1. Lecture 6: Earth as a Planet 1.The Young Earth 2.Earth as a planet: interior 3.Plate tectonics 4.Atmosphere

2. News from Mars: Opportunity Mars Rover at Santa Maria Crater - Feb. 2011

3. News from Mars:

5. The Formation of the Earth Precise timeline of early events.

6. The Planets

7. Earth as a planet - interior

8. Earth interior - seismic waves

9. Earth interior - seismic surface waves

10. Earth as a planet - plate tectonics

11. Plate tectonics

12. Earth as a planet - plate tectonics

14. Earth - plate collision & subduction Kustowski et al.(2006) Evidence from seismic tomography for the subduction of the plate under Japan. Variations in shear-wave velocity, v S

15. Earth as a planet - plate tectonics

17. Earth as a planet - tectonics

18. The Terrestrial Planets Mercury Venus Earth Mars

19. Mars as a planet - interior Earth

20. Mars as a planet - NO plate tectonics

21. Wyatt et al. [2004]; Data from Mars Odyssey THEMIS basalt dust “altered basalt” (smectite, palagonite, zeolites) Surface composition from thermal emission spectra Mars as a planet - the surface

22. Earth as a planet - atmosphere

23. Main points to take home: 1) Hadean Earth (4 430 - 4 000 Myr): heavy bombardment epoch, outgassing, oceans 2)Earthquakes & seismic waves - interior map 3)Earth’s interior is differentiated - iron core 4)Plate tectonics - Earth’s crust is broken into plates; mantle convective currents cause these plates to move 5)Atmosphere - Earth had 3 types of atmospheres, in terms of composition; today’s is mostly N 2 (78%) and O 2 (21%).