He fought Spanish soldiers before puberty, convinced a friend not to assassinate Napoleon as a teen, provoked an archbishop to violence, brokered a peace with some bandits, took on a mob, and once broke out of prison. His name is François Arago, and he just might be the most interesting physicist in the world.
UNC - Charlotte associate professor of physics Dr. Gregory Gbur has chronicled François Arago's life in a must-read blog post. Arago's life reads like a swashbuckling adventure story crossed with a political thriller, with starring roles for mathematics and physics. When Arago wasn't neck deep in political intrigue or narrowly escaping death, he was a major player in the acceptance of the wave theory of light.
...he would attempt and fail to measure variations of the speed of light. This result can be considered the first experimental evidence of the constancy of the speed of light, a fundamental part of Einstein's special theory of relativity; with the help of Augustin-Jean Fresnel, Arago would be able to interpret this result as a consequence of the wave nature of light.
Arago would return the favor to Fresnel. In 1818, for a prize competition of the Académie des Sciences, Fresnel proposed that the wave nature of light explained the phenomenon of diffraction. The physicist Poisson countered that Fresnel's explanation was absurd, because it predicted that a bright spot of light should exist in the shadow of an opaque disk. Arago performed the experiment to test this "absurd" hypothesis, and in fact verified it; this discovery led to the wide and final acceptance of the wave nature of light!
At this point Arago was only about 32 years old. Impressed? Just wait until you read more details of this badass physicist's life!
Image: provided by Dr. Gregory Gbur