Are we alone in the universe? Of all of humanity’s most profound ponderings
whilst perched on porcelain thrones, that one’s probably the biggest. It's
also one of the most difficult to answer. As of today, nobody knows if Earth is a singular
oasis or simply one amongst countless celestial sanctuaries harbouring life.
Despite this uncertainty, it's a question worth asking. Because, for better or for worse, first
contact with an alien race would arguably be the most important event in the entire 200,000-year
history of our species, surpassing even the invention of the wheel or the discovery of fire.
The knowledge that there are other intelligent species out there would
fundamentally change what it means to be human,
irrevocably altering our understanding of both the universe and our place within it...
...But here's the thing. It might have happened already.
And I’m not talking about some Area 51-government-conspiracy crap. I mean,
we may have already received an unambiguous and well-documented message from the stars.
This is the story of the Wow! Signal - mankind's first contact with aliens... maybe.
On the 15th of August 1977, Jerry Ehman was sitting in his kitchen,
scrutinising a substantial stack of seemingly senseless scribblings - each page was covered
in random numbers and letters as though someone had sneezed on them while eating alphabet soup.
But, as a research scientist with the SETI project,
Jerry Ehman's trained gaze could discern this cosmic code. Because it was data
from one of the world's most powerful radio telescopes, nicknamed Big Ear.
Unlike regular telescopes that use lenses and mirrors to magnify visible light,
telescopes like Big Ear are designed to gather radio signals originating in deep
space, and it was this info contained in Jerry Ehman’s alphabetti spaghetti printouts.
Each of the 50 columns represented a different frequency channel, and the numbers and letters
within those columns displayed the strength of any incoming radio signals of that frequency.
Low numbers meant weak signals - background noise mostly - and high numbers meant stronger
signals. The columns were only wide enough for a single character, so signals above a
9 were assigned a letter (A meant a signal strength of 10, B - 11 , C - 12 and so on).
Jerry had searched through literally thousands of pages like these during
the 4 years Big Ear had been hunting aliens, without finding anything of
particular interest. But on that fateful day in 1977, his eye was drawn to a signal
that looked like nothing he'd never seen before - 6EQUJ5 - an alphanumeric string
so startling that Jerry circled it in red pen and scribbled the now famous 'Wow!' annotation.
The so-called Wow! signal had several attributes that made it so remarkable. To start, it was a
staggering 30 times stronger than background radio noise. It had also only registered in
one of Big Ear's 50 frequency channels, meaning it was what we would call a narrow-band signal.
Narrow-band radio signals aren't typically made by natural sources - they're generated by technology.
As soon as he saw the signal, Jerry Ehman knew that he might be looking
at humanity’s first contact with aliens. But as Carl Sagan once said,
extraordinary claims require extraordinary evidence. The first thing the SETI team had
to do was make sure the Wow! Signal really *was* something extraordinary.
Observing the universe through a radio telescope is a notoriously finicky business for the simple
reason that radio waves are absolutely bloody everywhere. A ceaseless cacophony
of cosmic clamour, including stars, black holes, and quasars, constantly emit radio
waves like drunk gunslingers in an intergalactic saloon. Closer to home, terrestrial technologies
also rely on radio waves, like TVs and telephones, only compounding the chaos.
If anyone was going to take the Wow! Signal seriously,
it had to be demonstrated that it hadn't come from any of these other sources.
Galactic radio noise could be swiftly eliminated because the Wow! Signal was far too strong. Other
natural phenomena like stars and quasars could also be ruled out, because they emit radio
waves across a wide range of frequencies, not a single narrow band. They also tend to emit them
constantly over millions, even billions of years, but when Big Ear listened to that same section of
sky the following night, the mysterious signal was gone. Finally, interference from earth-based
technology also seemed extremely unlikely. The Wow! Signal traced an unmistakable bell-shaped
curve, matching the expected signature of a space-based source passing directly over
the telescope. Earth-based interference, on the other hand, typically produces sporadic pulses.
So, the signal was seemingly artificial and came from the cosmos. That must mean it was aliens,
right? Well, not necessarily. The scientists first had to confirm that the signal hadn't
come from our *own* radio wave-producing space-based technology - satellites.
It didn't take them long. You see, in the late 70s, fewer than 300 satellites orbited
earth - and none of them were supposed to be nearby on the night in question. Moreover,
Big Ear’s data showed that the Wow! Signal’s source was stationary relative to the stars.
In other words, to have produced the Wow! Signal, one of the fewer than 300 satellites in existence,
would have to have been in exactly the right part of the sky at exactly the right time, moving in
exactly the right direction at exactly the right speed to match the motion of the stars around it.
