The following essay was prepared for the Future Generations Forum, a hopeful and inspiring Web home for profound questions and lively discussion about our relationship with people not yet born. It is posted here by the kind permission of the World Future Society, sponsors of that Forum.
We were the only game in town -- but not for long. The young radio astronomer was fresh out of grad school. The ink on his diploma was as wet as he was, behind the ears, when he hit upon this ludicrous idea. Why not, Frank Drake figured in 1959, use his employer's radio telescope to search for intelligently generated signals from the stars? Only do so quietly, Drake cautioned himself; this science-fiction search might well be professional suicide. So he set to work, quietly assembling a crude, one-channel listening station, to train on two nearby, sunlike stars.
Then the Cocconi and Morrison article came out. In a brief letter in the scientific journal Nature, the two Cornell professors proposed the very search which Drake was setting out to perform! This is a prime example of what I call the Parenthood Principle: when a great idea is ready to be born, it goes out in search of a parent. Sometimes, it finds more than one. Now Schrodinger's cat was out of the bag, and Drake had to go public. But discretion still ruled the day. Even his first detection, of a classified military aircraft, was of necessity held close to the chest.
Today, SETI science has emerged out of the fringes, into the scientific mainstream. Along the way, we have developed technologies the likes of which the young Drake could scarcely have dreamed. Drake has grayed into the elder statesman of an established scientific discipline. In the past four decades, thousands of humans have conducted hundreds of searches for our cosmic companions, scanning billions of microwave and optical channels and spending millions of dollars in the process. SETI is no longer a four-letter word. But for all of our efforts, we are today no more successful than Drake had been with that first search at Green Bank.
So why do Drake, and his professional colleagues, and many a dedicated amateur, and your faithful correspondent himself, all continue to hit our heads against the brick wall of SETI silence? Possibly because this is the cheapest lottery ticket, with the highest potential payoff, in humanity's history. What is the worth of that one-in-a-zillion longshot of gaining entry into the cosmic community? The value of Encyplopaedia Galactica is incalculable. Even if we never manage to pry open its cover, the sure knowledge of its existence is enough to shake our species out of its chronic complacency. What's a trifling telescope or two, alongside that kind of payoff? To play is to anticipate defeat; to pass is to demand it.
We can improve our chances for success by redefining SETI. For as presently practiced, SETI is as narrowly focused as the spectral emissions which we hope to intercept. What started off as a search for microwave beacons should be expanded to encompass all signaling technologies which we can conceive, whether or not we can achieve them ourselves at our present level of societal and technical adolescence. Might we some day launch robotic interstellar probes? If so, then we should have an organized strategy for seeking out such probes launched by more advanced societies. Can we imagine the day when we will be capable of great feats of astroengineering? Then our present efforts should include a search for the engineering marvels of our more capable neighbors. Might our own starships someday leave a detectable residue? Then the search for the advanced propulsion signatures of others should be on our agenda. If we can imagine it, then we should be looking for it! For, as Haldane's Law teaches us, the universe is not only queerer than we imagine, it is queerer than we can imagine.
It could well be that we are at the midpoint of SETI. If technology continues to advance as it has in the past, forty years from now will likely see another billion-fold increase in search space. And perhaps that's what it's going to take to achieve SETI success. For this field of study offers little to he or she who demands instant gratification. Lest we become discouraged, we should remember that the forty years since Drake's first search constitute a mere eyeblink in human history.
So, where will SETI be in four more decades? Thus far, our technological progress (which SETI both reflects and stimulates) has been exponential. Like the expanding universe hypothesis, we have insufficient data to detect any slowing of that trend. In all likelihood, our receivers will soon span the electromagnetic spectrum, from radio through microwaves into the infrared, across the visible, ultra-violet, X-ray, gamma ray and cosmic ray spectra, all in real time. We are developing technologies today that will enable us to see in all directions at once. Forty years from now we will be scanning farther out in time and space than Drake ever deemed possible. If there are electromagnetically polluting civilizations out there, surely we will have detected their photonic debris by then!
Or, perhaps not. It could well be that as civilizations advance, they become, by design or chance, effectively invisible. In which case, forty years from now, we'll have arrived at an epiphany: we are not alone, but we might as well be.
And how might such an understanding impact on our view of humanity's place in the cosmos? My guess is that it would send us back to forty years ago, when we were the only game in town.
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this page last updated 4 January 2003
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