On April 8, it will be exactly four decades since radio astronomer Frank Drake swung an antenna skyward hoping to find something other than the faint hiss of gas and galaxies. Drake was searching for a narrow-band whistle, a signal from a distant civilization.

His pioneering experiment used a small radio telescope in Green Bank, West Virginia. Since then, the search for extraterrestrial intelligence (SETI) has progressed to vastly improved equipment. Nonetheless, the dismaying fact is that none of the small coterie of scientists pursuing SETI have yet managed to find a single, confirmed chirp from the dark depths of the cosmos. The aliens, who I feel confident are out there, remain frustratingly out of sight.

But not out of mind. Today’s SETI experiments are some 100 trillion times better than Drake’s original search. In the next decade, new technologies and new telescopes will improve the capabilities for finding celestial societies by another factor of a thousand. While no one can be sure of success, many astronomers involved in these efforts, including me, suspect that we could soon have our first detection of an alien signal.

Preparing for Contact

If so, what happens next? Is humankind prepared to learn that the fictional aliens of Hollywood have living, unpredictable counterparts in the local galactic neighborhood? Would the news galvanize people with the excitement of a major discovery – or, alternatively, sound the alarms of fear?

The SETI Declaration

PhotosToGo Cultures have collided before - ruins from the Mayan civilization.

In addition, the SETI researchers themselves have adopted an informal protocol that outlines actions to be taken by the discoverers. This protocol, A Declaration of Principles Concerning Activities Following the Detection of Extraterrestrial Intelligence, assumes that our first tip-off of alien presence will be a radio (or optical) fingerprint: a signal from space.

This is the type of search that I’m involved in. It is, of course, a direct descendant of Drake’s 1960 experiment. My employer, the SETI Institute, is currently using the 1000-foot diameter Arecibo Radio Telescope in Puerto Rico to examine approximately a thousand nearby star systems for alien transmissions. This type of reconnaissance makes a lot of sense. It doesn’t involve the assumption that the aliens are mounting a prodigious effort to get in touch. If a civilization 100 light years distant has an antenna the size of Arecibo, and beams a signal straight towards us, then a paltry 10 kilowatt transmitter will be sufficient to catch our attention.

NASA The Arecibo Radio Telescope - searching for extra terrestrial life

Finding a signal may be our best hope for locating cosmic confreres. Anticipating this, the Declaration defines a series of steps that researchers should undertake to verify that the broadcast is truly extraterrestrial, and then it urges a rapid announcement to the astronomical community, to local governments and to the public. In other words, if our radio telescopes pick up ET, you’ll quickly be reading about it in the papers. And because so many among the populace are convinced that aliens exist (even to the point of being blasé), there’s little chance of rioting in the streets.

Mind you, some people, particularly in the United States (where belief in government conspiracy is considered a mark of political sophistication), are sure that a SETI detection would be hushed up rather than let loose on a labile public.

I am amused by this paranoia. Most SETI experiments, including all of the US efforts, are privately funded, and the government has no involvement. More to the point: there is no policy of secrecy within the research community, which means that – even as an interesting signal is being received – the scientists will be excitedly e-mailing friends and relatives.

I’ve seen this process in action on a few occasions, when our experiment has been briefly fooled by picking signals from space probes. These messages from robots that we’ve sent to the edge of the Solar System have many of the hallmarks we expect from an alien signal. While my colleagues and I were looking wild-eyed at the computers, I noted that the government showed no interest. The media, on the other hand, did.

And even those who believe in a government conspiracy over UFOs could hardly claim the same for SETI. A signal from space is not something you can stack up in a secret hangar or hide behind six layers of barbed wire in the desert. A SETI signal can be easily confirmed and will be impossible to hide. There was a parallel in the seventeenth century. When clerics forced Galileo to desist from publishing his discoveries of Jupiter’s large moons (a strong proof that the Earth was not the center of the Universe), he reputedly swallowed hard and muttered that "still, it moves." In other words, the evidence for his discovery was sitting in the sky awaiting confirmation by anyone with a cheap telescope and a few minutes’ time. The same is true of a SETI signal: the word will be out, and fast.

Australia National Telescope Facility The Parkes Telescope in Australia is part of SETI's SERENDIP programme

Alien hardware

Of course, it’s also conceivable that we will find not a signal, but alien artifacts. Imagine that Hubble or some other large telescope accidentally captures an image of the exhaust radiation from an interstellar rocket. Or perhaps we will trip over colossal feats of astro-engineering involving the rearrangement of an alien society’s entire planetary system. Such discoveries would undoubtedly be reported just as quickly as a SETI signal. The consequences, to my mind, would also be similar: a mammoth news story, inspiring follow-up research by just about every astronomer on the planet.

