By 1514, the reclusive cleric Nicolaus Copernicus had written and hand-copied an initial outline of his heliocentric theory-in which he defied common sense and received wisdom to place the sun, not the earth, at the center of our universe, and set the earth spinning among the other planets. Over the next two decades, Copernicus expanded his theory through hundreds of observations, while compiling in secret a book-length manuscript that tantalized mathematicians and scientists throughout Europe. For fear of ridicule, he refused to publish.In 1539, a young German mathematician, Georg Joachim Rheticus, drawn by rumors of a revolution to rival the religious upheaval of Martin Luther's Reformation, traveled to Poland to seek out Copernicus. Two years later, the Protestant youth took leave of his aging Catholic mentor and arranged to have Copernicus's manuscript published, in 1543, asDe revolutionibus orbium coelestium(On the Revolutions of the Celestial...