E&S:Lecture 2

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  1. Big Bang
    • -All the mass and energy came into being
    • -13.7 billion years ago
    • -thought more as wave or a ripple on nothingness
  2. The total "amplitude of energy of our universe
    10^69 J
  3. Why is the total energy of the universe actually zero?
    The poitive energy represented by matter is cancelled by the negative potential energy represented by gravity
  4. The current temperature of space
    3 K
  5. Hubble's Law
    • -found that the galaxies were receding from us at a rate that was proportional to their distance.
    • -the universe is expanding.
  6. Dark matter
    • 1. unknown type of matter hypothesized to account for a large part of the total mass in the universe.
    • 2. Appears to have mass
    • 3. 25%
  7. Total mass of Dark Matter in the universe vs. The Total mass of Ordinary Matter.
    -It is estimated that the total mass of dark matter in the universe is currently five times the total mass of ordinary matter.
  8. Dark energy
    • 1. a hypothetical form of energy that exerts an ever increasing negative, repulsive pressure on the universe.
    • 2. Dominant form of energy in atmophere
    • 3. 72%
  9. When did the Sun collapse from a cloud of dust and gas?
    4.5 billion years ago
  10. The energy of star formation
    1. The lower the density of the cloud, the bigger it needs to be to initate collapse
  11. What does gravitational collapse result in?
    1. results in a conversion of gravitational potential energy into kinetic energy of molecules and atoms, or heat
  12. How long will the Sun burn?
    1. High mass stars burn brightly for millions of years before they exhaust their nuclear fuel. The sun, which is a relatively low mass star will burn for ~10 billion years
  13. Formation of the Solar System
    Our solar system formed from a compositionally mature cloud of dust and gas that included mostly hydrogen and helium, but also heavier elements formed inside long-dead stars.
  14. Earth Interior Structure
    • 1. inner core: dense, iron-rich
    • 2. outer core: dense: iron-rich
    • 3. mantle: less dense
    • 4.crust: cool
  15. The “falling” of dense material towards the center of the Earth during differentiation did what?
    • 1. released additional gravitational potential energy,
    • 2. resulting in conversion to additional thermal energy
  16. How is heat from the interior of the earth transported to the surface?
    • 1. Thermal convection
    • -hot fluid rises,spreads and cools, then it sinks,causing hot to rise again
    • -much more efficient at transporting heat over large distances.
    • 2. Thermal conduction
    • -heats transfers by vibrational and kinetic energy between adjacent molecules
  17. Earth's atmospheric composition
    • 1. Nitrogen (79%)
    • 2. Oxygen (20%)
    • 3. argon (1%)

    *80km thick
  18. Earth's ocean deepness
    4 km
  19. Percent of Earth covered by water
  20. Earth formed
    4.6 billion years ago
  21. First sign of life appeared
    3.5 billion years ago
  22. first fish appeared
    • 500 million years ago
    • - ostracoderms.
  23. first multicelled organisms appeared
    650 millions years ago
  24. Humans appeared
    2 million years ago
  25. oxygen first appeared
    3 billion years ago
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E&S:Lecture 2
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