1. What is the aim of astronomy (such as Copernicus's work)? More importantly, what are NOT the aims of astronomy, according to Osiander? (How does the astronomer differ from the philosopher?)
2. Can you figure out why Osiander says that, if Venus truely moved along an epicyclic path, then the observed diameter of venus would change so much that its biggest apparent diameter would be four times its smallest apparent diameter?
Copernicus's Preface to Pope Paul III
3. Why was Copernicus afraid to publish his work for decades?
4. What reasons does Copernicus give for publishing his work in the end?
5. What does Copernicus mean by "Astronomy is written for astronomers"? Why does he say it?
De Revolutionibus
6. Why should anyone study the stars, according to Copernicus?
7. According to Copernicus, what "perplexities" still remain in astronomy?
8. What arguments does Copernicus offer for the following claims -- and in each case, are they better or worse than Ptolemy's?
(a) The universe is spherical
(b) The Earth is spherical
(c) The heavenly bodies move in eternal, uniformly circular motion
(d) The Earth has a circular motion on its axis
(e) The earth is not necessarily at the center of the universe (ch.s 6-8)
(f) The sun is at the center of the universe, and the Earth circles the sun
(g) the order of the planets