People
Pythagoras
Euclid
Galileo
Newton
Michelson
Lorentz
Minkowski
Einstein
Albert Michelson
Towards the end of the nineteenth century, Albert Michelson took part in one of the most momentous changes in modern physics. At the time, it was thought that light passed through a medium (called the aether) much like sound waves passing through air.
In 1887, Michelson, working with Morley, provided evidence that the aether did not exist. He did this by showing that measurements of the velocity of light remained constant, despite the speed of around 30 kilometers per second at which the Earth orbits the Sun.
Michelson-Morley Experiment
Michelson used a device known as an interferometer. Coherent light enters the device, and is split into two beams by a half-silvered mirror. These beams of light are then reflected back by ordinary mirrors, and combined again by the half-silvered mirror. The resulting interference pattern is captured by a detector.
Allowing for experimental error, this showed that the velocity of light is constant.
Click here to run animation...
Further information on the Michelson-Morley experiment may be found here.
Further information on Michelson's life may be found here.
