6. Layers inside the Earth Mantle: Zone of rock nearly 2,900km thick Makes up almost 67% of Earth’s mass Layers of the Mantle: Lithosphere: uppermost part of the mantle and the crust above it; cool and brittle. The boundary between the crust and mantle is referred to as the MOHO Asthenosphere: solid rock with the ability to flow due to heat and pressure (plasticity) Mesosphere: increasingly dense and solid rock layer (aka “Lower Mantle”)
7. Layers inside the Earth Core: Center of the earth made up mostly of iron Outer core: dense liquid layer about 2,250km thick Inner core: dense solid layer about 1,228km thick Together the inner and outer core make up about 33.3 % of Earth’s mass
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9. P and S Waves Liquids and Solids How Do We Know? Seismic Wave Studies We will talk more about seismic waves when we study Earthquakes!
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14. The Complex Motion of the Earth 300 km/sec • How fast is our Milky Way Galaxy moving in the Local Group of galaxies? 250 km/sec • How fast is the Solar System moving around the Milky Way Galaxy? 30 km/sec • How fast is the Earth revolving around the Sun? 0.5 km/sec • How fast is the Earth spinning?