Free Mirror Earth by Michael D. Lemonick Page B

arise naturally, acknowledged John Buridan, the rector of the University of Paris, in the early 1300s, but God could do things that wouldn’t happen naturally. A half century later, another French scholar and cleric, Nicole Oresme, went a step further, arguing that other worlds
could
arise naturally. Aristotle’s assertion that “down” must mean “toward the Earth” wasn’t the only way to look at it. If you allowed “down” to mean “toward a heavy body,” the problem went away. Leonardo da Vinci suggested that this might be the case for the Moon. The fact that the Moon doesn’t fall to Earth suggests, he wrote in his notebooks, that it was its own center of attraction, with its own complement of water, air, and fire. The German theologian and philosopher Nicholas of Cusa, who influenced Leonardo’s thinking, wrote:
    Rather than think that so many stars and parts of the heavens are uninhabited and that this earth of ours alone is peopled … we will suppose that in every region there are inhabitants, differing in nature by rank and all owing their origin to God, who is the centre and circumference of all stellar regions.
    Even as theologians and scholars and natural philosophers were wrestling with Aristotle’s ideas, his competition, the atomists, showed up as well, after a millennium in obscurity. The writings of the original atomists had disappeared with the rise of Aristotle, but a Roman philosopher named Lucretius, writing in the first century B.C., had preserved their ideas.In 1417, Lucretius’s atomist manuscript, titled
De rerum natura
(On the nature of things) was translated into Latin as well.
    This was something of a problem. Having worked themselves into an outrage that some dead Greek had dared put a limit on how many worlds God could create, here came another dead Greek who rejected such a limit, but who was also pretty explicitly an atheist. Even worse, Lucretius’s lyrical writing meant that his work was thought of primarily as a work of poetic literature at first. He sneaked onto everyone’s must-read list before anyone could focus on his heresy.
    Still, by the late 1500s, the notion of a plurality of worlds had become respectable, as long as it was expressed properly. God could make as many worlds as he wanted, in principle. But in practice, he’d just made ours (this was the line a young Galileo took, decades before he turned his telescope on the heavens). The arguments, as always, were purely theological, with no practical implications at all.
    This wouldn’t last long, however. In 1543, a Polish cleric and astronomer named Mikołaj Kopernik or Niklas Koppernigk, later Latinized to Nicolaus Copernicus, died and posthumously published a manuscript. Titled
De revolutionibus orbium caelestium
(On the revolutions of the heavenly spheres), it argued that the motions of the planets through the night sky could be best explained if the Earth and the other planets orbited the Sun, rather than everything orbiting the Earth. A preface to the manuscript suggested that this was a purely mathematical exercise—it didn’t mean the Earth
actually
orbited the Sun. But a man named Andreas Osiander, who was overseeing the printing of the book, may well have added thepreface without Copernicus’s permission. Osiander was evidently appalled at the challenge to Church doctrine this new model of the solar system implied. The Earth must be central because it was in the very first sentence of the Bible, and because humans were the focus of God’s closest and most loving attention.
    As a result of both the preface and his death, Copernicus never got in trouble with Church authorities. The same can’t be said for those who followed him—especially an ex-monk named Giordano Bruno, who was burned at the stake in 1600 by the Inquisition for a long list of heresies. Among them were his loudly proclaimed belief in magic, his