Astronomers first tuned radio telescopes to the stars in 1960 — but in the 62 years since, we haven’t found much when it comes to hints of extraterrestrial life. The strongest hint of anything out there is a tantalizing but ambiguous 72-second-long radio burst detected from outer space in 1977. In the intervening years, it’s come to be called the Wow! Signal, and frustrated astronomers because it’s never repeated.
