1	powers of 10, scales, motion of earth
2	motion of earth, celestial sphere, phases of moon, eclipses
3	Copernican revolution, law of gravity, Kepler's laws
4	light and matter, telescopes (Chs 2, 3)
5	Sun, including fusion
6	stars
7	stars, ISM
8	stellar evolution
9	solar system
10	solar system
11	galaxies (MW, active galaxies, types)
12	galaxies, dark matter
13	cosmology

extra credit quizzes: math, life in the universe