Shapiro: radar time-delay test of general relativity

What changed

Radar round-trip delay became a specified observational test of general relativity.

Scientific scope

1964 proposed fourth test only; later measured results and improved tests are excluded.

Evidence

The linked sources identify this contribution and its scope. WRS has not independently reconstructed the scientific claims. This record is the sole-author 1964 proposal. The later multi-author radar observations, subsequent precision improvements and the general theory of relativistic light propagation are separate.

Contributors

• Irwin I. Shapiro · SCIENCE: Named source author of the scoped work; individual effort shares are not measured.

• Shapiro, Fourth Test of General Relativity
• Shapiro et al., Fourth Test of General Relativity: Preliminary Results

Provisional WRS assessment, edition 2026-10-16.1. Independent expert calibration is pending. This grade does not certify correctness or assign ownership.

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