In 1977, a radio telescope in Ohio received a 72-second signal from space. Some believe the Wow! signal is evidence of alien life. In 2016 a scientist claims to have cracked the mystery.
Physicists Speculate on Extraterrestrial Communication
In the early 1960s, two physicists from Cornell University, Philip Morrison and Giuseppe Cocconi, attempted to understand how extraterrestrials (if they existed) might contact inhabitants of Earth. They decided that intelligent aliens might try to use radio waves, as they can be efficiently produced with little energy and are able to travel through the vacuum of space at nearly the speed of light. When the subject of a possible frequency came up, they established that one of the most meaningful frequencies might be 1420 megahertz (MHz), the vibrational frequency of a hydrogen molecule, the most common element in the universe.
Since no licenses are given to broadcast in the 1420 MHz frequency range, they postulated that any incoming signal in this range would have to come from space. They also predicted that any such signal created by intelligent extraterrestrials would be powerful enough to get our attention.
The Construction of “The Big Ear”, Ohio University’s Radio Telescope
Shortly after Morrison and Cocconi speculated how aliens might communicate with us, construction began of a large radio telescope in Delaware, Ohio. According to a BBC article, the telescope was designed by Dr. John D. Kraus, and construction spanned from the Fall of 1956 to its completion in 1963.
Nicknamed “The Big Ear”, the pivoting radio telescope spanned an area slightly larger than 8 Olympic-sized swimming pools.
The Big Ear observatory was associated with Ohio State University and eventually came to be used by the Search for Extraterrestrial Intelligence (SETI) program to scan the skies for possible incoming signals generated by extraterrestrials.
The Wow! Signal
On the night before Elvis Presley died, at 10:16pm Eastern Standard Time (EST) on August 15th, 1977, the Big Ear radio telescope picked up a resounding and unusual 72-second radio signal at 1420.4556 MHz. The signal was initially 6 times louder than the background noise created by deep space, and then rapidly increased to 31 times louder as it directly hit the radio telescope’s receiver.
The signal was recorded and translated to a computer printout on perforated paper by an IBM 1130 mainframe. With the coding system used at the time, the signal manifested on the printout as a sequence of numbers and letters: “6EQUJ5”. Michael Brooks, author of 13 Things That Don’t Make Sense, explained the coding system within his book, “The letters and numbers are, essentially, a measure of the intensity of the electromagnetic signal as it hit the receiver. Low power was recorded with numbers 0 to 9; as power got higher, the computer used letters: 10 was A, 11 was B and so on.” Considering this explanation, one can see that the U in the number/letter sequence represents quite a loud and powerful signal.
Three days later, on August 18, 1977, a 37 year-old SETI volunteer and professor at Ohio State University named Jerry Ehman received the printout which had been brought over by a bike messenger. While sitting at his kitchen table and analyzing the data, Ehman saw the 6EQUJ5 sequence, circled it, and wrote “Wow!” with a red pen in the margin of the paper. Thus, identifying what is known as “the Wow! signal.”
The Wow! Aftermath
Ehman informed SETI scientists of the discovery, and the astounded scientists were able to trace the signal to an area of space northwest of the globular cluster M55 near the constellation of Sagittarius. Curiously, no stars or planets could be detected in the area where the signal supposedly originated.
For the next month, the Big Ear remained aimed at the area of space where the Wow! signal was found, but the signal was never detected again. Since then, many scientists have tried to pick up the signal, but nothing like it has ever been heard since.
In 1997, the Big Ear was closed down and disassembled.
What Was the Wow Signal?
In the years since the Wow! signal was received, Jerry Ehman and his SETI colleagues have spent considerable time attempting to identify the source of the signal. They have ruled out ground-based broadcast signals, space debris, and various types of potential transmissions (satellite, military, and aircraft). Ehman has suggested that it could have been a classified military satellite or a terrestrial radio signal bouncing off of space debris.
The Wow! signal does resemble exactly what scientists think an extraterrestrial signal might sound and look like, but there is no proof that this is the case. It is possible that there is a natural explanation, as scientists continue to learn about the ambient sounds of outer space, yet the Wow! signal remains distinct from other known sounds that have emanated from space.
In an interview with The Atlantic, Robert Gray, an amateur astronomer and author of The Elusive Wow, defended his belief that it was a non-terrestrial radio signal:
“…there’s not much doubt that the “Wow!” signal was a radio signal, rather than something from a natural source like a quasar. That’s because Ohio State was using a receiver with fifty channels, which is sort of like having fifty AM radios, each tuned to adjacent stations. With the “Wow!” there wasn’t any noise on any of the channels except for one, and that’s just not the way natural radio sources work. Natural radio sources diffuse static across all frequencies, rather than hitting at a single frequency. So it’s pretty clear that this was a radio signal and not a quasar or pulsar or some other natural radio source, of which there are millions. It was very narrow band, very concentrated, exactly like a radio station, or a broadcast, from another world would look.”
In 2012 scientists at the Arecibo Observatory in Puerto Rico sent a series of messages in the direction of the Wow! signal.
2016 Update: Mystery Solved?
In February 2016, a professor of astronomy in Florida, Antonio Paris, claims to have solved the mystery. It didn’t occur while poring over data, but while driving his car.
“Out of the blue, I was looking at a truck passing on a bridge overhead as I drove under it. It occurred to me it could have been an object that went over us, just like the truck; a truck we will never see again. It could have been a comet or asteroid that came over us so many years ago.”
After the idea struck him, Paris analyzed the paths of comets which were not yet known in 1977, and found “two culprits which went all the way back to the original source of the signal. They were there on the same exact date, time, and in the neighborhood from where the signal was detected.”
So how would a comet create the legendary signal?
“As comets come closer to the sun, the heat melts them and they send out giant clouds of icy water. It creates a ‘halo of hydrogen’ around the comet. In just the right situation, there’s a chance that ‘halo of hydrogen’ could have given off the ‘Wow! Signal,'”
Paris will have a chance to test his theory as the two comets are set to return over the next two years, although in 1977, they appeared at the same time.
Google Trends History
The Google Trends graph below shows interest in the Wow! signal over time. While the search term continues to experience ups and downs, a peak surge of interest transpired in June 2012.
Since the early 1960s, physicists have hypothesized that if aliens exist, they may try to communicate with Earth via radio waves in the specific frequency of 1420 MHz. In 1977, a 72-second radio transmission near 1420 MHz was received by a radio telescope in Delaware, Ohio. Although it is speculated to have originated near the constellation of Sagittarius, scientists have not been able to identify the exact origin of the signal. Many people believe that the signal is the best evidence of possible extraterrestrial communication, yet there is no scientific proof that the signal was extraterrestrial in nature. In 2016, a Florida astronomer analyzed data from comets unknown in 1977 and theorized that the signal was created by one or two passing comets, a theory which may be tested in the next two years.
There are those who also speculate that the mysterious signal could have terrestrial origins, but there is no evidence to support those claims either.
Quite simply, no one knows what the signal was.
Updated March 14, 2016
Originally published July 2014