On August 15, 1977, the Big Ear Observatory in Ohio received an unusually strong radio signal. The signal was so unique that astronomer Jerry Ehman was so amazed that he drew a red circle around it and scribbled the word “Wow!”. Since then, the Wow! signal, as it has become known, has baffled scientists who have been unable to identify its source. But a new project aimed at solving the signal’s mystery may be on the way to a breakthrough.
Using archived data from the former Arecibo Observatory in Puerto Rico, the Arecibo Wow! (AWOW) project has found similar data that suggests the 47-year-old radio signal was the result of a rare event in which a giant hydrogen cloud glowed with ultra-brightness. The team’s project page notes that a paper describing their findings will soon be submitted for peer review in a scientific journal.
Abel Mendez, an associate professor of physics and astrobiology at the University of Puerto Rico who led the study, admits that he only began to look into the Wow! signal in depth earlier this year. “To be honest, for me, and for many astronomers, the Wow! signal was kind of a coincidence,” he told Gizmodo. “So, I didn’t pay any attention to it.”
Mendez has spent years studying habitability throughout the universe by observing stars and the planets orbiting them. In May, he stumbled across a video explaining the “Wow!” signal and became fascinated. “I thought maybe we could find something cool in our data,” he said.
The Wow! signal attracted so much attention because of its unusual strength, lasting for 72 seconds, despite its relatively narrow bandwidth (a narrow bandwidth near the 1420 MHz hydrogen line). Being so powerful and packing so much energy into such a narrow frequency makes it likely to be man-made. This clearly sparked alien rumors, with some people believing the transmission was sent from an extraterrestrial civilization.
Wanting to see if they could find any other similar signals, AWOW Project researchers looked at data collected by the Arecibo Telescope between 2017 and 2020. They found a similar narrowband signal near the hydrogen line, although it wasn’t as intense as the original Wow! recording.
A similar phenomenon to the Wow! signal has been produced by an interstellar cloud of cold hydrogen (HI) in our galaxy, but at a brightness two orders of magnitude lower. Mendes and his team believe that the Wow! signal could have become so bright because of a sudden increase in brightness caused by a temporary source of radiation, such as a magnetar. A magnetar is a type of neutron star with a very strong magnetic field that can excite atoms in the hydrogen cloud, causing a sudden increase in brightness.
“That’s unusual,” Mendes said. “What are the chances that a magnetar would be right behind those clouds, with enough radiation to stimulate them, and that someone would be looking in that direction at the same time?”
Mendes and his team plan to make follow-up observations using the Extremely Large Telescope in Chile to pinpoint the cloud behind the signal they found in the archived data. The astrobiologist is determined to learn more about his new obsession. “I’ve learned more about the Wow! signal in the past few months than I’ve ever learned in my entire life,” he says.
more: Scientists claim mysterious ‘Wow!’ signal is from a comet, not aliens
