Farewell to Reality

by Jim Baggott

  4 Freeman Dyson, From Eros to Gaia, Pantheon, New York, 1992, p.306. Quoted in Farmelo, The Strangest Man, p.336.

  5 Feynman, p.188. This quote appears in the caption to Figure 76.

  6 Quoted in Kragh, Quantum Generations, p.204.

  7 Willis Lamb, Nobel Lectures, Physics 1942—1962, Elsevier, Amsterdam, 1964, p.286.

  8 Quoted by Kragh, Quantum Generations, as ‘physics folklore’, p.321.

  9 Nambu, p.180.

  10 Steven Weinberg, Nobel Lectures, Physics 1971—1980, edited by Stig Lundqvist, World Scientific, Singapore, 1992, p.548.

  11 Interview with Robert Crease and Charles Mann, 7 May 1985. Quoted in Crease and Mann, p.245.

  12 Our friends at the Particle Data Group list the mass of the W particles as 80.399±0.023 GeV, or 85.713 times the mass of a proton, and the mass of the Z0 as 91.1876±0.0021 GeV, or 97.215 times the mass of a proton.

  13 Rolf Heuer, ‘Latest update in the search for the Higgs boson’, CERN Seminar, 4 July 2012.

  14 The particle ‘consistent’ with the Higgs boson was found to have a mass around 125—6 GeV.

  15 CERN press release, 4 July 2012.

  16 Interview with Robert Crease and Charles Mann, 3 March 1983. Quoted in Crease and Mann, p.281.

  Chapter 4: Beautiful Beyond Comparison

  1 Letter to Heinrich Zangger, 26 November 1915. The colleague in question was German mathematician David Hilbert, who was in pursuit of the general theory of relativity independently of Einstein. See Isaacson.

  2 Isaac Newton, Mathematical Principles of Natural Philosophy, first American edition, translated by Andrew Motte, published by Daniel Adee, New York, 1845, p.81.

  3 Of course, this doesn’t mean that the flashlight is really ‘stationary’. The flashlight is spinning along with the earth’s rotation on its axis and moving around the sun at about 19 miles per second. The solar system is moving towards the constellation Hercules at about 12 miles per second and drifting upwards, above the plane of the Milky Way, at about 4 miles per second. The solar system is also rotating around the centre of the galaxy at about 124 miles per second. Add this together, and we get a speed of about 159 miles per second. This is the speed with which the earth is moving within our galaxy. Now if we consider the speed with which the galaxy moves through the universe …

  4 Albert Einstein, Annalen der Physik, 17 (1905), pp. 891—921. An English translation of this paper is reproduced in Stachel, pp. 123—60. This quote appears on p.124.

  5 The relationship can be worked out with the aid of a little high-school geometry. The time interval on the moving train is equal to the time interval on the stationary train divided by the factor , where v is the speed of the train and c is the speed of light. If v = 100,000 miles per second and c = 186,282 miles per second, then this factor has the value 0.844. This means that the time on the moving train is dilated by about 19 per cent. So, 24.1 billionths of a second becomes 28.6 of a second.

  6 Actually, this experiment is complicated by the fact that, when transported at an average 10 kilometres above sea level, an atomic clock actually runs faster because gravity is weaker at this height above the ground. In the experiment described here, this effect was expected to cause the travelling clock to gain 53 billionths of a second, offset by 16 billionths of a second due to time dilation. The net gain was predicted to be about 40 billionths of a second. The measured gain was found to be 39±2 billionths of a second.

  7 Again, the GPS system requires two kinds of corrections — the speed of the satellites causes a time dilation of seven thousandths of a second and the effects of weaker gravity at the orbiting distance of 20, 000 kilometres from the ground causes the atomic clocks to run faster by about 45 thousandths of a second. The net correction is therefore 38 thousandths of a second.

  8 The length of the train contracts by a factor where, once again, v is the speed of the train and c is the speed of light. If the train is moving at 100,000 miles per second and the speed of light is taken to be 186, 282 miles per second, then this factor is 0.844.

  9 Albert Einstein, Annalen der Physik, 18 (1905), pp. 639—41. An English translation of this paper is reproduced in Stachel, pp. 161—4. This quote appears on p.164.

  10 Poincaré’s paper is cited by Lev Okun, Physics Today, June 1989, p.13.

  11 See note 3 in Chapter 3, above. The full equation is E2 = p2c2 + m2c4, where p is the momentum of the object, m is its ‘rest mass’ and c is the speed of light. For massless photons with m = 0, the equation reduces to E2 = p2c2, or E = | p | c, where | p | represents the modulus (absolute value) of the momentum. Photons have no mass but they do carry momentum. You might be tempted to apply the classical non-relativistic expression for momentum — mass times velocity — and so conclude that for photons | p | = mc, so E = mc2 after all. But this is going around in circles. For photons m = 0, so we would be forced to conclude that photons have no momentum. What this means is that the non-relativistic expression for momentum does not apply to photons.

