بسم الله الرحمن الرحيم
The Fine-Tuning of the Universe for Intelligent Life
By: Luke A. Barnes
إعداد: أ. مصطفى نصر قديح
[arXiv:1112.4647v2 [physics.hist-ph] 7 Jun 2012]
· هذا تلخيص لأحد أهم الأبحاث التي عثرت عليها وتتحدث عن الضبط الدقيق للكون، قام به الدكتور Luke A. Barnes وهو باحث ما بعد الدكتوراه في معهد سيدني لعلم الفلك في جامعة سيدني. ويعمل على علم الكونيات، تشكل المجرات، والضبط الدقيق للحياة.
· البحث يأخذ درجة امتياز في تحقيق المراد، فلم اختر البحث لاسم الكاتب نفسه أو لدرجته العلمية الكبيرة، ولكن للتوثيقات العالية في البحث وما فيه من نقولات هامة عن علماء كبار، البحث يلخص على الباحث عشرات الكتب التي يبتغي بها وجهته للحصول على اعترافات من العلماء بالضبط الدقيق في الكون، فأظنه قد حقق هذا بنجاح.
· من أجمل ما في البحث أن الباحث لم يتعرض لعقيدته النصرانية بالنفي أو الإثبات، هو فقط ركز على مسألة ضبط الكون بطريقة تتسبب في وجود حياة ذكية.
· البحث يقع فيما يقرب من 77 صفحة ويرد كذلك على كل حجج فيكتور ستينجر ويفندها بطريقة علمية رصينة.
· كما يرد البحث على القول بوجود أكوان متعددة ومدى صحة هذا الادعاء ومكانته العلمية.
· اهتممت في البحث بنقل الضبط الدقيق للكون ونقد الأكوان المتعددة ولم اتطرق إلى نقد حجج فيكتور ستينجر، وذلك لاحتياجي إليه في العمل على كتابي، لكني سأعود إليه في وقت لاحق ان شاء الله، واعمل على تنقيحه أكثر.
· من مميزات البحث أنه حديث نسبيا فهو يعود ل سنة2012. ويُعد أحد أحدث المقالات العلمية التي ترد على الملحد فيكتور ستينجر.
· هذا هو الملخص على عُجالة.
· The fine-tuning of the universe for intelligent life has received much attention in recent times. Beginning with the classic papers of Carter (1974) and Carr & Rees (1979), and the extensive discussion of Barrow & Tipler (1986), a number of authors have noticed that very small changes in the laws, parameters and initial conditions of physics would result in a universe unable to evolve and support intelligent life. [Luke A. Barnes: The Fine-Tuning of the Universe for Intelligent Life, University of Sydney, Australia, June 11, 2012. p2]
· FT is precise enough to distinguish itself from a number of other claims for which it is often mistaken. FT is not the claim that this universe is optimal for life, that it contains the maximum amount of life per unit volume or per baryon, that carbon-based life is the only possible type of life, or that the only kinds of universes that support life are minor variations on this universe. These claims, true or false, are simply beside the point. [Luke A. Barnes: The Fine-Tuning of the Universe for Intelligent Life, University of Sydney, Australia, June 11, 2012. P3]
· FT غير دقيقة بما فيه الكفاية لتميز نفسها عن عدد من المطالبات الأخرى من أجله غالبا ما تكون خاطئة. FT ليس الادعاء بأن هذا الكون هو الأمثل للحياة، وأنه يحتوي على أكبر قدر ممكن من الحياة لكل وحدة حجم أو لكل باريون، أن الحياة القائمة على الكربون هو النوع الوحيد الممكن للحياة، أو أن أنواع فقط من الأكوان التي تدعم الحياة هي اختلافات طفيفة في هذا الكون. هذه المطالبات، صحيحة أو خاطئة، هي ببساطة خارج عن الموضوع.
· The reason why FT is an interesting claim is that it makes the existence of life in this universe appear to be something remarkable, something in need of explanation. [Luke A. Barnes: The Fine-Tuning of the Universe for Intelligent Life, University of Sydney, Australia, June 11, 2012. P3]
· السبب FT هو ادعاء مثير للاهتمام هو أنه يجعل وجود الحياة في هذا الكون يبدو أن شيئا ملحوظا، وهو أمر بحاجة إلى تفسير.
