2. Johannes Kepler and His Scientific Contributions By Katelyn Cooper

3. Apprenticeship Lived from 1571-1630 German moved to Prague to become Brahe’s apprentice Brahe told him to watch the orbit of Mars, so Brahe could continue with his theory on the solar system He kept him occupied with the orbit of Mars because Brahe didn’t trust Kepler, he thought one day, Kepler would eclipse him as the premier astronomer of his time.

4. Kepler’s Theory Kepler believed in the Copernican System, which placed the sun directly in the center of the planets orbits. Kepler realized Aristotle was wrong when he said that the orbits of planets were circular. In the system Copernican assumed they were circular also. Kepler proved that the theory was not wrong but the shape of the orbit was, the orbits were flattened circles, also known as ellipses.

5. First Law of Planetary Motion Kepler’s first law stated that the sun was not the center of planet’s orbits but at one focus. Which means the sun’s distance is constantly changing.

7. Equal Area Law of Planetary Motion The line joining the planet to the Sun sweeps out equal areas in equal times as the planet travels around the ellipse. The planet moves faster when it is closer to the sun. 2 parts: the perihelion and the aphelion

9. Harmonic Law of Planetary Motion The ratio of the squares of the revolutionary periods for two planets is equal to the ratio of the cubes of their semimajor axes. Kepler's Third Law implies that the period for a planet to orbit the Sun increases rapidly with the radius of its orbit.

10. P represents the planet’s period of revolution R represents the planets axis’

11. Interactive Sites Kepler's First Law Simulation of Orbit

12. Bibliography "Johannes Kepler: the Laws of Planetary Motion." Johannes Kepler: the Laws of Planetary Motion. 15 May 2006. Spaulding, Nancy E. Earth Science. Dallas: McDougal Littell, 1999. 405-406. Porter, Roy, and Marilyn Ogilvie. Dictionary of Scientists. 3rd ed. Vol. 1. Great Brittain: Helican, 2000. 554-557.