It’s the most famous “message” in the search for alien life, but the 40-year mystery may have been solved – and the answer has nothing to do with extraterrestrials.
A new study suggests that, rather than possible radio contact from alien life, the Wow! signal could have been caused by two comets passing by Earth.
Professor Antonia Paris from St Petersburg College believes hydrogen clouds around the comets may have emitted radio waves.
“I came across the idea when I was in my car driving and wondered if a planetary body, moving fast enough, could be the source,” Professor Paris told New Scientist.
“'These two comets were not detected until after 2006. Therefore, the comets and their hydrogen clouds were not accounted for during the signal emission.'
Since the detection of the infamous radio signal on 15 August 1977, some have claimed it was a call from aliens.
The 72-second transmission was picked up at the Big Ear radio observatory in Ohio, coming from the direction of the Sagittarius constellation.
When astronomer Jerry Ehman detected the signal, he circled it on the computer printout along with the word “wow!”
At the time, astronomers ruled out that the signal came from Earth and could find nothing in the solar system that could have produced it. Despite continued efforts, no further signals have ever been found.
Not everyone is on board with the comet theory. James Bauer of the Jet Propulsion Laboratory in Pasadena, California, suggests, “If comets were radio-bright at 21 centimetres [the wavelength the signal was observed at], I would be puzzled as to why they aren’t observed more often at those wavelengths.”
In October last year, astronomers discovered that KIC 8462852, a star located 1,480 light-years away from Earth, is producing a series of bizarre light fluctuations that researchers cannot explain.