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Comparative Planetology

  • Comparing/contrasting planets
  • Goal is to understand how they are different, why they are different, and what we can learn from the differences

Terrestrial Planets

  • Surfaces probably started out the same
    • Rocky material
    • Heavily bombarded
  • What changed?
    • Weather?
    • Geological activity?
  • Inside
    • Measured with seismic waves
    • Layers
      • Core
      • Mantle
      • Crust
    • Magnetic fields
      • Information about the inside
      • Requirements
        • Electrically conducting fluid
        • Convection in that layer
        • Moderately rapid rotation

Why they are different

  • Size
    • Bigger planets star warmer longer
    • Leaders to more volcanism
    • Outgassing
    • Magnetic field
  • Distance from the Sun
    • Rain, snow, ice oceans
      • Create erosion
    • Escape velocities
      • Atmospheric layers can escape the gravity
  • Rate of rotation
    • Drives wind and weather
    • Magnetic field

Astronomy Planet