# Johannes Kepler

**Topics:**Johannes Kepler, Tycho Brahe, Kepler's laws of planetary motion

**Pages:**4 (1136 words)

**Published:**January 16, 2008

Kepler's first major astronomical work, Mysterium Cosmographicum, was the first published defense of the Copernican system. On July nineteenth 1595 he had an epiphany. He realized that regular polygons bound one inscribed and one circumscribed circle at definite ratios, which, he reasoned, might be the geometrical basis of the universe. After this hypothesis failed he began to look into three-dimensional polyhedral. He realized that regular polygons bourn one inscribed and one circumscribed by spherical orbs; nesting these solids, each encased in a sphere, within one another would produce six layers, corresponding to the six known planetsMercury, Venus, Earth, Mars, Jupiter, and Saturn. By ordering the solids correctlyoctahedron, icosahedrons, dodecahedron, tetrahedron, cubeKepler found that the spheres could be placed at intervals corresponding (within the accuracy limits of available astronomical observations) to the relative sizes of each planet's path, assuming the planets circle the Sun. Kepler also found a formula relating the size of each planet's orb to the length of its orbital period: from inner to outer planets, the ratio of increase in orbital period is twice the difference in orb radius. However, Kepler later rejected this formula, because it was not precise enough. Later, he rejected this experiment because he couldn't get it precise enough.

As he indicated in the title, Kepler thought he had revealed God's geometrical plan for the universe. Much of Kepler's enthusiasm for the Copernican system stemmed from his theological convictions about the connection between the physical and the spiritual; the universe itself was an...

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