The Scientific Revolution was a result of European pioneers challenging beliefs that had already been established. In previous centuries, philosophers were the knowledgeable ones who acted as our present-day scientists. A famous Greek philosopher, Aristotle, concluded that the Earth was made up of the two heavy elements: earth and water. Also, the atmosphere was composed of the two lighter elements, air and fire, which floated above the ground. Along with these ideas was the original idea of a geocentric theory, which stated that the Earth was at the center of the universe. Knowledge of science and the universe was thought to be very exact and perfect, illustrated by the thought that the planets were all spherical and that they orbited is circular orbits. Yet, certain scientists disagreed with the common belief and challenged these thoughts. Beginning with the knowledge of the Pythagorean theorem, founded by no other than Pythagoras, other scientists began to introduce new ideas relating to physical objects in the universe and their movement patterns. These scientists, which included Nicholas Copernicus, Danish Tycho Brahe, Johannes Kepler, and Galileo Galilei, incited a new beliefs, which ultimately resulted in the European Scientific Revolution.