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The Big Bang

The Big Bang. Inflationary Expansion. Solves the horizon problem Solves the flatness problem Growth of quantum fluctuations. The uncertainty principle.

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The Big Bang

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  1. The Big Bang

  2. Inflationary Expansion • Solves the horizon problem • Solves the flatness problem • Growth of quantum fluctuations

  3. The uncertainty principle According to quantum mechanics, we cannot know the energy of a system on small time scales. The smaller the time scale, the larger the uncertainty in the energy.

  4. Where did the universe come from? The mass in the universe may have sprung forth from the vacuum, from nothing!

  5. Virtual Particles

  6. E=mc2 If the energy is uncertain, so is the mass. If the mass is uncertain, so is the number of particles.

  7. Virtual pair production Particles, along with their anti-particles, can be created out of nothingness. In general, these particles last for a very small fraction of a second, at which time they annihilate each other and return the energy they “borrowed.”

  8. Discussion What happens to my virtual particles pairs that are around at the time of inflation?

  9. Inflation During the era of inflation, the universe expanded so rapidly, the pairs of particles were ripped apart and unable to annihilate each other.

  10. Discussion What does this tell us about the amount of anti-matter in the universe?

  11. Where’s the antimatter? If this idea is correct, there should be equal amounts of matter and antimatter in the universe today. Where did all the antimatter go?

  12. Spontaneous Symmetry breaking The decay of a massive particle called the K-meson, or the kaon for short, decays more often to matter than it does to antimatter. The asymmetry is very tiny, on the order of one part in 300 million. Why this should be is still a mystery.

  13. We are made up of the residue For every proton in the universe there must have been 300 million protons and antiprotons that were annihilated.

  14. CMBR

  15. Discussion Why can’t the CMBR be from a population of unresolved stars at high redshift?

  16. Discussion If I proposed building an x-ray satellite in order to observe the CMBR at a time when the Universe was hotter than 3000 K, would you fund such a mission?

  17. Maybe the Universe starts here?

  18. Discussion If you take a bunch of protons and smash them together what would you expect to happen?

  19. proton – proton chain

  20. Proton-Proton chain too slow Even at 15 million K, it takes on average 14 billion years at a rate of 100 million collisions per second to fuse two protons to produce a deuterium atom in the Sun’s core.

  21. Matter and photons The higher the temperature of the CMBR, the higher the energy of the photons The higher the energy, the more massive the particles that can be created

  22. Protons and neutrons At temperatures greater than 1011 K, CMBR photons had enough energy to create proton-antiproton and neutron-antineutron pairs

  23. H to He ratio Because the Universe has about 75% H and 25% He by weight, we know that there must have been 7 protons for every neutron at the time of nucleosyhthesis.

  24. Matter and Energy in the universe

  25. Electric and Magnetic Waves

  26. General Relativity or Quantum Mechanics? These two theories disagree inside a black holes. Because we can never see inside a black hole does it even matter?

  27. Unified Field Theory Einstein tried to explain the electromagnetic force using curved spacetime and failed. Was accomplished by Kaluza, but it required four space dimensions and one time dimension

  28. Messenger particles Today, most scientists believe that the transmission of a force must be quantized Forces are caused by the exchange of virtual particles

  29. The 4 fundamental forces

  30. What’s the difference? The difference between the forces is their strength and the distance over which they can act. Electromagnetism and gravity can act over infinite distances. The nuclear forces can act only over very small distances.

  31. But if the observable universe is very small, there is no effective difference between the range of the forces. Furthermore, the more energy you give to the messenger particles the stronger the force will appear.

  32. Electroweak force 10-12 sec after Big Bang Temperature 1015 K Observable universe about 1 mm in diameter Photons of the CMBR had enough energy to turn into W particles No difference between the electromagnetic force and the weak force.

  33. The Electronuclear force At 10-35 sec Temperature 1027 K No difference between the strong, weak, or electromagnetic forces.

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