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How to Pick Up Aliens

In 1992 NASA will begin scanning the skies for evidence of intelligent life elsewhere in the universe. What will we do if they find it?



. . . advanced civilizations might be operating radio beacons, possibly to attract the attention of emerging societies and bring them into contact with a community of long-established intelligent societies existing throughout the galaxy.

No, that's not the scriptwriter's guide for Star Trek: The Next Generation. That's a recent brochure from NASA, this generation.

The space agency is on the prowl for extraterrestrials. Its $70 million hunt--the Search for Extraterrestrial Intelligence Microwave Observing Project (SETI MOP)is a decade-long, horizon-to-zenith sky scan, the most ambitious search yet for radio transmissions from outer space. And if NASA's antennae lock onto an alien transmitter, U.S. policymakers are going to have to make unprecedented decisions:

Who uncodes the message?

Do we call in the Soviets for advice?

What are the national security implications?

At what point do we clue in the public?

Who gets to reply on behalf of planet Earth?

Do we want to call attention to ourselves at all?

Understandably, extraterrestrial relations take a backseat to the space station on NASA's list of priorities. But an independent, ad hoc group of scientists and scholars has been working on these questions, and after much mulling they have crafted sober suggestions for handling First Contact.

The informal group of brainiacs includes a Parisian astronomer, a University of Alabama sociologist, a high-ranking official of the U.S. State Department, an Austrian lawyer who has written a book called Relations With Alien Intelligences, the head of the American Astronomical Society, and a NASA astronomer who is a 14-year veteran of the search and a leading spokesperson for SETI MOP.

In 1987 the group gathered at an international scientific congress in Brighton, England, and distilled its wisdom into a nine-point protocol, a blueprint for international cooperation should any Earthling discover that we are not alone. The group is loath to call its document a treaty. "It's not an agreement between governments, but among people engaged in research," cautions codrafter Michael Michaud, director for the State Department's Office of Advanced Technology. Michaud stresses that his work with the group has been as a private citizen, not as a representative of the U.S. government.

The drafters were given their first endorsements in April by the International Academy of Astronautics and the International Institute of Space Law--two Paris-based professional organizations that represent scientists, engineers, and lawyers concerned about the exploration and use of space. The drafters hope the International Astronomical Union will follow suit when it holds its next world congress in 1991. By 1992 they hope to have an endorsement from the United Nations. The year 1992 is triply symbolic: it's been designated "International Space Year" by the UN, it marks the 500th anniversary of Columbus's discovery of the New World, and it's the year SETI MOP will end its research-and-development phase and turn its electronic ears skyward. Once the agreement is on deposit with the secretary general of the UN, the drafters will begin to ask individual research organizations, like NASA, to sign.

One of the main forces behind the ad hoc group--Allan Goodman, a Georgetown University dean who teaches tomorrow's diplomatic corps the fine art of international relations--has jumped the gun a bit by lobbying the White House to support the agreement. In a memo to President Bush dated the day after his inauguration Goodman argued, "The SETI agreement serves American interests by codifying further the norms and rules governing space exploration, promoting international scientific cooperation, and protecting from institutional censorship and secrecy our citizens' right to know about discoveries that profoundly affect their lives."

Goodman--who also works as a guest commentator for Voice of America, writes a column for the Los Angeles Times syndicate, consults for the RAND Corporation, and has authored several books on national security and the Vietnam and Korean wars--is a realist. "I sent [the memo] to President Bush's national security adviser, which probably means that it's in a large container resembling a garbage can," he says. "But the purpose was to show that you could write seriously about the subject."

Goodman, 44, is a staid, down-to-earth man whom you'd never find at a Star Trek convention. "I don't like science fiction, and I don't read it," he says. But he thinks SETI MOP is worthwhile no matter what your disposition is toward extraterrestrials. "You can be agnostic, you can be a passionate believer that there's nothing out there, or a passionate believer that there's got to be something," he says. "The fact is our technology between now; as we speak, and 1990 is growing at such a rate that it is conceivable we might be able to hear the whole electromagnetic spectrum and detect things we've never heard before. We might be able to answer the question, 'Is there anybody out there?'"

