Across
- 3. an object that orbits the Sun, is round, and has a clear neighborhood
- 5. all existing matter and space
- 7. an orbiting object used to collect data
- 8. weak tide that occurs when the Sun, Moon, and Earth form a right angle
- 10. a giant cloud of gas and dust that forms the stars and planets
- 13. The theory that the universe rapidly expanded from one central point
- 15. tool used to analyze the composition and motion of stars
- 17. when an object contains a lot of matter for its size
- 18. a luminous ball of hydrogen gas
Down
- 1. the joining of two atoms
- 2. a crewless object used to safely explore outer space
- 4. the daily rise and fall of coastal water
- 6. tool used to view distant objects
- 9. the amount of matter in an object
- 11. billions of stars, gas, and dust held together by gravity
- 12. strong tide that occurs when the Sun, Moon, and Earth align
- 14. pull towards all objects that have mass
- 16. when the wavelength of the light increases showing that the object is moving farther away