KEPLER

Johannes Kepler (1571-1630) worked to define the laws of planetary motion. He was very attached to an idea that the planets followed paths defined by imaginary solid objects which, he believed, showed the perfection of the mind of god. When more accurate instruments provided evidence that his pre-conceived idea was wrong, it took great personal honesty for him to admit it and devise his correct theory (one he never liked) that equal areas of an orbit are swept out in equal time.