In my book, that's pretty conclusive,
but the evidence against the satellite theory doesn't stop there.
You see, it wasn't just the strength and signature of the Wow! Signal that was so unusual - it was
also the frequency it was resonating at: 1420 MHZ. That’s incredibly close to something called’’’
the hydrogen line, the frequency at which hydrogen atoms naturally emit radio waves.
The significance of that seemingly random coincidence might not be
immediately obvious, so let me explain.
Hydrogen - the cosmos’ most copious element, is so abundant that sensitive
radio telescopes are able to detect its perpetual radio hum everywhere. Thus,
tuning our telescopes to this particular frequency unveils a wealth of knowledge
about the fabric of the universe. Succinctly put, 1420 MHZ is arguably the single most important
radio frequency for *any* young civilisation seeking cosmic comprehension. Chances are,
if we’re listening to it, then so is everyone else - for the very same reasons.
You probably know where I’m going with all of this. Contacting a distant civilisation
across the boundless expanse of space is a tricky business. There’s no way of knowing
what languages they speak, even what sense organs they might possess… but the hydrogen
line is universal. Any alien wanting to be heard would be wise to transmit at 1420 MHZ.
For this - and other - reasons, 1420 MHZ is an internationally protected radio frequency
reserved solely for scientific research - nobody else is allowed to use it. Going back to the
satellite theory for a second, to have produced the Wow! Signal, not only would a satellite need
to have been in the right part of the sky at the right time, moving in the right direction at the
right speed - it would need to have been transmitting on an illegal frequency too.
It was clear the Wow! Signal wasn’t the result of interference or misidentification,
nor a malfunction - the telescope was tested thoroughly, and no issues were found,
plus it would have been a hell of a coincidence if a random
instrumentation error perfectly replicated the exact signal researchers were seeking.
So, to summarise. The Wow! Signal was a narrow-band radio signal that,
so far as we know, must have been generated by some kind of technology. It originated in space,
it wasn't the result of earth-based interference,
and it was sent on a very specific frequency that we believe aliens might use to contact us.
All of this leads me to one pretty obvious question. Why the fuck isn’t the Wow! Signal
considered to be the most important scientific discovery in the history of the human race?
Well, that rather rude question has a very simple answer: since that fateful day in 1977,
the Wow! Signal has never been detected again. We've scoured the skies with far bigger and better
telescopes than Big Ear, but almost 50 years on and there's been nothing. Not a whisper.
Until we verify the signal through a second observation, doubts will linger
about its nature and origin. True, nobody has provided a compelling (non-alien) explanation,
but that doesn't automatically mean there isn't one. We may just have missed something,
or perhaps the signal was generated by some kind of natural phenomenon we haven't
discovered yet. Without more data from further observations, it's impossible to say for sure.
As the years pass without the return of the Wow! Signal, doubt steadily seeps in.
After all, if this was the interstellar equivalent of E.T. slipping into our DMs,
why suddenly cut the transmission?
It's also worth mentioning that Big Ear detected no modulation of the signal,
meaning, so far as we can tell, there was no actual information encoded within it. Again,
why? If an alien intelligence went to all the trouble of getting in touch across the galaxy,
wouldn't it have made sense to actually *say* something?
Almost 50 years on from the detection of the WOW! Signal,
it continues to both fascinate and frustrate the scientific community. Back in 2017,
an astronomer of somewhat dubious credentials claimed to have traced the signal back to a couple
of previously uncatalogued comets enveloped in radio wave-emitting hydrogen gas clouds.
Several astronomers (with significantly more impressive credentials) soon pointed
out that the comets in question wouldn't have been in the right
part of the sky when the Wow! Signal was recorded, and even if they had been,
comets don't produce the right kind of radio signals in the first place.
In short, it was a bust. But the fact the story made headlines around the world shows
that people are still intrigued by this most mysterious missive.
More recently, as we've begun to map our galaxy in greater detail,
astronomers have attempted to pinpoint the exact star system from which the
Wow! Signal might have originated. During a 2020 survey, Spanish astronomer Alberto
Caballero identified 66 stars in the Sagittarius constellation as possible
candidates. Work is already underway to search these stars for signs of life.
Will we find an advanced civilization orbiting one of them, wondering why
the hell it's taking us so long to reply to their voicemail message? Only time will tell.
After recording the Wow! Signal, the Big Ear telescope continued its search for
extraterrestrial life until 1995, making it the longest-running SETI project ever
conducted. In the 22 years Big Ear patiently listened to the radio wave whispers of the
universe, it never detected anything remotely similar to the Wow! Signal,
which to this day remains one of science's greatest enigmas.
Thanks for watching.