In August 1977, a radio telescope caught this,
uh, just roaring, deafening signal from deep
space. Yeah. And it lasted exactly 72 seconds.
Right. Exactly 72 seconds. And it looked completely
identical to the mathematical prediction of an
intentional alien broadcast down to the, you
know, the precise frequency. But then it just
vanished. Vanished. Yeah. For decades. Nothing
but absolute silence. So welcome to the Deep
Dive. Our mission today is taking a single comprehensive
Wikipedia article and extracting the absolute
most mind -bending details about one of the greatest
modern mysteries of space exploration. The wow
signal. The wow signal. And for you listening
right now, if you love cutting through the noise
to get straight to the mechanics of an anomaly
that just defies all standard explanations, well,
this is your masterclass. It really is. And looking
at your backdrop right now, the visual perfectly
sets the tone here. We have these retro 1970s
computer punch cards, and they're seamlessly
fading into these really expansive modern star
charts. Yeah, I love it because we are standing
right at the interception of somewhat primitive,
clunky 1970s computing and incredibly vast cosmic
mysteries. I mean, it is the ultimate cold case
of astronomy. It's a single data point, so physically
perfect, yet so frustratingly solitary that it
has kept astrobiologists just agonizing over
the data for nearly half a century. So let's
establish the scene. It's August 1977. We are
at Ohio State University. University's radio
telescope, which was affectionately nicknamed
Big Ear. And a volunteer astronomer named Jerry
Ammon is reviewing the data. And back then, you
know, reviewing data wasn't looking at a sleek
monitor. Oh no, not at all. It meant physically
perusing massive stacks of continuous form -line
printer paper that was just spat out by an IBM
1130 mainframe computer. Right, just reams of
it. So he's looking down at these endless columns
of alphanumeric characters, and he sees a string
of text so shocking that he grabs a red pen,
circles it, and actually writes the word, wow,
in the margin. The literal margin notes of history.
Exactly. Okay, let's unpack this. The text he
circled notoriously reads as 6EQUJ5. And we really
need to clear up the biggest public misconception
right away here. Yes, please. Because this isn't
to cipher, right? It's not a secret alien alphabet
we need to translate. It's just a volume knob.
That's a perfect way to put it. Right. Like the
system measures signal to noise ratio, and when
the volume gets dangerously, ear -shatteringly
loud, it literally runs out of numbers one through
nine and just switches over the letters. Yeah.
The measuring system adopted for this specific
experiment was incredibly rigid. Like, a blank
space on that line printer paper just meant the
intensity was normal, ambient background noise.
It's just the static of the universe. Exactly.
Between zero and one standard deviation above
the baseline. The numbers one through nine meant
it was one to nine standard deviations above
that noise. OK. But if a signal went above nine,
the computer switched to the alphabet. So A meant
an intensity of 10 to 11, B meant 11 to 12, and
so on. Which means tracing that alphabet all
the way up to you puts us at an intensity of
30 standard deviations above the background noise.
I mean, that is a massive spike in radio energy.
It is a deafening roar. And the mechanical rhythm
of how this was recorded is, well, it's vital
to understanding why it's so compelling. So,
the Big Ear Telescope sampled the incoming radio
signal for exactly 10 seconds. Then, the IBM
computer took exactly two seconds to process
that sample and physically strike a single character
onto the printout. Okay, so every character is
a 12 -second window. Right. So when you read
down that specific column 6 EQ UJ5, you're looking
at a 12 -second pulse beat by mechanical beat.
Wow. It captures a signal that rises dramatically
out of the background static, hits this unbelievable
peak of intensity at you, and then steadily fades
back down into the noise. Here's where it gets
really interesting. Because, you know, knowing
the mechanics of the code is one thing, but a
loud noise shouldn't immediately make a rational
astronomer think of aliens. No, it shouldn't.
The physical anatomy of the signal is what makes
it so legendary, specifically the duration. It
lasted for exactly 72 seconds. Now, I'm stuck
on this 72 second window. Because, like, if I'm
an advanced civilization trying to contact another
world, I'm leaving my transmitter on all year.
You think so, yeah. I'm broadcasting continuously.
Why, 72 seconds, couldn't it just be a random
Earth radio broadcast sweeping past the telescope?
Or like a passing military plane? See, that is
the logical first assumption. But the 72 second
duration is actually the absolute strongest piece
of evidence against it being an Earth -based
broadcast. Wait, really? How? We have to look
at the physical engineering of the Big Ear Telescope.
