Across
- 3. Vast collection of stars, like the Milky Way
- 4. Known as Earth's "sister" planet
- 6. Earth-centered solar system model
- 9. Sun-centered solar system model
- 10. - Gaseous planets further from the sun
- 11. Italian astronomer and physicist
- 13. Earth's natural satellite
- 14. The center of our solar system
- 16. Planet with a tilted axis
- 18. Small rocky object in space
Down
- 1. Our home planet
- 2. Largest planet in our solar system
- 5. Closest planet to the Sun
- 7. Former ninth planet in our solar system
- 8. Eighth planet from the Sun
- 12. Rocky planets closest to the sun
- 13. The Red Planet
- 15. Known for its beautiful rings
- 17. Imaginary line around which Earth rotates