Michelson-Morley Experiment

The Michelson-Morley experiment is a perfect example of a null experiment, one in which something that was expected to happen is not observed. The consequences of their observations for the development of physics were profound. Having proven that there could be no stationary ether, physicists tried to advance new theories that would save the ether concept. Michelson himself suggested that the ether might move, at least near the Earth. Others studied the possibility that rigid objects might actually contract as they traveled. But it was Einstein's theory of special relativity that finally explained their results.

The significance of the Michelson-Morley experiment was not assimilated by the scientific community until after Einstein presented his theory. In fact, when Michelson was awarded the Nobel prize in physics in 1907, the first American to receive that honor, it was for his measurements of the standard meter using his interferometer. The ether wind experiment was not mentioned.

There has also been some controversy as to how the experiment affected the development of special relativity. Einstein commented that the experiment had only a negligible effect on the formulation of his theory. Clearly it was not a starting point for him. Yet the experiment has been repeated by others over many years, upholding the original results in every case. Even if special relativity did not spring directly from its results, the Michelson-Morley experiment has convinced many scientists of the accuracy of Einstein's theory and has remained one of the foundations upon which relativity stands.