Big Questions in ScienceSebastian de Haro, fall 2012
Big Questions in Science, fall 2012. SdH, AUC   2
Big Questions in Science, fall 2012. SdH, AUC   3
Big Questions in Science, fall 2012. SdH, AUC   4
Big Questions in Science, fall 2012. SdH, AUC   5
Robbert Dijkgraaf NRC 05-05-11: Total amount ofInformation on earth is 1 zettabyte      bytes                      Big Que...
1 bitBig Questions in Science, fall 2012. SdH, AUC                               2011.            7
   Wave-like pattern encoded in wave function:              Big Questions in Science, fall 2012. SdH, AUC   8
   Wave propagation            Big Questions in Science, fall 2012. SdH, AUC   9
Big Questions in Science, fall 2012. SdH, AUC   10
“Traditionally these are questions for philosophy, but                      philosophy is dead. Philosophy has not kept up...
Big Questions in Science, fall 2012. SdH, AUC   12
Big Questions in Science, fall 2012. SdH, AUC   13
?Big Questions in Science, fall 2012. SdH, AUC   14
   Steven Weinberg:     Petty reductionism: whole to parts.     Grand reductionism: “To reduce the world of     physica...
The rest                Biology             ChemistryStatistical physics/condensed matterQuantum mechanics/relativity/clas...
   Weinberg: “One of the members of the [SSC]    board argued that we should not give the    impression that we think tha...
   Philip Anderson: “They [the results of particle    physics] are in no sense more fundamental    than what Alan Turing ...
   “By far the most important [prediction] is super symmetry    which is fundamental to most attempts to unify Einsteins ...
Intermediate areas:                                      Therest                                      De rest             ...
Big Questions in Science, fall 2012. SdH, AUC   21
Big Questions in Science, fall 2012. SdH, AUC   22
   Singularities     Big Bang     Black Holes   The problem of infinities   Most serious: information loss           ...
Big Questions in Science, fall 2012. SdH, AUC   24
Big Questions in Science, fall 2012. SdH, AUC   25
   Pierre-Simon Laplace (1749-1827).     Escape velocity.     Earth:     ‘Black star’:                 Big Questions i...
   Einstein 1915: mass implies curvature of space-time.   Curvature is perceived as gravitational attraction.           ...
 Black hole itself cannot be seen. Indirect evidence: matter swallowed up by supermassive black  object. Predictions: t...
 Black hole itself cannot be seen. Indirect evidence: matter swallowed up by supermassive black  object. Predictions: t...
   If as heavy as the sun: one meter.   Supermassive (one million suns): size of the solar system.   Milky Way: Sagitta...
Big Questions in Science, fall 2012. SdH, AUC   31
Big Questions in Science, fall 2012. SdH, AUC   32
   Free fall.                 Big Questions in Science, fall 2012. SdH, AUC   33
   Heaviest objects, not even light can escape.   Fish in the water analogy.   Free fall.                 Big Questions...
   1973 Bekenstein develops black hole thermodynamics.   1974 Hawking: black holes emit radiation.   The key: quantum f...
Big Questions in Science, fall 2012. SdH, AUC   36
Hawking Radiation             Big Questions in Science, fall 2012. SdH, AUC   37
   If we wait long enough, the black hole will    evaporate.   Radiation contains no information about    what went in....
Big Questions in Science, fall 2012. SdH, AUC   39
Big Questions in Science, fall 2012. SdH, AUC   40
   Black holes emit radiation.   The radiation is thermal, contains no information.   Information is lost.   New level...
Big Questions in Science, fall 2012. SdH, AUC   42
Big Questions in Science, fall 2012. SdH, AUC   43
Big Questions in Science, fall 2012. SdH, AUC   44
Big Questions in Science, fall 2012. SdH, AUC   45
Big Questions in Science, fall 2012. SdH, AUC   46
Big Questions in Science, fall 2012. SdH, AUC   47
Big Questions in Science, fall 2012. SdH, AUC   48
Big Questions in Science, fall 2012. SdH, AUC   49
Big Questions in Science, fall 2012. SdH, AUC   50
   Alice and the cat have different descriptions of reality.   Their points of view are mutually exclusive.   Describe ...
