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Observed Features of the Universe

Observed Features of the Universe. • Universe is homogeneous and isotropic on lengths > 100 Mpc. • Universe expanding uniformly. • thermal background of radiation with T~3K. • chemical composition is roughly 75% H, 25% He, + trace.

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Observed Features of the Universe

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  1. Observed Features of the Universe • Universe is homogeneous and isotropic on lengths > 100 Mpc • Universe expanding uniformly • thermal background of radiation with T~3K • chemical composition is roughly 75% H, 25% He, + trace • ordinary matter is more abundant than ordinary antimatter • nearly scale invariant spectrum of CMB fluctuations • hierarchy of structure from 1 kpc to 1 Mpc scales • universe is spatially flat • ordinary matter is a minority (1/6x) of all matter • matter is a minority (1/4x) of all energy • expansion rate accelerating

  2. Observed Features of the Universe • Universe is homogeneous and isotropic on lengths > 100 Mpc • Universe expanding uniformly • thermal background of radiation with T~3K • chemical composition is roughly 75% H, 25% He, + trace • ordinary matter is more abundant than ordinary antimatter • nearly scale invariant spectrum of CMB fluctuations • hierarchy of structure from 1 kpc to 1 Mpc scales • universe is spatially flat • ordinary matter is a minority (1/6x) of all matter • matter is a minority (1/4x) of all energy • expansion rate accelerating

  3. Why is the Universe homogeneous and isotropic? Robs (t0) = radius of observable universe today ~ 1/H0 ~ t0 Robs (t) = size of same patch at time t

  4. Why is the Universe homogeneous and isotropic? Robs (t0) = radius of observable universe today ~ 1/H0 ~ t0 Robs (t) = size of same patch at time t

  5. >> 1 universe decelerating Why is the Universe homogeneous and isotropic? Robs (t0) = radius of observable universe today ~ 1/H0 ~ t0 Robs (t) = size of same patch at time t HORIZON PROBLEM

  6. >> 1 universe decelerating Why is the Universe so FLAT? Recall: FLATNESS PROBLEM

  7. Why so few monopoles? if monopoles are stable: MONOPOLE PROBLEM

  8. t HORIZON PROBLEM FLATNESS PROBLEM MONOPOLE PROBLEM

  9. HORIZON PROBLEM FLATNESS PROBLEM MONOPOLE PROBLEM t accelerated expansion

  10. INFLATION inflation = finite period of accelerated expansion

  11. w < -1/3 means KE < V/2 Planck units

  12. INFLATIONARY MENU ENTRANCE EXIT INFLATION phase transition “chaos” stochastic “tunneling from nothing” defect driven Slow roll flat potentials power-law potentials two or more fields tensor (R + a R2 +…) fermi condensate KE driven oscillation extended scalar field decay bubble nucleation de Sitter fluct’s

  13. Density Perturbations H nearly constant

  14. Density Perturbations inflation ends, H-1 grows

  15. for scalar field, B and E = 0 Newtonian gauge: F = Y

  16. kh >>1:

  17. large x  oscillating nearly scale invariant ! small x  growing

  18. large x  oscillating small x  growing

  19. More generally … need this to be small w ~ -1: INFLATION w >> 1: EKPYROTIC/CYCLIC

  20. AMPLITUDE Strategies 1) Evolve u -equation 2) famous trick 3) heuristic:

  21. The Cyclic Universe w/Neil Turok with many important contributions from: Justin Khoury (Princeton), Burt Ovrut (Penn) and Nathan Seiberg (IAS)

  22. Consensus (big bang + inflation) big bang

  23. Consensus (big bang + inflation) big bang inflation

  24. Consensus (big bang + inflation) Cyclic PJS & Neil Turok “bang” big bang inflation radiation radiation matter matter dark energy dark energy ?? ???

  25. Consensus (big bang + inflation) Cyclic PJS & Neil Turok V Y “bang” big bang inflation radiation radiation matter matter dark energy dark energy ?? ???

  26. Consensus (big bang + inflation) Cyclic PJS & Neil Turok “bang” big bang inflation radiation radiation matter matter dark energy V dark energy ?? ??? Y

  27. Consensus (big bang + inflation) Cyclic PJS & Neil Turok “bang” big bang inflation radiation radiation matter matter dark energy V dark energy ?? ??? Y

  28. Consensus (big bang + inflation) Cyclic PJS & Neil Turok V Y “bang” big bang inflation radiation radiation matter matter dark energy dark energy ?? ???

  29. Consensus (big bang + inflation) Cyclic PJS & Neil Turok “bang” big bang inflation radiation radiation matter matter dark energy V dark energy ?? “contraction” ??? Y

  30. Consensus (big bang + inflation) Cyclic PJS & Neil Turok the “bounce” “bang” big bang inflation radiation radiation matter matter dark energy dark energy ?? “contraction” ??? “crunch”

  31. Consensus (big bang + inflation) Cyclic PJS & Neil Turok the “bounce” “bang” big bang inflation radiation radiation matter matter dark energy “contraction” dark energy ?? “crunch” ??? Reproduces successful predictions

  32. Consensus (big bang + inflation) Cyclic PJS & Neil Turok the “bounce” “bang” big bang inflation radiation radiation matter matter dark energy “contraction” dark energy ?? “crunch” ??? Fewer ingredients: no need for inflation

  33. Consensus (big bang + inflation) Cyclic PJS & Neil Turok the “bounce” “bang” big bang inflation radiation radiation matter matter dark energy “contraction” dark energy ?? “crunch” ??? Dark energy given a purpose

  34. Consensus (big bang + inflation) Cyclic PJS & Neil Turok the “bounce” “bang” big bang inflation radiation radiation matter matter dark energy “contraction” dark energy ?? “crunch” ??? Avoids infinities?

  35. Consensus (big bang + inflation) Cyclic PJS & Neil Turok the “bounce” “bang” big bang inflation radiation radiation matter matter dark energy “contraction” dark energy ?? “crunch” ??? More complete theory of cosmic history

  36. The Cyclic Universe “branes” V Y Y Field-theory M-theory

  37. The Cyclic Universe THE BOUNCE V Y

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