137 - Arthur I. Miller [41]
By Kepler’s day the Christian Kabbalah was considered one of the “handmaidens” of true wisdom, along with alchemy and astrology. But all this clashed with the onset of a new, materialistic science that claimed to be able to predict the course of cannonballs and planets using mathematics, but only if a division were made in nature between dead and live matter. For mathematics could be applied only to the former, not to the latter.
Kepler’s model of the universe
When Kepler was growing up, there was a flood of astrological, kabbalistic, and alchemical texts being published. Anything attributed to Hermes Trismegistus was hailed as a revelation. They held readers spellbound, the vaguer the better. Kepler was hooked; his enormous imagination was sparked.
Why was the world as it was? Why were there six planets (Mercury, Venus, Earth, Mars, Jupiter, and Saturn)? Why were they at certain distances from the sun? What was the relationship between their distances from the sun and their speeds? Might the answers to these questions lie in certain arrangements of geometrical figures?
By this time Kepler was a district mathematician, teaching mathematics and astronomy at the Protestant Seminary in Graz. During one of his classroom lectures on geometry he happened to draw an equilateral triangle. Inside it he drew a circle touching all three sides and around it another circle touching its points, just as Pythagoras had described. Suddenly it all fell into place. It was a model of the universe.
Clearly the reason why there were six planets was because there were five perfect solids symbolizing the five intervals between the planets. The planets moved on spheres that circumscribed the five solids. Calculating the distances of the planets from the sun, Kepler drew up a new image of Copernicus’s universe with the sun at the center and nested planetary spheres on which the planets moved. The sphere of Mercury inscribed an octahedron, that of Venus an icosahedron, that of Earth a dodecadron, that of Mars a cube, and that of Saturn a tetrahedron, which the orbit of Jupiter circumscribed.
Kepler’s 1596 model of the universe. (Kepler, Mysterium Cosmographicum [1596].)
Kepler attributed this revelation to “divine ordinance.” He had “always prayed to God [that] Copernicus had told the truth.” In his diary, he noted the fateful day when God spoke to him: July 19, 1595.
He was convinced he had discovered God’s geometrical plan of the cosmos, which God had made in his own image. He published his work in 1596 in a book entitled Mysterium Cosmographicum (The Mystery of the Universe).
However, his model was not in total agreement with Copernicus’s data, especially the data for the orbit of Mercury. Despite his mystical leanings, Kepler was a new breed of scientist. He required theories to be supported by data. He decided that what he needed was more precise data. Copernicus’s were not good enough.
From circles to ellipses
Among the people to whom Kepler sent his new book was the greatest observational astronomer of the day, Tycho Brahe. Kepler by now was a handsome twenty-five-year-old with a high forehead, immaculate goatee, aquiline nose, and a look of piercing intelligence. Tycho, as he was always known, was twice Kepler’s age. He sported a mustache so immense that it looked like a walrus’s tusks and was famous for his prosthetic nose, having had his real one cut off in a duel. He had a copper nose for everyday and a gold and silver one for special occasions.
Tycho achieved his world-renowned accuracy by making all his observations from his monstrous-looking observatory, Uraniburg, on the island of Hveen, off the coast of Denmark. But to Kepler’s annoyance, Tycho refused to reveal his data to anyone until he had refined his own model of the universe—in which every planet except the earth orbited the sun and the entire assemblage, in turn, orbited the earth.
Impressed with Kepler, Tycho offered him a position