Johannes Kepler was a mathematician, astronomer, and astrologer; this was at a time in the world when astronomy and astrology went hand and hand. He is known for having created three laws of planetary motion that bear his name. The first law states that the planets orbit the Sun in an elliptical pattern, also known as the law of ellipses (Kepler). This built off of Copernicus’ theory of a heliocentric solar system with the planets having circular orbit (Kepler). The second law states that there is an imaginary line that runs from the center of the Sun to each planet. This line sweeps across equally in areas and in time; also known as the law of equal areas (Kepler). Kepler’s third law states that ratio of the squares of the periods of any two planets is equal to the ratio of the cubes of their average distances from the Sun, also referred to as the law of harmonies (Kepler). Kepler was an assistant to a wealthy nobleman and astronomer, Tycho Brahe. Their relationship was historically tumultuous (NASA). They came from completely different backgrounds and disagreed on many topics. Eventually, Kepler was able to convince Brahe to believe in a heliocentric solar system as opposed to a geocentric system (NASA). Brahe suffered an untimely death due to mercury poisoning, shortly after he willed his observatory to Kepler. There is much debate in the scientific world as to whether or not Kepler had a hand in Brahe’s death (NASA).