The “Wow!” signal
More than 43 years ago in 1977, a telescope called The Big Ear received a signal of a much stronger sound wave than is commonly heard in space. Radio astronomer Jerry Ehman was so impressed by the powerful signal from space, that he circled the reading on the computer printout that said “6EQUJ5” and wrote the comment, “Wow!” next to it, hence the signal’s name. Was that evidence of alien life or not? We don’t know that yet and the mystery of the “Wow!” signal still remains.
Explained almost 3 years ago:
https://earthsky.org/space/wow-signal-explained-comets-antonio-paris