The Wow Signal was detected on 15 August 1977 by the Big Ear radio telescope at Ohio University.
It is named after the notation of the word “WOW!”, which was inscribed on the computer printout on which it appeared by the excited astronomer who spotted it two days later.
This red inked exclamation would come to symbolise what many believed was the first contact from aliens. But was this a sign of first contact? And if not, what was it?
The Wow Signal
In the 1970s, NASA was scouring space for radio signals that might be communications from intelligent aliens. As part of the Search for Extra-Terrestrial Intelligence (SETI), they had teams of volunteers working on the project from 1973 onwards.
On 17 August 1977, it seemed one such volunteer might have found the holy grail of extra-terrestrial communications. Would this be the signal that changed our understanding of the universe forever?
It was on that date that astronomer Jerry R. Ehman was reviewing data from the c University when he saw the entry 6EQUJ5. Recorded on 15 August, this was no ordinary alpha-numeric combination. It signified an intense narrowband radio signal. Most significantly, it met the very specific criteria astronomers expected from intelligent extraterrestrial communication. Thrilled, he scribbled the word that would give the signal its distinctive name, “WOW!”
Over the decades, Wow has come to symbolise the hope of such contact, capturing the public imagination. So what caused that sound on 15 August 1977? And was it a sign of intelligent life beyond Earth?
The 1977 Space Signal Sound
The Jerry Ehman Signal lasted a full 72 seconds and was both intense and loud. The sound emitted could be described as somewhere between white noise and an old fashioned modem after dialling up.
Attempts at Replication
Ehman and many other astronomers have since attempted to replicate the Wow Signal. For the entire month after Big Ear detected it, the telescope was kept pointed exclusively at the Sagittarius Constellation from where it was believed to have originated. But despite ongoing attempts, the 1977 Space Signal would never be detected again.
Explaining the Wow Signal: Theories
Over the decades, some have held onto the belief that the Wow Signal was the first contact from intelligent life in outer space. However, astronomers now generally agree that this was not the case. In fact, it is said that such signals were not uncommon in the early days of SETI due to primitive technology being unable to perform immediate checks and follow ups.
There have been many theories in trying to explain the signal – natural phenomena, such as comets, and spy satellites just two among them.
The more recent but relatively unresearched discovery of something called Fast Radio Bursts (FRBs) has also been posited as a possible cause. In the simplest terms, an FRB is a fleeting, intensely bright and powerful blast of radio waves originating from somewhere in deep space. Within a matter of milliseconds, an FRB will release as much energy as hundreds of millions of suns. Also known as Lorimer Bursts, after the American astronomer who discovered them in 2007, they are one of the great mysteries of astrophysics. The burst discovered by Lorimer released energy equivalent to 500 million suns.
FRBs can be one-off emissions or repeated events and occur as often as every ten seconds. The sources of FRBs remain unexplained. Different FRBs may have different sources, among which neutron stars called magnetars are just one candidate.
An Intriguing Mystery
Unless it is detected again, it is unlikely that the Wow Signal will ever be fully explained. But that hasn’t stopped people trying.
In 2020, amateur astronomer Alberto Caballero claimed to have identified a sun-like star called 2MASS 19281982-2640123 as the most probable source of the signal.
Despite this theory however, the hunt continues. Even with the destruction of Big Ear in 1997 and significant reduction in funding for SETI projects, it seems there will always be those with their eyes on the skies.