Big Ear telescope detection of the Wow! Signal

On August 15, 1977, astronomers using the Big Ear Radio Telescope at Ohio State University detected a powerful, 72-second narrowband radio signal. The event became famously known as the ‘Wow! Signal’ after astronomer Jerry Ehman wrote the word in red ink on the computer printout data.

The signal was notable for its intensity and its distinct pattern of increasing and then decreasing in strength, which suggested a celestial origin rather than an earthly one. It was detected while scanning the Sagittarius constellation.

Despite follow-up investigations by the SETI Institute, the phenomenon has never been repeated. While some characteristics initially suggested the possibility of extraterrestrial intelligence, the lack of repetition has led many to believe it was a natural astronomical event. Recent theories suggest the burst may have been caused by a flare from a magnetar interacting with a cold hydrogen cloud.