Researchers scan the skies daily for non-terrestrial signals, and for those who don’t know, we actually stumbled upon something at 11.16pm on August 15, 1977 as a radio telescope in Ohio swept its gaze through the constellation of Sagittarius. It was called the Wow! Signal for good reason, and it might have been an extraterrestrial beacon that was periodically broadcasted in a sweeping lighthouse beam, which would explain why we haven’t been able to detect it again. Continue reading for a video and more information.

In August 1977 an Ohio State University radio telescope detected an unusual pulse of radiation from somewhere near the constellation Sagittarius. The 37-second-long signal was so startling that an astronomer monitoring the data scrawled “Wow!” on the telescope’s printout. The signal was within the band of radio frequencies where transmissions are internationally banned on Earth. Furthermore, natural sources of radiation from space usually cover a wider range of frequencies.

As the nearest star in that direction is 220 million light years away, either a massive astronomical event – or intelligent aliens with a very powerful transmitter would have had to have created it. The signal remains unexplained.

[Sources 1 | 2]