  12 The equation is M = m/ , where M represents the ‘relativistic mass’, m the ‘rest mass’, v is the speed of the object and c is the speed of light. This seems to suggest that a passenger with a rest mass of 60 kg travelling at 100, 000 miles per second would acquire a relativistic mass of about 71 kg. However, there are caveats — see text.

  13 Letter to Lincoln Barnett, 19 June 1948. A facsimile of part of this letter is reproduced, together with an English translation, in Lev Okun, Physics Today, June 1989, p.12.

  14 Hermann Minkowski, ‘Space and Time’, in Hendrik A. Lorentz, Albert Einstein, Hermann Minkowski and Hermann Weyl, The Principle of Relativity: A Collection of Original Memoirs on the Special and General Theory of Relativity, Dover, New York, 1952, p.75.

  15 Greene, The Fabric of the Cosmos, p.51.

  16 Newton, Mathematical Principles, op cit., p.506.

  17 Albert Einstein, ‘How I Created the Theory of Relativity’, lecture delivered at Kyoto University, 14 December 1922, translated by Yoshimasa A. Ono, Physics Today, August 1982, p.47.

  18 Wheeler, with Ford, p.235.

  19 In A. J. Knox, Martin J. Klein and Robert Schulmann (editors), The Collected Papers of Albert Einstein, Volume 6, The Berlin Years: Writings 1914—1917, Princeton University Press, 1996, p.153.

  Chapter 5: The (Mostly) Missing Universe

  1 Albert Einstein, Proceedings of the Prussian Academy of Sciences, 142 (1917). Quoted in Isaacson, p.255.

  2 This is commonly known as Olbers’ paradox, named for nineteenth-century German amateur astronomer Heinrich Wilhelm Olbers. If the universe were really static, eternal, homogeneous and infinite, then it is relatively straightforward to show that although distant stars are dimmer, the fact that there are many more of them should mean that their total brightness does not diminish with distance. Consequently, the night sky would be expected to be ablaze with starlight. Recent investigations suggest that history has been rather kind to Olbers, and that others, such as sixteenth-century English astronomer Thomas Digges, deserve rather more credit for articulating this paradox. See Edward Harrison, Darkness at Night: A Riddle of the Universe, Harvard University Press, 1987.

  3 Isaac Newton, Mathematical Principles of Natural Philosophy, first American edition, translated by Andrew Motte, published by Daniel Adee, New York, 1845, p.504.

  4 George Gamow, My World Line: An Informal Autobiography, Viking Press, New York, 1970, p.149. Quoted in Isaacson, pp. 355—6.

  5 Albert Einstein, Zeitschrift für Physik, 16 (1923), p.228

  6 Hubble’s law can be expressed as v = H0D, where v is the velocity of the galaxy, H0 is Hubble’s constant for a particular moment in time and D is the so-called ‘proper distance’ of the galaxy measured from the earth, such that the velocity is then given simply as the rate of change of this distance. Although it is often referred to as a ‘constant’, in truth the Hubble parameter H0 varies with time depending on assumptions regarding the rate of expansion of the universe. Despite this,
the age of the universe can be roughly estimated as 1/H0. A value of H0 of 70 kilometres per second per megaparsec (2.3 × 10-18 per second) gives an age for the universe of 43 × 1016 seconds, or 13.6 billion years.

  7 On submitting a paper describing their calculations to the journal Physical Review, Gamow added the name of fellow émigré physicist Hans Bethe to the list of authors. Bethe had not been involved in the work but Gamow, the author of the successful Mr Thompkins series of popular science books, had a reputation as a prankster. The possibilities afforded by a paper authored by Alpher, Bethe and Gamow had captured his imagination. Inevitably, it became known as the alpha-beta-gamma paper. The paper was published in 1948, on April Fool’s Day. Gamow had originally marked it to indicate that Bethe was author in absentia, but the journal editor had removed this note. Bethe (who, as it turned out, was asked to review the manuscript) didn’t mind. ‘I felt at the time that it was rather a nice joke, and that the paper had a chance to be correct, so that I did not mind my name being added to it.’ (Quoted by Ralph Alpher and Robert Herman, Physics Today, August 1988, p.28.) However, Alpher was not overly impressed. The subject of the paper was his doctoral dissertation. Both Gamow and Bethe were established physicists with international reputations. Anyone reading the paper would likely conclude that these more esteemed physicists had done all the work.

  8 Fred Hoyle, The Nature of the Universe, BBC Third Programme, 28 March 1949. A transcript of this broadcast was subsequently published in The Listener in April 1949. This quote is taken from Hoyle’s original manuscript, selected pages of which are available to view online at http://www.joh.cam.ac.uk/library/special_collections/hoyle/exhibition/radio/.

