Copernicus worked for years on his book describing his theory, and did not publish it until near the very end of his life. He entitled it, "De revolutionibus orbium coelestium" ("On the Revolutions of the Heavenly Spheres"), and published it in 1543. The work was far from perfect: Copernicus assumed that the planets moved in circular revolutions (they actually revolve in ellipses, though the orbit of the earth is nearly circular), and Copernicus also thought that the sun stood motionless as some kind of stationery temple in the universe. | Copernicus worked for years on his book describing his theory, and did not publish it until near the very end of his life. He entitled it, "De revolutionibus orbium coelestium" ("On the Revolutions of the Heavenly Spheres"), and published it in 1543. The work was far from perfect: Copernicus assumed that the planets moved in circular revolutions (they actually revolve in ellipses, though the orbit of the earth is nearly circular), and Copernicus also thought that the sun stood motionless as some kind of stationery temple in the universe. |