Astronomy Crossword

3. A system of stars, dust, dark matter, stellar remnants, and interstellar dust
9. The distance that light travels in one year
10. The outer layer of a star's atmosphere
11. The earth's only natural satellite
12. A curved movement around something
13. A layer of gas surrounding a planet
15. The sun and all of the objects that orbit around it
16. A stream of plasma released from the Sun's corona
17. All of space and time and their contents
18. A small solar system body that produces a coma and a tail

1. The explanation for the existence of the universe
2. A description of the universe with Earth at the center, with the sun and planets orbiting around it
4. The explosion of a star
5. Has a very strong gravitational field
6. Stars that form an outline of something
7. Debris from outer space that end up on the surface of a planet
8. The spiral galaxy containing the Earth
14. An object that orbits around another object
15. Objects containing plasma held together by gravity
19. The star at the center of our solar system