169
varia
Fig. 14. Model representing the solar system in terms of notional Platonic forms. Kepler, Johannes. Mysterium cosmographicum…, 1596.
mathematical terms. Eventually, they divorced astronomy from theology, forever marrying astronomy to physics47. The importance of the Laws of Planetary Motion was not immediately recognized. Perhaps it was because the crucial proofs were buried deep inside an enormous volume; or perhaps because Kepler’s use of Latin was not particularly lucid48. Also, the elliptical orbits are nearly circular, thus not suffi ciently different to quickly discomfit planetary theories describing circular orbits49. In any case, Kepler’s contemporaries, even Galileo, were incapable of recognizing the profound significance of
his achievement. In fact, it was not fully appreciated for another century, not until Isaac Newton’s Law of Universal Gravitation became widely known and proved Kepler’s findings. It is ironic that Kepler himself never realized the importance of the Laws that he had formulated50. Instead, he was more proud of his explanation for the number of planets and their spacing in the solar system. Although these latter ideas are completely false, they eventually led to the Laws of Planetary Motion and to the birth of modern cosmology. In the Mysterium cosmographicum, published in 1596, the twenty-five year old Kepler addressed and answered