It’s been almost a century since Einstein introduced the special theory of relativity. All observational tests to date confirm both the special and the general theory. These tests have ranged from sensitive laboratory experiments involving optics, atoms, nuclei, and subnuclear particles to the observation of orbiting clocks, planets, and objects far beyond the Solar System.
The general theory of relativity will soon be tested with high precision by Stanford University’s Satellite Test of the Equivalence Principle (STEP), 1 and observations by the worldwide array of gravitational-wave detectors presently under construction are expected to test the theory in the extreme realm of strong gravitational fields and high velocities (see the articles by Clifford Will and by Barry Barish and Rainer Weiss in Physics Today, Physics Today 0031-9228 52 10 1999 38–and https://doi.org/10.1063/1.882860 October 1999, pages 38 and 44 , respectively).
Numerous relativistic issues and effects play roles in...