Big bang theory

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Across
  1. 3. short waves
  2. 5. islands of stars
  3. 6. most abundant element in the universe
  4. 7. radiation left over from the big bang
  5. 8. what the universe used to be made of
Down
  1. 1. all matter that exists
  2. 2. long waves
  3. 4. used to study light
  4. 6. second most abundant element in the universe