a universe created solely to serve him, God presides over all from the Empyrean above, sending forth his messengers the angels to guide and control the heavenly bodies. Such had been the thought of Christians for more than a thousand years. Then came the influence of a new science. Tycho Brahe "broke the crystal spheres of Aristotle"[1] by his study of the comet of 1572; Galileo's telescopes revealed many stars hitherto unknown, and partly solved the mysteries of the Milky Way; Kepler's laws explained the courses of the planets, and Newton's discovery of the universal application of the forces of attraction relieved the angels of their duties among the heavens. Thinkers like Bruno proposed the possibility of other systems and universes besides the solar one in which the earth belongs. And thus not only did man shrink in importance in his own eyes; but his conception of the heavens changed from that of a finite place inexplicably controlled by the mystical beings of a supernatural world, to one of vast and infinite spaces traversed by bodies whose density and mass a man could calculate, whose movements he could foretell, and whose very substance he could analyze by the science of today. This dissolution of superstition, especially in regard to comets was notably rapid and complete after the comet of 1680.[2] Thus the rationalist movement with the new science opened men's minds to a universe composed of familiar substances and controlled by known or knowable laws with no tinge remaining of the supernatural. Today a man's theological beliefs are not shaken by the discovery of a new satellite or even a new planet, and the appearance of a new comet merely provides the newspaper editor with the subject of a passing jest.
Yet it was fully one hundred and fifty years after the publication of the De Revolutionibus before its system met with the general approval of scholars as well as of mathematicians; then nearly a generation more had to elapse before it was openly taught even at Oxford where the Roman Catholic and Lutheran Churches had no control. During the latter part of this period, readers were often left free to decide for themselves as to the relative merits of the Tychonic and Copernican or Copernican--
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