The example of Kepler shows that the Christian convictions of these towering figures of science were not incidental to their work. Rather, these convictions were the scientists’ guiding inspiration. “For a long time.” Kepler wrote, “I wanted to become a theologian. Now, however, behold how through my effort God is being celebrated through astronomy.” A strong advocate of Copernicus’s heliocentrism, Kepler held that the sun- centered cosmos was an image of the Holy Trinity, with God represented by the sun, Christ by the stars and planets, and the Holy Spirit by the motions of the heavenly bodies.” When Kepler discovered that planets do not move in circular but rather in elliptical orbits, he was criticized by some theologians as rejecting the beauty of God’s creative plan. These theologians reasoned that surely God would have used perfect circles to choreograph the planetary motions!

Kepler, however, was certain, based on his deep Christian faith, that God had employed an even more beautiful pattern, and he labored hard to decipher it. When he discovered what it was—his three laws of planetary motion—he experienced something of a spiritual epiphany. Kepler announced that his laws showed that God had used a far simpler and more elegant scheme than the one previously delineated in the Ptolemaic system of cycles and epicycles. In a prayer concluding The Harmony of the World, Kepler implored God “graciously to cause that these demonstrations may lead to thy glory and to the salvation of souls.”

Kepler’s laws posit uncanny relationships. For instance, Kepler’s third law states that the square of the time of a planet’s revolution is proportional to the cube of its mean distance from the sun. How could anyone have figured that out? Kepler did in large part because he was convinced that there had to be a beautiful mathematical relationship there hidden andwaiting for him. Part of his Christian vocation was to find it and promulgate it to the greater glory of God. Kepler’s success leads to the surprising recognition that religious motivation can sometimes result in breakthrough discoveries that change the course of scientific history.