On August 15, 1977, a strong narrowband radio signal was detected emanating from constellation Sagittarius and appeared to be non-natural in origin. Astronomer Jerry R. Ehman was reviewing recorded data a few days later when he discovered the anomaly. In his excitement he circled the reading on the computer printout and wrote “ Wow!” beside it, which is why it’s now called the “Wow” signal.


Unfortunately, the signal has not been detected since. While there are hypotheses, there are no known natural explanations for the signal. The Wow signal is currently the best-known chance that we have received a radio signal from an advanced alien race.