Across
- 2. The number of rocky planets in are solar system
- 4. any planet with a rocky surface
- 6. The star in the middle of our solar system
- 10. studies rocks on other planets
- 13. planet that supports life
- 14. closest planet to the Sun
- 15. the only habitable planet
- 17. considered to be Earth's sister planet
Down
- 1. an event or series of events that causes change to the surface of a planet
- 3. Initials for National Aeronatics and Space Administration
- 5. a feature that forms on the surface of a planet
- 7. all the living things on a planet
- 8. necessary for human survival
- 9. mixture of gases surrounding a planet
- 11. Our solor system is located in the
- 12. The red planet
- 16. all the liquid water on a planet