Goodman got interested in such matters in 1985 when, as associate dean of Georgetown's Foreign Service School, he invited James Beggs, then NASA's chief administrator, to speak to his Georgetown Leadership Seminar. Beggs told the audience that if we ever discover evidence of intelligent life out there, we'll probably do so before the year 2000. Intrigued, Goodman asked his guest, Does any international agreement cover a close encounter with an alien civilization? The query drew a blank.

Goodman hit the books. He was soon poring over the 1967 "Treaty Governing the Activities of States in the Exploration and Use of Outer Space." Endorsed by 86 nations, this UN treaty stipulates that space exploration be conducted for the benefit of all mankind, and instructs signatories to inform the secretary general of "the nature, conduct, locations and results" of their activities in space. But it hasn't always been observed to the letter.

In the brief history of international space law, Goodman learned, the only specific reference to extraterrestrial life was in a 1979 UN treaty titled "Agreement Governing the Activities of States on the Moon and Other Celestial Bodies." That treaty requires all space-faring nations to "promptly inform the secretary general, as well as the public and international scientific community . . . of any indication of organic life."

This treaty was too vague, Goodman concluded. What about nonorganic evidence, like robot probes? Another problem is that, unlike the earlier treaty, the 1979 one has not been signed by either the U.S. or the Soviet Union. Only 11 countries have signed so far--France, Austria, India, Morocco, Peru, Guatemala, the Philippines, Uruguay, Romania, Chile, and the Netherlands--hardly the vanguard in the search for extraterrestrials.

So Goodman wrote a new agreement. He admits he was naive at first, envisioning First Contact as a close encounter between our shuttle astronauts and an alien spacecraft, or the unearthing of some otherworldly artifact by a new lunar expedition. His first draft, finished in December 1985, even contained a clause granting extraterrestrial spacemen the same diplomatic immunity that the '67 treaty affords Earth astronauts from any country should they splash down in unfriendly waters.

Goodman circulated his draft, and NASA contacts sent him to Jill Tarter. An expert in high-energy astrophysics, Tarter hooked up with NASA's SETI while doing postdoctoral work at the agency's Ames Research Center near Palo Alto, California. She is rumored to be the model for the fictional Ellie Arroway, the astronomer who intercepts an alien message in Carl Sagan's novel Contact: both women are brilliant, outspoken scientists at the top of a male-dominated profession; both are passionate in the belief that SETI should be a planetwide effort transcending local politics. Tarter tacitly acknowledges her connection to Arroway. "Carl's an old friend," she laughs.

Before Goodman came along, Tarter and fellow NASA researcher John Billingham had been prodding the international scientific community to draft an agreement regulating SETI-type research. They saw Goodman as a valuable ally, but thought his agreement needed work. "We had a long discussion with Allan," recalls Tarter, who says they convinced Goodman that the probability of an extraterrestrial visit was extraordinarily low.

Though Tarter is a big Star Trek fan, she knew that interstellar travel wasn't as easy as "Ahead Warp Factor 7, Mr. Sulu." She explained to Goodman that even at the velocity of light--the universal speed limit, according to Einstein's theory of relativity--a journey to the nearest stars would take years. And boosting a modest payload to a fraction of the speed of light would require hundreds of thousands of times more energy than the U.S. electric industry generates in a year.

Tarter encouraged Goodman to dump the idea of face-to-face contact with ETs and to start thinking about communicating with them via radio waves. Radio, after all, is cheap, safe, and effective. The antennae of NASA's deep-space network are still picking up signals from the Pioneer 10 spacecraft, which was launched in 1972 and is now some four billion miles away, even though it transmits with one twentieth the energy of a candle flame. The 1,000-foot-diameter radio telescope in Arecibo, Puerto Rico, could theoretically communicate with a similar observatory parked halfway to the center of the galaxy.

