The Michelson-Morley Experiment, conducted in 1887 by Albert A. Michelson and Edward W. Morley, aimed to detect the presence of the hypothetical luminiferous aether, a medium through which light was thought to travel. The experiment used an interferometer to compare the speed of light in perpendicular directions, expecting to find differences based on Earth's motion through the aether. However, the results showed no significant difference in light speed, contradicting the aether theory. This unexpected outcome contributed to the development of Albert Einstein's theory of special relativity, which eliminated the need for aether and fundamentally changed our understanding of space and time.