On August 15, 1977, a most unusual signal was detected by astronomer, Dr. Jerry R. Ehman, while working for the Search for Extra Terrestrial Intelligence (SETI) project at The Big Ear radio telescope of Ohio State University. Ehman stated it was “… the strangest signal I had ever seen … At first, I thought it was an earth signal reflected from space debris, but after I studied it further, I found that couldn’t be the case.”
The “Wow! Signal” obtained its name from Ehman, who wrote ‘”Wow!” after reviewing the printout. The signal has never been explained and never noticed again.
Some speculate this unusual signal was the reflection of a transmission from Earth due to a satellite or microlensing of a natural signal from a nearby star. Ehman points out that this cannot be the case. The signal was transmitted at 1420 MHZ, which is a forbidden transmission by international agreement. The circled letters 6EQUJ5 describes the intensity variation of the signal, which neared the Hydrogen spectrum line and seemed to originate from the region of the constellation Sagittarius, roughly 2.5 degrees south of the fifth-magnitude star group Chi Sagittarii.
There have been approximately 100 unsuccessful attempts to hear this signal again. Although the Wow! signal remains unexplained, Paul Shuch of the SETI League has made the interesting observation that: “Either the Wow signal from space was the intercepted radiation from another civilization, or it’s a previously undiscovered astrophysical phenomenon. Either possibility is mind-boggling.”