One of astronomy’s most enduring mysteries, the ‘Wow! signal,’ has taken a surprising turn. This enigmatic radio signal, detected in 1977 by the Big Ear radio telescope, initially sparked excitement as a potential sign of extraterrestrial intelligence. The signal’s intensity and specific frequency, 1,420 megahertz, a frequency naturally emitted by hydrogen, fueled speculation. However, the ‘Wow! signal’ remained a solitary event, with no similar signals ever detected. Now, a new study offers a compelling explanation for the signal’s origin, suggesting it was not an alien message but rather a rare cosmic occurrence.
Abel Méndez, a planetary astrobiologist and director of the Planetary Habitability Laboratory at the University of Puerto Rico, and his colleagues propose that the ‘Wow! signal’ was a fortuitous detection of an extremely intense flare striking an interstellar cloud of hydrogen gas. This flare, they argue, was likely emitted by a magnetar, a type of dense, magnetic star. The intense radiation from the magnetar would have caused the hydrogen cloud to emit the radio waves detected by Big Ear.
This theory gained traction when Méndez and his team discovered eight similar, albeit fainter, signals in archival data from the Arecibo Observatory. These signals, recorded between February and May 2020, exhibited narrowband radio emissions close to the 1,420 megahertz frequency. The presence of multiple signals, each lasting two to three minutes, further strengthens the argument for a natural origin.
The researchers suggest that these signals are likely caused by hydrogen clouds illuminated by flares from magnetars, though these flares are much weaker than the one that might have produced the ‘Wow! signal.’ Méndez theorizes that if these fainter signals had been illuminated for a longer period, they would have matched the strength of the ‘Wow! signal.’
While the new hypothesis has sparked excitement among astronomers, it has also been met with some skepticism. The idea of a magnetar flare illuminating a hydrogen cloud to produce such a specific signal has never been directly observed. Additionally, critics point to the multiple coincidences required for this scenario to unfold: the Big Ear telescope being pointed at the right spot, the magnetar flare occurring at the right time, and the emitted radiation aligning perfectly with the 1,420 megahertz frequency.
Despite these reservations, the new research presents a compelling alternative to the long-standing mystery of the ‘Wow! signal.’ Future research will delve deeper into archival data from the Arecibo Observatory and utilize the capabilities of the Very Large Array, a network of radio telescopes in New Mexico, to pinpoint the locations of the signals and study the properties of the hydrogen clouds. These efforts hold the potential to unravel the true origins of the ‘Wow! signal’ and its newfound counterparts, adding another layer of complexity and wonder to the universe we inhabit.
