Space crossword puzzle

123456789101112131415
Across
  1. 2. A collection of stars and their systems
  2. 5. small rocky objects that
  3. 6. A cloud of dust and gas in space illuminated by one or more stars
  4. 8. The gasses surrounding the surface of a planet
  5. 10. A body that orbits a star (like the sun)
  6. 11. A system where two stars rotate around each other
  7. 15. A group of stars that form a specific pattern
Down
  1. 1. A small and dim galaxy
  2. 3. A person who is trained to travel in a spacecraft
  3. 4. A cavity in the ground of a celestial body
  4. 7. The gaseous outer layer of the sun's atmosphere
  5. 8. The studies of celestial bodies
  6. 9. The path of a celestial body in its revolution about another
  7. 12. Naturally-formed body that orbits planets
  8. 13. A scientist who studies the universe
  9. 14. angular distance of two celestial bodies