TYCHO & KEPLER

Science writer Ferguson (Measuring the Universe, 1999, etc.) fully illuminates a 17th-century collaboration that launched a true understanding of the solar system.

At their first meeting in 1600 in Prague, Danish nobleman Tycho Brahe was 53, German mathematician and teacher Johannes Kepler just 28. Brahe was a renowned “naked eye” astronomer, having observed and accumulated data on planetary positions and movements for more than three decades; Kepler was obsessed with the idea that God’s universe must be structured from regular geometric and harmonic patterns that numbers could ultimately reveal. There were a few commonalities: both had leaned away from Catholicism, and both had earned favors casting “calendars” (horoscopes) with astrological portents in which neither really believed, although Brahe consulted with kings, Kepler with burgomasters. With intimate knowledge of both the great Dane and the obscure Lutheran (not nearly as reticent, Ferguson asserts, as some accounts have held), the author masterfully follows each across the turbulent stage of northern Europe after the Reformation to their common destiny: final obliteration of the thousand-year-old tenet of Ptolemaic astronomy, long rooted in ecclesiastical belief, that the Sun and its planets orbit Earth. Brahe is in decline, while Kepler’s fixation on fitting planetary orbits within geometric solids is, we now know, close to a nutball scheme. Yet little more than a decade later, after Brahe died in 1604 pleading to his assistant, “Let me not have lived in vain,” Kepler produced his immutable Laws of Planetary Motion. “Kepler had become a virtuoso in the use of Tycho’s observations,” Ferguson observes, “devising ingenious ways to exploit their unique accuracy and comprehensiveness. Such mastery of the creative nexus between observation and theory has seldom been achieved and never surpassed in the entire history of science.”

Meticulously instructive both on a scientific revolution and the personalities who achieved it.