1. History of Astronomy Review

2. Universe in 2 parts: imperfect Earth and perfect heavens – 55 spheres

3. Believed that the heavens were perfect; motion & shapes circles and spheres

4. Epicycles used to explain retrograde motion

5. Made repeated observations; believed the heliocentric model where sun and moon orbit earth, but all other planets orbit the sun

6. Aligned sunset, sunrise and moonset at solstices

7. Measured Earth’s radius using shadows

8. Celestial bodies are spheres moving around a central fire that is blocked out by a counter Earth

9. Planets move on elliptical paths at non- uniform velocities

10. f=ma

11. Discovered moons of Jupiter, rings of Saturn, phases of Venus, sunspots

12. P 2 /A 3

13. Heliocentric universe

14. Every two particles of matter attract each other with a force dependent on mass and inverse square of distance

15. Planets orbit the sun in elliptical orbits

16. An object remains in motion or at rest unless acted upon by an outside force

17. A planet sweeps out equal areas in equal amounts of time

18. The extent to which an ellipse is stretched

19. Amount of light reflected from the surface of a planet