The “Copernican Revolution” denotes the change from an earth-centered picture of the universe to a sun-centered one, and it had repercussions far beyond astronomy. It began with the Polish astronomer Nicolaus Copernicus and his publication of On the Revolutions of the Celestial Spheres in 1543. The traditional geocentric, or “Ptolemaic,” picture had been heavily modified since the days of Ptolemy, but Copernicus was the first to suggest discarding it entirely. Copernicus’s new picture offered several advantages for understanding and calculating planetary movements, but the idea of a sun-centered universe with the earth in motion contradicted the common-sense perception of an unmoving earth as well as the dominant school of Aristotelian physics. It also contradicted several passages in the Bible that seemed to show an unmoving Earth, most famously Joshua’s bidding the sun to stand still.