General Relativity

In 1859, the French mathematician and astronomer Urbain Le Verrier discovered that the perihelion of the orbit of the planet Mercury was not where Newton's law of gravity had predicted it to be. He blamed the discrepancy on a flaw in Newton's law. An explanation of this discrepancy was offered by Einstein in 1916 through his theory of general relativity. A century later, the true cause of this discrepancy was found: The planets and asteroids which orbit the Sun experience the gravitational attraction of only about 99.99% of the mass of the Sun. Thus they behave as if there is an apparent center of mass of the Sun which is offset from the Sun's true center of mass by 4,375 meters. Using this offset with Newton's law yields very accurate results for the orbits of all objects orbiting the Sun. These results were developed in ordinary three-dimensional space using classical celestial mechanics. General relativity provides a close approximation to these results, yielding an estimate of the offset equal to 4,429 meters. Being an approximation, it follows that the assumptions which underlie general relativity are not necessarily correct. Indeed, there seems to be no justification for such notions as that spacetime is curved.