If the artifact were right on our doorstep, however, it would trigger a different response. We might – as suggested by Arthur C. Clarke - discover a purpose-built monolith on the Moon. Another intriguing possibility is that we could find a time capsule at one of the Lagrangian points – gravitational dead spots in the Earth-Moon system where an alien memento could float in endless space storage. Perhaps we’ll suddenly uncover an interstellar probe hanging out in our Solar System, or maybe the aliens will actually land at 10 Downing Street and demand satisfaction.

Such scenarios are entirely different (and, to my mind, enormously less probable) than the SETI success that I am considering here. They would provide physical evidence we could cart to the lab and – in the case of alien visitation – might confront us with a lethal threat. Some of the social researchers who consider what will happen if we find ET point to historical analogs such as Orson Welles’s 1938 War of the Worlds radio broadcast, which panicked many people on the US East Coast. Such an apocalyptic reaction might follow a close encounter of the physical kind. But a microwave radio signal or a flashing infrared light beam, reaching us from hundreds or thousands of light-years away, is no reason to board the windows and head for the hills.

Instead, we’ll slew all the telescopes we can in the direction of the incoming signal. Every observatory that can aim its instruments ET’s way will do so. We’ll quickly know something about the type of star system that houses this newly found society, as well as its distance. In addition, we can hope to measure slow shifts in the frequency of the incoming signal, caused by the Doppler effect as the transmitter moves. Assuming ET is broadcasting from a planetary surface, we’ll be able to compute the length of the alien planet’s day, and its year.

SETI The mesage sent out from the Arecibo Telescope - could you decode it?

Message in a radio wave

All of this information will be exciting, yes, but what would really knock our hosiery off is to know what the aliens are saying. That requires additional work beyond detection. To make them more sensitive, the SETI receivers add up the incoming radio waves over fixed period – the time constant – which is typically a second or so. As a result, any variations in the signal that are faster than once per second are smoothed out and lost. A terrestrial TV signal, for example, varies about five million times per second, so if your home set were to have a one-second time constant, you’d find the telly a bore (or perhaps I should say, more of a bore). The screen would be a slowly changing, gray wash of light.

Simply shortening the receivers’ time constant isn’t the trick, however. That just weakens the signal and makes it noisier. What we need is to boost the signal first, so we can still detect it even with a shorter time constant. In practice, that means SETI researchers will have to build far larger telescopes than they have today - perhaps ten thousand times larger. That’s currently a financial impossibility, but if an alien signal is detected I fully expect that the money will be found to construct this super-instrument.

Suppose it happens. Suppose that we have not only tuned in to ET’s broadcast, but we are happily downloading the bits that constitute the message. These bits will be recorded and distributed for analysis. After years of work, either we will succeed in figuring them out, or we won’t.

It’s probably realistic to assume that we will comprehend the aliens only if they are broadcasting deliberately, trying to communicate with other worlds. They could be engaged in altruistic efforts either to enlighten their neighbors or simply get in touch with young, technological societies such as our own. In that case they’ll devise a message that can be decoded fairly straightforwardly.

Since it’s overwhelmingly likely that any civilization we detect will be technologically far older than our own, the message would be of great interest. The aliens could allow us to short-circuit thousands of years of research into physics, astronomy, and chemistry, and tunnel our way into a far more sophisticated future. This could be compared to the rediscovery of classical science during the Renaissance, but would be of much greater magnitude. (Mind you, this windfall of knowledge will impose certain burdens. Scientists, for example, will suddenly be confronted with answers to research problems that have consumed their entire careers. These earthly scientists may not be entirely gratified to yield their chance for a Nobel Prize to the aliens!)

Department of Education, Mexico A Mayan Codex - a cryptological puzzle from the past

Such a sudden discovery of knowledge is possible, and it’s an exciting thought. But it’s also conceivable – and I personally think more probable – that the message will be difficult and perhaps impossible to decode. Imagine if the classical Greeks were given the bits belched out by a modern telecommunications satellite. The Greeks were not dumb, but they wouldn’t get very far in understanding this torrent of information.

The same could well happen to us. Imagine everyone from professional cryptographers to amateurs with a flair for puzzles taking a crack at understanding the hieroglyphics from space. The aliens’ message would become the equivalent of a Mayan Codex or the Dead Sea Scrolls. Centuries of human effort might be expended in an attempt to understand this cosmic riddle beamed our way from a society we can never meet. When the headlines of the initial discovery are only a distant memory, humankind might still be busying itself with the message.

The signal is the message

Such thoughts are quite speculative – and they are also, in some sense, irrelevant. The detection of an alien civilization will certainly be the biggest news story of all time. And it will be a lasting story, both because researchers will continue searching for the message contained within the signal and because it will heighten the hunt for other signals. But to paraphrase Marshall McCluhan, the signal is the message. For a million years, humans have lived on this planet surrounded by a bubble of isolation. We have seen the Universe, like a vast and intricate construction, stretching billions of light-years in all directions. We have not, as yet, found any inhabitants.

But if SETI someday becomes a discovery, rather than an experiment, the bubble will burst, and we will suddenly share the cosmic stage with myriad others. It is hard to imagine a greater metamorphosis.

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