Unlike modern radio telescopes, you know, the
massive dishes you see tilting and pivoting to
track an object across the sky, Big Ear was essentially
fixed to the ground. Oh, right. It was a transit
instrument. Exactly. It could tilt slightly up
and down to adjust its altitude, but to scan
across the sky from east to west, it literally
relied on the rotation of the Earth. So it was
just staring at a thick strip of the sky, letting
the earth spin, do the panning. You got it. And
because of the specific width of the telescope's
observation window, combined with the exact rotational
speed of the Earth, a fixed celestial object
in deep space would stay in Big Ear's view for
exactly 72 seconds. Wow. Not 71, not 73. If a
continuous stationary signal was beaming toward
Earth from a distant star system, the telescope
would pick it up as a gradual increase in volume
for the first 36 seconds as the telescope's beam
rotated into the signal. It would peak right
in the middle and then display a gradual decrease
for the final 36 seconds as the telescope rotated
away. So 36 seconds up, peak at the U, and 36
seconds down. It perfectly maps to a stationary
point source in deep space. It is flawless. I
mean, a passing airplane or a satellite in orbit
moves independently of the Earth's rotation.
They would streak across the observation window
much faster, or they'd linger longer, which would
totally destroy that perfect 72 -second bell
curve. That makes total sense. And the frequency
of the signal is just as important as the shape
of it. The signal came in at exactly 1 ,420 megahertz.
Yes, the hydrogen line. Exactly. Now back in
1959, physicists Philip Morrison and Giuseppe
Cocconi wrote a seminal paper predicting that
if an advanced alien civilization wanted to communicate
across the galaxy, they would inherently use
this exact frequency. And the physics behind
that choice are fascinating. It's not arbitrary
at all. 1420 megahertz is the natural emission
frequency of neutral hydrogen, right? Yes, which
is the most abundant element in the entire universe.
Right. So if you look at a neutral hydrogen atom,
you have a proton and an electron. Both possess
a quantum property called spin. Correct. And
occasionally the electron flips its spin direction.
When that spin flip transition happens, the atom
releases a tiny amount of energy in the form
of a radio photon with a wavelength of exactly
21 centimeters. Which equals a frequency of 1420
megahertz. Exactly. Any technologically advanced
civilization anywhere in the universe would know
this fundamental rule of physics. They absolutely
would. It is a universal constant. So it kind
of operates like the universal maritime distress
channel. Oh, that's a good analogy. Like, if
you are a ship out on the ocean and you want
to hail another vessel, you don't just pick a
random radio frequency and hope someone is listening.
No, of course not. You broadcast on the dedicated
channel that you know every other sailor is already
actively monitoring. Right. And what's fascinating
here is that on Earth, that specific 1420 megahertz
frequency is actually a globally protected spectrum.
Really? Protected how? By international agreement,
it is reserved exclusively for passive astronomical
research. Terrestrial transmissions, so military
radar, commercial radio, television broadcasts,
they are strictly forbidden by law from broadcasting
anywhere near that frequency to prevent interference.
Wow. that precisely mimics a deep space origin,
lasts exactly the length of time a deep space
object should, and comes in on the one universally
protected frequency that physicists predicted
an alien civilization would use. Everything about
its physical profile just screamed extraterrestrial.
But, I mean, if we have the perfect signature
and the perfect frequency, why didn't we just
point every dish on Earth at that spot in the
sky and start talking back? Well, that's the
tragedy of it. Yeah, this leads us directly into
the geographical ambiguity of the signal, which
has to be the most agonizing data limitation
in modern astronomy. We literally didn't know
exactly where to point. We didn't. And it comes
down to a quirky design limitation of the Big
Ear Telescope's data processing. How'd it work?
Big Ear utilized two feed horns. Think of them
as two separate antennas sitting side by side,
pointing in slightly different directions in
the sky following the Earth's rotation. OK. To
filter out background static, The receiver system
was designed to electronically subtract the signal
of one horn from the other. Right. That makes
sense for cleaning up the data. Yeah, but the
problem is the wow signal hit one of the feed
horns, but not the other. And because the computer
only recorded the difference between the two
horns to save processing power, it was physically
impossible to determine which of the two horns
actually received the incoming signal. Oh, no.
So we had the declination, the up and down coordinate
locked in perfectly. Yes. But For the right ascension,
the side -to -side coordinate, we were left with
two entirely separate, non -overlapping regions
in the constellation Sagittarius. Exactly. It's
like knowing a screen came from the fifth floor
of an apartment building. But because of the
echo, you don't know if it came from the apartment
on the far left or the apartment on the far right.
