Time Stamp	HTML Slide
[00:00]	Solution Sets
[00:16]	Self-Review
[00:19]	Self-Review Success
[01:55]	Geocentric and Heliocentric Models
[04:18]	Modern View of the World
[04:48]	Ancient View of the World
[07:03]	Flat Earth
[07:21]	Round Earth
[08:18]	Eclipse Shadows. I
[08:59]	Eclipse Shadows. II
[09:38]	Eclipse Shadows. III
[10:23]	Radius of the Earth
[13:11]	Geocentric Models
[17:20]	Ptolemy's Model. I
[18:24]	Ptolemy's Model. II
[19:05]	Ptolemy's Model. III
[20:32]	Angles on the Sky. I
[20:48]	Angles on the Sky. II
[23:20]	Parallax. I
[27:37]	Parallax. II
[30:15]	Retrograde Motion
[30:51]	Geocentric Models (reprise)
[35:07]	Heliocentric Models

Learning Objectives

1. Understand the geocentric (Earth-centered) and the heliocentric (Sun-centered) models of the solar system.

   1. Define the key difference between the two models.

   2. Visualize how the deferents and epicycles of the geocentric model could vary the observed size and brightness of a planet over time.

   3. Critique Aristotle's arguments against the heliocentric system.

   4. Visualize how retrograde motion could be achieved within each model.

   5. Comprehend whether or not parallax would occur under each model.

   6. Sketch the observed phases of Venus within each model.

2. Comprehend the parallax effect, and its scaling with orbital radius and with the distance to a nearby star.

3. Grasp how key observations made by Galileo with the newly invented telescope contradicted the geocentric cosmological model of his day.