   1993 Gerard ’t Hooft   Thought experiment: box volume                                      E          R   Entropy: m...
   ’t Hooft 1993 “dimensional reduction”   Susskind 1994 “holography”   Maldacena 1997 holography in string theory   2...
There is no baby universe branching off, as I once thought. Theinformation remains firmly in our universe. I’m sorry to di...
 Black holes can radiate, which gives rise to information paradox Paradigm to solve this problem: holography – confirmed...
   Gravity 5d            4d particle physics (QCD)   Gravity 4d            3d particle physics                 Big Quest...
Temperature Hawking radiation                                   Temperature materialSmall perturbations of black hole     ...
   Common element in all holographic dualities:    “long” distances in one theory correspond to    “short” distances in t...
Long-distance cutoff                                           UV cutoff               Big Questions in Science, fall 2012...
   Gravity seems equivalent with physics of    conducting materials   Also connections with hydrodynamics              B...
Big Questions in Science, fall 2012. SdH, AUC   61
Big Questions in Science, fall 2012. SdH, AUC   62
Big Bang       String Theory                                                            Cosmology                         ...
   Contextual models with local overlaps and    interaction within general framework.   Unity: connection of distant are...
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9 What Is Reality?

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Big Questions in Science series, (9 of 9). Class taught at AUC (University of Amsterdam) during the 2012-2013 fall semester.

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9 What Is Reality?

  1. 1. Big Questions in ScienceSebastian de Haro, fall 2012
  2. 2. Big Questions in Science, fall 2012. SdH, AUC 2
  3. 3. Big Questions in Science, fall 2012. SdH, AUC 3
  4. 4. Big Questions in Science, fall 2012. SdH, AUC 4
  5. 5. Big Questions in Science, fall 2012. SdH, AUC 5
  6. 6. Robbert Dijkgraaf NRC 05-05-11: Total amount ofInformation on earth is 1 zettabyte bytes Big Questions in Science, fall 2012. SdH, AUC 6
  7. 7. 1 bitBig Questions in Science, fall 2012. SdH, AUC 2011. 7
  8. 8.  Wave-like pattern encoded in wave function: Big Questions in Science, fall 2012. SdH, AUC 8
  9. 9.  Wave propagation Big Questions in Science, fall 2012. SdH, AUC 9
  10. 10. Big Questions in Science, fall 2012. SdH, AUC 10
  11. 11. “Traditionally these are questions for philosophy, but philosophy is dead. Philosophy has not kept up with modern developments in science, particularly physics. Scientists have become the bearers of the torch of discovery in our quest for knowledge. The purpose of this book is to give the answers that are suggested by recent discoveries and theoretical advances. They lead us to a new picture of the universe and our place in it that is very different from the traditional one, and different even from the picture we might have painted just a decade or two ago. Still, the first sketches of the new concept can be traced back almost a century.” (The Grand Design).Big Questions in Science, fall 2012. SdH, AUC 11
  12. 12. Big Questions in Science, fall 2012. SdH, AUC 12
  13. 13. Big Questions in Science, fall 2012. SdH, AUC 13
  14. 14. ?Big Questions in Science, fall 2012. SdH, AUC 14
  15. 15.  Steven Weinberg:  Petty reductionism: whole to parts.  Grand reductionism: “To reduce the world of physical phenomena to a finite set of fundamental equations (or principles)” (Freeman Dyson). “Search for the common source of all explanations.” Big Questions in Science, fall 2012. SdH, AUC 15
  16. 16. The rest Biology ChemistryStatistical physics/condensed matterQuantum mechanics/relativity/class.mech Particle physics / gravity String Theory, M-theory Big Questions in Science, fall 2012. SdH, AUC 16
