Tycho & Kepler: The Unlikely Partnership That Forever Changed Our Understanding of the Heavens

Article excerpt

Tycho & Kepler:

The Unlikely Partnership That Forever Changed Our Understanding of the Heavens

by Kitty Ferguson

Walker & Company, 2003; $28. 00

When Copernicus first proposed a universe with the Sun at its center in 1543, most of his sixteenthcentury contemporaries regarded the idea as interesting but hardly revolutionary. Geometrically, it made little difference whether the Sun or the Earth stood still, and the crude observations of the time offered precious little evidence for telling one case from the other. Even those partial to a sun-centered scheme hedged their bets by harrumphing, at least in public, that, yes, this Copernicus was a clever fellow, but whatever the merits of his model, it was, after all, only a model. God could have chosen to make the Earth revolve around the Sun-but simply didn't.

In private, though, some of his contemporaries believed He did. Tycho Brahe, a Danish nobleman and amateur astronomer, thought Copernicus might be on to something. Tycho had seen a new star appear in the heavens in 1572, and he determined that it lay far beyond the Moon, in a region of the firmament where, according to the conventional astronomy of his day, nothing ever changed. Convinced that the old picture of the Earth-centered universe needed repair, Tycho proposed a hybrid system in which the Sun carried the orbiting planets around a stationary Earth. But Tycho knew that his proposal would be just another clever model without the support of careful astronomical measurements-measurements Tycho, with the right resources, would be happy to make.

King Frederick II of Denmark provided the money Tycho needed for his purposes, and granted him the little island of Ven (formerly Hven), at the mouth of the Baltic Sea, within view of Hamlet's fabled castle, Elsinore. There Tycho erected a battery of precise sighting devices (the telescope had not yet been invented); for almost thirty years, he and a staff of assistants compiled nightly observations of the positions of the planets.

As the data accumulated, however, Tycho found he lacked the mathematical skills, not to mention the time away from his aristocratic lifestyle, to make the calculations he needed to prove his point. …