Albert A. Michelson was a leader in the field of physics, contributing many discoveries related to the measurement of the speed of light. He conducted the famous Michelson-Morley experiment were he disproved the presence of a luminiferous ether that supposedly filled space, challenging classic Newtonian physics. Using an interferometer he measured the speed of light in air to be 299,864±51 km/s and estimated the speed of light in vacuum as 299,940 km/s. In 1907 he won the Nobel Prize in Physics “for his optical precision instruments and the spectroscopic and metrological investigations carried out with their aid." He was the first American to win a Nobel Prize.