Across
- 1. group of billions of stars
- 8. a star and all of the objects that revolve around it
- 11. large object in space that orbits a star such as the sun
- 12. ball of ice, rock, frozen gases, and dust that orbits the sun
- 13. warming of the atmosphere because of trapped heat energy
- 14. asteroid that hits the surface of a planet
Down
- 2. envelope of gas surrounding an object in space
- 3. glowing ball of hot gas that makes its own energy and light
- 4. dark area on the sun's surface
- 5. process by which particles combine to form a new particle
- 6. natural satellite that orbits a planet
- 7. brief streak of light seen when an asteroid enters the earth's atmosphere
- 9. rocky object that orbits a star
- 10. region where most asteroids orbit the sun