Goodman maintains that interstellar travel may be practical for an advanced civilization: there may be holes in our theories and physical constraints that we don't have an inkling of at present. But he saw Tarter's point. "It occurred to me that if I tried to push an agreement that stressed physical contact, the chances of success would be nil," he says. "So I took their advice: to concentrate on radio as the initial means of contact."

Tarter and Billingham invited Goodman to attend the 1986 Congress of the International Astronautical Federation in Innsbruck, Austria, where he presented a paper that spelled out the basic principles that a SETI agreement might incorporate ("Diplomacy and the Search for Extraterrestrial Intelligence"). The following year the group drew up the nine-point protocol at the Astronautical Federation's conference in Brighton, England. Goodman didn't attend, but he estimates that more than 30 delegates helped shape the agreement. The drafters continued to correspond, with Michael Michaud of the State Department acting as informal secretary. Some fine tuning was done at a conference at Georgetown in September 1988. Though Tarter and Michaud say everyone approved of the agreement's basic principles, there were some minor haggles over wording.

The nine articles of the "Declaration of Principles Concerning the Detection of Extraterrestrial Intelligence" are as straightforward as the Ten Commandments.

Article one stipulates, not in so many words, that Thou Shalt Wait Before Calling the Media. Inserted at the insistence of astronomers such as Peter Boyce of the American Astronomical Society, article one directs research organizations discovering a possible alien signal to hold off making a public announcement until they "verify that the most plausible explanation for the evidence is the existence of extraterrestrial intelligence rather than some other natural phenomenon."

Originally, the space lawyers were "woefully ignorant" of this need, says Boyce. "Everybody assumes [the communicator] will be like ET and start talking right away. It won't be like that at all!" He added that the more information that is packed into a signal, the more difficult it will be to pick out from random background noise.

"Crying wolf is really bad news in this arena," notes Tarter. NASA, she says, already has rigorous procedures to test whether radio signals are of extraterrestrial origin. First, Earth-created signals need to be weeded out, which radio telescopes can do easily. A radio telescope, a gargantuan satellite dish, gathers electromagnetic waves and focuses them on an antenna at its center. If a signal is from Earth, it will come in from every direction. But if a signal is from an alien sending us intergalactic mail, it will only come in when the radio telescope is aimed at the ET's home.

Another way to prevent false alarms is by comparing the movement of the signal to the orbit of the ET's suspected home. NASA also double-checks signals with observatories all around the world. Even the computer software that runs the radio telescopes is suspect. "Probably the easiest way to create a hoax would be to put the signal into the software," says Tarter. "This may become the new hacker's delight."

Article two of the agreement states that before going public, the discovering party will "inform all other observers or research organizations that are parties to this declaration, so that [they] may seek to confirm the discovery by independent observations . . . and so that a network can be established to enable continuous monitoring of the signal."

Article two is not just scientific glasnost. Earth's rotation may carry the signal temporarily out of range of our tracking stations, and we may risk losing part of the message, maybe the most important part--the primer that would help us decode the rest of it. Even by observing the physical properties of the signal alone, says Tarter, we can learn a lot about the source and the technological level of the senders.

Once the "phenomenon" has been positively identified as an extraterrestrial signal, article three comes into play. The discoverer is supposed to inform the UN secretary-general and a half dozen international scientific organizations that represent the world's space scientists. Observers are to report to the Central Bureau for Astronomical Telegrams of the International Astronomical Union--the same clearinghouse major observatories use to notify each other of comets and novae.

Article four calls for the prompt dissemination of the confirmed detection of extraterrestrial intelligence, "openly and widely through scientific channels and the public media." The discoverer, appropriately, wins the right to hold the first press conference.

