AST 2002 Chapter Notes - Chapter 3: Deferent And Epicycle, Apparent Retrograde Motion, Geocentric Model
Document Summary
The greeks developed a tradition of trying to understand nature without relying on supernatural explanations, and of working communally to debate and challenge each other"s ideas. They used mathematics to give precision to their ideas which allowed them to explore in greater depth. They saw the power of reasoning from observations. Model- a conceptual representation created to explain and predict observed phenomena. The greeks constructed conceptual models of the universe in an attempt to explain what they observed in the sky. Pythagoras was teaching about the earth being round. Geocentric model- spherical earth at the center of a great celestial sphere. To account for the fact that the sun and moon each move gradually eastward through the constellations, the greeks added separate spheres for them, with these spheres turning at different rates from the sphere of the stars. They also added additional spheres for each planet. It was difficult for them to explain the apparent retrograde motion of the planets.
