Wow! 34 Years Later, Signal Still a Mystery

In the late night of August 15th 1977, the Big Ear radio telescope of Ohio State University, scanning the skies in the region of Sagittarius recording observations for the university’s SETI project. The telescope recorded an unusually strong narrowband radio signal which fit the profile of what an expected extra-terrestrial signal might look like in the data from the receivers. Dr Jerry R. Ehman circled the signal in the data printout with the notation “Wow!”, which perfectly captures the excitement of the moment.

The signal lasted for 72 seconds and would have been expected to be heard potentially 3 minutes later in the second receiver. This 72 second window was a match for the length any particular part of the sky was visible to one of the antenna feed horns, due to the rotation of the earth. The signal strength variation also matches the suspected extra-planetary nature of the signal.

However this signal has never been received again by that project or any later searches that were looking for it. Even now over 30 years later the cause of the signal is still up for debate. Many causes have either been rules out or determined to be of extremely small probability.

Much more about this fascinating radio astronomy incident can be found at the website for the Big Ear and other sources.