  17. 17.  Weinberg: “One of the members of the [SSC] board argued that we should not give the impression that we think that elementary particle physics is more fundamental than other fields, because it just tended to enrage our friends in other areas of physics. The reason we give the impression that we think that elementary particle physics is more fundamental than other branches of physics is because it is. I do not know how to defend the amounts being spent on particle physics without being frank about this.” Big Questions in Science, fall 2012. SdH, AUC 17
  18. 18.  Philip Anderson: “They [the results of particle physics] are in no sense more fundamental than what Alan Turing did in founding the computer science, or what Francis Crick and James Watson did in discovering the secret of life.” Big Questions in Science, fall 2012. SdH, AUC 18
  19. 19.  “By far the most important [prediction] is super symmetry which is fundamental to most attempts to unify Einsteins General Relativity with Quantum Theory. This would be confirmed by the discovery of super partners to the particles that we already know. The Superconducting Super Collider (the SSC) was being built in Texas and would have reached the energies at which super partners were expected. However, the United States went through a fit of feeling poor and canceled the project half way. At the risk of causing embarrassment, I have to say I think this was a very short sighted decision. I hope that the US, and other governments will do better in the next millennium. (Stephen Hawking, Millennium lecture)” Big Questions in Science, fall 2012. SdH, AUC 19
  20. 20. Intermediate areas: Therest De rest Biology Chemistry Statistical physics/condensed matter Quantum mechanics/relativity/class.mech Particle physics / gravity String Theory, M-theory Snaartheorie, M-theorie Big Questions in Science, fall 2012. SdH, AUC 20
  21. 21. Big Questions in Science, fall 2012. SdH, AUC 21
  22. 22. Big Questions in Science, fall 2012. SdH, AUC 22
  23. 23.  Singularities  Big Bang  Black Holes The problem of infinities Most serious: information loss Big Questions in Science, fall 2012. SdH, AUC 23
  24. 24. Big Questions in Science, fall 2012. SdH, AUC 24
  25. 25. Big Questions in Science, fall 2012. SdH, AUC 25
  26. 26.  Pierre-Simon Laplace (1749-1827).  Escape velocity.  Earth:  ‘Black star’: Big Questions in Science, fall 2012. SdH, AUC 26
  27. 27.  Einstein 1915: mass implies curvature of space-time. Curvature is perceived as gravitational attraction. Big Questions in Science, fall 2012. SdH, AUC 27
  28. 28.  Black hole itself cannot be seen. Indirect evidence: matter swallowed up by supermassive black object. Predictions: time delay, gravitational lensing. Big Questions in Science, fall 2012. SdH, AUC 28
  29. 29.  Black hole itself cannot be seen. Indirect evidence: matter swallowed up by supermassive black object. Predictions: time delay, gravitational lensing. Big Questions in Science, fall 2012. SdH, AUC 29
  30. 30.  If as heavy as the sun: one meter. Supermassive (one million suns): size of the solar system. Milky Way: Sagittarius A*. Big Questions in Science, fall 2012. SdH, AUC 30
  31. 31. Big Questions in Science, fall 2012. SdH, AUC 31
  32. 32. Big Questions in Science, fall 2012. SdH, AUC 32
  33. 33.  Free fall. Big Questions in Science, fall 2012. SdH, AUC 33
  34. 34.  Heaviest objects, not even light can escape. Fish in the water analogy. Free fall. Big Questions in Science, fall 2012. SdH, AUC 34
  35. 35.  1973 Bekenstein develops black hole thermodynamics. 1974 Hawking: black holes emit radiation. The key: quantum fluctuations of vacuum. Big Questions in Science, fall 2012. SdH, AUC 35
  36. 36. Big Questions in Science, fall 2012. SdH, AUC 36
  37. 37. Hawking Radiation Big Questions in Science, fall 2012. SdH, AUC 37
  38. 38.  If we wait long enough, the black hole will evaporate. Radiation contains no information about what went in. Information disappears. Black holes violate quantum mechanics. Big Questions in Science, fall 2012. SdH, AUC 38
  39. 39. Big Questions in Science, fall 2012. SdH, AUC 39
  40. 40. Big Questions in Science, fall 2012. SdH, AUC 40
