SETI: an Exercise in fatuous Whimsicality?
Among the intelligentsia of our age, few scientists of international note have displayed more preoccupation with the idea of extraterrestrial intelligence than did the late Dr Carl Sagan. He wrote extensively on the subject in several of his numerous books, mostly non-fiction but including one novel, a science fiction extravaganza entitled Contact.
On 3 March 1972, the spacecraft Pioneer 10 was launched from Cape Kennedy, expressly to explore the environment of Jupiter and, en route, to photograph any of the estimated 500,000 or so minor planets that it might encounter while negotiating the asteroid belt between Mars and Jupiter. Swinging around the giant planet, the craft's velocity was accelerated by Jupiter's gravity to a speed of 11 km per second sufficient to send it hurtling onward to become the first man-made artifact ever to leave the solar system, never to return.
A few weeks prior to the launch date, Dr Sagan came up with a novel idea, which he put to the project directors at NASA. Would they agree, he asked, to the placement of a small metal plaque on the spacecraft's structure, upon the surface of which would be engraved a message from Earth? In the event of the craft ever being intercepted by a race of intelligent beings, this message would tell them precisely where in the galaxy it had originated from, in what epoch it had been dispatched and - by means of a pair of simple drawings depicting an adult man and woman - what manner of beings had "posted" this letter to the stars. The message would be written in the language of science, on the assumption that any race sufficiently advanced to pluck a speeding artifact out of deep space would have no difficulty in interpreting its meaning.
To Sagan's delight (tempered, perhaps, by a measure of surprise) the NASA authorities welcomed the idea and gave him the go-ahead. The plaque, of gold-anodized aluminum and measuring 15 by 23 cm, was hastily prepared and attached to the antenna support struts. Pioneer 10 was successfully launched and our celestial epistle was on its way. Some 80,000 years from now it will have covered the distance to Alpha Centauri, our nearest stellar neighbor; but it's not going to Alpha Centauri. It is heading towards a point on the celestial sphere close to the boundary between the constellations Orion and Taurus, where there are no nearby stars. In the infinitesimally small likelihood of Dr Sagan's fond hopes ever being realized, it certainly won't happen within a period of many millions of years. As Sagan himself says in his book, The Cosmic Connection: "In the next 10 billion years, Pioneer 10 will not enter the planetary system of any other star, even assuming that all the stars in the galaxy have such planetary systems."
Fifteen months after the launch of Pioneer 10, its sister craft, Pioneer 11, blasted off from Cape Kennedy, carrying an identical message. Within the next few years, Voyager 1 and Voyager 2 were launched to explore the outer planets of the solar system, both of them, like their Pioneer forebears, destined never to return to Earth. They both carried the by now familiar diagram, but the "letter" had by now become a parcel. Aboard each craft is a long-playing record featuring electronically encoded images of Earth, spoken messages from an international assortment of political leaders and dignitaries, stirring music from some of our greatest composers and sounds from nature ranging from birdsong to the haunting calls of communicating whales. Assuming that the hearing of the recipients (if indeed they have ears at all) will be tuned to detect the frequency of this medley of sound, it is interesting to speculate on what they will make of it all.
By now the idea of interstellar communication had fired the imagination of people all over the world, although it was universally recognized that the probability of our messages ever being received and accurately interpreted was too remote to be regarded as anything more than a whimsical flight of fancy. Sagan, as much as anyone, was cognizant of this. But his thinking encompassed much more than the mere notion of correspondence by a cosmic postal service.
For more than a century now, radio signals have been racing at the speed of light through the vastness of space. Given that there are 25 individual stars within a distance of 12 light years from Earth, we can estimate by very rough extrapolation that those radio waves have by now streamed past some thousands of stars and whatever planets they might harbor. This is an unutterably small number when reckoned against the enormity of the universe and the likelihood that any one of them might be home to an intelligent life form must be considered improbable - although, in the light of our present dearth of knowledge, by no means impossible. What we can of course say is that if any of the earliest radio emissions from Earth should today be detected by intelligent beings on a world on the periphery of an Earth-centered sphere with a 100-light year radius, and if they decided to contact us, we would not receive their reply until sometime around the year 2108.
But rather than to sit and wait for the phone to ring, Dr Sagan and a group of colleagues elected to reverse the process: they would set a program in motion whereby they would actively hunt for electronic emissions emanating from other worlds. Thus the Search for Extraterrestrial Intelligence (SETI) came into being.
