars, your chances of seeing a tusker are pretty limited and it will take a long time to succeed. Compare that with having one thousand guys with binoculars looking for elephants. Suddenly, you'll be finding a lot of elephants.”

The Hat Creek radio waves are collected, bundled, and carried to waiting computers that split them into four categories based on their radio frequency. Generally, two of the bundles go to SETI and two to Berkeley, a sharing that made the Allen Array so appealing in the first place. SETI needed the solidity
of the Berkeley lab to be credible when it approached potential donors, and Berkeley needed the sexiness of SETI. With both Jill Tarter and Jack Welch convinced it should go up at Hat Creek, the momentum was hard to stop.

The antennas are designed and programmed to pick up distant radio waves (a relatively low-energy form of radiation) at a frequency between 1,420 megahertz and 1,660 megahertz. That's a region of the radio end of the electromagnetic spectrum that has less competing background “noise” from the universe than most others and, as a result, more radio waves, and more distant radio waves, can be detected. In radio astronomy and SETI parlance, that range is called the “Cosmic Water Hole,” because it exists between the points on the spectrum where radio waves from interstellar hydrogen (H) and interstellar hydroxyl ions (OH) arrive on Earth. It was Bernard “Barney” Oliver, a top engineering executive at the Hewlett-Packard Company, the early head of the NASA SETI program and later the first president of the SETI Institute, who gave the “water hole” its name. The logic was simple: The spectral region between H and OH was relatively tranquil and quiet, rather like water (H
₂
O), and the relative calm seemed obviously to be a function of the breaking apart of interstellar H
₂
O. Oliver proposed that any advanced civilization would be able to similarly identify the “water hole” as a good frequency for communications, and the scientific-extraterrestrial community agreed. “Where shall we meet our neighbors?” Oliver famously asked decades ago. “At the water-hole, where species have always gathered.” Many SETI observations are still done at Hat Creek and elsewhere at water-hole frequencies.

As Hat Creek station scientist Rick Forster explained it, a major reason for choosing Hat Creek as home to the array was that it was especially quiet in the “water hole.” Many other kinds of man-made radio noise now pollute that region of the radio spectrum, and it's increasingly hard to find places where that new noise doesn't drown out signals that might be coming from far away. Locations like Hat Creek, the scrub deserts of New Mexico and Arizona, and the high Atacama in Chile are home to the best new radio arrays because—while they still have to account for radio waves coming
from cell phones, high-definition television, and military satellites—there is far less radio noise from surrounding human activity than most places.

The SETI Institute is always struggling for money, but the overall enterprise is more capable and stable now than ever before. So, fifty years into SETI, it seems entirely fair to ask this question: Why, if scientists and ET enthusiasts are correct and there are many technologically advanced civilizations in the universe, have we neither heard nor seen any signs of them? Earth would plausibly be the kind of place intelligent extraterrestrials might try to contact, since its atmosphere has been awash in probably the most telling signatures of life—oxygen, ozone, and water—for 2 billion years. For the last hundred years, we've also put out an enormous amount of radio traffic that could plausibly be detected from deep space. Yet there have been no incoming messages detected. Some in astrobiology see SETI as the field's most vulnerable Achilles heel. Too much looking and listening; not enough finding. As a result, the half-century-old SETI policy of relying primarily on radio telescopes to listen for messages is frequently challenged. So, too, is the SETI decision to remain in a listening mode rather than sending out pings and flares from Earth that might inspire a response. SETI scientists say listening offers the greatest chance for success, but increasingly, others disagree.

But ask Frank Drake whether the absence of contact means we're alone in the universe as the sole intelligent creatures, and he laughs. The assumption that underlies the question, that we've done enough SETI monitoring that something definitive should be known by now, is so far off base that to Drake it's much more humorous than it is threatening. The author of the 1963 “Drake Equation,” which sought to very roughly estimate the number of advanced civilizations in the universe, says that the current equation predicts the existence of one technologically evolved planet per every 10 million star systems. The Drake Equation says that the number of such advanced civilizations is equal to the sum of the number of stars born per year in our galaxy, times the number that have planets, times the number with planets in a habitable zone, times the fraction of those that go on to develop
life, times the fraction that develop intelligent life, times the fraction of such civilizations that reach a level of technological civilization capable of sending out signals, times the length of time they would be sending out detectable signals of life. The equation is widely discussed but, because it contains so many unknowns, it is more a conversation starter than a conversation finisher. Suffice it to say that the number of star systems observed so far is many, many times fewer than the 10 million Drake believes are needed to find a technologically advanced civilization. “We probably won't have something really scientifically useful to say for another twenty-five years—even if Hat Creek grows to three hundred fifty dishes,” he said.

It is a daunting task. While the Milky Way alone has some 100 billion stars and untold billions of planets, the distances between them all are so enormous, the possible methods of communicating are so varied, and the cosmic timing has to be just right. Think about it: Some form of life has existed on Earth for more than 3.8 billion years, evolved Homo sapiens have roamed the world for 250,000 to 400,000 years, but humans who know how to produce radio waves to be detected by presumed other civilizations have been around only a little more than 100 years and humans searching for radio signals from afar only 50 years. Given the time scales involved, that's very close to nothing. Assuming for a minute that other technologically advanced civilizations have flourished, what's to say that happened just at the time when we can make contact with them?

I returned the next morning to wander the array again. This time it was sunny and Mount Shasta rose elegantly to the east. I could better see the surroundings, and the logic of SETI as well. It took a while to sink in as I made my way around, but astrobiology needs SETI, despite the skepticism, the feel of science fiction, that it inevitably brings. Astrobiology may well find signs of living or once-living extraterrestrial organisms in the not-too-distant future, and that would be a discovery of Copernican proportions. But what would really turn the world on its head is the discovery of intelligent life elsewhere. And SETI, for better or worse, is the pathway—actually, the shortcut—to a discovery of that magnitude.

•   •   •

With potentially so much at stake, the SETI field has come alive in recent years with alternatives to the tried-and-true technology of radio astronomy. The California physicist twins Gregory and James Benford, for instance, believe that SETI is listening in on the wrong radio channels, that alien civilizations would be more likely to send out tiny bursts of sound than the kind of broadband blasts the SETI Institute has been listening for. Their approach, James Benford said, “is more like Twitter and less like
War and Peace
.”