· The intuition here is that if ours were the only universe, and if the causes that established the physics of our universe were indi
fferent to whether it would evolve life, then the chances of hitting upon a life-permitting universe are very small. As Leslie (Leslie J, Universes. Routledge, London,1989, pg. 121) notes, \[a] chief reason for thinking that something stands in special need of explanation is that we actually glimpse some tidy way in which it might be explained”. [Luke A. Barnes: The Fine-Tuning of the Universe for Intelligent Life, University of Sydney, Australia, June 11, 2012. P3]
· البديهة هنا هو أنه إذا كان لنا أن الكون الوحيد وإذا كانت الأسباب التي تثبت وفيزياء الكون ومؤشرات؟ fferent إلى ما إذا كان تطور الحياة، ثم فرص ضرب على الكون-السماح الحياة هي صغيرة جدا. كما ليزلي (1989، ص. 121) ويلاحظ، \ [أ] السبب الرئيسي للتفكير بأن شيئا يقف في حاجة خاصة من التفسير هو أننا في الواقع نلمح بعض الطريق مرتبة التي يمكن أن يفسر ذلك “.
· Consider the following tidy explanations:
· 1-This universe is one of a large number of variegated universes, produced by physical processes that randomly scan through (a subset of) the set of possible physics. Eventually, a universe will be created that is a member of the life-permitting set. Only such universes can be observed, since only such universes contain observers.
2-There exists a transcendent, personal creator of the universe. This entity desires to create a universe in which other minds will be able to form. Thus, the entity chooses from the set of possibilities a universe which is foreseen to evolve intelligent life. [Luke A. Barnes: The Fine-Tuning of the Universe for Intelligent Life, University of Sydney, Australia, June 11, 2012. P3]
· النظر في تفسيرات مرتبة التالية:
· 1- هذا الكون هو واحد من عدد كبير من الأكوان المتنوعة، التي تنتجها العمليات الفيزيائية التي تفحص بشكل عشوائي من خلال (مجموعة فرعية من) مجموعة الفيزياء ممكن. في نهاية المطاف، سيتم إنشاء الكون الذي هو عضو في مجموعة-السماح الحياة. فقط هذه الأكوان ويمكن ملاحظة، منذ فقط من هذه الأكوان تحتوي على المراقبين.
2-هناك وجود متعال، الشخصيه خالق الكون. يرغب هذا الكيان لخلق الكون الذي العقول الأخرى سوف تكون قادرة على تشكيل. وهكذا، اختار الكيان من مجموعة من الاحتمالات الكون الذي من المتوقع أن تتطور حياة ذكية.
· AP:If observers observe anything, they will observe conditions that permit the existence of observers. [Luke A. Barnes: The Fine-Tuning of the Universe for Intelligent Life, University of Sydney, Australia, June 11, 2012. P4]
· The anthropic principle is the best thought of as a selection eff
ect. Selection effect occur whenever we observe a non-random sample of an underlying population. Such effect are well known to astronomers. [Luke A. Barnes: The Fine-Tuning of the Universe for Intelligent Life, University of Sydney, Australia, June 11, 2012. P4]
· we know that our universe is in the life-permitting range. [Luke A. Barnes: The Fine-Tuning of the Universe for Intelligent Life, University of Sydney, Australia, June 11, 2012. P4]
· ونحن نعلم بأن كوننا هو في المدى الذي يسمح بالحياة.
