Across
- 4. what does the strength of gravity depend on.
- 5. located in the asteroid belt between mars and Jupiter.
- 6. small body of matter from outer space.
- 7. orbits the earth.
- 12. outer planets.
- 13. orbits the sun.
- 16. gaseous planets.
- 17. area of the solar system where the suns energy supports liquid water.
- 19. to close to the sun.
- 20. must have an abundant supply of oxygen.
Down
- 1. what is a scale model.
- 2. what protects astronauts.
- 3. rocky and terrestrial.
- 8. protects earth from radiation.
- 9. inner planets.
- 10. captures harmful charged particles from the sun.
- 11. biggest object in our solar system.
- 14. to far from the sun.
- 15. what does habitable mean.
- 18. what is the moon made out of.