On April 29th, 2019, the Parkes Radio Telescope in Australia was trained on our nearest galactic
neighbor- Proxima Centauri.
A small red dwarf roughly an eighth the size of our own sun, Proxima Centauri nonetheless
has been a candidate for Breakthrough Listen- a privately funded multi-million dollar initiative
to conclusively discover evidence of alien life by listening in on its transmissions.
That's because out of a possible three planets in orbit around our closest galactic neighbor,
just four light years away, Proxima Centauri b sits comfortably on the habitable zone of
its parent star.
And on that fateful day in 2019, scientists may have recorded the first evidence of intelligent
extraterrestrial life.
Scanning Proxima Centauri for signs of solar flares, the Parkes radio telescope recorded
something altogether different.
Buried amidst the radio noise being blasted out by the red dwarf was something unique,
a single narrowband transmission at a frequency of 982.02 MHz.
What's more, the signal repeated a total of five different times.
The signal was discovered by researchers working for the Breakthrough Listen initiative, a
program aimed at discovering intelligent alien life funded by Russian billionaire Yuri Milner.
Breakthrough Listen is SETI on steroids, with a survey that will eventually include over
a million stars in our own galaxy, and will even include over 100 galaxies outside of
our own.
But because aliens might be trying to communicate in ways other than radio, Breakthrough Listen
will also use extremely sensitive telescopes to look for laser signals amidst the light
put out by millions of stars.
Large, powerful lasers could put out concentrated light that a distant civilization would instantly
recognize as being artificial, and has thus been proposed as one of several extremely
likely ways civilizations may signal each other from across the galactic void.
At a total cost of $100,000,000, and after almost four years of operation, Breakthrough
Listen finally had compelling evidence of alien life.
But this isn't the first time odd radio signals have been detected, so what makes BLC1 so
unique, and why is it potentially alien in origin?
The first qualifier and what immediately got the attention of researchers is the narrowband
nature of the signal.
Natural cosmic phenomena almost always produce broadband signals, and as of yet only humans
are known to use narrowband radio signals.
This has raised the possibility that the signal is in fact, human in origin.
After all, the same sensitive telescopes being used to hunt for alien signals from stars
thousands of light years away are sensitive enough to be affected by interference from
the earth or space directly around it.
Sometimes, as in the case of one radio telescope facility, even a faulty microwave can cause
false positives in the data.
Yet if BLC1 is in fact coming from a man-made source, and at this point the responsible
assumption is that it is not alien in origin and just human interference, then it must
be coming from a particularly perplexing source that astronomers have yet to pin down.
That's because properties of the signal itself are extremely peculiar.
For starters, the signal may not even be from Proxima centauri, as the signal originates
from a sixteen foot wide circle around proxima centauri in the sky- that's quite a lot of
real estate.
What is notable though is that when astronomers moved the telescope away from the signal and
then back again hours later- a common technique to rule out earth interference- the signal
was still present.
In fact it would be detectable for thirty minute periods over several days.
Keep in mind that astronomers who were operating the telescope at the time did not even know
the signal was there- it was only discovered buried in the data a full year later.
Had they known it was there, they could have made even better observations which may have
helped prove or disprove its alien origin.
What's important is that the signal did in fact repeat in the same relatively small patch
of sky, and for up to thirty minutes at a time.
This means the only realistic explanation for earth-based interference would be a satellite,
yet for the signal to continue uninterrupted in such a small area of the sky would require
a satellite to be in an extremely high, and very slow moving orbit.
Otherwise, a normal satellite would simply move so fast that the signal would leave the
telescope's narrow listening cone after only a few minutes.
Now this isn't the first time that astronomers have found an exciting signal from space,
only to discover later it was coming from an unregistered spy satellite.
However, this satellite would have to be in an unrealistic orbit over the earth that would
seem to have little to no functionality for its operators.
Even more damning is the fact that the signal does not modulate, meaning that there is no
information in the signal.
It's just a steady, clear tone- something that again, would have no known value to human
operators.
Even more interesting is that the signal increased in frequency over time as it was observed,
in the exact same way that a signal being broadcast from the surface of a planet or
moon would do as the body it was stationed on slowly rotated in space.
The only way this could be replicated in a man-made source would be if the object creating
this transmission slowly increased its frequency for again, an unknown reason.
Detractors have pointed to the lack of information in the signal as making it unlikely to be
alien in origin, and as we mentioned earlier the signal does in fact not contain any information.
It's simply a monotone broadcast that continues without interruption.
However, there is one type of artificial radio signal that we humans use that matches the
same properties of BLC1 perfectly, and something that aliens would no doubt also be using:
radar.
Our own radar emissions have washed over several of our nearest galactic neighbors by now,
so would it be any surprise if alien radio astronomers inadvertently blasted our own
planet with their radar too?
What would be perhaps entirely too coincidental however would be two intelligent species with
similar level of technology arising right next door to each other, but then again the
universe is so vast that probability is almost certainly 100%.
Roll the dice enough times and almost anything is possible- including two galactic neighbors
blasting each other with their radar.
With the answer to the greatest question mankind has ever asked on the line: are we alone?-
science must tread very carefully and err on the side of caution.
So for now, the reasonable assumption is that BLC1 is simply some unknown form of man-made
interference.
However, BLC1 is by far the strongest candidate ever discovered for alien life- beating out
even the infamous Wow!
Signal discovered in 1977.
With several more years of listening to go, and a plethora of new radio astronomy equipment
being built now, humanity may soon have the answer to the ultimate question.
And if we're really lucky, that answer may come from right next door, creating a very
real possibility of one day meeting our alien neighbors face-to-face.
And hopefully not having them eat our brains.