{
  "slug": "the-plates-that-were-set-aside",
  "title": "The Plates That Were Set Aside",
  "href": "/strata/the-plates-that-were-set-aside/",
  "field": "astronomy",
  "claim": {
    "statement": "Thus the results of the expeditions to Sobral and Principe can leave little doubt that a deflection of light takes place in the neighbourhood of the sun and that it is of the amount demanded by Einstein’s generalised theory of relativity, as attributable to the sun’s gravitational field.",
    "claimants": "F. W. Dyson, A. S. Eddington and C. Davidson (Sobral observations by A. C. D. Crommelin and C. Davidson; Principe observations by A. S. Eddington and E. T. Cottingham)",
    "citation": "F. W. Dyson, A. S. Eddington and C. Davidson, “A determination of the deflection of light by the sun’s gravitational field, from observations made at the total eclipse of May 29, 1919”, Philosophical Transactions of the Royal Society of London, Series A, 220, 291 to 333. Received 30 October 1919, read 6 November 1919, published 27 April 1920. DOI 10.1098/rsta.1920.0009.",
    "year": 1920,
    "headline_as_printed": "Sobral 4-inch: 1\".98 with a probable error of about ±0\".12; Principe: 1\".61, probable error about ±0\".30; Sobral astrographic plates, given little weight: 0\".93 (1\".52 with the refraction and aberration scale). Alternatives printed on p.291: Newtonian 0\".87, Einstein 1\".75."
  },
  "records": [
    {
      "file": "data/sobral-4inch.json",
      "role": "claimant-data",
      "name": "Sobral 4-inch: Table II (196 per-star differences), equations of condition, normal equations of Tables III to VI with printed solutions, Table VII, printed results",
      "url": "https://astronomyforchange.org/wp-content/uploads/2021/06/DysonOriginalPaper_1919TSE_rsta.1920.0009.pdf",
      "licence": "No licence statement on the scan (Royal Society download stamp). Only transcribed numbers, with citation, are shipped; the scan and its page images are not.",
      "licence_url": "https://doi.org/10.1098/rsta.1920.0009",
      "retrieved": "2026-09-22",
      "sha256": "4fdab471f0ed634ac0635613a8b71ecc69afe717ef954ebd0148323198015bc4",
      "units": 196
    },
    {
      "file": "data/sobral-astrographic.json",
      "role": "claimant-data",
      "name": "Sobral astrographic: Table IX (18 rows), the p.311 five-star declination measures on 16 plates, the report’s equations and per-plate results, p.312 results",
      "url": "https://astronomyforchange.org/wp-content/uploads/2021/06/DysonOriginalPaper_1919TSE_rsta.1920.0009.pdf",
      "licence": "No licence statement on the scan (Royal Society download stamp). Only transcribed numbers, with citation, are shipped; the scan and its page images are not.",
      "licence_url": "https://doi.org/10.1098/rsta.1920.0009",
      "retrieved": "2026-09-22",
      "sha256": "88d6d751150cac067318ae776b328c096b90f0c287c4df6d1015f8faa94ffe3c",
      "units": 16
    },
    {
      "file": "data/principe.json",
      "role": "claimant-data",
      "name": "Principe: final-stage residual columns and star coefficients for the four comparisons, printed normal equations and results",
