September 27th, 2022

Big Bang to Humankind

  • The moon likely formed when a huge (~planet-size) world collided with Earth, and a chunk flew off.
    • The moon’s materials match the composition and age of Earth’s except for those destroyed in great heat.

5 Stages of Terrestrial Planetary Evolution

(terrestrial = a planet you can stand on)

  1. Origin
  2. Differentiation
    • Worlds become sphere
    • Denser things go towards the center
      • Earth has the Crust, Mantle (the majority), and Core (made of Iron)
        • Outer core is liquid, inner core is solid
      • We know what’s in Earth by measuring seismic waves during earthquakes
  3. Late Heavy Bombardment
  4. Geological Activity
  5. The Big Chill
    • Fuel for volcanoes comes from nuclear fission (things breaking apart and releasing energy)
    • This fuel is used up over time, and the amount of fuel is correlated with its size. After it runs out, volcanic activity stops, and that’s The Big Chill.

Electricity = Magnetism

  • Earth’s magnetic field comes from moving molten rock inside of it.
    • It creates a shield for Earth against damaging particles from solar winds.