There was a precedent to their initiative in that, in 1960, Dr Frank Drake, a scientist at the National Radio Astronomical Observatory in West Virginia, detected a radio signal that seemed to be coming from a Sun-like star 12 light years distant. This gave rise to a good deal of excitement, but it was not long before the signal vanished. It reappeared several weeks later, but this time was soon identified as a transmission from a military aircraft broadcasting on an unauthorized channel. Far from being dismissed as just so much time wasted, however, the event was hailed as a positive demonstration that the detection of radio signals from an alien civilization was a practical possibility.
Be that as it may, a program called META (an acronym for Mega-channel Extraterrestrial Assay) was established in 1983 by the Planetary Society, whereby a search would be conducted to encompass the entire sky within a huge array of parallel swaths, all of them narrower than the diameter of the full Moon, sweeping repeatedly across the heavens and "listening" for about two minutes to every star encountered within an extremely narrow frequency range. Over the course of the ensuing five years, some 60 trillion observations were made at various frequencies. Within this vast multitude, just 11 observations yielded the kind of response the scientists were looking for. Alas though, in every case the signal persisted for a very short period of time before disappearing, never to return. Thus, although each of these observations passed muster in every other respect, they all failed the one most important test: not one of them could be verified. And so the search continues.
Which brings me to the focus of this article, which I put forward rather tentatively in recognition of Carl Sagan's immense reputation and undeniable brilliance. Simply put, is he correct in his apparent perception that electro-technological sophistication is the only criterion by which advanced intelligence can be measured? Is it not entirely possible that there might be other beings "out there" who are far more intellectually advanced than we are, yet who have never invented radio or, indeed, anything like any of the modern conveniences that we take for granted?
Consider this: sometime between 2575 and 2467 BC, at the behest of one of the pharaohs of the Fourth Dynasty , the ancient Egyptians built a pyramid, a single structure that covered an area of some 5.3 hectares - large enough to encompass, quite comfortably, a grouping of St Peter's in Rome, the cathedrals of Florence and Milan, Westminster Abbey and St Paul's Cathedral. At its base, the four sides of the Great Pyramid average 230.26 meters in length, with a difference between the longest and the shortest of just 20.32 cm - a tiny fraction of one per cent of the average length.
With uncanny precision the Pyramid's four sides are orientated to face the four cardinal points of the compass. This, in concert with a wealth of other geometrical features within the structure, suggests convincingly that it was built for some purpose hugely at odds with the traditional belief that it was intended to serve merely as an obscenely extravagant repository for a royal sarcophagus.
Some 2.3 million blocks of limestone and granite went into the Great Pyramid's structure: huge blocks of solid rock, many of them weighing several tons. Some of these had to be lifted almost 150 meters into the air before being placed into position with a precision that was and still remains nothing less than mind-boggling. Elsewhere in the Giza complex there are granite blocks, also high above ground level, which are so heavy that in the whole of the modern world there are only two cranes of sufficient power to lift them as much as a meter into the air.
How were such marvels of engineering achieved? Many theories have been advanced, some of them quite plausible; but no one knows for sure or, in all probability, ever will. What we do know, however, is that the great monuments of Giza were erected without resorting by any means to the generation of electricity. Small wonder that Jean-Francois Champollion, the founder of modern Egyptology, was once moved to remark that beside the Egyptians of old, "we in Europe are as Lilliputians."
In more recent history, men of towering intellect arose - men like Plato and Aristotle, Pythagoras and Euclid, Copernicus, Galileo, Newton the list is endless. In the sixteenth and early seventeenth centuries, William Shakespeare penned some of the greatest works of literature ever written. Perhaps "quilled" would be a better word, since at the time of his death the invention even of the dipping pen still lay more than two hundred years in the future.
Imagine, now, that there is a scientist of Dr Carl Sagan's ilk on a planet orbiting a star just a little further from us than, say, 105 light years. Right now, at this moment in time, he turns his radio telescope onto a not-too-distant star which, if he had access to the Hertzprung-Russell diagram, he would recognize as a yellow dwarf of the type G2V on the main sequence. This star, although he doesn't know it, harbors a planet called Earth. He studies the computer printout for a few minutes, hoping to see a pattern that might be indicative of incoming radio signals. "Nope!" he says eventually, with a philosophy born of many disappointments, "there's no intelligent life anywhere near that one." And moves on to the next star.
Have I made my point?
Sagan, Carl: Pale Blue Dot. (Audiobook recording no publication details available)
Sagan Carl and Agel, Jerome: The Cosmic Connection, Papermac, 1981.
Hancock, Graham: Fingerprints of the Gods, Mandarin Paperbacks, 1995.
Encyclopedia Britannica, 1970 edition.