· There are a great many scientists, of varying religious persuasions, who accept that the universe is fine-tuned for life, e.g. Barrow, Carr, Carter, Davies, Dawkins, Deutsch, Ellis, Greene, Guth, Harrison, Hawking, Linde, Page, Penrose, Polkinghorne, Rees, Sandage, Smolin, Susskind, Tegmark, Tipler, Vilenkin, Weinberg, Wheeler, Wilczek. [Luke A. Barnes: The Fine-Tuning of the Universe for Intelligent Life, University of Sydney, Australia, June 11, 2012. P7] ……… References: [Barrow J. D., Tipler F. J., 1986, The Anthropic Cosmological Principle. Oxford: Clarendon Press] [Carr B. J., Rees M. J., 1979, Nature, 278, 605] [Carter B., 1974, in IAU Symposium, Vol. 63, Confrontation of Cosmological Theories with Observational Data, Longair M. S., ed., D. Reidel, Dordrecht, pp. 291-298] [Davis, 2006, The Goldilocks Enigma: Why Is the Universe Just Right for Life? Allen Lane, London] [Dawkins, 2006, The God Delusion. Houghton Miin Harcourt, New York] [Redfern M., 2006, The Anthropic Universe. ABC Radio National,] [http://www.abc.net.au/rn/scienceshow/stories/2006/1572643.htm] [Ellis G. F. R., 1993, in The Anthropic Principle, Bertola F., Curi U., eds., pp. 27{32] [Greene B., 2011, The Hidden Reality: Parallel Universes and the Deep Laws of the Cosmos. Knopf, New York] [Guth, 2007, Journal of Physics A: Mathematical and Theoretical, 40, 6811] [|, 2003, Masks of the Universe, 2nd edn. Cambridge University Press] [Hawking S. W., Mlodinow L., 2010, The Grand Design. Bantam, p161] [Linde A., 2008, in Lecture Notes in Physics, Vol. 738, Inflationary Cosmology, Lemoine M., Martin J., Peter P., eds., Springer, Berlin, Heidelberg, 2011b, ArXiv e-prints: 1101.2444] [Penrose R., 2004, The Road to Reality: A Complete Guide to the Laws of the Universe. Vintage, London, p758] [Polkinghorne J. C., Beale N., 2009, Questions of Truth: Fifty-One Responses to Questions about God, Science, and Belief. Westminster John Knox Press, Louisville, Kentucky] [Rees M. J., 1999, Just Six Numbers: The Deep Forces that Shape the Universe. Basic Books, New York] [Smolin L., 2007, in Universe or Multiverse? Carr B., ed., Cambridge University Press] [Susskind L.,2005, The Cosmic Landscape: String Theory and the Illusion of Intelligent Design. Little, Brown and Company, New York] [Tegmark M., Aguirre A., Rees M. J., Wilczek F., 2006, Physical Review D, 73, 023505] [Vilenkin A.,2006, ArXiv e-prints: hep-th/0610051] [Weinberg S.,1994, Scientific American, 271, 44] [Wheeler J. A., 1996, At Home in the Universe. AIP Press, New York] [Carr B. J., ed., 2007, Universe or Multiverse? Cambridge University Press, Cambridge, UK]
The Laws of Nature
· “. . . [In previous sections] we have derived all of classical physics, including classical mechanics, Newton’s law of gravity, and Maxwell’s equations of electromagnetism, from just one simple principle: the models of physics cannot depend on the point of view of the observer. We have also seen that special and general relativity follow from the same principle, although Einstein’s specific model for general relativity depends on one or two additional assumptions. I have offered a glimpse at how quantum mechanics also arises from the same principle, although again a few other assumptions, such as the probability interpretation of the state vector, must be added. [The laws of nature] will be the same in any universe where no special point of view is present.” [Luke A. Barnes: The Fine-Tuning of the Universe for Intelligent Life, University of Sydney, Australia, June 11, 2012. P7] [V.Stenger: The Fallacy of Fine-Tuning: Why the Universe is Not Designed for Us, p 88, 91]
· when our models do not depend on a particular point or direction in space or a particular moment in time, then those models must necessarily contain the quantities linear momentum, angular momentum, and energy, all of which are conserved. Physicists have no choice in the matter, or else their models will be subjective, that is, will give uselessly different results for every different point of view. And so the conservation principles are not laws built into the universe or handed down by deity to govern the behavior of matter. They are principles governing the behavior of physicists.” [Luke A. Barnes: The Fine-Tuning of the Universe for Intelligent Life, University of Sydney, Australia, June 11, 2012. P7] [V.Stenger: The Fallacy of Fine-Tuning: Why the Universe is Not Designed for Us, p 82]
· What if the laws of nature were different? Stenger says: what about a universe with a different set of “laws”? There is not much we can say about such a universe, nor do we need to. Not knowing what any of their parameters are, no one can claim that they are fine-tuned.” .” [Luke A. Barnes: The Fine-Tuning of the Universe for Intelligent Life, University of Sydney, Australia, June 11, 2012. P18] [V.Stenger: The Fallacy of Fine-Tuning: Why the Universe is Not Designed for Us, p69]