      "url": "https://astronomyforchange.org/wp-content/uploads/2021/06/DysonOriginalPaper_1919TSE_rsta.1920.0009.pdf",
      "licence": "No licence statement on the scan (Royal Society download stamp). Only transcribed numbers, with citation, are shipped; the scan and its page images are not.",
      "licence_url": "https://doi.org/10.1098/rsta.1920.0009",
      "retrieved": "2026-09-22",
      "sha256": "4a65cc1163cbd71b9413d964c2a033485cccc5f4bf7ca0aedd29e369c8ff2944",
      "units": 4
    },
    {
      "file": "data/harvey1979.json",
      "role": "control-data",
      "name": "Harvey 1979: lambda and standard error for all 14 plates reduced (Table II), Table III, selection facts",
      "url": "https://articles.adsabs.harvard.edu/pdf/1979Obs....99..195H",
      "licence": "Every page of the scan carries \"(c) The Observatory, Provided by the NASA Astrophysics Data System\". Only the printed numbers, with citation, are shipped; the scan is linked, not copied.",
      "licence_url": "https://ui.adsabs.harvard.edu/abs/1979Obs....99..195H/abstract",
      "retrieved": "2026-09-22",
      "sha256": "30072e3d009c367e9dd307f75ec06260e1a8c91ec38693a72eb30f184759d27d",
      "units": 14
    },
    {
      "file": "data/published.json",
      "role": "reference",
      "name": "Numbers printed in later papers: Gilmore and Tausch-Pebody 2022 Tables A2 and A4 (CC BY 4.0), Will 2014 VLBI value (CC BY 4.0), PDG 2026 provenance",
      "url": "https://www.repository.cam.ac.uk/bitstreams/811bf8da-3210-48e0-b58f-12084f0fe798/download",
      "licence": "Factual numbers with attribution; Gilmore and Tausch-Pebody 2022 and Will 2014 are CC BY 4.0",
      "licence_url": "https://creativecommons.org/licenses/by/4.0/",
      "retrieved": "2026-09-22",
      "sha256": "f01a5ce56be49120a6b1b5050bb215c0d56397b7c985aeef41a37328f74ba449",
      "units": 3
    }
  ],
  "anchor": {
    "what": "The report’s headline evidence recomputed by the page’s engine from the transcribed tables: all 28 Sobral 4-inch plate fits of Table II, the Principe final-stage slopes, and the Sobral astrographic five-star equation and Table IX.",
    "expected": "Sobral 4-inch 1.98\" (RA 2.06\", Dec 1.94\"); Principe 1.61\"; Sobral astrographic 0.93\" at e = 0.082 r, 1.52\" at e = 0.020 r, 0.99\" per-plate least squares, 0.86\" Table IX",
    "computed": "Sobral 4-inch 1.9797\" (RA 2.0737\", Dec 1.9327\"), with Table II exactly as printed 2.0118\"; Principe 1.6084\"; Sobral astrographic 0.9130\" at e = 0.082 r, 1.4979\" at e = 0.020 r, 0.9744\" per-plate least squares, 0.8600\" Table IX",
    "agrees": true,
    "tolerance": "Sobral 4-inch 0.01\" (the authors rounded alpha to 0.100 r before converting, worth 0.006\"); RA and Dec 0.02\" each (the report’s RA 2.06\" is itself 0.02\" from its own alpha); Principe 0.01\" (printed to 0.01\"); astrographic 0.035\" (0.019\" from the report’s rounding of alpha to 0.001 r plus about 0.015\" of per-plate discrepancies between the p.311 measures and the printed per-plate values); Table IX 0.005\". The default Table II state uses the two cells the authors’ printed normal equations imply, derived by the engine; with the table exactly as printed the headline is 2.012\", a documented gap of 0.032\"."
