Case identifier
AP-CASE-003
Case status
unresolved
Event date
Aug 15, 1977
Location
Big Ear radio telescope, Ohio
Documented sensors
Radio telescope
Witness count
Not specified in linked sources

What is confirmed

Big Ear detected the unusual radio signal on 15 August 1977. Its historical record motivates follow-up research.

Source: SETI Institute

What remains unknown

The original source has not been established here. A 2025 preprint proposes an astrophysical account, which should be evaluated as a hypothesis rather than a settled answer.

Source: arXiv

Documented chronology

  1. 15 August 1977

    Big Ear observation

    The narrowband signal is detected during a sky survey.

    Original source · SETI Institute
  2. 14 August 2025

    Archival reanalysis

    A preprint revisits the signal parameters and interpretation.

    Original source · arXiv

Evidence and provenance

RADIO

Historical narrowband observation documented by the SETI overview.

record · See the linked original source.

Original source
OTHER

A modern archival reanalysis proposes revised parameters; interpretation remains a research claim.

record · See the linked original source.

Original source

Official investigation

Not specified in the linked sources.

Physical evidence

Recorded radio measurement; no recovered physical object.

Competing explanations

Natural astrophysical emission, as discussed in a 2025 preprint.