Today is the birthday of physicist, mathematician, and astronomer Jean-Baptiste Biot, born in Paris in 1774. Biot had a short-lived stint in the French army due to an illness following the Battle of Hondschoote. He returned home and studied math at the École Polytechnique. By 1797 he was a college professor; he spent most of his tenure at the Collège de France. In 1803 Biot was sent to l'Aigle, a town northwest of Paris, to investigate a report of rocks falling from the sky. After conducting interviews and examining samples, Biot concluded the rocks were extraterrestrial in origin. Until then, the existence of meteorites was hotly debated. In 1804 Biot accompanied Joseph-Louis Gay-Lussac on a balloon flight, which reached about 4000 meters in altitude, to measure the magnetic, electrical, and chemical properties of the atmosphere. In 1820 Biot and Félix Savart discovered that the intensity of a magnetic field due to current flowing through a wire is inversely proportional to the distance from the wire. Biot also studied the properties of mica, which is why the mica-group mineral biotite is named after him.
