Space Crossword Puzzle

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Across
  1. 2. the most abundant form of matter in universe
  2. 3. force of attraction between masses
  3. 4. dense that only neutrons exist in its core
  4. 6. the non-living parts of an ecosystem
  5. 9. stars, planets, gas, and dust
  6. 10. one celestial object moves in front of another
  7. 13. hits Earth’s atmosphere and burns up
  8. 14. the remnant of a supernova
  9. 15. the destruction of habitats
  10. 17. a safety device
  11. 18. the rate at which the universe expands
  12. 20. the distance that light travels in one year
Down
  1. 1. affect population and ecosystem
  2. 5. the resulting charge of an atom
  3. 7. positively charged centre of an atom
  4. 8. the SI unit of energy
  5. 11. an object composed of rocky material, ice, and gas
  6. 12. a galaxy that has an irregular shape
  7. 16. eclipse full Moon passes into Earth’s shadow
  8. 19. Way the galaxy that includes the solar system