AWhat changed
Lunar laser-ranging analyses by Williams, Newhall and Dickey in 1996 and by Williams, Turyshev and Boggs in 2004 constrained differential Earth–Moon acceleration toward the Sun, geodetic precession and other relativistic parameters. The later work used a longer data span and updated model and reported results consistent with the stated relativistic framework within estimated uncertainties.
Scientific scope
Lunar laser-ranging analyses by Williams, Newhall and Dickey in 1996 and by Williams, Turyshev and Boggs in 2004 constrained differential Earth–Moon acceleration toward the Sun, geodetic precession and other relativistic parameters. The later work used a longer data span and updated model and reported results consistent with the stated relativistic framework within estimated uncertainties. The two analyses share much of the ranging data and JPL modeling and are not independent experiments. Bounds rely on orbital, tidal, lunar-structure, calibration and parameter-correlation assumptions; separating the strong-equivalence component uses a laboratory composition test, and the 2004 parameter β also uses the Cassini value of γ. The 1996 authors warn that numerical sensitivity to individual post-Newtonian parameters was not fully understood; the 2004 geodetic fit is strongly correlated with lunar-structure parameters. Neither paper invents lunar ranging or Nordtvedt theory. The later first author is recorded in source notes with full name while the earlier source uses initials; full cross-version identity reconciliation is open.
Evidence
The linked original works support the scoped statement and contribution attribution. WRS has not independently replayed experiments or reconstructed a full mathematical proof. The two analyses share much of the ranging data and JPL modeling and are not independent experiments. Bounds rely on orbital, tidal, lunar-structure, calibration and parameter-correlation assumptions; separating the strong-equivalence component uses a laboratory composition test, and the 2004 parameter β also uses the Cassini value of γ. The 1996 authors warn that numerical sensitivity to individual post-Newtonian parameters was not fully understood; the 2004 geodetic fit is strongly correlated with lunar-structure parameters. Neither paper invents lunar ranging or Nordtvedt theory. The later first author is recorded in source notes with full name while the earlier source uses initials; full cross-version identity reconciliation is open.
Contributors
- The named authors in the research record · SCIENCE: These are the listed authors of the cited contribution sources. Paper authorship does not quantify individual effort. An incomplete list is explicitly marked; same names are not automatically merged.
- Relativity parameters determined from lunar laser ranging
- Progress in Lunar Laser Ranging Tests of Relativistic Gravity
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