Across
- 3. distance based on the distance that light travels in one year
- 4. theory that explains the formation of the universe
- 5. used for small distances in space
- 7. _______ nuclear force is responsible for particle decay and powers stars
- 8. _______ shift describes an object moving away from Earth
- 9. a sphere of ionized gas that emits heat and light
- 10. a collection of billions of stars held together by gravity
- 11. the largest base unit of measurement used in space
- 12. orbits a planet
- 14. the weakest of the fundamental forces
- 15. used to measure the distance between planets in the same planetary system
- 16. planets, moons, and celestial objects orbiting a star
- 17. all of the matter and energy that exists
Down
- 1. _______ shift describes an object moving towards the Earth
- 2. an object that orbits a central star
- 6. force that causes like charges to repel and opposite charges to attract
- 9. _______ nuclear force holds atoms together
- 12. as this factor increases, the force of gravity will also increase
- 13. as this factor increases, the force of gravity will decrease