Signals From Aliens?

It seems like every so often somebody reports on alien signals being detected, and the signals turn out to be coming from some previously unknown non-alien source. The classic case was when pulsars were discovered. These objects send out regular signals, which were first interpreted as possible transmissions from a technologically advanced alien civilization. As it turned out, the periodicity was simply due to the unusual makeup of these objects rather than anything technological.

Also this last year, scientists became aware of a star that appears to be dimming over time in an unusual pattern. One possible hypothesis was that aliens were constructing some sort of megastructure, like a ringworld or a Dyson sphere, around the star. Subsequent measurements showed that there did not seem to be any additional energy emissions from the star that would indicate advanced technology, so the most likely explanation was a natural one.

But that didn't settle the question, either. As it turns out, the star has slowly been dimming for some time, ever since we started making measurements of it. While some of the natural explanations like a halo of comets around the star could account for some of the observations, they could not explain this long-term pattern. Most likely, the star is just behaving in an unusual, star-like manner that doesn't involve aliens, but the possibility is still out there.

Then recently, another set of anomalous signals were recorded. Several scientists have now gone on record stating that they think there is a good chance that this time, what we're seeing is some form of alien communication. But others are not so sure, no doubt remembering cases like pulsars which at first seemed to be such clear cases of regular, periodic signals that appeared technological in origin.

“We find that the detected signals have exactly the shape of an [extraterrestrial intelligence] signal predicted in the previous publication and are therefore in agreement with this hypothesis,” write EF Borra and E Trottier in a new paper. “The fact that they are only found in a very small fraction of stars within a narrow spectral range centered near the spectral type of the sun is also in agreement with the ETI hypothesis,” the two scientists from Laval University in Quebec write.


The research has appeaed in the journal Publications of the Astronomical Society of the Pacific, under the title 'Discovery of peculiar periodic spectral modulations in a small fraction of solar type stars'. It appears to have been originally suggested for publication with the name 'Signals probably from Extraterrestrial Intelligence', according to a pre-print version of the paper hosted online.

But they make clear that further work will need to be done to confirm or deny that hypothesis. That will need to be done by watching for the same signals on different equipment so that all other explanations can be discarded.

Given the size of the universe, the existence of alien life is basically guaranteed. Questions remain, though, about how common intelligent life is and how many of those species might have develop advanced technology. Recent research has shown that Earth does have some unusual characteristics not shared by a lot of other planets, such as a large moon and a strong geodynamo that protects the surface from cosmic radiation, which might mean that life-supporting worlds are few and far between.

And from there, the problem with determining the likelihood of other technological civilizations is that we only have a sample size of one, from which no statistical conclusions can be drawn. The less likely technologically advanced aliens are, the further we will have to go to find them - and the further their signals will have to travel to reach us. Humans have only been capable of broadcasting signals strong enough to reach into space for about a hundred years, and a hundred light years is no distance at all in interstellar terms.

I'll be watching this story to see if the alien hypothesis is upheld by subsequent research, or if the source turns out to be something natural like what happened with pulsars. Of course, contact from aliens would be pretty momentous, and if it does eventually happen, this is probably exactly how it would start - with anomalous readings that defy all other explanations.