Loading...
Initial language selection is based on your web browser preferences.
In 1926, Albert Michelson measured the speed of light using a method similar to the one we introduce. Instead of a toothed wheel, Michelson used an eight-sided rotating mirror, as shown in the model. The distance from the rotating mirror to a distant reflector was 35.5 km, making the total round trip distance for the light 71.0 km. The light completed this round trip in the time it took the mirror to rotate by one-eighth of a revolution. By knowing the distance to the fixed mirror and the required angular speed of the rotating mirror, Michelson was able to calculate the speed of light, which is approximately 3.00 x 10^8 m/s.
