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Earth

Earth. How We Know What We Know. The Inside Volcanoes Drills Gravity Magnetic Fields Earthquakes. The Outside Rocks (free) Maps Many Satellites Global Positioning. Some Earth Satellites. ISS. Aura. ADEOS-2. Terra. ICESat-2. GOES 13. Earth Observing Mission 2. Earth.

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Earth

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  1. Earth How We Know What We Know The Inside • Volcanoes • Drills • Gravity • Magnetic Fields • Earthquakes The Outside • Rocks (free) • Maps • Many Satellites • Global Positioning

  2. Some Earth Satellites ISS Aura ADEOS-2 Terra ICESat-2 GOES 13 Earth Observing Mission 2

  3. Earth

  4. Continental Plates – Global Positioning • Surface is moving • A few cm per year

  5. The Earth – Continental Drift

  6. The Earth – Deep Drilling • Greatest depth drilled = 12 km

  7. The Earth – Volcanoes • Provide samples from shallow interior of Earth

  8. The Earth – Volcanoes

  9. The Earth – Clues to the Interior • Gravity measures mass of Earth • Magnetic fields from interior • Fluid Layer • Conductor (metal) • Motion (rotation) • Earthquakes!

  10. Earthquakes San Andreas Fault

  11. Earthquakes • Different types of waves travel differently through the Earth • P-waves are pressure waves • Can travel through solids and liquids • S-waves are shear waves • Can travel through solids only • Surface waves travel only on the surface

  12. Earth’s Interior • The Crust • Thin layer of lightweight rocks • Rigid – can’t flow • The Mantle – largest part • Denser rocks • Plastic – can be deformed slowly • Flows over time • Cores • Mostly iron • Outer core – liquid • Inner core – solid Q. 29: Earth’s Magnetic Field

  13. Convection • Heat inside Earth causes expansion • Lower density causes hot areas to rise • Like water in a pan • Plastic mantle can flow as well • Continents carried on topof flowing mantle • Rigid crust can’t flow - it breaksinstead (sometimes)

  14. Earth’s Magnetic Field • Outer core is liquid metal • Currents can flow in it • Rotation of Earth regenerates field • Tilted compared to rotation axis • Direction/strength changes over time • Charged particles from Sun deflected by our magnetic field • Solar wind on atmosphere creates Aurora Borealis and Australis

  15. Earth’s Magnetic Field

  16. Factors Causing Earth’s Surface Features • Moving plates • Mountains • Ocean Trenches • Continents • Subduction • Erosion • Rain • Wind • Volcanoes

  17. Earth – Meteor Craters Q. 30: Earth’s Meteor Craters • Atmosphere blocks or slows all but the largest meteors • Only large meteors make it through • Erosion wipes out evidence of most of these • All but the largest get eliminated over time • In the long run, volcanism and subduction eliminate the rest • The oldest craters are all gone

  18. Barringer Meteor Crater

  19. Bosumtwi Crater

  20. The Earth: Atmosphere • Composition • Nitrogen • Oxygen • Moderates temperatures • Globally • Temporally

  21. The Earth: Water • Earth is only place in Solar System with liquid water on the surface • Allows life to develop?

  22. The Earth: Greenhouse Effect • Visible sunlight heats the surfaceof the Earth • Some reflected by clouds • Some reflected by Earth • Warm Earth reradiates infraredradiation • Penetrates most of atmosphere fine • Some is captured again • Since Earth is more efficient at transmitting visible than infrared, Earth is warmer than you would expect • The greenhouse effect

  23. Greenhouse Gasses • Some gasses are better at transmitting visible than infrared • Water vapor (H2O) – Not very efficient, but there’s a lot of it • Carbon dioxide (CO2) – Very efficient, reasonably abundant • Methane (CH4) – Extremely efficient, but very little of it • Most energy production produces carbon dioxide • Coal – produces the most • Oil – produces a lot • Natural gas – produces some • Nuclear, Solar, wind, Geothermal, etc. – produces none

  24. Life on Earth • Earth contains oxygen because of plants • Plants also absorb carbon dioxide • Killing plants warms the Earth Q. 31: Life on Other Planets

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