movement of the celestial bodies. It is thought that ancient peoples kept track of the movement of celestial bodies for the purpose of establishing yearly calendars for planting and harvesting, and in the aid of navigating on the open seas (Chaisson 30-31). The exact intentions of the ancient peoples can not ascertained due to the lack of written records. Many Historians assume it that the ancient’s quest for knowledge of the motion of celestial bodies was of a practical nature, not one of strict scientific inquiry.The ancient Greeks, who kept written records, applied the use of logic and careful observation in attempts to understand the physical and celestial world, as they knew it. The Greeks did not tend to study the practical and applied aspects of science, but were more so interested in the theoretical aspects of their inquiries (Adler 123). One person who studied the apparent motion of the celestial bodies was the Greek philosopher Aristotle who lived between 384-322 B.C. Aristotle using careful observation and logic mistakenly concluded that the Earth was at the center of the Universe and that all of the celestial bodies such as the Sun, Moon and the Stars moved in perfect circular orbits around the earth (Window 1). Aristotle’s view of the Earth as the center of the Universe was widely accepted and was the basis for the theories of other ancient astronomers. In an effort to further explain the Aristotelian concept of a geocentric universe, where every celestial object revolved around the earth, astronomers of that time came up with a model. In this model, each planet was assumed to move around a small circle, an epicycle. The center of this epicycle would then orbit in a larger circle around the Earth; this larger circle was termed as the deferent (see Fig. 1). With this type of model, the astronomers could explain the sometimes retrograde movement, the apparent reverse movement of some of the planets. By...
