Across
- 4. Known as the layer of Earth
- 8. What was the supercontinent called from 300 to 200 million years ago
- 11. Overall level of the ocean over the entire globe
- 13. A celestial object that orbits a star.
- 15. A system for the detection of objects and measuring water depth.
- 16. The edge of a tectonic plate.
- 17. An object that orbits some celestial body in space
- 19. The massive star that increases greatly in brightness.
- 20. Any preserved remains or traces of ancient life.
Down
- 1. A system for calculating position, distance, or other characteristic of a distant object
- 2. Instrument used to determine altitude.
- 3. People who deal with celestial objects, space, and physical universe
- 5. A _____ or deep gulf or fissure in the ground, like a crevasse.
- 6. A _____ develops when gravity compacts clouds of gas.
- 7. The shape of physical features on the earth.
- 9. change in speed or direction of an object.
- 10. The study of Earth's history, physical structure, and substance.
- 12. The force that attracts anything with mass.
- 14. energy What is the theoretical force that counteracts gravity
- 18. ________ can be exceptionally fast or exceedingly slow