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Johannes Kepler led an extremely productive life, his discoveries including the three laws of planetary motion, a proof of logarithms, and the discovery of two new polyhedra. He is most famous for the discovery of the laws of planetary motion. For a long time, Kepler worked as Tyco Brahe's assistant. This gave him the accurate data needed to make calculations on the orbit of Mars. He continued this work on Mars after Brahe's death. Kepler finally concluded that planetary orbits are not perfect circles-instead, they are ellipses with the sun at one foci. This is Kepler's first law of planetary motion. Kepler discovered his second law around the same time-that at different parts of its orbit a planet will move at different speeds, but that it will sweep out equal areas in equal time periods. Some time later, Kepler discovered his third and final law of planetary motion. This law states that the ration of the squares of any two planet's periods is proportional to the ratio of the cubes of their distance from the sun. T2=r3. |