One of the strangest mysteries of the universe that continues to baffle astronomers are the
phenomena of fast radio bursts or FRBs.
Lasting only a few milliseconds, these highly energetic bursts have only been known since
about 2001.
And while we don't yet know much about them, we can infer from their behavior that the
sources of the bursts seem to be very small.
So small in fact that the sources must be less than a few hundred miles across.
This eliminates a lot of possibilities as potential sources of the activity, including
most normal stars, sending us into another tier of explanations, none of them particularly
good so far.
One of those potential explanations are the activities of alien civilizations.
Unexplained radio signals from space are nothing new, the universe is teeming with natural
radio emitting objects.
But in the case of FRBs, they behave very strangely and one research team suggested
in 2015 that they seem to conform to a mathematical pattern, at least as far as the bursts known
at the time were concerned.
If present, that pattern doesn't really make much sense as far as our understanding of
cosmology goes.
And to add icing to the cake, they appear to originate invariably, again so far, from
only outside our galaxy.
A head-scratcher indeed.
They seem to be distant because of a metric known as the dispersion measure.
The FRB's emit the same thing at many frequencies at once.
Think of it as a radio station that beams out the same radio show on all frequencies
on the dial.
But those frequencies do not all travel at the same speed, some of the waves get delayed
by floating electrons in space.
This has the effect of higher frequencies crossing space faster than lower ones.
The bigger the difference in time between the two, the further away the origin of the
burst is.
As it turns out, the origins for the FRBs seems very distant.
And new research suggests they are very common, with thousands happening each day.
The reason we don't see them is because they happen so fast that we can only catch them
by chance.
More, just a few days ago research came out that found one that repeats.
This eliminates one of the main natural explanations, that of colliding neutron stars.
But even stranger, there is another kind of reported pattern to these bursts.
In 2015, researchers Michael Hippke and John Learned determined that of the 10 or so FRB's
known at the time, the delay between the arrival of the first and last parts of the signals
are always multiples of the number 187.5.
No known natural process can do that.
But, the pattern may not actually be real, more on that in a minute.
If that pattern is present, it might imply that the sources of the bursts line up at
regularly spaced distances from earth.
This is very difficult to explain with a natural explanation if we take the data at face value,
so much so that alien activity is the easy explanation in much the same way that finding
distance marker signs on a road would indicate human activity.
The odds are in the alien's favor in this case and are estimated to be 5 in 10,000 that
this pattern would just be due to chance.
But don't get excited yet, we could be misinterpreting the data.
And subsequent observations of FRB's since 2015 do not line up with the pattern, calling
the whole thing into question.
Why the first ten did and the subsequent bursts did not is a complete mystery but the current
consensus is that the pattern wasn't really there and that the effect was a statistical
flaw from having too small of a sampling to go on.
It could also be that the sources for the FRBs are in reality much closer to home.
They could have galactic origins and merely present the appearance of being billions of
light-years away by emitting long frequency waves before emitting short ones on a delay.
Or they could be even closer, it has been suggested that the FRBs are emissions from
our own spy satellites that we're accidentally picking up.
This is particularly interesting because a group of FRB-like signals that had been detected
by a single radio telescope were thought to be originating from space.
It turns out, they weren't.
They were coming from the microwave oven in the lunch room.
Another possibility is that superdense stellar remnants could be the sources, though this
explanation is somewhat weak because it's based on the fact that we really don't know
very much about the physics of how those produce radio waves.
Other potential explanations include oddly behaving solar flares, activity around black
holes, and many others.
So it's best not to run to the alien explanation just yet.
There's a good reason for this other than skepticism.
While sending out engineered signals that contain mathematical patterns would be a logical
way to announce your presence to the universe, there are a lot cheaper ways to do it.
FRBs, if they originate outside the Milky Way, would take a huge amount of energy to
produce, about the same amount our sun produces in a month or more.
In addition to that the signals are pretty ambiguous, they don't really look like something
aliens would intentionally send.
If your aim was to wow other civilizations with your math skills, you'd probably do something
less ambiguous, such as base a message on Pi or simply count out numbers like they did
in the movie "Contact".
And you would do it on selected frequencies as opposed to eating up energy by blasting
the signal out on a wide spectrum of frequencies as is the case with FRBs.
No two frequencies are the same where interstellar communications are concerned.
Certain ones, such as the hydrogen line that SETI places a high value on are better at
tagging your signal as a dead ringer for being artificial than other frequencies.
What you wouldn't do is intentionally make your communication questionable as in the
case of FRBs.
You'd want your signal to be loud and clear and easily understood as artificial.
This is not so with the FRBs.
But that's all based on the assumption that alien signals would come in the form of communications.
But, if we are any indicator, that would not be true in most cases.
The fact is we've only sent out a few intentional signals and we have a nasty habit of not repeating
them, which is one of the criteria SETI requires to call an alien signal an alien signal, it
must repeat and be independently verifiable by other scientists.
In reality most of our radio signals that aliens might pick up would be random things
like radar.
So that begs a question, if artificial, what if the FRBs are not designed for communications
at all?
Enter in a paper released on January 5th of 2017 by Manasvi Lingham and Abraham Loeb that
lays out just such an alien scenario that seems consistent with the data where a specific
type of alien activity would fit.
Their idea is that the FRBs might be extremely powerful for a reason: they are pushing sails.
They have determined that the frequencies where we see the FRBs just happen to be those
perfect for pushing spacecraft connected to huge sails.
They suggest that the beams powering them sweep by very rapidly explaining the short
duration of the bursts and that if they are indeed pushing spacecraft we should see that
in the light curves of the bursts.
They also note that not all FRBs need to be of alien origin, some may be natural or they
may all be natural.
Only time and more research will tell.
Thanks for listening.
I am futurist and science fiction author John Michael Godier currently with a new book coming
out.
It's called Supermind and tells the tale of a scientist that plays god and creates a simulated
universe and be sure to check out my other books at your favorite online book retailer
and subscribe to my channel for regular in-depth explorations into the strange, unusual and
interesting aspects of this amazing universe in which we live.