  9 Ralph Alpher and Robert Herman, Physics Today, August 1988, p.26.

  10 Quoted by Overbye, p.130.

  11 Quoted by David Wilkinson, ‘Measuring the Cosmic Microwave Background Radiation’, in P. James, E. Peebles, Lyman A. Page Jr and R. Bruce Partridge (eds.), Finding the Big Bang, Cambridge University Press, 2009, p.204.

  12 Quoted by Overbye, p.237.

  13 Guth, p.176.

  14 J. P. Ostriker and P. J. E. Peebles, Astrophysical Journal, 186 (1973), p.467.

  15 Quoted by Panek, p.240.

  Chapter 6: What’s Wrong with this Picture?

  1 Albert Einstein, ‘Induction and Deduction in Physics’, Berliner Tageblatt, 25 December 1919.

  2 Why ‘modulus square’? The modulus of a number is its absolute value (its value irrespective of its sign — positive or negative). We use the modulus-square instead of the square of the amplitude because the amplitude itself may be a complex number (containing i, the square root of -1) but, almost by definition, the probability derived from it must be a positive real number — it refers to something measurable in the real world. The modulus-square of a complex number is the number multiplied by its complex conjugate. For example, if the amplitude is 0.5i, the square of this is 0.5i × 0.5i = -0.25 (since i × i = -1), which suggests a negative probability of -25%. However, the modulus-square is 0.5i × 0.5(-i) = +0.25 (since i × i = 1), suggesting a positive probability of 25%.

  3 Letter to Albert Einstein, 19 August 1935. Quoted in Fine, pp. 82—3.

  4 John Bell, Physics World, 3 (1990), p.34.

  5 In Davies and Brown, p.52.

  6 Albert Einstein, ‘On the method of Theoretical Physics’, Herbert Spencer Lecture, Oxford, 10 June 1933.

  7 Lederman, p.363.

  8 The Planck scale is a mass-energy scale with a magnitude around 1019 GeV, where the quantum effects of gravity are presumed to be strong. It is characterized by measures of mass, length and time that are calculated from three fundamental constants of nature: the gravitational constant, G, Planck’s constant ħ divided by 2π, written h(pronounced ‘h-bar’) and the speed of light, c. The Planck mass is given by and has a value around 1.2 x_ 1019 GeV, or 1.2 × 1028 electron volts. The Planck length is given by and has a value around 1.6x10-35 metres. The Planck time is given by (the Planck length divided by c), and has a value around 5 × 1044 seconds.

  9 John Irving, A Prayer for Owen Meany, Black Swan, 1990, pp. 468—9.

  10 Albert Einstein, Preussische Akademie der Wissenschaften (Berlin) Sitzungsberichte, 1916, p.688. Quoted in Gennady E. Gorelik and Viktor Ya. Frenkel, Matvei Petrovich Bronstein and Soviet Theoretical Physics in the Thirties, Birkhauser, Verlag, Basel, 1994, p.86.

  Chapter 7: Thy Fearful Symmetry

  1 Letter to Hans Reichenbach, 30 June 1920.

  2 For the incurably curious, U(l) is the unitary group of transformations of one complex variable.

  3 SU(2) and SU(3) are special unitary groups of transformations of two and three complex variables, respectively.

  4 Interview with Robert Crease and Charles Mann, 29 January 1985. Quoted in Crease and Mann, p.400.

  5 Stephen P. Martin, ‘A Supersymmetry Primer’, version 6, arXiv: hepph/9709356, September 2011, p.5.

  6 Kane, pp. 53, 63.

  7 Martin, ‘A Supersymmetry Primer’, op cit., p.5.

  8 Woit, pp. 173—4.

  9 Kane, p.67.

  10 Randall, Warped Passages, p.269.

  Chapter 8: In the Cemetery of Disappointed Hopes

  1 Letter to Heinrich Zangger, 27 February 1938.

  2 Letter to Theodor Kaluza, 21 April 1919. Quoted in Pais, Subtle is the Lord, p.330.

  3 Letter to Paul Ehrenfest, 3 September 1926. Quoted in ibid., p.333.

  4 Leonard Susskind, The Landscape: A Talk with Leonard Susskind, www.edge.org., April 2003.

  5 Interview with Sara Lippincott, 21 and 26 July 2000, Oral History Project, California Institute of Technology Archives, 2002, p.17.

  6 Interview with Sara Lippincott, 21 and 26 July, 2000, ibid., p.26.

  7 Woit, pp. 173—4.

  8 Interview with Shing-Tung Yau, 7 February 2007. Quoted in Yau and Nadis, pp. 131—2.

  9 Michael Duff, ‘A Layman’s Guide to M-theory’, arXiv: hep-th/9805177v3, 2 July 1998.

  10 Kragh, Higher Speculations, p.303.

  11 Quoted by Randall, Warped Passages, p.304.

  12 Veltman, p.308.

  13 Sheldon Glashow and Ben Bova, Interactions: A Journey Through the Mind of a Particle Physicist, Warner Books, New York, 1988, p.25.