Maxwell’s Laws
· A universe governed by Maxwell’s Laws all the way down” (i.e. with no quantum regime at small scales) will not have stable atoms – electrons radiate their kinetic energy and spiral rapidly into the nucleus – and hence no chemistry (Barrow J. D., Tipler F. J., 1986, The Anthropic Cosmological Principle. Oxford: Clarendon Press, pg. 303). We don’t need to know what the parameters are to know that life in such a universe is plausibly impossible. [Luke A. Barnes: The Fine-Tuning of the Universe for Intelligent Life, University of Sydney, Australia, June 11, 2012. P18]
electrons
· If electrons were bosons, rather than fermions, then they would not obey the Pauli exclusion principle. There would be no chemistry. [Luke A. Barnes: The Fine-Tuning of the Universe for Intelligent Life, University of Sydney, Australia, June 11, 2012. P18]
gravity
· If gravity were repulsive rather than attractive, then matter wouldn’t clump into complex structures. Remember: your density, thank gravity, is 1030 times greater than the average density of the universe. [Luke A. Barnes: The Fine-Tuning of the Universe for Intelligent Life, University of Sydney, Australia, June 11, 2012. P18]
the strong force
· If the strong force were a long rather than short-range force, then there would be no atoms. Any structures that formed would be uniform, spherical, undifferentiated lumps, of arbitrary size and incapable of complexity. [Luke A. Barnes: The Fine-Tuning of the Universe for Intelligent Life, University of Sydney, Australia, June 11, 2012. P18]
electromagnetism
· If, in electromagnetism, like charges attracted and opposites repelled, then there would be no atoms. As above, we would just have undifferentiated lumps of matter. [Luke A. Barnes: The Fine-Tuning of the Universe for Intelligent Life, University of Sydney, Australia, June 11, 2012. P18]
electromagnetic force
· The electromagnetic force allows matter to cool into galaxies, stars, and planets. Without such interactions, all matter would be like dark matter, which can only form into large, diffuse, roughly spherical haloes of matter whose only internal structure consists of smaller, diffuse, roughly spherical subhaloes. [Luke A. Barnes: The Fine-Tuning of the Universe for Intelligent Life, University of Sydney, Australia, June 11, 2012. P18]
· fine-tuning relies on a number of independent life-permitting criteria. Fail anyof these criteria, and life becomes dramatically less likely, if not impossible. [Luke A. Barnes: The Fine-Tuning of the Universe for Intelligent Life, University of Sydney, Australia, June 11, 2012. P20]
entropy
· The problem of the apparently low entropy of the universe is one of the oldest problems of cosmology. The fact that the entropy of the universe is not at its theoretical maximum, coupled with the fact that entropy cannot decrease, means that the universe must have started in a very special, low entropy state. Stenger replies as follows. [Bekenstein J. D., 1973, Physical Review D, 7, 2333] and [Hawking S. W., 1975, Communications in Mathematical Physics, 43, 199] showed that a black hole has an entropy equal to a quarter of its horizon area. [Luke A. Barnes: The Fine-Tuning of the Universe for Intelligent Life, University of Sydney, Australia, June 11, 2012. P23]
· the observable universe has entropy equal to a black hole of the same radius. In particular, if the universe starts out at the Planck time as a sphere of radius equal to the Planck length, then its entropy is as great as it could possibly be, equal to that of a Planck-sized black hole. [Luke A. Barnes: The Fine-Tuning of the Universe for Intelligent Life, University of Sydney, Australia, June 11, 2012. P24]
· the density of the universe at the Planck time must be tuned to 60 decimal places in order for the universe to be life-permitting. [Luke A. Barnes: The Fine-Tuning of the Universe for Intelligent Life, University of Sydney, Australia, June 11, 2012. P27]
Can Inflation Explain Fine-tuning?
· Inflation, to set up a life-permitting universe, must do the following:
1. There must be an inflation field. To make the expansion of the universe accelerate, there must exist a form of energy (a field) capable of satisfying the so-called Slow Roll Approximation (SRA), which is equivalent to requiring that the potential energy of the field is much greater than its kinetic energy, giving the field negative pressure.
2- Inflation must start. There must come a time in the history of the universe when the energy density of the inflation field dominates the total energy density of the universe, dictating its dynamics.
