Across
- 4. Mercury has the fastest _____.
- 8. Venus is often referred as _____ a sister planet.
- 9. Earth's _______ is made up of gases
- 12. The smallest planet in our solar system is ______.
- 13. Mercury is the closest planet to the ___.
- 14. Earth is the third planet from the ___.
- 15. _____ is billions of years old.
Down
- 1. ______ is a cold,dusty, and rocky planet with a thin atmosphere.
- 2. Earth is the ____ largest planet in the solar system.
- 3. Venus is the _____ planet from the sun.
- 5. Venus has a ____ atmosphere.
- 6. Earth is the only known planet in our solar system to ______ life.
- 7. ____ is known as the red planet.
- 10. Mars is a prime candidate for ______ human exploration.
- 11. mars is the ______ planet from the sun.