Was Einstein Right? Testing Relativity at the Centenary

TL;DR

This paper reviews experimental tests of Einstein's relativity, confirming key principles and discussing future experiments that could further test or extend gravitational theories.

Contribution

It provides a comprehensive overview of experimental evidence supporting Einstein's relativity and discusses upcoming tests that may challenge or refine current theories.

Findings

Experiments confirm the Einstein Equivalence Principle.

Solar system tests strongly support general relativity.

Binary pulsar observations validate gravitational-wave damping.

Abstract

We review the experimental evidence for Einstein's special and general relativity. A variety of high precision null experiments verify the weak equivalence principle and local Lorentz invariance, while gravitational redshift and other clock experiments support local position invariance. Together these results confirm the Einstein Equivalence Principle which underlies the concept that gravitation is synonymous with spacetime geometry, and must be described by a metric theory. Solar system experiments that test the weak-field, post-Newtonian limit of metric theories strongly favor general relativity. The Binary Pulsar provides tests of gravitational-wave damping and of strong-field general relativity. Recently discovered binary pulsar systems may provide additional tests. Future and ongoing experiments, such as the Gravity Probe B Gyroscope Experiment, satellite tests of the Equivalence principle, and tests of gravity at short distance to look for extra spatial dimensions could constrain extensions of general relativity. Laser interferometric gravitational-wave observatories on Earth and in space may provide new tests of gravitational theory via detailed measurements of the properties of gravitational waves.