The case record
What was reported?
A strong narrowband radio signal recorded by Ohio’s Big Ear telescope in August 1977 has never been securely identified. Its famous notation is an intensity record, not a decoded extraterrestrial message.
Jerry Ehman noticed the sequence 6EQUJ5 while reviewing computer output and marked it with Wow! The six values describe successive samples as the telescope’s beam swept across the apparent source. Big Ear’s two-beam arrangement left uncertainty over the exact sky position.
Date is detection at Big Ear. The terrestrial map marks the instrument site, not the celestial source.
- Reported date
- 15 August 1977
- Witnesses
- Historical records, investigators and observers; see case-specific account · Not reliably reducible to a single count
- Investigation
- Historical and research accounts reviewed from: Jerry Ehman / Ohio State University Radio Observatory
Evidence in the record
The original printout and instrument design permit reconstruction of signal strength and duration. Ehman’s own explanation shows how the symbols represented intensity relative to background. The signal’s failure to recur limits follow-up tests.
Competing explanations
Official and research context
Ehman’s account documents an unusual radio detection whose origin was not established; the intensity code is not decoded message content.
Conventional explanations
Terrestrial interference, unusual natural radio emission and other instrumental or astronomical possibilities remain topics of study. An artificial extraterrestrial transmitter is a hypothesis, not an inference compelled by narrow bandwidth. Recent proposed mechanisms still require independent confirmation.
Arguments that remain contested
The emitting source and why the signal appeared only once remain unknown.
Locations & timeline
Coordinates are representative. Area and route labels do not imply exact paths or object positions.
- Primary reference location
Former Big Ear Observatory
Date is detection at Big Ear. The terrestrial map marks the instrument site, not the celestial source.
Representative research/inscription location · Approximate area radius: 2 km
40.250°, -83.050° · point · Regional reference only; not survey-grade
Record notes
Map coordinates are representative and do not establish an exact incident position.
Case-specific sources researched 8 September 2026. Evidence, alternatives, dates and representative geography reviewed.
Original dataset status: unresolved