{
  "id": "wow-signal-1977",
  "title": "The Wow! signal: six samples, many interpretations",
  "country": "United States",
  "category": "signal",
  "date": "1977-08-15",
  "date_label": "15 August 1977, local observing date",
  "location": "Delaware, Ohio — Big Ear observing area",
  "lat": 40.25,
  "lng": -83.05,
  "location_precision": "region",
  "location_note": "Approximate terrestrial receiving-site area. The marker is not the position or distance of the unknown radio source.",
  "summary": "Big Ear recorded a striking narrowband signal represented by six intensity symbols. The file examines the printout, receiver geometry and the limits of an observation without an established repeating source.",
  "verdict": "A documented radio observation; an artificial extraterrestrial transmitter is not established.",
  "sources": [
    {
      "id": "W1",
      "title": "Jerry Ehman: 30th anniversary technical report",
      "url": "https://www.bigear.org/Wow30th/wow30th.htm",
      "kind": "Investigator’s technical report",
      "language": "en",
      "note": "Revised in 2010; includes printout reproductions, corrections and a detailed discussion of instrument geometry."
    },
    {
      "id": "W2",
      "title": "Jerry Ehman: 20th anniversary report",
      "url": "https://www.bigear.org/wow20th.htm",
      "kind": "Earlier technical report",
      "language": "en",
      "note": "Earlier version useful for tracing corrections. It is not an independent observation."
    },
    {
      "id": "W3",
      "title": "Big Ear frequently asked questions",
      "url": "https://www.bigear.org/faq.htm",
      "kind": "Observatory reference",
      "language": "en",
      "note": "Observatory context and explanations for frequently repeated misunderstandings."
    },
    {
      "id": "W4",
      "title": "Big Ear surveys and technical articles index",
      "url": "https://bigear.org/surveys-menu.htm",
      "kind": "Observatory bibliography",
      "language": "en",
      "note": "Background to the instrument and its surveys. Individual articles have their own scope."
    }
  ],
  "sections": [
    {
      "title": "Observation brief",
      "text": "On the local evening of 15 August 1977, the Big Ear telescope recorded the signal later marked by Jerry Ehman with the handwritten word Wow. The sequence 6EQUJ5 represents binned intensity, not a received sentence. The six entries span about seventy-two seconds of the instrument’s sampling cycle. They describe the passage through the receiving pattern; they do not independently measure the total lifetime of the emitter.",
      "refs": [
        "W1",
        "W2"
      ]
    },
    {
      "title": "Reading the receiver correctly",
      "text": "Ehman’s technical accounts explain the two-horn arrangement and corrections needed to interpret the recorded coordinates. The unresolved horn assignment leaves alternative sky positions. A map pin in Ohio identifies where the data were collected, not an extraterrestrial destination. The distinction matters because a precise-looking coordinate can conceal an unresolved instrumental ambiguity.",
      "refs": [
        "W1",
        "W2"
      ]
    },
    {
      "title": "Inspector’s assessment",
      "text": "The central task is to reproduce what the printout means before explaining its cause. Preserve the original characters, then add a separate column for the intensity intervals each encodes. Do not replace binned values with exact measurements. Distinguish integration time, processing time and elapsed time. A trend that resembles a beam crossing is informative, but the test should also consider what other sources could produce the same sampling pattern.",
      "refs": []
    },
    {
      "title": "Limits of a single detection",
      "text": "A one-off observation can be genuine and still be insufficient for source identification. An attractive frequency, apparent strength and an absence of an immediate explanation do not jointly establish intelligence. Compare hypotheses by predictions: recurrence, bandwidth, motion, visibility in both horns and what other instruments should detect. This dossier does not endorse an absolute claim that all natural or terrestrial explanations have been eliminated; it documents the historical measurement and how to interrogate it.",
      "refs": []
    }
  ],
  "timeline": [
    {
      "date": "15 August 1977",
      "text": "Big Ear records the intensity sequence during its survey.",
      "refs": [
        "W1",
        "W2"
      ]
    },
    {
      "date": "Subsequent printout review",
      "text": "Ehman notices and marks the sequence after data collection.",
      "refs": [
        "W2"
      ]
    },
    {
      "date": "1997–1998",
      "text": "The twentieth-anniversary account sets out analysis and corrections.",
      "refs": [
        "W2"
      ]
    },
    {
      "date": "2007–2010",
      "text": "The thirtieth-anniversary report revises and expands the discussion.",
      "refs": [
        "W1"
      ]
    }
  ],
  "claims": [
    {
      "text": "6EQUJ5 is a representation of measured intensity.",
      "status": "Documented",
      "refs": [
        "W1",
        "W2"
      ]
    },
    {
      "text": "The six characters are a decoded extraterrestrial message.",
      "status": "Incorrect interpretation of the printout",
      "refs": [
        "W1",
        "W2"
      ]
    },
    {
      "text": "The observation supplies one unique source position and distance.",
      "status": "Not established",
      "refs": [
        "W1"
      ]
    }
  ],
  "hypotheses": [
    {
      "title": "A transient or intermittent celestial source",
      "status": "Open source class",
      "support": "The signal’s behaviour is analysed against the telescope beam pattern.",
      "limits": "A beam-shaped response alone does not identify a source or explain non-repetition.",
      "test": "Evaluate repeat observations against both candidate sky positions and documented sensitivity."
    },
    {
      "title": "Terrestrial interference or an instrumental pathway",
      "status": "Alternative source class",
      "support": "A complete signal audit must examine receiver and interference possibilities.",
      "limits": "A generic interference label is not an identified transmitter.",
      "test": "Specify a mechanism and test its expected frequency, timing and horn response."
    },
    {
      "title": "An artificial extraterrestrial transmission",
      "status": "Unverified interpretation",
      "support": "The observation motivated SETI interest.",
      "limits": "No decoded content or independently established transmitter follows from these records.",
      "test": "Require reproducible detections and independent instrument confirmation before attribution."
    }
  ],
  "tasks": [
    {
      "title": "Decode the recording convention",
      "body": "Convert the six symbols to intervals using the published convention, retaining the source values. Mark this as a derived table rather than raw receiver data."
    },
    {
      "title": "Keep both location solutions",
      "body": "Document coordinate epoch, horn assumptions and corrections. Do not average two alternative positions into a fictional third one."
    },
    {
      "title": "Build a follow-up ledger",
      "body": "For any follow-up study added later, list its sky coverage, frequency band, sensitivity and observing duration. A null result only constrains what that search could detect."
    }
  ],
  "author": "Eklipsis",
  "content_languages": [
    "en"
  ],
  "path": "/enquetes/wow-signal-1977",
  "source_url": "https://www.bigear.org/Wow30th/wow30th.htm",
  "location_source_url": "https://www.openstreetmap.org/?mlat=40.25&mlon=-83.05#map=8/40.25/-83.05",
  "reviewed_on": "2026-09-29",
  "edition": 1
}