Understanding the important philosophical and scientific changes initiated
by Copernicus with his Sun-centered view of our Solar System is the first
step in the development of the modern worldview. This chapter will show
how the heliocentric system gives an easily pictured explanation of the
retrograde motion of the planets and their varying brightness in our sky. We
will also give credit to Aristarchus of Samos who in 200 B.C. first proposed
such a Sun-centered idea. The contributions of others who followed after
Copernicus will also be described. The observations of Tycho Brahe and their
important role in Johannes Kepler's work will be outlined. Kepler's conclusions
about planetary orbits summed up in his three laws of planetary motion were
essential in our growing knowledge concerning our Solar System.
Chapter Skills:
After studying this chapter you should be able to
- Compare and contrast the Ptolemaic and Copernican systems
- Sketch Copernicus' explanation of retrograde motion
- Describe and use some geometrical properties of ellipses
- Describe the important observations of Brahe and their
impact on the development of modern astronomy
- State Kepler's three laws of planetary motion and be able to apply them.