The Wow! Signal lasted 72 seconds in 1977, has never been detected again, and remains the most compelling unexplained candidate in the history of the search for extraterrestrial intelligence.

On 15 August 1977, the Big Ear radio telescope at Ohio State University recorded a narrowband radio signal that lasted roughly 72 seconds. It came from the direction of the constellation Sagittarius, at a frequency near 1420 MHz, the natural emission line of neutral hydrogen. The astronomer Jerry R. Ehman, reviewing the printout a few [...] The post The Wow! Signal lasted 72 seconds in 1977, has never been detected again, and remains the most compelling unexplained candidate in the history of th