«Big Bang Cosmology, Quantum Tunneling from Nothing, and Creation William E. Carroll Laval théologique et philosophique, vol. 44, n° 1, 1988, p. ...»
"Big Bang Cosmology, Quantum Tunneling from Nothing, and Creation"
William E. Carroll
Laval théologique et philosophique, vol. 44, n° 1, 1988, p. 59-75.
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BIG BANG COSMOLOGY, QUANTUM
TUNNELING FROM NOTHING,
D'après certains physiciens, c'est l'effet tunnel quantique (quantum tunneling ) à partir de rien, concept utilisé pour rendre compte de l'émergence d'un vide de particules subatomiques, qui peut fournir une explication cohérente de la « création »
de l'univers à partir de « rien ». Dans l'examen de ce qui semble être les implications théologiques et philosophiques de la nouvelle physique, nous devons pourtant faire attention aux différents sens que peuvent avoir des expressions telles que «rien» et «origine de l'univers», ainsi qu'à la distinction entre création et changement. Ilfaut aussi se rappeler que la création est un concept métaphysique et théologique qui, comme tel, se trouve au delà du domaine des sciences naturelles.
SUM MA RY. — Recent work in Big Bang Cosmology employs insights from particle physics in an attempt to explain the Big Bang itself. Some physicists argue that the notion of "quantum tunneling from nothing, " which accounts for the emergence of subatomic particles from a vacuum, can provide a coherent explanation of the "creation" of the universe out of "nothing. "In examining the apparent theological and philosophical implications of the new physics, we must be careful to understand the different senses of "nothing" and "origin of the universe, "as well as the distinction between creation and change. Furthermore, creation is a metaphysical and a theological concept and, as such, is beyond the realm of the natural sciences.
" T HAD A VISION of a flash of universe appearing from nothing, appearing as a A result of the laws of physics. I felt a chill of awe and exhilaration like I have not felt before or since." The vision belongs to Professor Edward Tryon of the Department of WILLIAM E. CARROLL Physics and Astronomy, Hunter College of the City University of New York.1 In a 1973 issue of Nature, he writes : "In my model, I assume that our Universe did indeed appear from nowhere... Contrary to widespread belief, such an event need not have violated any of the conventional laws of physics." 2 The medieval alchemist who dreamed of changing base metals into gold seems sane in comparison to the contemporary physicist who speaks of getting everything from nothing.
How could such a "flash of universe" have appeared ? Quantum electrodynamics affirms that an electron, positron, and photon occasionally "emerge spontaneously" from a "perfect vacuum." And when this spontaneous generation occurs, "the three particles exist for a brief time, and then annihilate each other, leaving no trace behind." Such a spontaneous, temporary emergence of particles from a vacuum is called a "vacuum fluctuation," and is, according to Tryon, "utterly commonplace in quantum field theory." It seems that, as the authors of a 1979 article in the Scientific American observe, vacuums are full of all sorts of things called "virtual particles." 3
1. As quoted in The Globe and Mail (Toronto), 21 January 1985.
2. Nature, Vol. 246, 14 December 1973, p. 396.
3. Lewis P. FULCHER, Johann RAFFI.SKI, and Abraham KLEIN, "The Decay of the Vacuum," in Scientific American, December 1979, Vol. 241, No. 6, pp. 150-159. The authors use the term "virtual particles" to distinguish them from "real particles." To say that vacuums are full of "virtual particles" is a way to express a characteristic feature of the quantum mechanical explanation of "whatever is left in a region of space when it has been emptied of everything that can be removed by experimental means " When all such matter has been removed, the remaining space is not empty ; it remains "filled with electromagnetic radiation." See Timothy H. BOYER, "The Classical Vacuum," in Scientific American, August 1985, p. 70. Such fluctuating electromagnetic waves constitute an inherent feature of the vacuum, and to say that a vacuum is full of "virtual particles" is to affirm that from these fluctuating waves subatomic particles "pop" into existence.
In "Quantum Gravity" in Scientific American of December 1983 (pp. 112-129), Bryce DEWITT observes : "A true vacuum is defined as a state of thermal equilibrium at a temperature of absolute zero.
In quantum gravity such a vacuum can exist only if the curvature [of space] is independent of time.
When the curvature is time-dependent, particles can appear simultaneously in the vacuum (with the result, of course, that it is no longer a vacuum)... The particles generated by time-varying curvature appear randomly. It is not possible to predict in advance exactly where or when a given particle will be born. One can, however, calculate the statistical distribution of the particles'energy and momentum.
Particle production is greatest where the curvature is greatest and changing most rapidly. It was probably very large in the big bang and could have had a major effect on the dynamics of the universe in its earliest moments. It is not implausible that particles created in this way could account for all the matter in the universe ! Attempts to calculate big-bang particle production were begun... a decade ago...
Although several of the results are suggestive, none is definitive. Moreover, a major question hangs over the effort : What does one choose for the initial quantum state at the instant of the big bang ? Here the physicist must play God. None of the proposals made so far seems uniquely compelling. " (pp. 118Even DeWitt's "true vacuum" is quite different from the void, the existence of which, Aristotle and Aquinas would deny. DEWITT observes: "In classical physics flat, empty space-time is called the vacuum. The classical vacuum is featureless. In quantum physics a much more complex entity, with a rich structure, is given the name vacuum. Its structure arises from the existence in it of nonvanishing free fields, that is, fields far from their sources." (p. 115) Heinz R. PAGELS observes: "According to modern theory, a vacuum is not exactly nothing but is teeming with quantum particles that fluctuate between being and nothingness. These tiny particles can come into existence for a fraction of a second before they annihilate each other, leaving nothing behind.
