Across
- 3. Carbon decays to this element.
- 4. Radioactive element used to date once living materials.
- 8. Rocks left from the impact of an asteroid.
- 9. The estimated age of the Earth and solar system.
- 10. Older rocks are _______ younger rocks.
- 11. Uranium decays to this element.
Down
- 1. Radioactive element used to date celestial objects.
- 2. Material that decays to Argon. Found in bananas.
- 5. Rocks next to each other are of _____ age.
- 6. An impact from an asteroid.
- 7. The time it takes for an element to decay to half of its original mass.