  41. 41.  Black holes emit radiation. The radiation is thermal, contains no information. Information is lost. New level of unpredictability in physics. Big Questions in Science, fall 2012. SdH, AUC 41
  42. 42. Big Questions in Science, fall 2012. SdH, AUC 42
  43. 43. Big Questions in Science, fall 2012. SdH, AUC 43
  44. 44. Big Questions in Science, fall 2012. SdH, AUC 44
  45. 45. Big Questions in Science, fall 2012. SdH, AUC 45
  46. 46. Big Questions in Science, fall 2012. SdH, AUC 46
  47. 47. Big Questions in Science, fall 2012. SdH, AUC 47
  48. 48. Big Questions in Science, fall 2012. SdH, AUC 48
  49. 49. Big Questions in Science, fall 2012. SdH, AUC 49
  50. 50. Big Questions in Science, fall 2012. SdH, AUC 50
  51. 51.  Alice and the cat have different descriptions of reality. Their points of view are mutually exclusive. Describe black hole from point of view of an observer. Led to holographic principle. Big Questions in Science, fall 2012. SdH, AUC 51
  52. 52.  1993 Gerard ’t Hooft Thought experiment: box volume E R Entropy: measure # states # S~E Gravity in the Bulk Theory on Boundary Big Questions in Science, fall 2012. SdH, AUC 52
  53. 53.  ’t Hooft 1993 “dimensional reduction” Susskind 1994 “holography” Maldacena 1997 holography in string theory 2004 Hawking admits he lost his bet Big Questions in Science, fall 2012. SdH, AUC 53
  54. 54. There is no baby universe branching off, as I once thought. Theinformation remains firmly in our universe. I’m sorry to disappointscience fiction fans, but if information is preserved, there is nopossibility of using black holes to travel to other universes. If youjump into a black hole, your energy will be returned to our universebut in a mangled form which contains the information about whatyou were like but in a state where it can not be easily recognized. Itis like burning an encyclopedia. Information is not lost, if one keepsthe smoke and the ashes. But it is difficult to read. In 1997, KipThorne and I, bet John Preskill that information was lost in blackholes. The loser(s) of the bet were to provide the winner(s) with anencyclopedia of their own choice, from which information can berecovered with ease. I gave John an encyclopedia of baseball, butmaybe I should just have given him the ashes. Big Questions in Science, fall 2012. SdH, AUC 54
  55. 55.  Black holes can radiate, which gives rise to information paradox Paradigm to solve this problem: holography – confirmed by string theory: the world is 3- not 4-dimensional Gravity is a “fake” force Implications for reductionism? Big Questions in Science, fall 2012. SdH, AUC 55
  56. 56.  Gravity 5d 4d particle physics (QCD) Gravity 4d 3d particle physics Big Questions in Science, fall 2012. SdH, AUC 56
  57. 57. Temperature Hawking radiation Temperature materialSmall perturbations of black hole Electrical and thermal transport properties (conductivity) Big Questions in Science, fall 2012. SdH, AUC 57
  58. 58.  Common element in all holographic dualities: “long” distances in one theory correspond to “short” distances in the other. Big Questions in Science, fall 2012. SdH, AUC 58
  59. 59. Long-distance cutoff UV cutoff Big Questions in Science, fall 2012. SdH, AUC 59
  60. 60.  Gravity seems equivalent with physics of conducting materials Also connections with hydrodynamics Big Questions in Science, fall 2012. SdH, AUC 60
  61. 61. Big Questions in Science, fall 2012. SdH, AUC 61
  62. 62. Big Questions in Science, fall 2012. SdH, AUC 62
  63. 63. Big Bang String Theory Cosmology AstronomyParticle PhysicsQuantum Mechanics Oceanography Chemistry Biology Geology Medicine Sheldon Glashow (1975) Big Questions in Science, fall 2012. SdH, AUC 63
  64. 64.  Contextual models with local overlaps and interaction within general framework. Unity: connection of distant areas (IR/UV). Important question: Fundamental variables? Answer may depend on physical context. Roger Penrose : Grand reductionism does not exclude (rather, necessitates) philosophy. Connection math, arts, ethics. Big Questions in Science, fall 2012. SdH, AUC 64

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