Changes

Copernicus worked for years on his book describing his theory, and published it 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 major parts of Copernican theory are:

Copernicus worked for years on his book describing his theory, and published it 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 major parts of Copernican theory are:

# Heavenly motions are uniform, eternal, and circular or compounded of several circles (epicycles).

# Heavenly motions are uniform, eternal, and circular or compounded of several circles (epicycles).

# The center of the universe is near the Sun.

# The center of the universe is near the [[Sun]].

# Around the Sun, in order, are Mercury, Venus, Earth and Moon, Mars, Jupiter, Saturn, and the fixed stars.

# Around the Sun, in order, are [[Mercury]], [[Venus]], [[Earth]] and [[Moon]], [[Mars]], [[Jupiter]], [[Saturn]], and the fixed stars.

# The Earth has three motions: daily rotation, annual revolution, and annual tilting of its axis.

# The Earth has three motions: daily rotation, annual revolution, and annual tilting of its axis.

# Retrograde motion of the planets is explained by the Earth's motion.  

# Retrograde motion of the planets is explained by the Earth's motion.