And you were just staring at two doors, completely
paralyzed. But astronomers didn't just give up.
Let's fast forward to the modern day. because
our mapping of the cosmos has improved exponentially
since 1977. Oh, definitely. In 2022, an incredible
paper was published in the International Journal
of Astrobiology. Researchers utilized the Gaia
satellite database, which provides spectacularly
precise 3D maps of our galaxy to look at what
is actually sitting inside those two specific
antenna -pointed coordinates. And they found
something, right? They identified three likely
Sun -like stars. And one of them is a prime candidate.
A star designated 2MASS192819822640123. Quite
a catchy name. Right. But it's perfectly situated
about 1800 light years away. And it possesses
a temperature, a radius, and a luminosity incredibly
similar to our own sun. It aligns brilliantly
with theoretical estimations of where an intelligent
civilization might evolve. So we finally had
prime targets. But the silence has been deafening.
Yeah. I mean, the follow -up efforts to find
this signal again have been massive. They span
decades and utilize increasingly powerful technology.
Absolutely. Like Robert Gray searched for it
in the late 1980s with the Meta array at Harvard.
He tried again in the mid 1990s with the incredibly
sensitive, very large array in New Mexico. And
they didn't stop there. Right. As a direct response
to that 2022 discovery of the Sun -like stars,
the Breakthrough Listen project pointed both
the massive Green Bank Telescope and the Allen
Telescope Array right at those specific stars
for a highly coordinated search. They scanned
for hours. And they found absolutely nothing.
Nothing at all. This raises an important question
about how we validate anomalous data. Douglas
Vakosh, the president of METI Messaging Extraterrestrial
Intelligence, makes a crucial point about this.
What does he say? In the realm of science, a
discovery isn't truly a discovery unless it can
be replicated. Without replication, without being
able to point a telescope at a coordinate and
measure the phenomenon a second time, the wow
signal has very little scientific credibility
as a confirmed alien broadcast. So a one -off
event, no matter how flawlessly it aligns with
our mathematical predictions, is just an agonizing
anomaly. Exactly. So what does this all mean?
Since science demands replication, Researchers
have spent decades fiercely trying to prove it
was just a natural astronomical glitch or some
terrestrial error. Oh, yeah. The debunking attempts
are fascinating in their own right. Let's talk
about those. Well, one of the most famous recent
attempts came in 2017 from Antonio Paris, an
astronomy professor. He proposed that the signal
was caused by a massive naturally occurring hydrogen
cloud surrounding two comets. Comets Christensen
and Gibbs, I believe. Right, which were supposedly
moving through that region of space in 1977.
But the original Big Ear team dismantled that
theory in the literature with just ruthless efficiency.
They really did. They pointed out catastrophic
flaws in the math. First, those specific comets
weren't actually in the telescope's beam at the
correct time. Kind of a big problem. Yeah. Second,
the physics of cometary emission don't work.
Comets simply do not emit hydrogen signals anywhere
near the massive strength required to produce
a U on that printout. Right. And third, Paris's
theory couldn't explain the feed horn problem.
Comets move slowly across the sky. So if it was
a comet, the signal would have been picked up
by the first feed horn, and then a few minutes
later, it would have been picked up by the second
feed horn. But the wow signal only triggered
one. Exactly. Even Jerry Immen himself, the man
who wrote wow on the paper, he heavily doubted
the extraterrestrial hypothesis for a time. What
did he think it was? He proposed a terrestrial
explanation, suggesting it might have been a
secret military Earth signal that accidentally
bounced off a piece of space debris and reflected
perfectly back into the telescope. Oh, like space
jumps. Yeah, but even later retracted that skepticism.
Further physics modeling proved that a piece
of metallic space debris tumbling in low Earth
orbit simply cannot reflect a terrestrial signal
back into a fixed telescope to perfectly mimic
a deep space source with a flawless 72 second
rise and fall. Right, because space junk moves
far too fast and erratically. Exactly, it just
doesn't work. But just recently, the debate was
blown wide open again. In August 2024, the Planetary
Habitability Laboratory published a fascinating
preprint drawing on data from the Arecibo Observatory.
Yes. And they actually proposed a totally new
natural hypothesis that relies on some incredibly
complex astrophysics. This is currently one of
the most compelling natural explanations we have.
Break it down for us. So the researchers proposed
that the Wow signal was the result of a very
rare transient astrophysical event known as stimulated
emission, essentially a cosmic maser. OK. The
theory suggests there was a cold, dark cloud
of hydrogen gas sitting out in space. Suddenly,
it was struck by massive stellar emissions from
a highly energetic cosmic event behind it. Like
what? Perhaps a flare from a magnetar, which
is a ridiculously dense neutron star with a magnetic
field quadrillions of time stronger than Earth's.
