Space Science Puzzle

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Across
  1. 2. Gas that makes up Venus's atmosphere
  2. 7. The process that traps heat in the atmosphere
  3. 8. A name given to a ball of burning gas
Down
  1. 1. Fourth planet from the sun
  2. 3. Category given to pluto
  3. 4. Name given to whole of detected space
  4. 5. The hottest planet in our solar system
  5. 6. The biggest gas planet in our solar system