Across
- 4. leading theory about the origin of the universe
- 6. size of the Sun
- 7. heliocentric
- 10. a moon of Jupiter
- 11. "ringed planet"
- 15. highest mountain in the Solar System
- 18. moon of Mars
- 19. first person to focus the telescope to the heavens
- 21. someone who studies astronomy
- 22. a constellation meaning "Great Bear"
- 25. rocky body too small to be called planet
Down
- 1. movement of a planet on its axis
- 2. first man on space
- 3. brightest star in the Earth's sky
- 5. group of stars which forms imaginary patterns
- 8. a type of galaxy
- 9. named after the Roman god of love and beauty
- 12. natural satellite of the moon
- 13. famous comet appearing every 76 years
- 14. all the matter and energy and contents of space
- 16. meteoroid which falls to the ground
- 17. first artificial satellite ever launched
- 20. universe
- 23. nearest galaxy to the Milky Way
- 24. collection of gas,dust and billions of stars