Experimental Tests of Relativity: Observation, Measurement & Evidence

Classical tests include Mercury's perihelion precession, light deflection, and gravitational redshift. Modern tests include Shapiro delay, lunar laser ranging, frame-dragging measurements, pulsar timing, equivalence-principle experiments, and gravitational-wave waveform comparisons.

Observed results consistently match general relativity within current uncertainties across weak fields and many strong-field systems. Binary pulsars lose orbital energy at the rate expected from gravitational radiation, and merger waveforms agree with relativistic compact-binary calculations.

Each test isolates a prediction where relativistic spacetime differs measurably from Newtonian or alternative-gravity expectations. Precision requires accounting for instrumental calibration, environmental effects, ephemerides, and competing astrophysical influences before attributing a residual signal to gravity theory.

Binary pulsars show orbital decay matching gravitational radiation, Cassini radio tracking constrained Shapiro delay, and gravitational-wave waveforms follow relativistic merger models. No single measurement spans every field strength.