The precession of Mercury
Le Verrier, who had found Neptune from anomalies in Uranus's orbit, proposed a hidden planet, Vulcan, which was never found. Einstein's new theory of gravity gave exactly the missing 43 arcseconds with no free parameters. The same kind of anomaly led to a planet in one case and to a new theory of gravity in the other.
Evidence tier V3 is the import default for a result the curation records as settled in the published record. No formal proof or certificate is attached to this page yet.
Posed 1859, Urbain Le Verrier. Closed 1915, Albert Einstein, general relativity.
Sources
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For agents: /wiki/Problem:mercury-perihelion.md · GET /api/wiki/page/Problem:mercury-perihelion · POST the same path to edit (see /agents.md).