Inner Planets

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Across
  1. 1. Layers of gas surrounding a planet
  2. 6. Celestial object that orbits a planet
  3. 7. Type of terrain of the inner planets
  4. 8. Similar to Earth in some ways
Down
  1. 2. Fastest planet, as well as closest to the sun
  2. 3. Characteristic of the inner planets
  3. 4. Hottest planet in the solar system
  4. 5. Move repeatedly around an object
  5. 6. Has a volcano known as Olympus Mons
  6. 9. Only planet in the solar system known to sustain life