Michelson-Morley experiment explained by means of five methods

Abstract

The Michelson-Morley experiment (MME) is still important to physics, and not just to the history of physics. The hypothesis of contraction of bodies in the direction of their motion arose as an ad hoc hypothesis about the “contraction” of the Michelson’s interferometer arm in the direction of its motion. Even today this experiment is the “strongest argument” of this hypothesis, and of time dilation too. This work will present the explanation of the MME through five methods. The first method can be called the traditional method, which was applied by Michelson, but not correctly. The other methods are the explanation of the MME with the interferometer located at an acute angle to the direction of Earth’s motion; with the light clock; using Galilean transformation in polar coordinates and using the Doppler effect formula. All these methods give the same solution, and this solution is in accordance with the experiment’s result. Solutions derived from these five methods represent a natural explanation for the result of the MME – without weird terms and without unscientific assumptions.