Galaxy & Lightyears Puzzle

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Across
  1. 1. The distance light travels in a year
  2. 6. The telescope the helped us discover there could be 100 billion other galaxies in the universe
  3. 8. the whole cosmic system of matter and energy of which Earth, and therefore the human race, is a part
Down
  1. 2. A big ball of gas filled with many stars, dust, and dark matter
  2. 3. The Galaxy where earth and the sun are located
  3. 4. The heart of our solar system
  4. 5. the branch of science which deals with celestial objects, space, and the physical universe as a whole.
  5. 7. An illuminated ball of fiery gas