Science

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Across
  1. 5. condensed together
  2. 6. a collection of solar systems
  3. 7. The theory the the universe started from a big explosion
  4. 8. getting smaller and more dense
Down
  1. 1. The study of the origin of the universe
  2. 2. the expanding collection of space matter
  3. 3. always getting farther apart and growing
  4. 4. someone who studies space