Tycho Brahe was one of the most colorful astronomers in history. Born on December 14, 1546, in Denmark, Tycho was "adopted" (some say kidnapped) by his childless uncle at the age of one. Either way, his father, a Swedish nobleman, did not seem to mind. (Brahe's given name was "Tyge," but the Latinized version is more common.)

Brahe received an excellent education. At the age of 13 he entered the University of Copenhagen, where he studied rhetoric and philosophy. He was well on his way toward a career in politics when he witnessed an eclipse of the Sun on August 21, 1560. Brahe spent the next two years studying mathematics and astronomy. He moved on to the University of Leipzig in 1562 where a tutor tried to influence him to study law, but Brahe refused to be diverted.

In August 1563, he made his first recorded observation, a close grouping between Jupiter and Saturn. (It...