EXCEPTING monarchs, only a few people have become sufficiently outstanding in their time and discipline to be remembered mainly by their Christian names. Leonardo and Michelangelo have this distinction, and Ms Bernhardt as "the divine Sarah" might just about be said to qualify. Also distinguished in this way, however, is the Danish astronomer Tycho Brahe, born 450 years ago today and called among the cognoscenti "Tycho".
Tycho was born to a noble family at Knudslrup in Sweden on December 14th, 1546. An eclipse of the sun seen when he was still a student at Copenhagen University directed his attention to astronomy, and in particular to the works of Ptolemy whose theories, Tycho noticed, did not seem to explain exactly the positions of the planets in the heavens. He decided the only way to understand their movement was by constant observation, and to this task he devoted the remainder of his life.
In 1572, the discovery of a new star in the constellation Cassiopeia established Tycho's reputation, and his book about it, De Nova Stalla, has given us the word nova for any celestial newcomer of this kind. In 1576 he was given Hven Island, close to Elsinore, by King Frederick II, and here he built Uranienborg, the "Castle of the Heavens", a mecca for astronomers in succeeding decades. Tycho's observations over 20 years at Uranienborg, sans the telescope which had yet to be invented, were accurate enough for him to determine the length of the year to within one second.
Tycho was not without his eccentricities. Having lost his nose in a duel as a student, he wore a large artificial replacement made of gold and silver - a device which rivals unkindly suggested he used as an instrument for making observations. He also kept a hunchbacked fool called Jeppe, whom he is said to have rescued from being roasted alive by a band of mercenaries, and whose half wilted utterances the astronomer allegedly regarded as a kind of oracle.
After the death of his patron Frederick in 1597, Tycho Brahe moved to Prague to become court mathematician to Emperor Randolph II, and died there four years later. It was left to his pupil, Johannes Kepler, to put Tycho's carefully crafted observations to spectacular use by formulating his famous Third Law, an empirical principle which provided the key to the mechanics of the universe with a verbal resonance and conceptual complexity which belies its origins nearly four centuries ago. "The squares of the periods of revolution of the planets are proportional to the cubes of the major axes of their elliptical orbits."