Challenge it words

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Across
  1. 3. galaxy: no shape
  2. 5. traces of other elements
  3. 6. all existing matter
  4. 10. galaxy: football shaped
Down
  1. 1. : gravitationally bound system
  2. 2. force
  3. 4. astronomical object
  4. 7. a clump
  5. 8. galaxy: has arms
  6. 9. way: galaxy that contains our Solar System