case western reserve university



"Failure" Leads to Breakthrough

Understanding light and its relationship to other physical phenomena was a major goal of 19th-century physics. In 1879, physicist Albert A. Michelson measured the speed of light at 186,350 miles per second (plus or minus about 30 miles per second).

By the 1880s, when Michelson had become one of the first faculty members at the Case School of Applied Science, scientists believed that light waves needed a medium on which to travel through space. They called this medium "lumeniferous aether," literally a light-bearing gas that they believed surrounded the planet.

Albert Michelson

Michelson and chemist Edward W. Morley of Western Reserve University, noted for his ability to construct experimental instruments, decided to determine the extent to which the directional flow of this" aether" would affect the speed of light traveling through it. They conducted careful tests in 1887 using an interferometer, a device designed by Michelson to split and reflect light beams along precise paths. To their great disappointment, they found no difference between the speed of the light beam traveling in the direction of the "aether wind" vs. the beam traveling in the opposite direction. The significance of this finding as disproving the "aether" theory became clear later, and was reflected in Albert Einstein's Special Theory of Relativity, which underlies much of modern physics.

Edward Morley

Michelson and Morley themselves were never quite convinced of the non-existence of the aether, however. Although Michelson left Case shortly afterward, both he and Morley continued experiments separately that attempted to find the phenomena missing from their famous work. Morley remained at Western Reserve, where he gained further fame for his work that established the atomic weights of oxygen and hydrogen, for which the American Chemical Society has designated the campus of the University a National Historic Chemical Landmark.

In 1907, Michelson became the first American scientist to receive a Nobel Prize, recognizing his "optical precision instruments and the research carried out with their aid."


Schematic drawing of the interferometer
used in the Michelson-Morley experiments.