Johannes Kepler is now remembered for discovering the three laws of planetary motion, and writing about them in books that were published in 1609 and 1619. He also did important work in optics, discovered two new regular polyhedra, gave the first mathematical treatment of close packing of equal spheres, gave the first proof of how logarithms worked, and devised a method of finding the volumes of solids of revolution. This can be seen as contributing to the development of calculus. Not only did he help the development of calculus, but he calculated the most exact astronomical tables known today. This accuracy did much to establish the truth of heliocentric astronomy, which states that the sun, and not the earth, was the center of the planetary system.Kepler was born in the small town of Weil der Stadt in Swabia, and moved to nearby Leon berg with his parents in 1576. His father was a mercenary soldier and his mother the daughter of an innkeeper. Johannes was their first child. His father left home for the last time when Johannes was five, and is believed to have died in the war in the Netherlands. As a child, Kepler lived with his mother in his grandfather's inn. He tells us that he used to help by serving in the inn. It was said that the customers of the inn were sometimes startled by the child's unusually high math skills. Kepler's early education was in a local school and then at a nearby seminary, from which he went on to enroll at the University of Tubingen.At this time, it was usual for all students at a university to attend courses on mathematics. These courses usually included the four mathematical sciences: arithmetic, geometry, astronomy and music. However, what was taught depended on the university. At Tubingen, Kepler was taught astronomy by one of the leading astronomers of the day, Michael Maestlin. The curriculum included geocentric astronomy. This is the study of how all seven planets at the time - Moon, Mercury, Venus,...
