Verification of general relativity: tests in the Solar System

Abstract

In 1900, Isaac Newton’s worldview of gravity, space, and time still prevailed — that the gravitational force was a universal, direct, and instantaneous action-at-a-distance between the masses of the Universe, that bodies and light rays moved through an “absolute space, in its own nature, without anything external” whose geometric structure was rigidly Euclidean without end, and that the dynamics of physical law unfolded with respect to an “absolute, true, and mathematical time (flowing) equably without relation to anything external” (Newton 1687). Through the twentieth century that edifice was overthrown and replaced by Albert Einstein’s general relativity (GR) perspective – that gravity is an interaction transmitted by a causal and dynamic field whose sources are all forms of energy, including its own contributions, and which then acts elsewhere upon the same; and that the metrical relations between the clocks, rulers, and signals throughout the cosmos are dynamic, non-Euclidean, locationally dependent, and established by the fields of gravity. The detailed structure of metric gravitational field components in the Solar System has in all cases been found to match the predictions of GR in a variety of experiments which primarily employed radar and laser ranging between Earth and other planets or spacecraft.