Saturday, January 23, 2021

What are the chances of BLC1 being a message from another star system?

Mankind has been looking for communications from the stars for many years now, to little or no avail. There was the famous "Wow!" signal back in 1977, when a regular and unexplained radio signal was received for all of 72 seconds. "Unexplained", of course, does not mean it was sent by little green men in search of pen pals; it just means that there is an awful lot that we still don't understand about what goes on in deep space.

Nevertheless, many people were intrigued by a second "Wow!" signal, technically known as BLC1 (Breakthrough Listen Candidate 1), picked up by the Breakthrough Listen project at Parkes Observatory in Australia a couple of months ago. The actual signal in question was recorded on 29 April 2019, but was only spotted by a student going through archival records in October of 2020. This was a much longer-lasting event than the 1977 one, lasting some 30 hours, and it took the form of a very narrow band radio signal in the part of the radio spectrum often used by earth's satellites and spacecraft. It appeared to be emanating from Proxima Centauri, the closest star to our sun.

So, is this a "technosignature", a deliberate message from a technologically-advanced civilization living on one of the two planets orbiting our next closest sun? Well, the chances, it seems, are pretty slim.

For one thing, the signal only APPEARS to be coming from Proxima Centauri - it could actually be coming from much further afield BEHIND Proxima Centauri. And there are many other things it could also be: an echo or reflection of an outbound radio signal from earth, or from one of our satellites or spacecraft, or a natural signal from some odd kind of quasar or pulsar, about which we know very little.

Experts have met the finding with a healthy dose of skepticism. The chances of two civilizations so close together and using a similar kind of technology are considered to be vanishingly small.

So, little green men from Proxima Centauri? Probably not. 

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