The Wow! signal: a remarkable radio event

On 15 August 1977, Ohio State University’s Big Ear radio telescope detected a strong, narrowband signal that became known as the Wow! signal. Astronomer Jerry Ehman circled the unusual printout and wrote “Wow!” beside it, giving the event its enduring name. Its frequency and brief passage through the telescope’s beam made it interesting to researchers searching for possible signals from beyond Earth.

But the signal was not detected again in follow-up observations, and its source was never identified conclusively. A one-off signal is not confirmation of an intentional transmission: interference, an astronomical source or an instrumental or observational issue must also be considered. The event remains intriguing precisely because the available data are limited.

It is often presented in popular culture as evidence of alien contact, but that goes beyond what the observation can establish. The Wow! signal is a genuine historical radio detection whose origin remains unresolved—not a verified message from extraterrestrial intelligence. [1]

Editorial note: This feature summarises the published sources listed below; it is not a new archive investigation. The accompanying image is AI-generated illustration, not an archival photograph or evidence of the event.