Edward W. Morley

Edward W. Morley was an American chemist and physicist whose precision measurements improved the atomic weight of oxygen and whose interferometry work with Albert A. Michelson tested for luminiferous ether.

Michelson–Morley experiment: An 1887 interferometry experiment that found no detectable difference in the speed of light along perpendicular directions through the presumed ether. Morley’s best-known collaboration used interference fringes to test Earth’s motion through ether.
Interferometer: An instrument that compares waves traveling along different paths by observing their interference. The Michelson–Morley apparatus used this general method to compare light travel times.
Oberlin College: A private liberal arts college in Oberlin, Ohio, founded in 1833. Morley studied and spent most of his academic career at Oberlin.
Albert A. Michelson: A German-born American physicist renowned for precision optical measurements and the first American Nobel Prize in Physics. Michelson designed the interferometer and partnered with Morley on their famous 1887 experiment.
Atomic mass unit: A unit of mass defined as one-twelfth the mass of a neutral carbon-12 atom. Modern atomic weights use a standard that replaced the oxygen-based scale Morley helped refine.
Michelson–Gale–Pearson experiment: A 1925 interferometer experiment that measured the rotation of Earth through the resulting difference in light travel times. Morley’s later interferometry work with Dayton Miller helped refine measurements related to Earth’s rotation.
Michelson interferometer: An optical instrument that splits a beam, sends it along two paths, and recombines it to produce interference fringes. Its perpendicular light paths made the proposed ether-wind effect testable.
Yale University: A private research university in New Haven, Connecticut, founded in 1701. Morley received scientific training at Yale before beginning his Oberlin career.
Hendrik Lorentz: A Dutch physicist whose theories of electromagnetism and electron behavior helped shape modern physics. Lorentz analyzed the ether problem that the Michelson–Morley result sharpened.
Lorentz ether theory: A theory that retained a stationary ether while explaining optical experiments through length contraction and related transformations. It shows that the null result did not immediately eliminate every ether-based interpretation.

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Aether theoriesRelated: The experiment bearing both names became the most famous test of luminiferous aether.