How did Einstein's theory of relativity fare against classical Newtonian physics in early tests?

Einstein's theory of relativity, which includes the special theory of relativity and the general theory of relativity, was developed in the early 20th century and it challenged some of the fundamental assumptions of classical Newtonian physics. However, the predictions of relativity have been thoroughly tested and have consistently been found to be in agreement with observations.

One of the early tests of relativity was the Michelson-Morley experiment, which was designed to measure the relative motion of the Earth through the "luminiferous aether," a hypothetical medium that was thought to be the medium through which light waves propagated. The results of this experiment were not in agreement with the predictions of classical physics, but they were in agreement with the predictions of relativity.

Other early tests of relativity included the measurement of the deflection of light by the sun, the prediction of the perihelion shift of Mercury, and the observed reduction in the rate of atomic processes in strong gravitational fields. These predictions of relativity were also found to be in agreement with observations. In general, relativity has been extremely successful in explaining a wide range of phenomena and is now an essential part of our modern understanding of physics.