Tycho Brahe

Born on 14 December 1546 in Knudstrup, Denmark, astronomer Tycho Brahe produced incredibly detailed astronomical tables. As a child he was abducted by his wealthy uncle, who raised Brahe at his castle. Brahe studied law at the University of Copenhagen, but his conversion to astronomer began when he witnessed a total solar eclipse in 1560. Three years later Brahe observed a conjunction of Jupiter and Saturn and found that existing astronomical tables were inaccurate. He set out to make regular, accurate observations of the heavens. He obtained quadrants and other instruments (the telescope had not yet been invented) to establish his own observatory. In 1572 he observed what he considered a new star in the sky—unthinkable at the time, when the stars were thought to be static. (In reality, Brahe’s star was actually the explosion of one: a supernova.) Brahe built his grand Uraniborg Observatory on the island of Ven. He measured the positions of hundreds of stars and concluded that the planets orbited the Sun, which in turn orbited Earth. His star pupil was Johannes Kepler, who after Brahe’s death would use his mentor’s observations to devise his famous laws of planetary motion.

Date in History: 14 December 1546