Emphasis Preaching Journal

Galileo, 1564-1642, the great Italian astronomer and physicist, challenged Aristotle's position that the universe revolved around the earth. He discovered that the Milky Way was a myriad of stars, that Jupiter had four satellites, the uniqueness of Saturn, and the phases of Venus and Mars. His continued studies and discoveries led him in 1632 to publish his masterpiece, A Dialogue on the Two Principal Systems of the World, which proposed the Copernican theory that the earth moves around the sun.