Across
- 2. Added epicycles to explain retrograde planetary motion
- 7. Proposed early model with nonmoving stationary Earth
- 10. Inner rocky planets like Mercury and Earth
- 13. Planet passing in front of another body
- 14. Earth centered model of the universe
- 15. Apparent shift in position of an object
- 16. Discovered four moons orbiting around Jupiter in 1609
- 17. Chunks of ice and dust orbiting sun
- 19. Space debris burning in Earth's atmosphere
- 20. Proposed early model placing sun at the center
- 22. Calculated elliptical planetary orbits using Brahe's observations
Down
- 1. Largest planet in our solar system array
- 3. Oval-shaped paths followed by planets in orbit
- 4. Apparent backward looping motion of a planet
- 5. Sun-centered model proposed by Copernicus in 1543
- 6. Force holding objects in their orbital paths
- 8. Center object held by gravity pulling planets
- 9. Small circular paths added to planetary orbits
- 11. First identified asteroid belt object now dwarf planet
- 12. Rocky or metallic space debris throughout space
- 15. Reclassified as dwarf planet due to shared orbit
- 18. Instrument collecting light to magnify distant objects
- 21. Eight major celestial bodies orbiting the sun