Across
- 2. The force that keeps a planet from moving in orbit.
- 4. The Earth turning on its own axis is called _____________.
- 6. Layer of gas that surrounds a planet.
- 8. A star and the planets orbit around it.
Down
- 1. Planet closest to the Sun.
- 3. What do we call the chunks of rock that travel around the Sun?
- 5. The second planet closest to the Sun.
- 7. Nicknamed 'the red planet'.