01:750:109 Chapter Notes - Chapter 3.1: Orbital Speed, Semi-Major And Semi-Minor Axes, Orbital Period
Document Summary
Don"t know when greeks first began to think that earth is round but the idea was taught by. Both greek and modern explanations of planetary motion lies in the idea of creating models of nature. A scientific model is a conceptual representation created to explain and predict observed phenomena. Just like how an airplane model may not completely represent every aspect of a real airplane, a scientific model may not fully explain all our observations of nature. Aristotle cited earth"s curved shadow on the moon during lunar eclipses as evidence for a spherical earth. The greek model was therefore a geocentric ("earth-centered") model of the universe, with a spherical earth at the center of a great celestial sphere. Couldn"t explain the apparent retrograde motion and didn"t accept that the planetary spheres sometimes turned forward and sometimes turned backward because of their deeply held belief in. "heavenly perfection" (heavenly objects could only move in perfect circles.
