ELEMENTARY DERIVATION OF THE ADVANCE OF THE PERIHELION OF A PLANETARY ORBIT

An elementary derivation of the law for the advance of the perihelion of a planet in orbit about the sun is given. This is obtained by comparing a Kepler ellipse in a Lorentz coordinate system, with one in Schwarzschild coordinates, related by the areal constant, and attributing the variation entirely to an increase in the angular coordinate. The result is shown to be entirely in agreement with the classical value.