Across
- 2. a probe sent to Venus
- 4. Earth's sister planet
- 5. small planets that have rocky surfaces
- 7. rotates from east to west
- 8. closest planet to the sun
- 9. 70% surface is covered by water
Down
- 1. trapping of heat by the atmosphere
- 3. terra or "Earth"
- 6. microwave-sized remote-control rover
- 8. the "red planet"