If NASA is the lucky one, the fateful announcement will be made jointly by the Office of Space Science and Application in Washington, D.C., and NASA's SETI headquarters at the Ames Research Center in California. Tarter believes that NASA will have to tread a "dicey fine line" between making a premature announcement and beating the inevitable rumors and half-truths to press.

Article five maintains that "all data necessary for confirmation of detection should be made available to the international scientific community through publications, meetings, conferences and other appropriate means." In addition, by the terms of article six, all data will be recorded and stored permanently for future analysis.

The drafters worry about how government censorship might hamper scientific progress. As some scientists have speculated, a conversation with ETs--even if years elapse between question and answer--could advance our technology immeasurably. "A simple yes or no to the question of whether fusion energy research should be pursued would be worth tens of billions of dollars to the governments of Earth," SETI pioneer Frank Drake told Atlantic magazine last year.

At a talk Tarter gave at the Smithsonian Institution's Air and Space Museum in April, several members of the audience warned that the CIA or some other government agency might try to muzzle the scientists. "I don't think that can happen in our country," answered Tarter. One elderly gentleman rehashed the theory that there's a government corspiracy to hide the truth about UFOs.

Goodman, however, fears that the government might find a pretext to classify even the most innocuous "Hello. How are you?" He's speaking from experience. Between 1975 and 1980, Goodman served as a CIA analyst and an assistant national intelligence officer. He also briefed President Jimmy Carter on national security matters. "The scenario I worry about most is the detection of radio waves that appear to be nonnatural," he says. "And for the hell of it, or because it's interesting, or because it's the logical thing to do, somebody gives the tapes to the National Security Agency and says, can you make any sense out of this?

"The NSA breaks the code but won't reveal the information, because to do so would reveal intelligence sources and methods, that is to say, the power of their code-breaking. . . . [The message] is censored and restricted from the public and other countries not because it exists or what it says, but what the government can do in analyzing it."

Tarter won't speculate about what the aliens might want to tell us, but she has a strong hunch about how they'll address their communique. "It will not be a message sent to California or to the Soviet Union," she says, "but to the planet Earth." Decoding the signal might take years and require the best minds on this planet, she says, and Commission 51--the body of the International Astronomical Union concerned with SETI research--has been entrusted with keeping an up-to-date list of scientists who would be willing to work on such a project.

Article seven, Thou Shalt Not Clutter the Airwaves, requires the agreement's signatories to petition the International Telecommunication Union to protect the appropriate frequencies from any earthly interference. This is a sore spot for all radio astronomers. The radio airwaves are as jammed as city streets at rush hour with signals pulsing out of everything from fax machines to military radars to microwave ovens. NASA's SETI MOP will concentrate on what's called the "microwave window"--the portion of the spectrum between the infrared and long-wavelength radio regions that has the least interference from background noise. But, as a recent NASA publication warns, "if use of the microwave spectrum continues to increase at its present rate, the greatest exploration opportunity in the history of mankind may be placed . . . beyond our reach for the foreseeable future."

Article eight forbids any signatory from responding to a signal until "appropriate international consultations have taken place." The agreement does not specify what "appropriate" means.

The final article requires committees from the International Academy of Astronautics and the International Astronomical Union to "conduct a continuing review of procedures." If evidence of extraterrestrial intelligence is found, the parties will set up an international committee "to serve as a focal point for continuing analysis . . . and also provide advice on the release of information to the public."

Exobiology, the study of the origin and distribution of life in the universe, is a respectable science today. But not long ago the public indiscriminately lumped serious scientists with UFOlogists, Trekkies, and purveyors of ancient-astronaut theories. In fact in 1978 Senator William Proxmire awarded NASA his "golden fleece" award when he learned the agency was conducting SETI research. Proxmire struck again in 1982, tacking an amendment onto an appropriations bill that temporarily prevented NASA from spending any newly approved money on SETI.

