Wow! Signal: Did Aliens Tried To Contact Us in the Late 70s?

The Wow! signal was an inscrutable radio signal received by the Big Ear Radio Observatory of Ohio in August 1977, which kindled the debate of whether it was sent by an intelligent extraterrestrial species. The signal apparently came from the Sagittarius constellation and had incongruous characteristics, which many suspected to be the hallmark of extraterrestrial origin.

The complete signal lasted for 72 seconds, as recorded by the radio telescopes at the Big Ear Observatory. However, interestingly enough, despite numerous attempts by scientists, this odd signal was not detected again. After the discovery of this signal, many hypotheses were proposed to substantiate its origin and cause of emission, but none of them were successful in explaining the result. The Wow! signal remains the strongest candidate for extraterrestrial communication that humans have ever received.

How it got the ‘Wow!’ name

When something truly sensational occurs, people usually say “OMG!” or “Awesome!”, but on August 15, 1977, renowned astronomer Jerry Ehman was sitting at his desk at the Big Ear radio research laboratory when he saw the printout from the computer printing six epochal characters (6EQUJ5). Those six characters later turned out to be the greatest riddle of space science to date, and he chose the simplest expression of all. Jerry, flabbergasted at the sight of those six mysterious characters, got up, grabbed a nearby red pen, circled the letters on the printout and wrote, “Wow!” in the margin in astonishment.


(Photo Credit : (NAAPO/Wikimedia Commons)

At the time of discovering that arcane six-letter word, Jerry was a professor at Ohio State University and was volunteering with SETI (Search for Extraterrestrial Intelligence) at the Big Ear radio observatory. Unfortunately, the Big Ear lab no longer exists in its original form. It was disassembled in 1998 to expand the neighboring golf course. It was indeed a ‘big’ radio observatory lab. Its most notable feature was a vast aluminum ground plane with the dimensions 150 x 85 meters—three times the area of a normal football pitch!

Jerry’s computer at the Big Ear observatory used to continuously scan the sounds coming from deep space and Jerry would monitor those signals. If something unusual popped up, he was responsible for notifying his other SETI companions.

What he witnessed that day on the printout was like the answer to a prayer!

Harbinger for the Wow! signal

Two decades before the discovery of the ethereal Wow! signal, physicist Philip Morrison and Giuseppe Cocconi from Cornell University had attempted to surmise how an intelligent extraterrestrial species might try to communicate with the species residing on Earth. Their best bet was on radio signals, as radio waves are relatively easier to produce than other signals and don’t require an enormous amount of energy to travel astronomical distances.

The duo felt that the aliens would select a frequency range that would be understood by creatures who understand math and chemistry. For those who don’t know, hydrogen is the most abundant chemical element in the entire universe. Zap an atom of hydrogen and it will begin resonating at a particular rate, i.e., 1420 MHz.

Their argument was that if an extraterrestrial species happened to be intelligent and would seek to attract our attention, they would choose a frequency likely to be heard and easily discernible from artificial signals. Thus, intelligent aliens would probably want the beacon signal they send to be at a frequency that makes it through the atmosphere with little or no competing background noise.

And on the fateful day of August 15, the signal came, exactly as predicted!


What Jerry saw at the Big Ear observatory was a radio signal very close to 1420 MHz frequency (1420.4556 to be precise). It lasted 72 seconds and was aberrantly loud.

If you look at the printout, you will see an outlier sequence of numbers and letters—6EQUJ5—that is markedly different from the rest of the characters, all of which are numbers.


The Wow! signal represented as “6EQUJ5”. (Photo Credit : (NAAPO/Wikimedia Commons)

The numbers and letters are a measure of the intensity of the various radio signals received by the receiver. Signals with low power were measured with numbers 0 to 9, but as the power increased, the system used letters instead; 10 was represented by A, 11 was B and so on. So, by the time you get to the last few letters of the alphabet, you would be getting a very high-intensity prodigious signal that is distinctly different from the usual cosmological noise.


Plot of Wow! signal fitted with a Gaussian function representing a near-perfect bell curve (Photo Credit : Maxrossomachin/Wikimedia Commons)

When Jerry saw the letter U (U is the 21st letter of the alphabet), that’s when he knew that something strange was up. He had never seen any signal of such intensity before.

Moreover, the scale for measuring intensity is logarithmic, instead of linear. This implies that the Wow! signal was roughly 30 times louder than the ordinary noise of the cosmos.

Many experts speculated that this signal was some kind of “hello” from aliens!

Was it really a beacon signal sent by aliens?

More than being surprised, Jerry was puzzled. He was curious about where the mysterious signal came from and what it meant. After a few attempts, SETI scientists were able to track the origins of the signal and determined that it originated from the Sagittarius constellation. However, when they scoured deeper for the more definite source, there was nothing there—no planet and no star—but the shape, intensity, and frequency of the signal insinuated intentionality, rather than stochasticity.


Sagittarius constellation (Photo Credit : Till Credner/Wikimedia Commons)

Jerry and his team examined all the alternative explanations that could possibly justify the occurrence of the Wow! signal as being normal, rather than an outlier. But the Wow! signal evaded almost every suggestion put forth to explain it. For one reason, that frequency range is protected—no one on Earth is permitted to transmit/communicate on the frequency in which the Wow! signal was observed. SETI scientists concluded that it was not from an aircraft or spacecraft passing overhead as so many skeptics pointed out. No discovered planets or asteroids were in a position to have reflected the obscure signal onto our planet. Even complicated astronomical events like gravitational lensing and interstellar scintillation failed to justify the occurrence of the Wow! signal.

In conclusion, yes, extraterrestrial intelligence is still a candidate explanation for the Wow! signal, but there’s no tangible evidence for that either!

Meanwhile, Jerry’s famous scrap of the printout with his distinctive handwriting rests in the archives of the Ohio Historical Society. In these days of manufactured sensations and fake stories, the Wow! signal remains a genuine mystery with potential implications unprecedented in the field of space science. For many, it continues to be the most exciting unsolved mystery that we have in relation to our search for extraterrestrial intelligence!


  1. Universities Space Research Association
  2. Harvard University
  3. Penn State University
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About the Author:

Hussain Kanchwala is an Electronic Engineer from University of Mumbai. He is a tech aficionado who loves to explicate on wide range of subjects from applied and interdisciplinary sciences like Engineering, Technology, FinTech, Pharmacy, Psychology and Economics.

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