AST101H1 Chapter Notes - Chapter 9: Planetary Geology, Seismic Wave, Outer Core
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AST101H1 Full Course Notes
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Planetary geology: study of how worlds (planets, dwarf planets, moons, comets, asteroids) came to be. Seismic waves: vibrations travelling through interior and along surface after an earthquake; tell us about internal structures of earth. Earth"s core has two distinct regions: a solid inner core and a molten outer core. Differentiation: gravity separating materials, resulting in layers made of different materials. Mercury"s large core: giant impact blasted away its wouter layers. Moon"s small core: moon formed out of debris (containing little high-density metal) blasted out of earth"s outer layers. Planet"s outer layer consists of relatively cool and rigid rock called the lithosphere. The smaller the world the thicker the lithosphere. Thin lithosphere is brittle and can crack easily. A thick lithosphere is stronger and inhibits the passage of molten rock from below, making eruptions and formations of mountains less likely. Geological activity: ongoing changes (volcanic eruptions, earthquakes, erosions)
