Astronomers Heard This Once. It Never Came Back.

72 seconds. One signal. Never heard again. On August 15, 1977, a radio telescope in Ohio picked up a signal from deep space so strong that an astronomer circled it with a red pen and wrote one word: "Wow!" Nobody has ever found where it came from. It has never repeated. In this video: What the Big Ear telescope recorded that night Why the signal looked exactly like what we would expect from an intelligent source The explanations scientists have tried: a comet, an error on Earth, and something else The Fermi paradox: if the universe is so big, where is everybody? Rare Earth, the Zoo hypothesis, the Dark Forest and the Great Filter Is the silence empty... or is it someone choosing not to speak? Subscribe for a new space mystery every week. #WowSignal #SpaceMystery #FermiParadox