The Wow! Signal: 72 Seconds from a Silent Sky and a Message That Never Repeated

On the evening of 15 August 1977, Ohio State University’s Big Ear telescope scanned the sky as usual. It was not taking pictures. It was listening to narrow radio channels for a signal that might come from another civilisation. An IBM 1130 computer recorded intensity in 12-second intervals and printed symbols on paper.

Several days later, volunteer astronomer Jerry Ehman reviewed the printouts at home. In the middle of columns of small numbers he saw 6EQUJ5. The code represented a signal rising above the background, reaching a peak marked U, and then falling again. Ehman circled the six characters in red and wrote “Wow!” in the margin. The signal’s name came from that handwritten reaction.