“The earth is not alone, it is not like a single apple on a tree; there are many apples on the tree, and there are many trees in the orchard.”
— John Burroughs, The Breadth of Life, 1915.
“Forty years as an astronomer have not quelled my enthusiasm for lying outside after dark, staring up at the stars. It isn’t only the beauty of the night sky that thrills me. It’s the sense I have that some of those points of light are the home stars of beings not so different from us, daily cares and all, who look across space with wonder, just as we do.”
— Frank Drake, Is Anyone Out There?, 1992.
“Why are you here?
Are you listening?
Can you hear what
I am saying?”
— 30 Seconds to Mars, Fallen.
Out here in the galactic boondocks, our stellar neighbors are far more than a hop, skip, and jump away, at least until we learn to manipulate gravity. A sad state of affairs for us cosmic hicks, for sure.
The closest star system to our own is a trinary star system known as Alpha Centauri. Even if we had the capacity to travel there at the speed of light, which is sadly impossible, it would take us over four years to get there. With present technology, it would be a manned mission roughly eighty thousand years in duration. And that’s one-way.
The first two stars in the system, Alpha Centauri A (or Rigil Kentaurus) and Alpha Centauri B (or Toliman), are sun-like stars that orbit each other every eighty years — and they do so in an elliptical orbit, which is to say that the distance between them varies throughout their orbital path. They are collectively known as the binary star Alpha Centauri AB. While we don’t have data yet, it could be the case that planets revolve around both of these individual stars. In addition, there may also be planets orbiting AB as a whole.
And that’s not all.
The third star, Alpha Centauri C, more popularly known as Proxima Centauri (named such given its proximity to us), is a red dwarf star, small and dim relative to our sun, and it orbits AB every 550 thousand years. At 4.24 light years away, it also stands as the closest single star to our sun. Two planets have already been confirmed to be orbiting the star. Proxima c, discovered in 2019, is described as a chilly super-earth or mini-Neptune thought to have a ring system. It completes an orbit every 5.2 earth-years and is so distant from its star that its unlikely to be a native home to life as we know it.
More intriguing, however, is Proxima b, discovered three years earlier. Its only slightly larger than earth and orbits its star every 11 earth-days or so, with that orbit falling within the habitable or “goldilocks” zone. In other words, if it has an atmosphere, it could hold liquid water on its surface and may be host to life. The issue is that Proxima b is a flare star, which is to say it has extremely intense outbursts of radiation that may make life there uninhabitable — but there’s still debate.
With a thick enough atmosphere and a strong enough magnetic field, some say there could conceivably be sufficient protection. Though bursts of radiation may slowly strip away the atmosphere, such large planets are thought to both retain their internal heat and remain volcanically active, suggesting it may be capable of replenishing that atmosphere. There is also the possibility that it is tidally locked, meaning that the same side of the planet always faces the sun, akin to how only one side of the moon always faces the earth. If this is the case, the far side of the planet may be shielded from the radiation, perhaps even the twilight areas, potentially allowing life to develop and evolve.
Given its our closest neighbor, Proxima has captured the attention of science fiction writers, scientists — and billionaires, too.
Founded by Julia and Yuru Milner in 2015, Breathrough Initiatives is a space-science-based program aiming to search for extraterrestrial intelligence (ETI). It is divided into projects, among them Breakthrough Starshot, which aims to develop a swarm of tiny space probes that would be shot towards Alpha Centauri with a laser at 20% the speed of light. Another such project is Breakthrough Listen, which is a beefed up rendition of SETI. Since 2015, this project has been buying time on radio telescopes all across the planet to search our skies for ETI technosignatures.
Five years after its inception, on December 18th, 2020, news leaked in the British newspaper The Guardian regarding a strange signal they picked up through a radio telescope at Parkes Observatory in New South Wales, Australia.
It seems that on April 29, 2019, a team of scientists began using the telescope to observe Proxima Centauri for 26 hours in order to study its stellar flares. At the same time, they were also archiving data to later scour for potential technosignature candidates. It was ultimately Shane Smith, an undergraduate student at Hillside college and intern at Kerkley’s SETI program, who discovered the strange signal as he was subjecting the data to analysis in late October of 2019. The signal has now earned the title BLC1, short for Breakthrough Listen Candidate 1.
Every article I’ve read regarding the signal stresses that its just a candidate and that in all likelihood it will prove to be nothing. Even so, it has earned the title of the first candidate signal, and is so peculiar that some are comparing it to 1977’s still-unexplained Wow! Signal.
On Event Horizon, a YouTube channel hosted John Michael Goldier, he held an interview with Jason Wright, an associate professor at the Penn State University’s Department of Astronomy and Astrophysics and a member of Breakthrough Listen’s advisory board, where they spoke about the signal. Wright went over the careful process of elimination such a signal must go through before being accepted as an ETI technosignature.
One test involves “nodding,” where the telescope fixes its gaze at a targeted area of the sky for 30 minutes, then “nods” the telescope a bit away from target, and then fixates there. If the signal is still being picked up, clearly it wasn’t from the original targeted area, but constitutes noise — cell phone signals, aircraft radars, FM stations, and so on. Then the telescope nods back to the original target to see if the signal is still there.
There are good reasons to be this cautious. Between 1998 and 2015, a radio telescope had been picking up transient bursts of radio signals they called “perytons.” In 2015, they realized the source was the microwave oven in the breakroom being opened during luch time. People were opening the door too quickly, accounting for the anamolous bursts.
This was the same observatory — Parkes Observatory.