  },
  "control": {
    "name": "Harvey’s 1979 Zeiss Ascorecord remeasurement of the surviving Sobral plates, recombined from his per-plate Table II by his stated rule (weights equal to the reciprocal of the squared standard error)",
    "citation": "G. M. Harvey, “Gravitational Deflection of Light: A re-examination of the observations of the solar eclipse of 1919”, The Observatory 99, 195 to 198 (December 1979). ADS 1979Obs....99..195H. Plates measured by E. D. Clements; the author thanks C. A. Murray for guidance throughout the work.",
    "computed": "4-inch 1.9080 ± 0.1039\"; astrographic 1.5397 ± 0.3339\"; the two fresh determinations combined by his rule 1.8668 ± 0.1047\"",
    "as_printed": "4-inch 1\".90 ± 0\".11; astrographic 1\".55 ± 0\".34; combined 1\".87 ± 0\".13 (the combined error does not follow from his stated rule)"
  },
  "power": {
    "grade": "B-published-sensitivity",
    "planted": "Einstein’s deflection (lambda = 1) against Newton’s (lambda = 0.4971), set against Harvey’s own printed per-plate standard errors combined by his rule: control standard error 0.0594 in lambda for the 4-inch and 0.1908 for the astrographic plates. Also planted in 4000 copies of his Table II (each plate drawn about lambda = 1 with his printed error) and recombined by the unmodified control.",
    "recovered": "Separation between the hypotheses: 8.47 control standard errors (4-inch) and 2.64 (astrographic); probability of landing two standard errors clear of the other hypothesis 1.000 and 0.738. In the planted copies the astrographic control landed two standard errors above Newton in 73.9 per cent.",
    "verdict": "the 4-inch remeasurement COULD have confirmed or refuted an Einstein-sized deflection (8.5 standard errors between Einstein and Newton); the astrographic remeasurement, the only fresh look at the set-aside plates, could NOT decide on its own (2.6 standard errors), and the page says inconclusive for it",
    "trusts": "Harvey’s per-plate standard errors, his choice of nine of the sixteen astrographic eclipse plates, his exclusion of one comparison plate and of the star nearest the Sun on plates 2, 6 and 11. He printed no star positions, so the control cannot be rerun."
  },
  "null_through_claimant_method": {
    "applicable": true,
    "what": "The report’s 4-inch procedure (the same reduce function as the anchor: 28 separate plate fits, eclipse mean minus comparison mean, declination weighted twice) on synthetic plates with the claimants’ seven-star geometry, each real plate’s fitted constants, the shared scale-plate term, and Gaussian star errors with the spread of the real residuals.",
    "result": "With Newton’s 0.87\" planted the method returns 0.869\" ± 0.136\" and reaches 1.75\" in 0 of 10000 runs (seed 20260922; residual sigma 0.0238 r). It covers accidental error only, not a systematic difference common to all eclipse plates."
  },
  "verdict": {
    "category": "VINDICATED",
    "as_of": "2026-09-22",
    "sources": [
      "T. Damour, “21. Experimental Tests of Gravitational Theory”, revised August 2025, in Review of Particle Physics (Particle Data Group), 2026 web edition, pages dated 1 June 2026.",
      "Clifford M. Will, “The Confrontation between General Relativity and Experiment”, Living Reviews in Relativity 17, 4 (published 11 June 2014). DOI 10.12942/lrr-2014-4. CC BY 4.0. Quoted from the arXiv text, arXiv:1403.7377v1, and checked against the published text (Europe PMC, PMC5255900), where the four passages quoted here read the same except that the years are set as 1969–1975, without spaces."
    ],
    "would_change": "A reproducible measurement of the Sun’s deflection of light, radio or optical, departing from the relativistic value by much more than its stated errors with its systematic errors controlled, would change this verdict. What would reopen only the narrower question of the set-aside plates, without touching the physics: a complete modern digitisation and scale-free reduction of the surviving Sobral astrographic plates returning a deflection near 0.87″ with an error well below 0.3″.",
    "scope": "the claim as the 1920 report makes it: that light passing the Sun is deflected by the amount Einstein’s theory demands, not the Newtonian half",
    "narrow_question": "The set-aside Sobral astrographic plates on the 1979 remeasurement alone: INCONCLUSIVE between Einstein and Newton."
