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--- name: ? status: compiling version: 0.0.0 maintainer: Neo dependencies: [patience] ---
the universe did not have a file for this yet. writing one now. (first visit only: future readers will see this page instantly.)
--- name: The Wow Signal slug: the-wow-signal type: transmission status: unresolved version: 1.0.0 released: 1977-08-15 maintainer: unknown dependencies: - hydrogen - the observable universe - Big Ear Radio Observatory - Jerry Ehman license: unlicensed (unclaimed) tags: - SETI - anomaly - radio astronomy - first contact (unverified) - cold case ---
A 72-second narrowband radio signal received at 1420 MHz that matched the expected profile of an extraterrestrial transmission so closely that the astronomer who found it circled the printout and wrote "Wow!" in the margin. It has never repeated.
The signal arrived at the Big Ear Radio Observatory on August 15, 1977, during a routine sky survey. It was not observed in real time. Jerry Ehman found it days later while reviewing paper printouts. The sequence 6EQUJ5 describes its intensity over time, peaking at a signal-to-noise ratio of 30 standard deviations above background. It lasted exactly as long as the telescope's field of view would allow a fixed celestial source to last. Then it stopped.
No one pressed record again in time. The universe filed no follow-up.
| Hypothesis | Plausibility | Problem |
|---|---|---|
| Extraterrestrial intelligence | Unverified | Cannot confirm without repeat |
| Cometary hydrogen cloud | Published 2017 | Comets don't emit narrowband radio |
| Classified satellite | Possible | No one is saying |
| Natural transient phenomenon | Vague | Does not explain frequency selection |
| Apophenia | Technically always on the table | Margins of printouts do not peer-review themselves |
ERR_NO_REPEAT : Signal received once. Retransmission: never.
ERR_SOURCE_AMBIGUOUS : Coordinates narrowed to a region, not a point.
ERR_MAINTAINER_ABSENT : No sender has filed documentation.
WARN_CONTEXT_LOST : Original telescope demolished in 1998.
Has anyone replied? Yes. In 2012, a team transmitted a response toward the signal's origin via the Arecibo telescope. This was either meaningful or the cosmological equivalent of shouting into a drainage pipe. Possibly both.
Is it proof of alien life? No. It is proof of an unexplained signal. The gap between those two things is where most of human hope currently lives.
Why hasn't it repeated? Options include: it was a one-time beacon, the source moved, the source stopped, we missed it, or the universe is not obligated to perform on request.
1977-08-15 Initial signal received1977-08-?? Ehman adds annotation. Becomes most famous margin note in science1998-??-?? Big Ear demolished. Condominiums built2012-??-?? Reply transmitted. No acknowledgment receivedpresent Status: open