Another test he mentioned dealt with frequency changes. If the frequency of the signal is always the same, you know its not from space, because earth is spinning, and our telescope during the observation will change its direction as the earth rotates.
These two tests it appears to have passed. BLC1 isn’t coming from earth, it seems, but originates from the direction of Proxima Centauri, and is very likely artificial. They came to this conclusion because it’s a narrow-band signal at 982.002 megahertz, and there is no presently known way nature can produce it. The signal also “drifts,” which is to say it is changing ever so slightly in frequency. The peculiar thing is that the signal is drifting upward, not down, as would be expected. It also doesn’t have any trace of modulation, which is to say it’s essentially a tone that doesn’t appear to convey any data. If it is from an ETI, its apparently just an announcement of their presence, nothing more.
This doesn’t rule out the possibility that the signal is coming to us from one of our own satellites, however, or one of our interplanetary or interstellar probes. While not mentioned by Wright, in subsequent articles I’ve read regarding BLC1 its also been emphasized that despite the fact they were observing the flares of Proxima during this observation, the telescope isn’t fixed on it as a narrow target, but on the general vicinity of the star from our geocentric perspective. In other words, it did not necessarily come from Proxima, but may have originated from a far greater distance behind the star.
In any case, an apparently vital test involves targeting Proxima with a radio telescope yet again to see if the signal repeats, and though their have apparently been subsequent observations, the signal, as of December 2020, has yet to be detected again. This step seems to be considered a major one by the Breakthrough Listen team, as it was by the original SETI practitioners.
I was considerably intrigued when Wright began speculating on the signal itself, as he offered some possibilities I haven’t heard that often, if at all, despite my rather prolonged interest in all aspects of this subject. For instance, he made the point that even if this did prove to be a signal originating from an ETI, it doesn’t necessarily mean that the intelligence in question arose on a planet around Proxima Centauri. To the contrary, it may have journeyed there, or merely sent a probe that in turn sent the signal.
Even further, Wright suggests that the signal may actually only be coming to us from the nearest node or relay station in a vast, interstellar network. He uses the analogy of cell phones. When you talk on a cell phone with your friend, your two cell phones aren’t communicating directly with one another in “point-to-point” fashion. Instead, your cell phone connects with the nearest node — a cell phone tower — which boosts and relays the signal to the next tower, which boosts the signal and relays it to the next, and on and on along a circuitous route until your friend receives it from the tower closest to them. As opposed to direct communication, the power requirements are minimal and the signal gets a boost every time it hops to another tower. Given what we currently understand, this would be the most efficient means of interstellar communication.
The apparent source of the signal we recieve, in other words, may not constitute the true source of the signal, even if it does prove to be coming from Proxima. If an ETI based on a planet surrounding Alpha Centauri A or B, or surrounding AB as a whole — or an ETI based a hundred light years away — desired to capture our attention via radio transmissions, it may use just such a network. Given that Proxima Centauri is the closest star to our sun, the closest radio tower to earth may be based on a planet, moon, or even a satellite revolving around Proxima Centauri, regardless as to whether that star has inhabited planets.
There could be other reasons to use the relay stations, too. After all, this network would allow an ETI to announce their presence to an alien species such as ourselves and potentially inspire a response, even a visitation like Breakthrough Starshot, yet at the same time conceal the signal’s actual point of origin. In other words, these relays may provide a buffer, not giving away their location, but merely letting us know we’re not alone in the universe.
One might therefore assume, from all of the above, that if we humans were seeking out ETI, we might listen in or send a message to our closest neighbor, the most logical fucking target of all. Despite this, we have, so far as I’ve been able to discern, never sent such a message toward Proxima Cen — despite the fact that through Active SETI or METI (Messaging Extraterrestrial Intelligence) we’ve apparently sent rougly 30 messages to other individual stars between 17 and 24,000 light years distant. On top of this, despite the fact that SETI requires a signal to repeat in order to confirm it as ETI in nature, as mentioned earlier, the vast majority of our transmissions appear to have been sent in a single day and then ceased.
I’m even not sure if we’ve ever listened for potential transmissions from Proxima until now. If not, this would suggest that for some reason we expect more out of our neighboring ETI than we are willing to do ourselves.
Even so, maybe its more intuitive for a potential Proxima ETI to transmit to our star system than it is for us to transmit, or even listen, to their own. Proxima Centauri is part of a trinary star system, after all, and assuming for the moment that an ETI developed on Proxima b, they may have a far greater inclination for interplanetary and interstellar travel. Aside from the potential planets in their own star system, their neighboring stars are far closer to them than we are to Proxima. Planet-based and space-based telescopes would potentially be able to study a wide variety of planets, and all within conceivable reach of rocket technology, perhaps spawning an earlier desire to achieve interstellar travel. Be it by means of parallel genesis or panspermia, perhaps their own planet wasn’t the only life-bearing rock in their trinary system, either, and their discovery of extraterrestrial life would lead them to reasonably conclude that the cosmos must be teeming with life.
“In physics, we count one, two, infinity,” said Jill Tarter of the SETI Institute. “If we have one example, it could be singular. The second you find another example, then you know its universal.”
So after exploring the hypothetical planets around the three stars in their own system (and perhaps even planets in orbit around the AB duo as a whole), and after having discovered life on those other planets, perhaps they turned a radio telescope in their communications network towards other neighboring stars, hoping to reach out even further into the potential cosmic community. One of those stars may have been our own sun, and we may have picked up their transmission, which we dubbed BLC1.
That or someone’s heating up a Hot Pocket in Parkes’ cafeteria.
Transmissions to Earth 