I thought of ETIs because of recent sudden reports of their appearance. About 40 residents of the town of Stephenville in Texas reported seeing a UFO a few weeks ago. And then the website Machines Like Us highlighted the reception of a mystery signal by a radio telescope in Puerto Rico. Nothing definitive has been said about the source of either signal, leaving the field ripe for speculation by ETI believers.

Now I think it is likely that there is life somewhere out there in the universe. The huge number of stars in the universe seem to imply that as long as the probability of life emerging spontaneously is not zero (and we know this is true since we are here), then we should not be surprised at it occurring in other places, perhaps in many places. The catch is that given the size of the universe, the probability of any one of these forms of life encountering another is very small. The most likely way that we will detect their presence is by accident, if they happen to send out a signal strong enough in all directions so that is it detectable by us even at these huge distances. Even then, although we would know the direction from which the signals came, it would be hard to know how far away they are. The premise of Contact was that a planet fairly close to us (near the star Vega just 25.3 light years away) containing ETI had received our old TV signals, thus discovering our existence, and then decided to reach out to us.

But although I think that it is likely that ETIs exist, what I am really skeptical about are the usual reports of UFOs and other sightings, where alien spacecraft dart hither and thither at high speed, playing peek-a-boo with us. If intelligent life evolved near other stars long enough ago that they could travel the likely millions of years necessary to get to Earth, they must be possessed of a vastly superior science and technology than us simply in order to even find us.

After going to all that trouble, why would they then start playing the fool, scaring the daylights out of rural Americans? And why is it that it seems like it is mostly rural Americans who get these visits? Why don’t they drop in on Central Park in New York City?

While it seems likely that the present kinds of UFO sightings are nothing more than misidentifications, the idea that we could receive a signal from ETIs is intriguing and worth mulling over. The most likely thing to happen is that we do get some sort of identifiable, non-noise, intelligently created electromagnetic signal from outer space, broadcast by the inhabitants of some distant planet without any specific intention of contacting anyone, just the way our own radio signals have been beamed out to the universe for the last 100 years or so and TV signals for about 70 years. Electromagnetic waves have some huge advantages as communication devices: they can carry detailed information, can travel through the vacuum of empty space, and travel at the fastest possible speed allowed by the laws of science, which is the speed of light. But that very fact shows how limited our reach is, since it would take about 100,000 years for these waves to just cross our own Milky Way galaxy.

Even if we did get such an unambiguous signal about the existence of an ETI from some source and could decipher it, there is little that we could do with it, just the way that a distant civilization would be baffled if, millions of years from now, they were to pick up the weak signal from a broadcast of American Idol. We would not be able to communicate back and the long times involved in sending and receiving messages would sap the enthusiasm of the most ardent believer in ETI. In science fiction, this limitation is overcome by invoking speculative scientific exotica like black holes and worm holes that enable space travelers to circumvent the speed-of-light limitation and somehow ‘tunnel’ to distant locations in very short times. But while that meets the plot needs of authors, there is no hard evidence that such things exist or, if they do, could be used for such kinds of travel.

But if we leave all these kinds of exotica aside, what intrigues me is what would happen if we simply experience the absolute minimum, which is the receipt of some signal that unambiguously indicates that somewhere out there, however far away and unreachable, there exists intelligent life. Would that change anything here? Would it influence the way we think and behave amongst ourselves, even if there was no possibility of actually communicating with that intelligent life? Or would the novelty soon wear off, and we go back to our usual practice of killing each other?

Next: How should we react to receiving a signal?

POST SCRIPT: Wisdom beyond any price

What would be do without our profoundly wise national commentariat?