The question of whether the universe hosts other inhabited worlds has been the subject of earnest and passionate debate for at least 2,400 years. The earliest opinion on record was expressed by Metrodorus, a Greek philosopher who lived in the fourth century BC. "To consider the Earth as the only populated world in infinite space," he wrote. "is as absurd as to assert that in an entire field of millet only one grain will grow."

Luminaries during the intervening centuries who believed in a richly populated universe include Johannes Kepler, Isaac Newton, Voltaire, Immanuel Kant, and Benjamin Franklin. Perhaps the earliest forerunner of SETI MOP was conducted by William Herschel, the 18th-century British astronomer who discovered the planet Uranus. Herschel scoured the moon's surface for signs of civilization and imagined that he saw roads, pyramids, and forests.

It wasn't until the 19th century that scientists proposed schemes for communicating our existence to the hypothetical extraterrestrial. Karl Gauss, the great German mathematician, suggested planting an immense forest in the shape of a right triangle. Presumably, this was to let the aliens know we had discovered the Pythagorean theorem, mathematics being the universal Ian guage. Some of his colleagues suggested that building immense bonfires in the Sahara might do the trick just as well.

As planetary astronomy progressed from spyglasses to satellite flybys, scientists found no evidence of non-Earth life forms. The other planets in our solar system appeared too hot or too cold, too airless or enveloped by noxious gases. Exobiologists have pinned their final flickering hopes of finding life on Saturn's moon Titan and on Mars, where there might be fossil traces of microorganisms in the subsoil, remnants of a time billions of years ago when the red planet still possessed liquid water.

That leaves the stars. But they're trillions of miles farther away. No earthly telescope can resolve habitable planets at interstellar distances. In 1959, however, Cornell University physicists Philip Morrison and Giuseppe Cocconi proposed that electromagnetic waves would be the ideal medium for interstellar communication and even suggested one relatively static-free portion of the electromagnetic spectrum--the 21-centimeter wavelength of the hydrogen atom--that other civilizations might reserve for a galactic broadcasting network.

The first to pick up the gauntlet was Frank Drake, a young astronomer with the National Radio Astronomy Observatory in Green Bank, West Virginia. In 1960 Drake spent about two weeks observing a pair of nearby stars with a single-channel receiver. Drake whimsically named the search Project Ozma, after the mythical land over the rainbow in Frank Baum's children's books. Result: one heart-pounding false alarm, which turned out to have emanated from a passing military plane. Otherwise, silence.

Since then more than 40 SETI endeavors have been conducted in half a dozen countries. Some are government funded. Others are private efforts, such as Harvard University's current Mega-Channel Extraterrestrial Assay, which is bankrolled by a $100,000 grant from Steven Spielberg.

They all share one trait: failure. Not one has turned up a signal that can be verified as originating from an extraterrestrial civilization. Of course, the logistics of the problem are enough to scare off all but the most patient and optimistic astronomers. There are about 400 billion stars in the Milky Way alone, and millions of frequencies that alien intelligences might be broadcasting on. The guesstimates of how many civilizations exist out there range from a million to zero. How long might they last before they blew themselves up? How long might they conduct their own SETI projects before they got bored and gave up?

NASA, however, believes it can narrow the odds considerably with a device, now being perfected, called the multichannel spectrum analyzer (MSA), which ultimately will be able to eavesdrop on 10,000,000 channels per second, at a frequency range 10,000 times greater than monitored in previous SETI surveys. While radio telescopes act as the ears, collecting and focusing electromagnetic emanations from the sky, the MSA and its accompanying computer system act as the brains, separating the faint, narrow-band signal of an extraterrestrial message from the vastly noisier electromagnetic emissions of our own technology and from the broad-band radiation from natural sources like the sun. During the 90s NASA will conduct both a general sky survey and a more intense targeted search of 800 to 1,000 sunlike stars within a 100-light-year radius of Earth.

