The signal was recorded in 1977 and was initially thought to be an extraterrestrial transmission. On August 15, 1977, the Big Ear Observatory in Ohio received an unusually powerful radio signal. The signal was so unique that astronomer Jerry Ehman expressed his amazement by drawing a red circle around it and scrawling the word “Wow!”.
Ever since, the so-called “Wow!” signal has baffled scientists as they have been unable to identify its source. However, a new project dedicated to solving the mystery surrounding the signal may have made a breakthrough. Using archived data from the former Arecibo Observatory in Puerto Rico, the Arecibo Wow! Project (AWOW) has unearthed similar data suggesting that the 47-year-old radio signal was the result of a rare event in which a giant hydrogen cloud super-glowed and shone brightly.
According to the research team’s project page, a paper containing the results will soon be submitted to a scientific journal for review. Abel Mendez, an associate professor of physics and astrobiology at the University of Puerto Rico who led the study, admitted that he only studied the Wow! signal in detail earlier this year. “I have to admit, the Wow! signal was something of a fluke for me and many other astronomers,” he told Gizmodo. “So I never paid any attention to it at all.” For years, Mendez has studied the habitability of the universe by observing stars and the planets orbiting them. In May, he came across a video describing the Wow! signal and was immediately hooked. “I thought this was an amazing thing to find in our data,” Mendez said.
The Wow! signal attracted so much attention because it was unusually strong for 72 seconds while having a relatively small bandwidth (near the 1420 MHz hydrogen line). The fact that it was so powerful and contained so much energy, despite being so narrow in frequency, suggested that it was an artificial signal. This obviously sparked alien rumors, with some believing the communication was sent by an extraterrestrial civilization.
The researchers behind the AWOW project wanted to see if they could find another similar signal. So they looked at data collected by the Arecibo telescope from 2017 to 2020. They found a similar narrowband signal near the hydrogen line, although less intense than the original Wow! recording. The emergence of the Wow! signal was the result of an interstellar cloud of cold hydrogen (HI) in the galaxy, but it was two orders of magnitude less bright. Mendes and his team believe that the brightness of the “Wow!” signal could be due to a sudden brightening from a temporary source of radiation, such as a magnetar. Magnetars are a type of neutron star with a very strong magnetic field that can excite atoms in the hydrogen cloud, causing a sudden brightening.
“That’s unusual,” Mendez said. “What are the chances that there’s a magnetar right behind one of these clouds, emitting radiation strong enough to excite that cloud, and at the same time, someone looking in that direction?” Mendez and his team plan to carry out further observations using the Very Large Telescope in Chile to pinpoint the exact cloud behind the signal they found in the archived data. The astrobiologist is determined to learn more about his newfound obsession. “I’ve learned so much more about the Wow! signal in the last few months than I’ve ever learned in my entire life,” he said.