Across
- 1. Earth-centered model of the universe
- 5. the side-to-side lines in the sky
- 6. when the Sun appears directly over the equator
- 7. Observed the skies and discovered 4 moons of Jupiter
- 10. backward loops that planets would appear to do about once a year
- 12. Made accurate instruments and measurements of the planets
- 17. Smaller circles that planets move in
- 18. farthest north & south that the Sun appears in the sky
- 21. Established the three Laws of Planetary Motion
- 22. law object at rest will stay at rest
Down
- 2. Used to locate specific stars
- 3. Distance that light travels in one year
- 4. study of universe
- 8. 12 major constellations in the ecliptic
- 9. constructed the best geocentric model
- 11. larger circle in which planets orbit the earth
- 13. Sun-centered model of the universe
- 14. All mass exerts a force on all other mass
- 15. the up-and-down lines in the sky
- 16. law force equals mass times acceleration
- 19. law for every action there is an equal and opposite reaction
- 20. the plane where the Sun and planets travel