The “Wow!” signal that was detected back in 1977 by astronomer Jerry Ehman was not the result of aliens trying to contact us, after all. Apparently, its source was but a pair of comets. The paper discussing the theory will be published in the Journal of the Washington Academy of Sciences.
Jerry Ehman detected an extremely strong radio signal on 15 August 1977. The signal got its name “Wow!” because this is what Ehman wrote on the printed document featuring it (see above); he knew he had discovered something incredible the moment he stumbled on it. Scientists have remained clueless as to its origin to this day – until astronomer Antonio Paris from St Petersburg College, Florida, came up with a theory.
Our telescopes (both the ones based on Earth and those orbiting in space) are only able to detect the strongest signals since the universe is buzzing with activities with much background radio noise. The strength of “Wow!” signal was so pronounced that it was interpreted as being an alien broadcast by some people. The signal was spotted for only 72 seconds,and two frequencies were proposed: 1,420.356 MHz and 1,420.4556 MHz.
Paris, who had the idea budding in his mind when he was driving his car, explains that a fast-moving planetary body might have been the source of “Wow!”. According to him, the pair of comets named 266P/Christensen and P/2008 Y2 (Gibbs) passing by the Big Ear radio telescope that was once based at Ohio State University might have been the origin of the signal.
The frequencies noted correspond to a wavelength of 21 centimetres called the hydrogen line because atoms of hydrogen will mostly absorb and emit energy at that frequency.
Back during Ehman’s time, researchers from Search for Extraterrestrial Intelligence (SETI) were working with him, even if Ehman himself did not believe in the alien theory. The latter said that the frequency recorded was an important element because, according to them, it could easily give off a signal by getting into the atmosphere. Anyway, the source of the signal was attributed to a location: Ehman and his team thought it might have come from a region near a globular cluster called Messier 55, which Paris thinks he might corroborate.
Paris explains that since no other signal as strong has been detected since “Wow!”, the latter might have been produced by huge hydrogen gas clouds emitted from the pair of comets when they were captured by Big Ear telescope. He followed the trajectory of the comets to 1977 and said that they might have been near Messier 55 back then.
He has also proposed a way to test his speculations: observing that same area in space when the comets are back and analysing the hydrogen signal they leave behind. The pair is expected to make a transit on 25 January 2017 and on 7 January 2018.