Is it possible that we’ve already been contacted by alien life, but just missed
the call? Potentially - perhaps probably - yes. If any hypothetical civilizations out there
are searching for us in the same way as we’re searching for them… then they’re listening in
to radio signals from space and then sending out their own. Here on Earth, we’ve sent many signals,
some deliberately and others accidentally… but throughout history we’ve also detected a number,
too. And some especially strange ones that still elude explanation.
So, could any of these be more than natural phenomena?
This is Unveiled and today we’re taking an extraordinary look at
four of the weirdest radio signals detected from space.
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Radio waves were discovered in the 1880s, and within a few decades,
we’d developed the technology to communicate over long distances. It wasn’t until the 1930s,
however, that radio astronomy was invented, when the engineer Karl Jansky, who worked for
Bell Telephone Laboratories, discovered radio interference coming from the constellation of
Sagittarius. Inspired by Jansky, in 1937 amateur astronomer Grote Reber developed
the first radio telescope and conducted the world’s first sky survey of radio signals.
But it was actually World War Two that arguably pushed radio technology farther than ever before.
Radio was still a new technology in the war and many scientists were brought in to work on it.
Some continued after the war, eventually applying it again to astronomy. We grew to realize that
while radio waves on Earth are a convenient way to send messages… these same signals are
also produced by powerful astronomical events. Anything from the closest star to us, the sun,
to distant pulsars, galaxies, and supernovas can all make radio signals that reach our planet.
Among other things, however, this somewhat complicates the search for alien life in the
universe; because if they are contacting us, how do we tell their message apart from the countless
other signals in the sky? In order to eliminate other possibilities, then, astronomers need to
determine every type of object that can make radio waves and learn their patterns. For now,
there are still many strange signals that scientists haven’t been able to figure out…
so the big question remains: Are they unknown objects, or proof of actual life?
In January 2022, astronomers announced that they’d picked up a signal unlike anything else they had
ever seen before. The team of researchers was led by astrophysicist Dr. Natasha Hurley-Walker,
from the International Centre for Radio Astronomy Research in Perth, Western Australia.
They discovered a strange set of radio waves originating about
4,000 light years away, which is actually quite close on an astronomical scale.
Using the Murchison Widefield Array (or, MWA) telescope in Western Australia, the team captured
and analyzed the signal, which seemed to appear and disappear over the course of a few hours.
About three times per hour it would release massive bursts of energy, which the researchers
kept track of. These bursts were sometimes so strong that they constituted one of the brightest
objects in the night sky. Most objects powerful enough to produce them would also have X-ray
emissions, but that wasn’t the case here. This, plus the repetitive nature, then, quickly turned
the signal into one of particular interest. What the object apparently emitting it did seem to have
was a magnetic field... and, altogether the signal itself was active for about three months before
vanishing. Dr. Hurley-Walker called the signal “completely unexpected,” and “kind of spooky”.
But, so far, no definitive answer has been given for the source of these waves, and the
scientists involved in their discovery remain unsure. There are some predictions that it’s
a never-before-seen theoretical star called an Ultra-Long Period Magnetar, which could form from
a slow spinning neutron star… but might it have originated from an alien force of life, as well?
Not all unusual signals are new, however. There are some that astronomers have been
researching for many years and still with no real explanation in sight. And,
among the most mysterious signals in the universe are what are known as Fast Radio Bursts, or FRBs.
Fast radio bursts were discovered in 2007 by the astronomers Duncan Lorimer and David Narkevic…
and they continue to be extremely puzzling. In general, these signals are characterized
by very powerful but quick bursts of activity that often last mere milliseconds. Astronomers
have attempted to track them and they seem to mostly be generated within distant galaxies.
Again in 2022, though, scientists discovered a particular FRB,
this one even stranger than most others. The 2022 signal lasted for around three seconds,
making it the longest FRB recorded, and it flickered in a precise rhythm every 0.2 seconds.
Postdoctoral scholar Daniele Michilli said of the signal: “there were periodic peaks that were
remarkably precise, emitting every fraction of a second - boom, boom, boom - like a heartbeat”.
This “heartbeat” signal still has no definitive explanation either, and the true nature of FRBs
continues to defy current knowledge. So far, one of the leading theories is that FRBs are
also caused by rotating neutron stars… but, once more, could alien life be at play?
Perhaps the strangest (and certainly the most famous) signal ever received from the depths of
space is known as the “Wow!” signal. It was picked up in 1977 by the Big Ear radio telescope in Ohio.
Originating from somewhere in the direction of the Sagittarius constellation, too,
it received its namesake from the reaction of one of the astronomers who first reviewed the data.
That astronomer, Jerry R. Ehman, simply wrote “Wow!” on the accompanying printout.
The signal had a small fractional bandwidth and lasted for the full seventy-two seconds
that the Big Ear telescope had been looking at that part of the sky.
Scientists worldwide were incredibly excited at the time, because this had all the characteristics
of an alien message. The wow signal also peaked when the Big Ear was directly over it,
and it gradually fell in power as the telescope lost sight of it via Earth’s rotation. These
were all deemed to be traits that an expected extraterrestrial message would have… because
they were indicative of the type of message we would send, if roles were reversed. Unfortunately,
because of how the Big Ear interpreted the signal, it’s impossible to know exactly where
it came from. And, despite searching, it has never been heard again. Nevertheless, there’s still no
widely accepted explanation as to what the wow signal really was… and it therefore remains,
in the minds of many, the likeliest candidate that we’ve received for truly being an alien message.
But finally, and although some radio transmissions that reach us could be intelligent in origin,
others just seem to be bizarre and inexplicable. This is certainly true of a signal that scientists
recorded in 2020, which seemed to originate from somewhere around the center of our galaxy,
the Milky Way. It was bizarre for a number of reasons. Its brightness varied by a factor of
100 at different times, it was seemingly able to turn itself on and off like a light switch,
and it apparently had no predictable pattern to it. Odder still is the way
the radio waves reached us. They traveled through space with a high
polarization - its light oscillating only in one direction and rotating over time.
The astronomer Ziteng Wang said of this signal, “We’ve never seen anything like it”. Researchers
are still looking into what type of object could even create a signal like this one,
but so far there have been precious few answers offered up due to how unique it is.
The leading theory is that the signal could belong to a class of objects called
galactic centre radio transients, which are also sometimes known as cosmic burpers. Even that idea
doesn’t help all that much, however, because no one has any real idea what those are either.
The unprecedented signal also showed up for weeks at first, then stopped for months, but also,
sometimes, turned on and off within just a single day. Based on what astronomers know
of other signal types, no known astronomical object can produce such an erratic signal…
which is why theories abound as to what’s really pressing the button here.
Overall, it’s extremely difficult to find and track these radio signals in space.
Due to how vast the cosmos is, each telescope can only cover a tiny, tiny area of sky. In
order to find out more about the various radio signals that are produced in our universe, then,
astronomers have to find more samples and learn exactly which objects create them. Ideally they’d
be able to study each signal for as long as they want and point numerous telescopes at them,
but oftentimes these signals are just so fleeting… or else they’re billions of light years away.
For sure, it’s a difficult science to master, and we don’t yet know what alien
messages would look like… but could any of these instances have qualified as ET
contact? For now, those are the four weirdest radio signals detected from space.
What do you think? Is there anything we missed? Let us know in the comments, check out these other
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