When searching for radio signals of potential alien origin, SETI places one major restriction
on detections.
They must repeat.
That’s sensible because you can’t really verify and study something that doesn’t,
but at the same time you end up with a plethora of mysterious anomalous one off signals like
the Wow!
Signal that you never get to find out the origin of.
Of course, going by the only civilization that we have any experience with, ourselves,
throws a bit of a wrench in this.
Our own interstellar signals intended, admittedly half-heartedly, to be picked up by other civilizations
such as the Arecibo signal, didn’t repeat.
But what happens if you see a signal that does repeat?
We have just such a source now.
It’s a fast radio burst source known as FRB 121102.
The burst emanates from a small galaxy located at a whopping 3 billion light years from earth
and is a known source for fast radio burst emissions having been discovered in 2012.
Three billion light years is a long way, and of course means that this burst happened three
billion years ago and we’re just seeing it now.
But the universe is old, it was already over 10 billion years of age when these bursts
happened so it’s possible for life and intelligence to have arisen in that galaxy that long ago.
Working against that, and FRBs in general, is that the longer you go back in the history
of the universe the less chemically diverse things are.
You need supernovas to create things like heavy metals, which in turn can form into
planets and this particular dwarf galaxy seems to be metal-poor.
Given the extragalactic nature of FRB’s and the distances and time involved with them,
it seems unlikely that they are the work of alien civilizations.
But the option is on the table, hypothetically speaking, with one theory being that they
are leakage from laser pulses used to power sail driven spacecraft.
The signals were found by a program called Breakthrough Listen, link below, a SETI project
which is searching for just such signals that could be of alien origin.
FRB 121102 was a good target, so on August 26th they took a look and found 15 pulses
at an unusually high frequency.
Coming from this already known source FRB’s, this bolsters the notion that whatever is
repeating the signals does not come from some cosmic cataclysm, but some other more permanent
source.
And this period of activity for FRB 121102 is continuing.
I know of at least one other group that detected one yesterday coming from this source.
And an apparently separate burst from another area of the sky is also ongoing.
This all dovetails with something that’s been suspected for a while.
Fast radio bursts are not rare.
Related to this detection is a paper by Anastasia Fialkov and Abraham Loeb, who were also thinking
about FRB 121102, link to all cited materials in the description below.
They calculated that an FRB occurs every second somewhere within the observable universe.
That’s a lot of FRB’s to study, and it’s surprising that we didn’t know about these
things until 2007, the year they were first discovered.
But, as with anything like this, in regards to FRB 121102 much further study is needed
on this source.
To get into alien origin theories for radio sources, you must first eliminate the potential
natural explanations first.
In this case, you must address the possibility of such things as very odd pulsars or magnetars
as being possible natural sources.
That’s assuming, of course, that pulsars themselves are natural or rather completely
natural, which they probably are but that’s a subject that’s surprisingly still debated,
see my video on that matter on this channel, links in the end screen of this video to that
video and others relating to the search for extraterrestrial intelligence.
Be sure to check them out.
Thanks for listening!
I am futurist and science fiction author John Michael Godier and if you would like to help
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