The Michelson-Morley experiment, conducted in 1887 by Albert A. Michelson and Edward W. Morley, aimed to detect the presence of the luminiferous aether, a medium thought to carry light waves. They used an interferometer to compare the speed of light in perpendicular directions, expecting to find differences due to Earth's motion through the aether. However, the experiment produced null results, showing no significant difference in light speed. This unexpected outcome challenged existing theories and 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.