Confidence is running high. John Rummel, director of NASA's exobiology programs, predicts that the device will gather more data in the first half hour it's used than was gathered in all previous SETI searches combined.

What if we do make First Contact? How do we respond? Do we respond? "I have to tell you, I haven't thought about it," says Goodman. "I don't know what we ought to do."

Rummel says we'll cross that bridge when we come to it.

Originally, the SETI agreement did contain a section on drafting a reply. No actual reply was written; instead the drafters scripted 12 general principles to consider before radioing a message from Earth. These principles run the gamut from "respect for the territory and property of others," "recognition of the will to live," and "fair play, justice and mercy" to "truthfulness and non-deception," "peaceful and friendly welcome," and "respect for knowledge, curiosity and learning." According to Goodman, this was largely the work of Ernst Fasan, an Austrian legal expert who has written extensively on the subject of "meta law"--the rules of conduct that must apply to all intelligent beings.

At the Brighton conference the drafters decided to break the reply principles out into a separate agreement. "The questions here are far more sweeping, addressing political and moral values," says the State Department's Michaud. "We're talking about organizing the entire human species. It could take years, if not decades."

The supplemental agreement, which has been put on the back burner, imagines that the guys from outer space might not be friendly forces. Before communicating with the ETs, scientists must "consider detailed information about mankind to be a commodity of high value which will not be transmitted without due attention to human security and well-being, and to reciprocity." If the visitors are hostile, "no nation shall act without consulting the Security Council of the United Nations."

Tarter chuckles when these caveats are brought up. "It was a very emotional thing," she says. "Everybody's favorite science fiction scenario of contact came to the surface. The agreement will probably have to be reconstituted from scratch."

Contemplating interplanetary war is downright presumptuous of us Earthlings, in the view of scientist Carl Sagan. In his book Cosmos, Sagan notes that because we've recently acquired the technical know-how to communicate over interstellar distances, any societies we contact will likely be more developed than ours. If they coveted our real estate, they could dispatch us easier than the white man dispatched the Indians or the aborigines. "If an interstellar armada appears in our skies," writes Sagan, "I predict that we will be very accommodating."

Sagan, Tarter, and other SETI scientists believe that such a civilization would have a system of ethics as advanced as its physics. In order to have avoided exterminating itself by nuclear war, pollution, or depletion of natural resources, it must have learned to live in harmony with its own members and nature. Some have suggested that it would need a code--something like Star Trek's prime directive--to keep it from meddling with the development of promising but still savage newcomers.

But not everybody believes that there's a kinder, gentler universe beyond the solar system. James Trefil, an astronomer at George Mason University, says the guiding principle of evolution is "nice guys finish last." Hunter-carnivores, for instance, tend to have bigger brains than peaceful, grass-munching herbivores. "From our experience in human affairs," says Trefil, "the ones who go out and colonize are not the noble savages living in peace, but the aggressive bastards like ourselves."

Any race with the will and the technology to circumnavigate interstellar space must be very aggressive and ambitious indeed, Trefil fears. He goes so far as to say that if they exist, it could be bad news for us. "They're the Klingons!" he warns.

Goodman concedes that there's a danger in searching for extraterrestrial life. "Based solely on human history," he says, "I can't think of any seafaring or colonizing civilization that didn't bring with it conquest, disease, slavery, and imposition of their values." But he adds, "There isn't any way to empirically test or verify either opinion. We don't know at what point technology makes people adopt new, more human values."

At this stage, Goodman notes, the point is moot. There's no way we can turn off the lights and pretend we're not at home. NASA has already sent several probes zipping out of the solar system with metal plaques revealing our position and with packets of written and recorded messages. In 1974 the radio telescope at Arecibo was used to broadcast a message to a distant star cluster. For the better part of a century now, radio and TV broadcasts have been leaking out of Earth's atmosphere and expanding outward at the speed of light. Conceivably, civilizations in nearby star systems could have unscrambled the carrier signals into sound and pictures and might already know a lot about our culture from such emissaries as the Lone Ranger, Lucille Ball, the Shadow, Mary Tyler Moore, Archie Bunker, Bill Cosby, and David Letterman. "We emit a vast amount of nonnatural radiation. Any space-faring civilization would discover us," asserts Goodman. "You can't hide Earth."

