18 Unsolved Mysteries That Have Been Thoroughly Solved

WOW! Alien Signal

The Wow! signal was a strong narrowband radio signal detected on August 15, 1977, by Ohio State University's Big Ear radio telescope in the United States, then used to support the search for extraterrestrial intelligence. The signal appeared to come from the direction of the constellation Sagittarius and bore the expected hallmarks of extraterrestrial origin.

Although the Wow! signal had no detectable modulation'a technique used to transmit information over radio waves'it remains the strongest candidate for an extraterrestrial radio transmission ever detected.