What is BLC-1 - That Weird Signal from Proxima Centauri?

On November 28, 1967, Jocelyn Bell, a young radio astronomer at The University of Cambridge, together with her supervisor Antony Hewish, found an unusual signal in data reported by their instrument. A signal, featuring regular flashes of energy, perplexed the astronomers - what could be generating this clock-like regularity?

At first, these signals were jokingly referred to as LGM - Little Green Men. After all, such signals could be navigational signals, guiding aliens in their travels around the galaxy. Soon, however, they were found to be rapidly-rotating neutron stars we know call pulsars.  

Now, astronomers are studying Breakthrough Listen Candidate-1 (BLC-1) a new, unexplained signal, showing signs of an intelligent source. And, this signal seems to be coming from the closest star to our own family of planets.

But, what IS it?

So, We're Going to Start off 2021 with Aliens?

During April and May 2020, astronomers at the Parkes telescope in Australia (performing analysis of stellar flares) captured an unusual signal appearing to come from our nearest stellar neighbor, Proxima Centauri. This tiny, cool red star, 4.2 light years from Earth, is gravitationally bound to a pair of larger stars, making up the Alpha Centauri system.

At least two planets are thought to orbit this diminutive star - Proxima b, a planet slightly larger than the Earth, huddled close to its parent star. The other, Proxima c, is a frozen world, far from its sun, several times larger than our home planet. 

Occasionally, astronomers with the Breakthrough Listen Project, searching for signs of intelligent life, find a signal which catches their eye. However, so far, each of these has proven to be an artifact of either natural processes or human-generated interference. 

In the movie Contact by Carl Sagan, when the alien signal was first received at the Very Large Array of radio telescopes by Dr. Ellie Arroway (played by Jodie Foster), the team immediately turns the radio telescopes away from where the signal was being seen. This process, known as going off-axis, can differentiate a localized signal coming from a single star from human-made interference which is usually scattered over a wide area. 

When astronomers turned their sights away from Proxima Centauri, they no longer heard the signal. This suggested a distant source - perhaps Proxima Centauri itself, or a planet orbiting our diminutive neighbor. 

Following roughly 150 minutes of signal recorded over 30 hours of observations, the signal - seen at 982.002 MHz - disappeared. 

Why is There ALWAYS a Terrible Price to Pay?

The innermost planet known known in the Proxima Centauri system orbits its parent star inside that system's habitable, or Goldilocks, zone where temperatures are "just right" for water to form on planets.  

This warmth is the result of Proxima b orbiting extremely close to its central star - just five percent of the distance between the Earth and Sun. This close orbit means the planet orbits Proxima Centauri every 11.2 days. 

What may seem to be a fortunate placement, however, comes at a terrible price. These close quarters with its local stellar furnace results in the planet being bathed in vast doses of radiation and charged particles. NASA studies show an atmosphere similar to the one found on Earth would be blown off Proxima b in just 100 million years. Without an atmosphere, life seems unlikely at best. 

"It's hard to imagine how you can have a stable climatic system and all the things you need to get from bacteria, which are hardy, up to intelligent animal life forms, which certainly are not. But I'd love to be proved wrong," Lewis Dartnell, astrobiologist at the University of Westminster, stated.

I'm Not Saying It Wasn't Aliens, But It Probably Wasn't Aliens

"Mankind has a deep need to explore, to learn, to know. We also happen to be sociable creatures. It is important for us to know if we are alone in the dark." - Stephen Hawking

Breakthrough Listen, a project founded to search the million stars closest to Earth for signs of intelligent life, has searched the skies since 2015.

Astronomers searching for signs of extraterrestrial life must sort through vast quantities of extraneous signals including satellites, electronics on Earth, and natural phenomenon in space.

For five 30-minute periods over the course of several days, astronomers saw the signal radiating from a region roughly half the size of a full Moon, centered on Proxima Centauri. 

The signal found by the Breakthrough Listen Initiative in October 2020 occurred over an extremely narrow range of wavelengths, which is rare in nature, suggesting an artificial source. However - the frequency at which it is seen - 982.002 megahertz - is not commonly used by electronic devices or communications systems. 

A true signal from an extraterrestrial civilization would have a narrow bandwidth, show amplitude or frequency modulations (providing information), it would be seen when looking at a target, and it would never be seen when looking away from the source. 

"Our WiFi, our cell towers, our GPS, our satellite radio - all of this looks exactly like the signals that we're searching for, which makes it very hard to tell if something is from space or from human-generated technology," Sofia Sheikh, a graduate student at Pennsylvania State University who is leading analysis of the signal explains.

Listen to our March 2020 interview with Sofia Sheikh discussing how we might find life on other worlds.

No signal has ever been found that fits all four of these characteristics - until now. 

As astronomers watched the signal, the frequency wobbled up and down the dial, similar to the way a satellite might transmit its telemetry to crews on the ground.

"It could be from the orbital motion of a planet, or from a free-floating transmitter, or from a transmitter on a moon," Penn State University astronomer Jason Wright explains.

The signal radiates at nearly an exact integer of 982 MHz, suggesting a human origin. After all - it would seem unlikely that an alien civilization would transmit at a frequency that just happened to coincide with round numbers in a human-designed timescale. 

We have seen tantalizing hints of alien intelligence before. On August 15, 1977, astronomers at the Big Ear Telescope picked up a 72-second signal that showed signs it was broadcast by an intelligent alien civilization. However, this "Wow!" signal never repeated, and so could not be confirmed. 

"A microwave oven in the break room of the Parkes radio telescope caused considerable consternation five years ago when it produced signals that, at first, suggested that something remarkable was happening in the distant cosmos. In fact, it was just someone heating up lunch," the SETI Institute reports.

So, Say Hello to the Nice Alien…

A look at what we know so far about the Proxima Centauri system. Video credit: Space.com

If the signal turns out to have an extraterrestrial origin, we would have the opportunity to respond to an alien civilization for the first time. The close proximity of the star would offer a chance to have a two-way conversation with an alien intelligence over a timescale of just a decade - well within human lifetimes. 

Any alien civilization that had achieved at least our level of astronomical sophistication would be able to detect life on our own planet - through radio waves and the chemical composition of our atmosphere. 

The discovery of an intelligent alien civilization living next door to us (on an interstellar level) would be one of the most important advances in the history of the human race. 

"It's pretty expected that every now and then you'll see something weird, but this is interesting because it's something that's weird that we're having to think about the next steps," Sheikh states.

Researchers at the Breakthrough Listen Project are carefully analyzing data from the event, trying to determine the cause of the signal. The team will soon release a pair of papers detailing this exciting finding. 

What we know about BLC-1, so far, is that astronomers may have stumbled upon a new astronomical phenomenon, interference from electronics (possibly military), or - perhaps- the first signs of intelligent life on another world.

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James Maynard is the founder and publisher of The Cosmic Companion. He is a New England native turned desert rat in Tucson, where he lives with his lovely wife, Nicole, and Max the Cat.

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