{
  "id": "opera-neutrinos-2011",
  "title": "OPERA: how an apparent violation of light speed was corrected",
  "country": "Switzerland",
  "category": "espace-temps",
  "date": "2011-09-23",
  "date_label": "23 September 2011 announcement; detection took place in Italy",
  "location": "CERN, Geneva — beam-source reference",
  "lat": 46.233,
  "lng": 6.055,
  "is_resolved": 1,
  "summary": "A neutrino timing result appeared to challenge the speed of light. Follow-up measurements and a timing-system fault changed the conclusion.",
  "sources": [
    {
      "id": "O1",
      "title": "CERN — announcement and subsequent updates",
      "url": "https://home.cern/opera-experiment-reports-anomaly-in-flight-time-of-neutrinos-from-cern-to-gran-sasso/",
      "language": "en",
      "note": "Dated institutional updates retain the correction alongside the initial claim.",
      "kind": "Source record · see provenance note"
    },
    {
      "id": "O2",
      "title": "CERN Document Server — 2012 OPERA timing measurement",
      "url": "https://cds.cern.ch/record/1498324",
      "language": "en",
      "note": "Original research record for the improved measurement.",
      "kind": "Source record · see provenance note"
    }
  ],
  "author": "Eklipsis",
  "content_languages": [
    "en"
  ],
  "path": "/investigations/opera-neutrinos-2011",
  "source_url": "https://home.cern/opera-experiment-reports-anomaly-in-flight-time-of-neutrinos-from-cern-to-gran-sasso/",
  "location_source_url": "https://www.openstreetmap.org/?mlat=46.233&mlon=6.055#map=8/46.233/6.055",
  "location_precision": "region",
  "location_note": "Approximate orientation marker for the named place or institution; not a surveyed observation point, protected excavation coordinate or recommended access route.",
  "reviewed_on": "2026-09-30",
  "edition": 1,
  "truth_type": "unknown",
  "verdict": "The apparent anomaly was corrected through measurements and instrumentation checks. The selected record supports a resolved timing problem, not time travel or a confirmed breakdown of relativity. Publishing an unexpected measurement for scrutiny is part of the scientific process.",
  "sections": [
    {
      "title": "Documented account",
      "text": "CERN announced the OPERA timing anomaly in September 2011 and invited scrutiny rather than declaring a discovery. The experiment compared a CERN beam with detection at Gran Sasso in Italy. CERN’s June 2012 update reported that four experiments found travel times consistent with light speed and attributed the original anomaly to a faulty element of the fibre-optic timing system.",
      "refs": [
        "O1",
        "O2"
      ]
    },
    {
      "title": "Evidence and its limits",
      "text": "The Swiss marker identifies the beam-source institution. It does not relocate the detector from Italy or depict a measured neutrino path on a surface map. A press release summarises an investigation; numerical details should be read in the collaboration’s paper.",
      "refs": []
    },
    {
      "title": "Inspector’s assessment",
      "text": "The apparent anomaly was corrected through measurements and instrumentation checks. The selected record supports a resolved timing problem, not time travel or a confirmed breakdown of relativity. Publishing an unexpected measurement for scrutiny is part of the scientific process.",
      "refs": []
    },
    {
      "title": "A reproducible next investigation",
      "text": "Compare the original announcement, intermediate fault checks and final measurements in date order. Track baseline, synchronisation, uncertainty and hardware configuration. Do not present the original estimate without its later correction or treat a later result as if it had been known at announcement time.",
      "refs": []
    }
  ],
  "timeline": [
    {
      "date": "23 September 2011",
      "text": "The anomaly is announced for independent scrutiny.",
      "refs": [
        "O1"
      ]
    },
    {
      "date": "23 February 2012",
      "text": "CERN describes possible timing-system effects under investigation.",
      "refs": [
        "O1"
      ]
    },
    {
      "date": "8 June 2012",
      "text": "CERN reports measurements consistent with the speed of light.",
      "refs": [
        "O1"
      ]
    },
    {
      "date": "30 September 2026",
      "text": "Eklipsis prepares this source-linked documentary synthesis. This is editorial review, not historical fieldwork.",
      "refs": []
    }
  ],
  "claims": [
    {
      "text": "A neutrino timing result appeared to challenge the speed of light. Follow-up measurements and a timing-system fault changed the conclusion.",
      "status": "Documented subject; interpretations qualified in the dossier",
      "refs": [
        "O1"
      ]
    },
    {
      "text": "The apparent anomaly was corrected through measurements and instrumentation checks. The selected record supports a resolved timing problem, not time travel or a confirmed breakdown of relativity. Publishing an unexpected measurement for scrutiny is part of the scientific process.",
      "status": "Documented explanation; scope remains bounded",
      "refs": [
        "O1"
      ]
    },
    {
      "text": "The map point represents the exact location of every reported event.",
      "status": "Incorrect; orientation only",
      "refs": []
    }
  ],
  "hypotheses": [
    {
      "title": "Timing-system fault",
      "status": "Supported correction",
      "support": "Follow-up checks identify an instrumentation problem.",
      "limits": "The exact numerical correction belongs to the technical record.",
      "test": "Compare corrected hardware and independent timing measurements."
    },
    {
      "title": "A physical excess over light speed",
      "status": "Original interpretation not sustained",
      "support": "The initial result appeared anomalous.",
      "limits": "Later measurements do not support that result.",
      "test": "Demand reproducible independent measurements after systematic checks."
    }
  ],
  "tasks": [
    {
      "title": "Audit the source record",
      "body": "Retrieve the named records for OPERA: how an apparent violation of light speed was corrected. Record author, edition, page or section and access date. Treat a catalogue, mirror or translation of one document as the same evidence, not independent corroboration."
    },
    {
      "title": "Build the dated evidence ledger",
      "body": "Compare the original announcement, intermediate fault checks and final measurements in date order. Track baseline, synchronisation, uncertainty and hardware configuration. Do not present the original estimate without its later correction or treat a later result as if it had been known at announcement time."
    },
    {
      "title": "Test the interpretation",
      "body": "Compare corrected hardware and independent timing measurements. Demand reproducible independent measurements after systematic checks. Record what would favour or weaken each explanation; leave unperformed work marked as proposed."
    }
  ]
}