Across
- 5. Planet similar in size to Venus
- 6. 99.8% of mass of our solar system
- 7. Burning balls of gas
- 9. Closest planet to the sun
Down
- 1. Planetesimals that formed orbits around planets
- 2. The hottest planet
- 3. Force that holds our solar system together
- 4. Gives Mars it's "reddish" color
- 8. First four planets are the inner _____ planets