Astronomy Unit 2

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Across
  1. 1. His laws describe planetary orbits
  2. 5. Planets appear to go backward
  3. 6. Force that pulls masses together
  4. 9. Velocity needed to leave orbit
  5. 10. Oval path of a planet
  6. 13. Physics of motion and gravity
  7. 15. Made of massive ancient stones
  8. 16. Resistance to changing motion
  9. 19. Greek who backed Earth-centered cosmos
  10. 20. Native American sky-aligned stone circle
  11. 21. Uses radio waves to find distances
  12. 22. Sun-centered
  13. 25. Study of the universe as a whole
  14. 26. Space where gravity acts
  15. 27. Earth-centered with epicycles
  16. 30. Put the Sun at the center
  17. 31. – Not held by gravity anymore
  18. 33. Shift in position from a new viewpoint
  19. 35. A push or a pull
  20. 37. Gravity and motion laws guy
  21. 38. How big something looks in the sky
  22. 39. Ancient stones that track the Sun
Down
  1. 2. Small orbit riding a larger orbit
  2. 3. Long half of an ellipse
  3. 4. Sun in the middle
  4. 7. Strength fades with distance squared
  5. 8. Saw moons of Jupiter through a telescope
  6. 11. One of two points in an ellipse
  7. 12. Earth-centered view of cosmos
  8. 14. Speeding up or slowing down
  9. 17. Earth-Sun distance measure
  10. 18. Gold nose charted stars pre-telescope
  11. 23. Makes the Moon look huge on horizon
  12. 24. Epicycles master; refined Earth-based model
  13. 28. Ancient heliocentric thinker
  14. 29. Shift from Earth to Sun center
  15. 32. Glowing gas clouds in space
  16. 34. Orbits a planet or moon
  17. 36. Large circular paths in old models