23 Questions about the world that still have no answer

On August 15, 1977, astronomer Jerry Ehman made an exciting discovery: a narrow-band radio signal originating from the constellation Sagittarius. This signal, lasting 72 seconds, matched the frequency of hydrogen, the most abundant element in the universe, and was thought to possibly indicate extraterrestrial life. Efforts to recapture the signal have led to silence, making it forever known as the “Wow! Signal.”