Across
- 3. very early stage of a planet
- 6. icy object past Neptune
- 11. fragment from a celestial body on earths surface
- 12. earth-like planets made of rock
- 13. early stage of a meteor
- 14. multiple bodys passing one point
- 15. measuring circular bodys
- 16. region of interplanetary space
- 17. main constituent of gas planets
Down
- 1. made of helium or hydrogen
- 2. planet lacking requirements
- 4. oval shape
- 5. icy body that releases gas and has a tail
- 7. long cliffs on mercury's surface
- 8. area around a star capable of liquid water
- 9. rotational motion opposite to primary orbit
- 10. unit of measurement in space
- 11. celestial body that enters earths atmosphere