A vacuum in that sense is like the surface of an ocean. Up close it is churning with waves, but from a longer distance such as from a jet plane, it appears smooth and placid. Similarly, any vacuum examined close up with the proper instruments is seen to be churning with tiny particles.""Before the Big Bang," Natural History, 92 (April 1983), p. 26.
BIG BANG COSMOLOGY
Tryon concluded : "If it is true that our Universe has a zero net value for all conserved quantities, then it may simply be a fluctuation of the vacuum, the vacuum of some larger space in which our Universe is imbedded. In answer to the question of why it happened, I offer the modest proposal that our Universe is simply one of those things which happens from time to time." 4 Or, as Professor Alan Guth of MIT remarked in 1983 : "It is often said that there is no such thing as a free lunch. The universe, however, is a free lunch." 5 What is important for the subject of this paper is not so much the accuracy of the details of these particular claims, but rather, what appear to be the philosophical and theological implications of the new physics.
We live in the aftermath of a giant explosion, or perhaps it might be more accurate to say that we live in the midst of a giant explosion : an explosion which commenced between 15 and 20 billion years ago, and from which our universe has been expanding ever since. Scientists dispute whether the forces generated in that cosmic Big Bang are so powerful that the universe will continue to expand until it dies a cold and lonely death, or whether the amount of stuff in the universe is sufficiently large so that eventually gravitational attraction will succeed first in stopping the expansion and then in reducing the universe to a small, hot cosmis mass. The destiny of the universe seems to be either ice or fire !
Most physicists refer to the Big Bang as a "singularity," that is, an ultimate boundary or edge, a "state of infinite density" where spacetime has ceased. Thus, it represents an outer limit of what we can know about the universe. Since all physical theories are formulated in the context of space and time, it would not be possible to speculate, at least in the natural sciences, about conditions "before" or "beyond" these categories.6 But it is precisely such speculation which has intrigued some contemporary The vacuum, according to quantum mechanics, is a system like any other system, and some cosmologists, arguing that every system will proceed toward a state of lowest possible energy, think that the energy in the universe at the moment of the Big Bang was less than the state before. In the words of Frank WILCZF.K : "Perhaps the reason that there is something instead of nothing is that nothing is unstable." Quoted in James TREFIL, The Moment of Creation (New York : Macmillan, 1983), pp. 205Nature, Vol. 246, op. cit., p. 397.
5. A. H. GUTH, "Speculations on the Origin of the Matter, Energy, and Entropy of the Universe," in Asymptotic Realms of Physics : A Festschrift in Honor of Francis Low, ed. by A. H. Guth, K. Huang, and R. L. Jaffe, (MIT Press, 1983), p. 215.
6. Paul DAVIES, God and the New Physics (New York: Simon and Schuster, 1983), pp. 18-19, p. 55.
Steven WEINBERG in The First Three Minutes (New York : Basic Books, 1977) and James TREFIL in The Moment of Creation, op. cit. are quick to point out the highly speculative nature of all theories about the very early existence of the universe. Davies, however, does remark that "a singularity is the nearest thing that science has found to a supernatural agent."(pp. 55-56) And he also notes that "an example of a singularity is the infinitely dense, infinitely compact state that marked the beginning of the big bang."
Davies would be advised to adopt what Roger Penrose and Stephen Hawking call the "principle of ignorance," that is, that "singularity is the ultimate unknowable, and therefore should be totally devoid of information." See: S. W. HAWKING, "Breakdown of a Predictability in Gravitational Collapse," Physical Review D, 14(1976), p. 2460. Penrose and Hawking, using elaborate mathematical arguments, contend that when gravity is strong enough singularities are unavoidable. This is the source of the view that the universe comes from a mathematical point. DAVIES observes : "These bizarre ideas [with respect to 'singularity'] can only be fully grasped by appeal to mathematics." (p. 19) There seems to be some confusion here between a mathematical and a physical analysis of the universe. And, as we shall see, even Trefil, despite his cautions, uses terms such as "nothing" and "creation" with inadequate precision. See footnote 12.
WILLIAM E. CARROLL
cosmologists who have offered refinements in Tryon's original proposal concerning a physical explanation of the universe's emergence from nothing. In a 1983 article Professor Alexander Vilenkin of Tufts University argues for "a new version of the inflationary scenario in which the Universe is spontaneously created from nothing[his italics]."7 Following on the work of Alan Guth — who is credited with the "inflationary model" of an expanding universe from a primal Big Bang — Vilenkin describes "the birth of the inflationary universe by quantum tunneling from nothing." 8 "Nothing," according to Vilenkin, is "a state with no classical space-time... the realm of unrestrained quantum gravity ; it is a rather bizarre state in which all our basic notions of space, time, energy, entropy, etc., lose their meaning." 9 Vilenkin, Guth, and others base their variation in the Big Bang theory on extrapolations from high energy physics. Today physicists describe our universe in terms of four fundamental forces [the strong, the weak, gravity, and the electromagnetic] and twelve elementary sub-atomic particles [six leptons and six quarks]. 10 These forces and particles are, however, "low temperature phenomena." As a result of evidence from background micro-wave radiation, physicists estimate the present temperature of the universe to be 2.7 degrees Kelvin (and getting colder). At the temperatures estimated at the time of the Big Bang itself, that is, temperatures around 1032 degrees Kelvin, all the forces of nature existed in a single, undifferentiated superforce, and all the now disparate sub-atomic particles had yet not acquired distinct identities. A fundamental transformation occurred in our very young universe, long before it was even one second old : in fact when it was about 10 ~35 second old. The rapid "supercooling" of the universe, a universe at the time but the size of a softball, produced a tremendous amount of energy, some of which condensed into matter.