So far no one is heading for the hills in anticipation of a War of the Worlds style invasion. Actually, if any notion gives SETI proponents reason for pause, it's the possibility that maybe we are alone in the universe.

Philosophically, they fall back on a principle called the "assumption of mediocrity." This states, in essence, that it's safer to assume Earth is a run-of-the-mill planet circling an equally nondescript star, rather than a one-of-a-kind oasis in an otherwise insentient universe. "Given the vastness of the universe," says Goodman, "it's impossible for me to conceive that there are 10(22) stars and around none of those stars are any planets." He believes that the same processes that created life on Earth would operate elsewhere in the cosmos.

Back in 1961 Frank Drake devised a complex formula--now called the Drake equation--for estimating the number of techno-savvy civilizations dispersed throughout the Milky Way. You start with the number of stars in the galaxy, and pass it through a series of successively smaller bottlenecks. Not all stars are suitable for incubating life. Most belong to spectral types that are too hot and short-lived, or too cool and feeble. A planet must be the right size and distance from its sun so that water can exist in the liquid state. Then life has to evolve--not just protozoa and lichens, but an intelligent, manipulative form capable of carving stone and smelting ore and eventually building its own radio telescopes. (Tarter sometimes argues that SETI is a misnomer. We're not looking for signs of extraterrestrial intelligence but for extraterrestrial technology. Dolphins and whales may be intelligent, but there's no way they could signal their existence to another planet.) Finally, the communicative phase of the alien civilization has to coincide with ours. Depending on what rough figures you plug into the Drake equation, you can come up with millions of civilizations or, if you count us, as few as one.

Trefil opts for the latter total. He's willing to concede that other planets may harbor the equivalent of algae or even dinosaurs, but believes that we are the only technological civilization in the galaxy. In his book Are We Alone?, coauthored with Robert T. Rood, Trefil argues that life, and especially intelligent, technology-building life, is probably a far more unlikely occurrence than earlier generations of scientists realized. If Earth's size or distance from the sun had differed by as little as 5 percent, if plant life hadn't developed photosynthesis and started pumping oxygen into the atmosphere, if animals hadn't evolved a way of utilizing this poisonous and corrosive gas, if the Earth didn't have a large satellite to whip up tides and create inland pools to serve as a springboard for the colonization of dry land, if our planet didn't experience periodic ice ages harsh enough to challenge man's ingenuity but not severe enough to wipe him out--you wouldn't be here reading this, argue Trefil and Rood.

Tarter won't even hazard a guess on the prevalence of life, intelligent or otherwise. "There's so much we do not know and cannot know from studying our statistic of one." Trefil agrees, adding that he is very much in favor of SETI. "The searches so far have not been nearly comprehensive enough," he says. "And besides, either answer--positive or negative--has major implications for the human race."

If NASA's SETI MOP turns up nothing, it wouldn't necessarily mean that we have the Milky Way to ourselves. To prove that conclusively, claims Tarter, we'd have to examine every star in the galaxy not only for directed signals but for the faint leakage of extraterrestrial radio, TV, or radar. This is well beyond our current capabilities.

But even under the most pessimistic circumstances, Tarter believes that the drafting of the SETI agreement would be more than an academic exercise because it helps promote global cooperation. Contemplating these questions, she says, "forces us to look at ourselves and our world with a slightly different perspective. The political lines we scratch on the surface of the planet and fight over so vigorously become insignificant. If we are alone, we have an even graver responsibility to preserve this very rare commodity on this planet."

Art accompanying story in printed newspaper (not available in this archive): photos/John Anderson, Carol Harrison.

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