Researchers with the Breakthrough Listen project have detected a curious signal coming from Proxima Centauri, the star closest to the sun. The signal has been identified as a possible alien transmission, but like so many examples in the past, this latest detection is likely to be another dead end.
Scientists with the $ 100 million Breakthrough Listen project funded by Israeli-Russian billionaire Yuri Milner are currently working on a research report detailing this signal, but news of the detection somehow leaked to The Guardian last week. With the cat comfortably out of the bag, details about the strange signal now come out, but the supporting data remains unavailable.
This is what we know.
The narrowband radio signal, found at 982.001 MHz, was picked up by the 210-foot radio telescope at the Parkes Observatory in Australia, as Scientific American reports. The emission was found to be from Proxima Centauri, a red dwarf at a distance of 4.2 light years. The system is home to two known exoplanets, one of which, Proxima Centauri b, lives within the habitable zone. Interestingly, the frequency of the signal drifted a bit. This could be a Doppler shift caused by movement of the source, such as an exoplanet in orbit.
The Breakthrough Listen team, led by Andrew Siemion of the University of California at Berkeley, was not looking for aliens at the time. They had previously been looking for signs of flares coming from the red dwarf, as these eruptions could adversely affect habitability in the Proxima Centauri system. This data was collected in April and May 2019, but the signal was only recently spotted. Shane Smith, an undergrad at Hillside College in Michigan and an intern at Berkeley’s SETI project, found the signal during a routine review of the 30 hours of data, according to SciAm (imagine if they turn out to be aliens – Smith would immediately become the most legendary intern in history).
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The emission turns out to be a one-time event that only occurs once in the dataset. Since there was no clear source for the signal, the team named it BLC-1, which means breakthrough listening candidate 1. This is the first official candidate signal for the 10-year project, which started in 2015. Penn State University astrophysicist Sofia Sheikh will be the lead author of the upcoming paper, expected in early 2021, as SciAm reports.
There is a very small chance that the signal was produced by an alien intelligence, be it an incidental radio leak or a targeted transmission designed to get our attention (i.e. a possible technical signature). Indeed, the Breakthrough Listen researchers themselves fully expect that BLC-1 is not aliens. As Pete Worden, the Executive Director of the Breakthrough Initiatives, told SciAm, “it’s like 99.9%,” not aliens.
Importantly, terrestrial interference, such as a microwave or any other distraction, has not yet been ruled out as a possible source of the radio radiation. BLC-1 releases the 1977 WOW! signal to the mind, which was not repeated either, making it difficult for scientists to study (recent research suggests it came from a hydrogen cloud caused by comets).
That BLC-1 came from aliens is unlikely for a number of reasons.
First of all, BLC-1 appears to be an unmodulated signal. It’s a dull, unchanging tone. If aliens tried to contact us, they would certainly make the message a little more interesting, such as sending a series of eye-catching prime numbers, as depicted in Carl Sagan’s Contact. The unmodulated nature of the signal also makes it a poor candidate for incidental radio leakage.
In addition, the room is absolutely filled with all kinds of natural radio signals. A natural source for BLC-1 is not immediately clear, but scientists will have to rule out things like our sun, Jupiter, neutron stars and pulsars, supernova remnants, radio galaxies, and so on.
Terrestrial sources will also have to be ruled out, along with satellites in orbit, as Seth Shostak, senior scientist at the SETI Institute, explained in a recent statement. post:
Indeed, it may simply be a telemetry signal from a satellite orbiting the Earth. After all, the orbital movement of these satellites causes their transmissions to rise and fall in frequency. And while you may think that the chances of accidentally tuning into a satellite are slim, think again. More than 2,700 working satellites are buzzing around our planet, providing weather information, images for Google Earth, GPS signals for navigation, and high-resolution photos for the military, just to name a few. This stream of information from hardware a few hundred kilometers above our heads is of course important to a high-tech lifestyle, but it blocks much of the radio spectrum. SETI scientists are trying to find a needle in a pile of pins.
It is also important to point out that the Proxima Centauri System is a very poor candidate for alien life as the star is a red dwarf. Such as Research shows, red dwarfs are subject to frequent and powerful solar flares, making it difficult for life to emerge and evolve around them. The exoplanet Proxima Centauri b is so close to its host star that it takes only 11 days to complete a single orbit.
And then there is the whole unbelievability of all of this. The odds that Proxima Centauri – the closest star to our solar system – is home to an intelligent civilization is so grossly unlikely that I don’t have the correct adjectives to describe how grossly unlikely it is. If our nearest neighbor is inhabited by aliens, and at the very same time we are there, that means the rest of the galaxy must be full of life. However, given the Great Silence and the Fermi Paradox, we cannot accept this conclusion. Indeed, if life is ubiquitous in both time and space, we should have seen signs of aliens by now (more on this topic here, here, here, and here).
This is not to say that the Breakthrough Listen team is wrong in considering aliens as a possible source of BLC-1. They are quite right to do so as there is no proper explanation yet to explain the foreign emission. In the future, radio astronomers should train their telescopes on Proxima Centauri in the hope of a repeat, while other scientists should investigate possible sources of the strange signal. We just have to be patient and not jump to conclusions, as is our tendency.
Correction: An earlier version of this article gave the wrong year for the WOW! signal.