  14 Gordon Kane, ‘String Theory and the Real World’, Physics Today, November 2010, p.40.

  15 Yau and Nadis, pp. 224—5.

  16 In P. C. W. Davies and Julian Brown, eds., Superstrings: A Theory of Everything, Cambridge University Press, 1988, p.194.

  17 Randall, Warped Passages, jacket copy.

  18 Greene, The Fabric of the Cosmos, jacket copy.

  19 Hawking and Mlodinow, p.181.

  20 Quoted by John Matson, Scientific American, 9 March 2011.

  Chapter 9: Gardeners of the Cosmic Landscape

  1 Albert Einstein, ‘On the Generalised Theory of Gravitation’, Scientific American, April 1950, p.182.

  2 ‘Have you noticed that Bohm believes (as de Broglie did, by the way, 25 years ago) that he is able to interpret the quantum theory in deterministic terms? That way seems too cheap to me.’ Letter to Max Born, 1952. Quoted in John S. Bell, Proceedings of the Symposium on Frontier Problems in High Energy Physics, Pisa, June 1976, pp. 33—45. This paper is reproduced in Bell, pp. 81—92. The quote appears on p.91.

  3 H. D. Zeh, Foundations of Physics, 1 (1970), pp. 69—76.

  4 These estimates are taken from Roland Omnès, The Interpretation of Quantum Mechanics, Princeton University Press, 1994. The original calculations were reported in E. Joos and H. D. Zeh, Zeitschrift für Physik, B59 (1985), pp. 223—43.

  5 John S. Bell, ‘Against Measurement’, Physics World, 3 (1990), p.33.

  6 Max Tegmark, ‘What is Reality?’, BBC Horizon, 17 January 2011.

  7 Peter Byrne, ‘Everett and Wheeler: The Untold Story’, in Saunders et al., p.523.

  8 Quoted by Peter Byrne, in Saunders, et al., p.539.

  9 Max Tegmark, ‘The Interpretation of Quantum Mechanics: Many W
orlds or Many Words?’, arXiv: quant-ph/9709032 v1, 15 September 1997, p.1.

  10 Adrian Kent, ‘One World Versus Many: The Inadequacy of Everettian Accounts of Evolution, Probability and Scientific Confirmation’, in Saunders, et al., p.309.

  11 Greene, The Hidden Reality, p.344.

  12 Andrei Linde, ‘The Self-reproducing Inflationary Universe’, Scientific American, November 1994, pp. 51—2.

  13 Raphael Bousso and Leonard Susskind, ‘The Multiverse Interpretation of Quantum Mechanics’, arXiv: hep-th/1105, 3796v1, 19 May 2011, p.2.

  14 Alan H. Guth, ‘Eternal Inflation and its Implications’, arXiv: hepth/0702178v1, 22 February 2007, pp. 9—10.

  15 Greene, The Hidden Reality, p.91.

  16 Ibid., p.155.

  17 Susskind, The Cosmic Landscape, p.381.

  18 Justin Khoury, Burt A. Ovrut, Paul J. Steinhardt and Neil Turok, ‘The Ekpyrotic Universe: Colliding Branes and the Origin of the Hot Big Bang’, arXiv: hep-th/0103239v3, 15 August 2001, pp. 3—4. Published in Physical Review D, 64, 123522 (2001).

  19 Jean-Luc Lehners, Paul J. Steinhardt and Neil Turok, ‘The Return of the Phoenix Universe’, arXiv: hep-th/0910.0834v1, 5 October 2009, p.4.

  20 Robert Adler, ‘The Many Faces of the Multiverse’, New Scientist, 26 November 2011, pp. 43 and 47.

  21 Greene, The Hidden Reality, p.188.

  Chapter 10: Source Code of the Cosmos

  1 Albert Einstein, ‘Motives for Research’, speech delivered at Max Planck’s sixtieth birthday celebration, April 1918.

  2 This was the title of Wigner’s Richard Courant lecture in mathematical sciences delivered at New York University on 11 May 1959. It was published in Communications on Pure and Applied Mathematics, 13 (1960), pp. 1—14.

  3 Max Tegmark, ‘The Mathematical Universe’, Foundations of Physics, 38 (2008), p.101: arXiv: gr-qc/0704.0646v2, 8 October 2007, p.l.

  4 Interview with Adam Frank: ‘Is the Universe Actually Made of Math?’, Discover, July 2008, published online 16 June 2008: http://discovermagazine.com/2008/jul/16-is-the-universe-actually-made-of-math.