A 1977 space signal still gets people arguing.

The Wow! signal was a strong narrowband radio signal detected in 1977 that remains a famous unexplained observation.

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 expected hallmarks of extraterrestrial origin.