MichelsonMarelyExperiment

The Michelson–Morley experiment was a landmark physics study conducted in 1887 by Albert A. Michelson with Edward W. Morley. It aimed to detect the luminiferous aether, a proposed medium through which light was thought to propagate, by measuring the earth’s motion relative to this medium.

The experiment used a Michelson interferometer, an optical device that splits a single light beam into two perpendicular paths using a half-silvered mirror. Each beam reflects off a separate mirror and returns to recombine at the beam splitter, producing an interference pattern. If the earth carried the apparatus through the aether, the two light beams would travel at different effective speeds depending on their direction, causing a detectable shift in the interference fringes when the apparatus was rotated.

Contrary to expectations, Michelson and Morley observed no significant fringe shift, a null result within the precision of their apparatus. The lack of observed ether wind suggested that the speed of light is the same in all directions, undermining the concept of a stationary luminiferous aether.

The null result played a crucial role in the development of modern physics. It challenged the classical notion of an absolute rest frame and helped pave the way for Albert Einstein’s theory of special relativity, which posits the invariance of the speed of light in all inertial frames. The experiment remains a foundational example of precision interferometry and is often cited as a turning point in the understanding of space and time. The Michelson interferometer continues to be a widely used tool in optical science and metrology.