  },
  "decided_by": "independent-replication",
  "years_to_decision": 56,
  "choices": [
    {
      "id": "cells",
      "label": "Table II cells",
      "options": [
        "implied",
        "printed"
      ],
      "default": "implied",
      "affects": [
        "4-inch limb deflection",
        "right ascension result"
      ],
      "inert": false
    },
    {
      "id": "decw",
      "label": "Declination weight",
      "options": [
        "2",
        "design",
        "1"
      ],
      "default": "2",
      "affects": [
        "4-inch limb deflection"
      ],
      "inert": false
    },
    {
      "id": "e",
      "label": "Assumed astrographic scale difference (r)",
      "options": [
        -0.02,
        0.02,
        0.082,
        0.17
      ],
      "default": 0.082,
      "affects": [
        "set-aside deflection",
        "position between Newton and Einstein",
        "the page’s own averaging of the three 1919 sets (value, chi-square and refusal)"
      ],
      "inert": false
    },
    {
      "id": "route",
      "label": "Astrographic route",
      "options": [
        "common",
        "table9",
        "perplate"
      ],
      "default": "common",
      "affects": [
        "set-aside deflection"
      ],
      "inert": false
    },
    {
      "id": "dpick",
      "label": "Orientation d for plates 7 and 12",
      "options": [
        "mean",
        "first",
        "second"
      ],
      "default": "mean",
      "affects": [
        "set-aside deflection",
        "scale at which Newton and Einstein are reached"
      ],
      "inert": false
    },
    {
      "id": "inst",
      "label": "Control instrument, recombined (section III)",
      "options": [
        "astrographic",
        "four_inch",
        "both"
      ],
      "default": "astrographic",
      "affects": [
        "control value",
        "control standard error"
      ],
      "inert": false
    },
    {
      "id": "pinst",
      "label": "Control instrument, weighed for power (section IV)",
      "options": [
        "astrographic",
        "four_inch",
        "both"
      ],
      "default": "astrographic",
      "affects": [
        "separation",
        "power",
        "power verdict",
        "planted copies"
      ],
      "inert": false
    },
    {
      "id": "drop",
      "label": "Leave out one of Harvey’s astrographic plates (power, section IV)",
      "options": [
        null,
        2,
        3,
        4,
        6,
        7,
        8,
        10,
        11,
        12
      ],
      "default": null,
      "affects": [
        "control value",
        "separation"
      ],
      "inert": false
    },
    {
      "id": "assign",
      "label": "Error assigned to the set-aside plates",
      "options": [
        "page",
        "g048",
        "g09",
        "none"
      ],
      "default": "page",
      "affects": [
        "combined deflection",
        "chi-square",
        "refusal",
        "range of set-aside values that would pass"
      ],
      "inert": false
    },
    {
      "id": "planted",
      "label": "Deflection planted in the null runs",
      "options": [
        "newton",
        "none"
      ],
      "default": "newton",
      "affects": [
        "null distribution",
        "count at or above 1.75\""
      ],
      "inert": false
    }
  ],
  "headline": "Recomputed from the numbers the 1920 report printed, the Sobral 4-inch plates give 1.980″ and Principe 1.608″, both near Einstein’s 1.75″ and far from Newton’s 0.87″; the set-aside plates give 0.913″ or 1.498″ depending on one assumed plate scale, the two theories lying 0.093 r of scale apart; and the 1979 remeasurement of those plates, 1.540 ± 0.334″, separates Newton from Einstein by only 2.64 of its own standard errors, too few to decide on its own.",
  "novelty": "We searched the Artificial Wasteland index and the open web on 2026-09-22 and did not find an interactive page that recomputes the 1919 Sobral astrographic result from the five-star measures printed in the 1920 report as a function of the assumed plate scale, beside the 1979 plate-by-plate remeasurement.",
  "ledger": {
    "claim_reproduced": {
      "value": true,
      "assertion": "anchor:sobral-4inch-principe-astrographic-through-engine"
    },
    "control_computed": {
      "value": true,
      "assertion": "control:harvey-table-ii-by-his-rule"
    },
    "control_can_confirm": {
      "value": false,
      "assertion": "power:grade-b-separation-and-planted-copies"
    },
    "rendered_figures_asserted": {
      "value": true,
      "assertion": "surface:every-data-fig-quote-row-and-loose-number"
    },
    "choices_are_live": {
      "value": true,
      "assertion": "choices:nine-parameters-move-named-outputs"
    },
    "planted_fault_caught": {
      "value": true,
      "assertion": "fault:shifted-table-ii-cell-and-harvey-row"
    },
    "refusal_asserted": {
      "value": true,
      "assertion": "refuse:scale-average-plate-pe-mixing"
    },
    "provenance_pinned": {
      "value": true,
      "assertion": "provenance:sha256-data-files"
    },
    "verdict_dated": {
      "value": true,
      "assertion": "verdict:category-date-sources-would-change-printed"
    }
  }
}