Astronomy Crossward puzzle

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Across
  1. 4. a planet's spin on its axis
  2. 6. everything in space
  3. 8. a person who studies space
  4. 10. a device used to make distant objects appear closer
  5. 12. a imaginary line going though the sphere's north and south poles
Down
  1. 1. the theory that the sun is in the middle of the solar system
  2. 2. the study of space
  3. 3. a on the surface of a planet or moon caused by a rock form space hitting the surface
  4. 5. the theory that the earth was once in the middle of the solar system
  5. 7. when a object travels around another
  6. 9. the force that pulls an object toward the center of a planet or moon
  7. 11. when an object spins around another object in space