Across
- 3. Older galaxies that are the second most common type of galaxy
- 7. A system of planets and dwarf planets gravitationally bound together
- 9. The explosion of a star
- 11. A large cloud filled with dust and gas in space
- 13. The force that attracts everything near it towards the center
- 14. A standard unit of measurement
Down
- 1. Required to back up a statement
- 2. The galaxy that Earth is inside of
- 4. The average distance between the Earth and the Sun
- 5. All space, time, matter, and energy on Earth
- 6. An object so dense that anything within a certain radius cannot leave its gravity
- 7. A way to prove any statement right or wrong
- 8. Most of the known galaxies are this:
- 10. The distance of how far light moves in one year
- 12. A collection of stars, dust, and gases held up by gravity