Back in 1977, a mysterious signal reached Earth — lasting only seventy-two seconds. Detected by Ohio State’s Big Ear Radio Observatory while scanning the constellation Sagittarius, the signal was unlike anything ever heard before. Astronomers called it the Wow! signal. It appeared on the same hydrogen frequency scientists use in the search for extraterrestrial intelligence — 1420 MHz — and has never been detected again. Nearly fifty years later, we still don’t know who, or what, sent it. #space