The Big Ear telescope was scanning at 1420.4056 megahertz on the night of 15 August 1977, the exact frequency at which hydrogen atoms vibrate across the universe, because Giuseppe Cocconi and Philip Morrison had argued years earlier that any species trying to be found would broadcast on that channel — and then, for 72 seconds, something did. (opens in new tab)

Jerry Ehman was sitting at his kitchen table in suburban Ohio a few days after 15 August 1977, flipping through a stack of dot-matrix printouts from the Big Ear radio telescope, when his red pen stopped over a vertical column of six characters: 6EQUJ5. He circled it, wrote “Wow!” in the margin, and handed astronomy […]