Elementary Ideas of Astronomy

Astronomy is one of the oldest sciences in human history, and for most of that history it was an inseparable part of physics -- indeed, Kepler's laws and Newton's law of gravitation were themselves formulated and verified using centuries of astronomical observation and data gathered by astronomers like Hipparchus, Aristarchus, Ptolemy, Copernicus and Tycho Brahe. Without Tycho Brahe's painstaking observations, Kepler's laws could never have been extracted; without Kepler's laws, Newton's law of gravitation could never have been formulated. This section works through several concrete, historically important examples of how simple observation and geometry -- available even in the ancient world -- were enough to work out real facts about the solar system: why the heliocentric model won out …