In past ages astronomers accepted the Ptolemaic system. Ptolemy was a philosopher and astronomer of Greek origin and a lecturer in the University of Alexandria which was celebrated as one of the great universities of those times. He wrote a book called the Almagest in which he gathered together the theories held by ancient astronomers, systematizing these laws in a way that represents the knowledge of astronomy of that time. The book became an authority and eastern and western students used it in their colleges as a text-book. Ptolemy founded an observatory and his observations of the heavens were accepted by all the astronomers of the time. According to his calculations the heavens were divided into nine circles, because he observed seven planets, calculating seven distant orbits through which they moved. The circle outside of the seventh was thought to be studded with the fixed stars. In order to make this theory clear the ancient astronomers used as an illustration the different layers of an onion - thus the curving surface of each layer adheres to the curve of each succeeding layer. Outside the eighth circle there was thought to be a ninth through which these colossal bodies were given the power to march in their destined course. They further believed this ninth sphere of action to be devoid of any solar bodies and that it moved through an invisible power, thus causing the motion of all the other stars within its radius. A motion of the outward layer of the onion moves all the inside layers with it. This, in brief, was the system of ancient astronomy. After centuries of scientific deduction it is proved that there is no fixed heaven; that which we see is an infinite space; these stars are hung like luminous lamps in this immeasurable atmosphere. There are neither eight nor nine nor ninety spheres and the stars are numberless. Later astronomers like Kepler and Newton discovered the law of attraction and repulsion there is a universal law of interdependence between the stars.