Across
- 1. scientist behind the theory of the super continents
- 5. the number age of a fossil
- 7. a change in frequency due to the Doppler effect.
- 8. formation of atoms more complex than the hydrogen atom.
- 9. a way to split up earths time periods the are 3
- 11. a way to split-ups earth time period there are 2
- 14. an event that causes a huge extinction
- 17. where we got our lakes from
Down
- 2. the the geologic age of a fossil
- 3. phrase use to describe the mass of a star
- 4. the time taken for the radioactivity of a specified isotope to fall to half its original value
- 6. the idea that at certain points in our history all continents were once together
- 10. a way to split up earth time periods there are 11
- 12. the idea that our planet is warming up
- 13. a theory of how the universe started
- 15. when the star burns out and dies
- 16. a point in our history where the world was colder