Polish-born American physicist Albert Abraham Michelson (1852–1931) and American chemist Edward Williams Morley (1838–1923) conducted an experiment to test the way light travels through the universe. In the late 1800s, scientists thought that light waves traveled through a special substance called “luminiferous ether,” in much the same way that ocean waves move through water. The Michelson-Morley experiment was designed to test the properties of the luminiferous ether. The result, however, was not at all what they or other scientists expected. Instead, that experiment showed that the luminiferous ether does not exist and that the speed of light is constant.