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The Expanding Universe And the Cosmological Constant * John D. Barrow

Delve into the complexities of the universe's expansion, dark energy, and cosmological constants. Discover the age, size, and forces shaping our vast cosmos. Learn about influential figures and cutting-edge theories. Unravel the secrets of space, time, and the future of our universe.

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The Expanding Universe And the Cosmological Constant * John D. Barrow

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  1. The Expanding Universe And the Cosmological Constant * John D. Barrow

  2. Determining accurate distances: a longstanding challenge

  3. A Hubble puzzle that you should follow!

  4. There is no centre and there is no edge

  5. Why is the Universe so old?

  6. A Recipe for Life helium + helium  beryllium helium + beryllium  carbon carbon + helium  oxygen

  7. Why is the Universe so Big ? hydrogen  helium  carbon 10 billion years of alchemy 10 billion years of expansion 10 billion light years of space

  8. The Universe is Almost Empty

  9. The Universe contains only1 Atom per cubic metre1 Earth per (10 l–yr)31 Star per (1000 l–yr)31 Galaxy per (107 l–yr)31 ‘universe’ per (1010 l–yr)3

  10. Our Universe Is Cool T 1/size

  11. Life-supporting Space is…. Almost emptyBig and OldDark and Cold

  12. Force Laws With The Spherical Property o F  1/r2 or F  r r Isaac Newton (1642-1727) F  A/r2 + Br Pierre Simon Laplace (1749-1827)

  13. A New Part of Gravity Acceleration: d2a/dt2 -GM/a2 + 1/3 c2a  - the ‘cosmological constant’ – does it exist? a3 sinh2[ct(3)/2] a3 t2 a3 exp[ct(3)]

  14. Einstein’s Static Universe (1917) Λ = ΛE =4Gρ/c2 R = ΛE-1/2

  15. De Sitter’s Accelerating Universe Always expanding exponential curve R = exp[t(/3]) No matter – only  It has no beginning and no end (1917) Willem De Sitter 1872-1934

  16. Friedmann’s universes 1888-1925 1922,1924

  17. The Vacuum Energy Density Same everywhere and in every direction + Same to all observers, no matter how they are moving 1st law of thermodynamics  0 = dE + pdV = d(Vc2) + pdV = (d)Vc2 + (c2 + p)dV so d = 0 means p = - c2 = constant Is the thermodynamic state of the universal vacuum H2 = (dr/dt)2/r2 = 8G/3 – k/r2 + c2/3 c2/3  8G /3 (Lemaître 1933)

  18. Dark Energy Dominates the Universe

  19. Will the Universe Expand Forever???

  20. The Violent End of the Solar System

  21. A Bio-friendly UniverseBig and OldDark and ColdBut only Just !

  22. A Big Mystery Why isn’t   10+66 cm-2 We observe obs  10-55 cm-2 ???? No galaxies if  > 10-54 cm-2

  23. A New Theory Gives   (1/ctnow)2 for the value of  seen by observers in the universe at time tnow For tnow = 13.7 billion years this gives   10-55 cm-2 as observed. It also predicts that the fraction of the universe’s energy density in the form of space curvature is k = –k/H2a2 = -0.0055 Minus sign  average positive curvature 1 = k + matter +  Testable in 2012-3 by Planck satellite Current obsns -0.0089 ≤ k ≤ -0.0009 J.D. Barrow and D. Shaw, Phys. Rev. Lett. 106, 101302 (2011), Phys. Rev. D 83, 04351 (2010)

  24. The Far, Far Future r  exp[ct(/3)] All stars die All black holes evaporate

  25. After 100 billion yrs The last vestige of the expanding universe Disappears from our view forever …… .. .

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