Michelson was fascinated with the sciences, and the Problem of measuring the speed of light in particular. While at Annapolis, he conducted his first experiments of the speed of light, as part of a class demonstration in 1877. His Annapolis experiment was refined, and in 1879, he measured the speed of light in air to be 299,864 ± 51 kilometres per second, and estimated the speed of light in vacuum as 299,940 km/s, or 186,380 mi/s. After two years of studies in Europe, he resigned from the Navy in 1881. In 1883 he accepted a position as professor of physics at the Case School of Applied Science in Cleveland, Ohio and concentrated on developing an improved interferometer. In 1887 he and Edward Morley carried out the famous Michelson–Morley experiment which failed to detect evidence of the existence of the luminiferous ether. He later moved on to use astronomical interferometers in the measurement of stellar diameters and in measuring the separations of binary stars.