Jerry Ehman circled the printout and wrote "WOW!" after spotting a powerful 72-second radio signal from Sagittarius. 😱 Detected by the Big Ear telescope on August 15, 1977, it was over 30 times brighter than the galactic background on the 21cm hydrogen wavelength that SETI believes an intelligent civilization might choose to communicate on. The signal has never been heard again. Was this our first contact with extraterrestrials? Or a one time cosmic coincidence? What do you think?