Scientists detect a strange signal from a nearby star — could it be aliens?

By Stefanie Waldek
December 22, 2020

After the collapse of the Arecibo Observatory radio telescope in Puerto Rico this month, I’ve had the movie "Contact" on my mind, and two scenes in particular. The first is when Jodie Foster visits the telescope, of course, and the second is when she’s reclining on the roof of her car, headphones on, and (spoiler alert!) hears an alien signal.

Credit: Auscape/Universal Images Group via Getty

Though "Contact," originally a novel by Carl Sagan, is a work of science fiction, some of the science behind it is not. Researchers around the world are continually monitoring the cosmos for signs of intelligent extraterrestrial life, including the team behind the Breakthrough Listen initiative. And that project, part of the Search for Extraterrestrial Intelligence (SETI) Institute, has had, well, a breakthrough.

As reported by The Guardian and Scientific American, the Breakthrough Listen astronomers discovered an unusual radio signal emanating from the direction of Proxima Centauri, the closest star to our sun, just 4.2 light-years away. The data was collected from the Parkes radio telescope in New South Wales, Australia, in April and May last year, and researchers have not been able to determine its source — at least not yet.

While astronomers very regularly encounter new radio waves in their observations, the vast majority of them come from human-made objects, whether that’s a microwave in the breakroom, a cell phone in the parking lot, or even a satellite in orbit. As such, researchers subject all discoveries to a series of checks to eliminate such interference. But this new signal, called Breakthrough Listen Candidate 1 (or BLC1), has cleared all of these checks, meaning it could be extraterrestrial in nature. 

Now, before you start thinking of little green men, radio waves emanate from many non-intelligent extraterrestrial objects, including nebulas, pulsars, and even planets like Jupiter. But BLC1 stands out from such signals due to its frequency — 982 megahertz — which is not typical of any known naturally occurring phenomenon. “For the moment, the only source that we know of is technological,” Breakthrough Listen project lead scientist Andrew Siemion of the University of California, Berkeley, told Scientific American. But human-made objects do not typically produce radio waves at this frequency, either.

Could BLC1 be a sign of intelligent alien life? It’s possible, though very unlikely. The team suggests it probably has a rather mundane source — they just haven’t determined what it is yet. But then again, it’s 2020, and I still have “alien invasion” open on my Bingo card.