The Michelson–Morley experiment, performed in 1887 by…

The Michelson–Morley experiment, performed in 1887 by Albert Michelson and Edward Morley at what is now Case Western Reserve University in Cleveland, Ohio, attempts to detect the relative motion of matter through the stationary luminiferous aether ("aether wind"), the postulated medium for the propagation of light.

The negative results are generally considered to be the first strong evidence against the then prevalent aether theory, and initiates a line of research that eventually leads to special relativity, in which the stationary aether concept has no role.

The concept of aether as a mechanical medium having a state of motion has been replaced in modern physics by the theory of relativity and quantum theory.

The experiment has been referred to as "the moving-off point for the theoretical aspects of the Second Scientific Revolution". (Earl R. Hoover, Cradle of Greatness: National and World Achievements of Ohio's Western Reserve (Cleveland: Shaker Savings Association, 1977))