3- Inflation must last. While the inflation field controls the dynamics of the expansion of the universe, we need it to obey the slow roll conditions for a sufficiently long period of time. The “amount of inflation” is usually quantied by Ne, the number of e-folds of the size of the universe. To solve the horizon and flatness problems, this number must be greater than ~ 60.
4- Inflation must end. The dynamics of the expansion of the universe will (if it expands forever) eventually be dominated by the energy component with the most negative equation of state w = pressure / energy density. Matter has w = 0, radiation w = 1/3, and typically during inflation, the inflation field has w = -1. Thus, once inflation takes over, there must be some special reason for it to stop; otherwise, the universe would maintain its exponential expansion and no complex structure would form.
5- Inflation must end in the right way. Inflation will have exponentially diluted the mass-energy density of the universe – it is this feature that allows inflation to solve the monopole problem. Once we are done inflating the universe, we must reheat the universe, i.e. refill it with ordinary matter. We must also ensure that the post-inflation field doesn’t possess a large, negative potential energy, which would cause the universe to quickly recollapse.
6- Inflation must set up the right density perturbations. Inflation must result in a universe that is very homogeneous, but not perfectly homogeneous. Inhomogeneities will grow via gravitational instability to form cosmic structures. The level of inhomogeneity (Q) is subject to anthropic constraints. The question now is: which of these achievements come naturally to inflation, and which need some careful tuning of the inflationary dials? is a bare hypothesis – we know of no deeper reason why there should be an inflation field at all. It was hoped that the inflation field could be the Higgs field [Guth A. H., 1981, Physical Review D, 23, 347]. Alas, it wasn’t to be, and it appears that the inflation’s sole raison d’^etre is to cause the universe’s expansion to briefly accelerate. There is no direct evidence for the existence of the inflation field. [Luke A. Barnes: The Fine-Tuning of the Universe for Intelligent Life, University of Sydney, Australia, June 11, 2012. P27-28]
Stars
· Stars have two essential roles to play in the origin and evolution of intelligent life. They synthesise the elements needed by life – big bang nucleosynthesis provides only hydrogen, helium and lithium, which together can form just two chemical compounds (H2 and LiH). By comparison, Gingerich [Barrow J. D., Morris S. C., Freeland S. J., Harper, C. L. J., eds., 2008, Fitness of the Cosmos for Life: Biochemistry and Fine-Tuning. Cambridge University Press, pg. 23] notes that the carbon and hydrogen alone can be combined into around 2300 different chemical compounds. Stars also provide a long-lived, low-entropy source of energy for planetary life, as well as the gravity that holds planets in stable orbits. The low-entropy of the energy supplied by stars is crucial if life is to “evade the decay to equilibrium” [Schrodinger E., 1992, What Is Life? Cambridge University Press] [Luke A. Barnes: The Fine-Tuning of the Universe for Intelligent Life, University of Sydney, Australia, June 11, 2012. P39]
1-Stellar Stability
· Stars are defined by the forces that hold them in balance. The crushing force of gravity is held at bay by thermal and radiation pressure. The pressure is sourced by thermal reactions at the centre of the star, which balance the energy lost to radiation. Stars thus require a balance between two very different forces – gravity and the strong force – with the electromagnetic force (in the form of electron scattering opacity) providing the link between the two. [Luke A. Barnes: The Fine-Tuning of the Universe for Intelligent Life, University of Sydney, Australia, June 11, 2012. P39]
· There is a window of opportunity for stars – too small and they won’t be able to ignite and sustain nuclear fusion at their cores, being supported against gravity by degeneracy rather than thermal pressure; too large and radiation pressure will dominate over thermal pressure, allowing unstable pulsations. [Barrow J. D., Tipler F. J., 1986, The Anthropic Cosmological Principle. Oxford: Clarendon Press, pg. 332] [Luke A. Barnes: The Fine-Tuning of the Universe for Intelligent Life, University of Sydney, Australia, June 11, 2012. P39]
