Nicolaus Copernicus impacted on how the world is understood. With the help of Ptolemy’s geocentric model of the universe, Copernicus invented the heliocentric system. In Copernicus’s system, the Sun was in the middle, and the other planets were orbiting the Sun, in Ptolemy’s model, all planets were orbiting the Earth. The motions of planets around the Sun were not circular. Copernicus’s model used Ptolemy’s observations to make epicycles in his model. The Copernican Model simplified the retrograde motion of planets that was observed by Copernicus. Ptolemy’s model only had 7 planets, but to explain the movements of the planets accurately, he had to add more spheres, in his model. Hence, his model had accurate predictions of the motions of other