The Multiverse

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The Multiverse

• Our Universe and others

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Our Early Universe

• Universe described by three numbers
• Omega
• gravity vs. expansion
• Ratio of baryons to bosons
  (matter to energy)
• Q
• the amplitude of primordial ripples.

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Omega

• Critical Mass Actual Mass

Matter we can see e.g. stars, galaxies
Dark Matter e.g. brown
dwarfs, neutrinos
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Matter

• Andrei Sakharov claimed that Proton abundance
  is allowed if
• Baryon number is not conserved
• Cosmic expansion is very fast
• Matter/Antimatter reactions not time-reversible,
  the direction of time is sensed thanks to
  expansion.

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Primordial Ripples

• The Universe is almost totally smooth. However,
  there are slight discrepancies in the densities
  of matter in certain areas.
• At time of the last scattering surface the
  Universe was about 3000oK.
• Q1x10-5

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Other important constants

• Lambda the energy density of empty space dark
  energy.

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What if these values were different?
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The Multiverse

• A collection of every possible Universe.
• Archipelagos of life-supporting Universes.
• Anthropic Reasoning
• Our Universe is the BEST (or most well suited to
  life) out of all other infinite possibilities.

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Different Universes

• Infinite possibilities.
• As computing power increases more adventurous
  models will be made.
• Small tweaks at present time, later greater
  changes

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Why Bother?

• Helps us understand the workings of our own
  Universe.
• May aid us in our search for the final theory of
  everything.
• Curiosity.

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Any Questions?