2- The Hoyle Resonance
· One of the most famous examples of fine-tuning is the Hoyle resonance in carbon. Hoyle reasoned that if such a resonance level did not exist at just the right place, then stars would be unable to produce the carbon required by life. [Luke A. Barnes: The Fine-Tuning of the Universe for Intelligent Life, University of Sydney, Australia, June 11, 2012. P40]
· Hoyle’s prediction is not an anthropic prediction”. As Smolin (2007) explains, the prediction can be formulated as follows: a.) Carbon is necessary for life. b.) There are substantial amounts of carbon in our universe. c.) If stars are to produce substantial amounts of carbon, then there must be a specific resonance level in carbon. d.) Thus, the specific resonance level in carbon exists. The conclusion does not depend in any way on the first, – anthropic” premise. The argument would work just as well if the element in question were the inert gas neon, for which the first premise is (probably) false. [Smolin L., 2007, in Universe or Multiverse?, Carr B., ed., Cambridge University Press] [Luke A. Barnes: The Fine-Tuning of the Universe for Intelligent Life, University of Sydney, Australia, June 11, 2012. P40]
· Ekstroom et al. (2010) considered changes to the Hoyle resonance in the context of Population III stars. These first-generation stars play an important role in the production of the elements needed by life. [Ekstroom S., Coc A., Descouvemont P., Meynet G., Olive K. A., Uzan J.-P., Vangioni E., 2010, Astronomy and Astrophysics, 514, A62 ] [Luke A. Barnes: The Fine-Tuning of the Universe for Intelligent Life, University of Sydney, Australia, June 11, 2012. P41]
· Even with a change of 0.4% in the strength of [nucleon-nucleon] force, carbon based life appears to be impossible since all the stars then would produce either almost solely carbon or oxygen, but could not produce both elements.” [Luke A. Barnes: The Fine-Tuning of the Universe for Intelligent Life, University of Sydney, Australia, June 11, 2012. P41]
· on the nucleon-nucleon force, and go further by translating these limits into limits on the fine-structure constant, α. A fractional change in
of one part in 105 would change the energy of the Hoyle resonance enough that stars would contain carbon or oxygen at the end of helium burning but not both. [Ekstroom S., Coc A., Descouvemont P., Meynet G., Olive K. A., Uzan J.-P., Vangioni E., 2010, Astronomy and Astrophysics, 514, A62] [Luke A. Barnes: The Fine-Tuning of the Universe for Intelligent Life, University of Sydney, Australia, June 11, 2012. P41]
· The ability of stars in our universe to produce both carbon and oxygen seems to be a rare talent. [Luke A. Barnes: The Fine-Tuning of the Universe for Intelligent Life, University of Sydney, Australia, June 11, 2012. P41]
Forces and Masses
·
· For hydrogen to exist – to power stars and form water and organic compounds – we must have me < mn – mp. Otherwise, the electron will be captured by the proton to form a neutron. [Damour T., Donoghue J. F., 2008, Physical Review D, 78, 014014] [Hogan C. J., 2006, Physical Review D, 74, 123514] [Luke A. Barnes: The Fine-Tuning of the Universe for Intelligent Life, University of Sydney, Australia, June 11, 2012. P42] Where: me = electron mass, mn = neutron mass and mp = proton mass.
· For stable atoms, we need the radius of the electron orbit to be significantly larger than the nuclear radius, which requires αβ/αs << 1 [Barrow J. D., Tipler F. J., 1986, The Anthropic Cosmological Principle. Oxford: Clarendon Press, pg. 320] [Luke A. Barnes: The Fine-Tuning of the Universe for Intelligent Life, University of Sydney, Australia, June 11, 2012. P42]. Where: α= Fine structure constant , β= electron mass / proton mass and αs = Strong force.
· We require that the typical energy of chemical reactions is much smaller than the typical energy of nuclear reactions. This ensures that the atomic constituents of chemical species maintain their identity in chemical reactions. This requires α2β/αs2<< 1 [Barrow J. D., Tipler F. J., 1986, The Anthropic Cosmological Principle. Oxford: Clarendon Press, pg. 320] [Luke A. Barnes: The Fine-Tuning of the Universe for Intelligent Life, University of Sydney, Australia, June 11, 2012. P42]..
