Alex's Crossword Puzzle

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Across
  1. 2. A group of many stars with gas, dust and
  2. 4. The solid part of a comets head
  3. 5. A celestial body that makes an orbit
  4. 9. The region of space around a black hole from which nothing can escape
  5. 10. an enormous cloud of dust and gas occupying the space between stars and acting as a nursery for new stars
  6. 13. matter
  7. 14. A cloud of gas and dust in space believed
  8. 18. The creation of new atomic nuclei and the centres of atoms
  9. 20. nucleus
  10. 22. Developed by a current of electricity
Down
  1. 1. into different substances
  2. 3. A celestial body that is in orbit around the Sun and has sufficient mass to overcome body forces
  3. 4. A proton or neutron especially in the
  4. 6. Of or relating to the stars
  5. 7. The origin of the universe
  6. 8. develop into a star
  7. 11. More than 100 substances that cannot be
  8. 12. a planet
  9. 15. another one
  10. 16. Related to universe, space or time
  11. 17. All of space and time and their contents including planets, stars and galaxies.
  12. 19. Any massive body of gas that shines by radiation from its internal energy sources
  13. 21. A path that one object in space takes