Johannes Kepler studied heliocentrism at a University in 1590. Kepler started as an assistant for Tycho Brain 1600 – 1601 and helped observe planet’s orbits but he assumed the orbit was a circle. He first started by looking at Mars. During different times, Mars seemed to have sped by and slowed down. He couldn’t seem to figure out what was causing it. Then the same year Tycho Brain died and told Kepler to keep looking at the stars. Kepler tried to find the mathematical explanation for the movement of Mars. Kepler had failed 40 times before he found out the formula for Mars’ orbit which took five years. Then Kepler realized it must be an ellipse in 1605 which formulated Kepler’s law of planetary motion. Four years later he published his findings in Astronomia Nova and suggested all planets move in elliptical patterns. Kepler also said that, “They move fast near the sun and slower the further from the sun you are.” He argued that the sun pulls the planets to make them go faster the closer they are to the sun.