Mystery around the 'Wow!' signal that came from space 50 years ago may finally have been solved

In the 1950s, Ohio State University launched the Big Ear Radio Observatory. The purpose of the observatory’s telescope was to “Search for Extraterrestrial Intelligence (SETI).” The telescope was designed to be sensitive to pick up even the faintest sounds from space. On August 15, 1977, astronomer Jerry Ehman detected an unusually strong signal that lasted for 72 seconds. Jerry was so stunned by the mysterious sound that he copied the signal on paper and scrawled the expression “Wow!” alongside it. Since then, scientists have been struggling to decipher the source of this “Wow!" signal. In a new study published in the Arxiv server, researchers have attempted to share some theories on the origin of this sound, and it is not related to aliens, per All That’s Interesting.

Since there were no noteworthy astrophysical phenomena behind the mysterious signal, the researchers assumed that the sound came from an artificial source. Over the years, scientists racked their brains to give potential explanations for it. Some suggested that it was radiation from a comet while others hypothesized human-made radio interference, an instrumental glitch, per Scientific American. But no one was sure of anything. However, the possibility that it was sent by aliens was equally considerable because suspicious radio waves or emissions are seen as signs of alien civilization.

But the latest study, conducted by a team of researchers led by Abel Méndez of the University of Puerto Rico at Arecibo has proposed a fresh hypothesis. And it doesn’t include the possibility of aliens.

After combing through sheaves of archival data to find records of radio emissions that bore similarities to this signal, the researchers speculated that the “Wow!" signal was the result of a flare from a hypermagnetized, hyperdense star called a “magnetar.” According to The U.S. Sun, a magnetar is simply a neutron star with a strong magnetic field. The magnetic field of a magnetar is about a thousand times stronger than that of a normal neutron star, and it can go up to a trillion times the magnetic field of Earth.

In the case of the “Wow!" signal, a specific type of magnetar called “soft gamma repeater (SGR)” is probably to blame. “We hypothesize that the 'Wow! Signal' was caused by sudden brightening from stimulated emission of the hydrogen line due to a strong transient radiation source, such as a magnetar flare or an SGR,” the researchers wrote in the paper. Also, IFL Science notes that this “Wow!" signal was the first detection of an astronomical hydrogen maser flare. Masers are lasers with the radiation of microwave wavelength.

“I would say, wow—I never thought of that. I never thought of the Wow! signal as being real and being produced by some weird astrophysical phenomenon,” Méndez said, per Scientific American. However, researchers say this theory too is a mere speculation and not the ultimate truth. “The flare-meets-hydrogen-cloud story is “definitely a bit speculative,” said study co-author Kevin Ortiz Ceballos. “We’re not saying that this is definitely the case. We’re saying that it’s a very exciting hypothesis.”

According to Scientific American, the “Wow!" signal was not only a narrowband signal; it was also in the 1,420 MHz frequency range, and it was 30 times more intense than any observed background noise. It appeared to come from near M55, a dense cluster of stars in the constellation Sagittarius. During their research, the team came across nearly eight signals that were in the same frequency spectrum, observed between February and May 2020.

Receiving so many signals in such a short period suggested that the source of this “Wow!" signal was natural, most probably hydrogen clouds emitting this frequency. Scientists have long known that clouds like these are common in interstellar space. With this information, the team attempted to reconstruct the scenario that played in the backstory of the 1977 signal. Perhaps a supernova slammed into a cloud, compressing it to such an extent that it exploded into a flurry of radio waves bursting with X-rays and gamma rays. This led them to hypothesize the possibility of a "magnetar."

Currently, Méndez and his team are going deeper into this investigation at the Very Large Telescope in Chile, to solve the mystery of this “Wow!" signal. Very recently, while Méndez was observing some red dwarf stars, he caught another set of some “Wow! signals” emanating from the background behind Teegarden’s Star. This esoteric mystery of the “Wow!" signal is only worthy of a one-word description that Jerry noted perfectly, “Wow!”