Experiments on the Speed of Light

Discussion of the different experiments that have been performed over time that deal with the speed of light.

This paper discusses Galileo as the first person to conduct an experiment to find the speed of light. The paper then describes how the astronomer Roemer was able to make the first real measurement of the speed of light, and looks at the experiments of Bradley, Fizeau, Grimaldi and Huygens, Young, Foucalt and Froome. The paper then notes that today, measurements of the speed of light have become more accurate with the help of lasers and caesium clocks and light is now known to be a constant and is defined as a standard.
“Galileo conducted the first experiment to find the speed of light. He used his own heart beat the speed of light between two hilltops separated by a few kilometers. In 1675, the astronomer Roemer was able to make the first real measurement of the speed of light. He noticed that Io, one of the moons of Jupiter, was eclipsed at regular intervals by Jupiter. He discovered that “for several months the eclipses lagged more and more behind the expected time, until they were running about eight minutes late” (Fowler 1). Then they gained speed again, to the point that they were eight minutes early. Roemer understood that the difference was caused by the closeness or distance of the earth from Jupiter. His predictions about the eclipses depended on the location of Jupiter in relation to the earth.”