That sounds intense. It is. This sudden immense
injection of energy into the cold hydrogen cloud
caused the atoms to synchronize their electron
spin flips. So it triggered a chain reaction.
Exactly. The energized cloud experienced a sudden,
dramatic, highly focused surge in brightness
at that exact 1420 megahertz frequency. It amplified
the background radiation exponentially for a
very brief period. So mechanically it's like
a cosmic neon sign. floating invisibly in the
dark. That's a great analogy. Right. It has all
the gas inside, but no electricity. Then a magnetar
flare plugs it into a massive momentary power
surge. The hydrogen gas burns blindingly bright,
beaming a highly focused laser of radio waves
right as our telescope happens to be sweeping
past that exact patch of sky. Yep. And then the
energy dissipates, the cloud shorts out, and
it goes dark forever. That perfectly captures
the mechanics of a cosmic maser. It accounts
for why the signal was so incredibly strong,
why it was locked precisely at the hydrogen frequency,
and most importantly, why we have never seen
it again despite decades of searching. Because
it was a one -time event. Right. It wasn't an
alien beacon left on. It was an astrophysical
flash bulb going off in the dark. But regardless
of whether it was a glowing cloud of synchronized
hydrogen gas, or an actual alien civilization.
I mean, the psychological impact of the Wow signal
remains profound. Oh, absolutely. It totally
changed our relationship with the cosmos. We
desperately wanted to reach back into the dark.
In 2012, for the 35th anniversary of the signal,
the Arecibo Observatory decided to officially
talk back. Yes, they did. They gathered 10 ,000
promotional tweets using the hashtag chasing
UFOs, which ironically was for a television show.
And they beamed this digital stream of Twitter
messages directly at nearby stars. The intention
to respond was a milestone in human history,
even if the execution was deeply, deeply flawed.
Deeply flawed is an understatement. Yeah, the
historical record of that event contains an incredible
irony. According to the former director of the
Arecibo Observatory, The sheer power required
to transmit that complex digital data caused
the transmitter to literally overheat shortly
into the very first transmission. Wait, they
blew out their own equipment trying to send tweets
to aliens? They did, and the data gets even worse.
How could it be worse? Because of the equipment
failure, The message was only sent in the direction
of one of their pre -selected star targets. And
none of the targets they chose were even in the
possible region of Sagittarius where the wow
signal actually originated. So to summarize our
grand cosmic greeting, we took 10 ,000 tweets,
pointed our massive radio dish at the entirely
wrong part of the sky, yelled into the void,
and promptly melted our own transmitter. Pretty
much, yeah. But despite our bumbling, the signal's
legacy endures. It showed up in the 1994 season
premiere of The X -Files. It was a foundational
plot point in the 2024 sci -fi series 3 body
problem. It just has this absolute grip on our
collective imagination. If we connect this to
the bigger picture... The WOW signal is the ultimate
tantalizing data point in the history of science.
It really is. Even if we never fully solve it,
it served a vital, transformative purpose. It
forced humanity to drastically refine the mathematics
and hardware of our radio astronomy techniques.
It forced us to seriously debate our cosmic communication
protocols, how we listen, and how we might responsibly
respond. And as we saw with the 2024 hydrogen
cloud maser theory, it is forcing us to look
much closer at rare transient astrophysical phenomena
that we might otherwise completely ignore. And
for you listening, whether you walk away from
this deep dive believing it was extraterrestrial
intelligence saying hello, or a freak energized
hydrogen cloud acting like a cosmic neon sign,
the 72 second anomaly proves just how much of
the universe's mechanics are still completely
unknown to us. We really don't know much at all.
We have only just opened our eyes to the radio
universe. And I want to leave you with one final
thought to mull over, building on what we discussed
about that strict 70 second window and the rotation
of the Earth. Oh, this is a good one. We spent
decades analyzing the contents of the signal.
But if it really was an extraterrestrial civilization
out there, what if the message wasn't hidden
in the radio wave itself? What if it was the
delivery? Right. What if the message was in the
exact timing of its arrival? What if an intelligence
out there calculated the exact rotational speed
of our planet, deduced exactly when our primitive
fixed radio telescopes would be sweeping past
that precise patch of sky and send a quick 72
second flash at the exact millisecond they knew
we'd be looking. It gives you chills. Just something
to think about the next time you look up at the
night sky.