Across
- 4. from the sun
- 5. fifth planet from the sun
- 7. natural/manmade object orbiting a planet
- 10. layers of gas
- 11. one who travels to space
- 12. 29.5 Earth years to orbit sun
- 14. go around
- 16. icy, dusty celestial object
- 18. bright lights at the poles of Earth
- 19. when light shines back
Down
- 1. crash
- 2. hottest planet in solar system
- 3. a celestial body orbiting sun
- 6. a space rock
- 8. only planet with known life
- 9. natural satellite around a planet
- 11. small pieces rock in solar system
- 13. a gas
- 15. in the middle
- 17. made from collisions