To what extent should students know the details of the Michelson-Morley experiment?
Knowledge of the details of the experimental setup is not required for the purposes of this Detailed study. It is sufficient that students know that the experiment attempted to measure the difference in the speed of light in two directions perpendicular to each other. They should understand that as Earth was considered to be moving through the hypothetical aether it was expected that there would be a small difference in the measured speed of light in the direction of Earth’s motion as compared to the direction perpendicular to the motion. The result of importance for students is that within the experimental errors no difference in the speed of light in the two different directions was found. This implied no support for the aether hypothesis but supported Einstein’s postulate that the speed of light would not depend on the motion of the observer.