· Tegmark et al. (2005)[Tegmark M., Vilenkin A., Pogosian L., 2005, Physical Review D, 71, 103523] studied anthropic constraints on the total mass of the three neutrino species. If ∑mυ≥ 1 eV then galaxy formation is significantly suppressed by free streaming. If ∑mυ is large enough that neutrinos are effectively another type of cold dark matter, then the baryon fraction in haloes would be very low, affecting baryonic disk and star formation. If all neutrinos are heavy, then neutrons would be stable and big bang nucleosynthesis would leave no hydrogen for stars and organic compounds. This study only varies one parameter, but its conclusions are found to be “rather robust” when ρΛ is also allowed to vary (Pogosian & Vilenkin, 2007)[Pogosian L., Vilenkin A., 2007, Journal of Cosmology and Astroparticle Physics, 2007, 025] . [Luke A. Barnes: The Fine-Tuning of the Universe for Intelligent Life, University of Sydney, Australia, June 11, 2012. P45].
· Leonard Susskind: [T]he up- and down-quarks are absurdly light. The fact that they are roughly twenty thousand times lighter than particles like the Z-boson . . . needs an explanation. The Standard Model has not provided one. Thus, we can ask what the world would be like is the up- and down-quarks were much heavier than they are. Once again – disaster [Leonard Susskind: The Cosmic Landscape: String Theory and the Illusion of Intelligent Design. Little, Brown and Company, New York, 2005, p176]. [Luke A. Barnes: The Fine-Tuning of the Universe for Intelligent Life, University of Sydney, Australia, June 11, 2012. P47].
· The problem is as follows. The mass of a fundamental particle in the standard model is set by two factors: mi = Γiv /√2, where i labels the particle species, Γi is called the Yukawa parameter (e.g. electron: Γe ≈ 2:9 x10–6, up quark: Γu ≈ 1.4 x 10–5, down quark: Γd ≈2.8 x 10-5), and v is the Higgs vacuum expectation value, which is the same for all particles see [Burgess C., Moore G., 2006, The Standard Model: A Primer. Cambridge University Press Cahn R., 1996, Reviews of Modern Physics, 68, 951][Luke A. Barnes: The Fine-Tuning of the Universe for Intelligent Life, University of Sydney, Australia, June 11, 2012. P48].
· Finally, suppose that the LHC discovers that supersymmetry is a (broken) symmetry of our universe. This would not be the discovery that the universe could not have been different. It would not be the discovery that the masses of the fundamental particles must be small. It would at most show that our universe has chosen a particularly elegant and beautiful way to be life-permitting. ][Luke A. Barnes: The Fine-Tuning of the Universe for Intelligent Life, University of Sydney, Australia, June 11, 2012. P48].
· Regarding the spectrum of fundamental particles, Cahn (1996) notes that if the couplings are fixed at high energy, then their value at low energy depends on the masses of particles only ever seen in particle accelerators. For example, changing the mass of the top quark affects the fine-structure constant and the mass of the proton (via ΛQCD). While the dependence on mt is not particularly dramatic, it would be interesting to quantify such anthropic limits within GUTs. [Cahn R., 1996, Reviews of Modern Physics, 68, 951] [Luke A. Barnes: The Fine-Tuning of the Universe for Intelligent Life, University of Sydney, Australia, June 11, 2012. P53].
· We conclude that anthropic reasoning seems to provide interesting limits on GUTs, though much work remains to be done in this area. [Luke A. Barnes: The Fine-Tuning of the Universe for Intelligent Life, University of Sydney, Australia, June 11, 2012. P54].
· The parameters of the standard model remain some of the best understood and most impressive cases of fine-tuning. [Luke A. Barnes: The Fine-Tuning of the Universe for Intelligent Life, University of Sydney, Australia, June 11, 2012. P54].
· We conclude that the universe is fine-tuned for the existence of life. Of all the ways that the laws of nature, constants of physics and initial conditions of the universe could have been, only a very small subset permits the existence of intelligent life. [Luke A. Barnes: The Fine-Tuning of the Universe for Intelligent Life, University of Sydney, Australia, June 11, 2012. P63].
· If the strong force were weaker, the periodic table would consist of only hydrogen. [Luke A. Barnes: The Fine-Tuning of the Universe for Intelligent Life, University of Sydney, Australia, June 11, 2012. P63].
· the expansion rate of the universe one second after the big bang must be fine-tuned to one part in 1016. ( Hawking: Brief History of Time. (1988)) notes that in inflation, if it happened, would explain why the expansion rate was so close to critical. [Luke A. Barnes: The Fine-Tuning of the Universe for Intelligent Life, University of Sydney, Australia, June 11, 2012. P65].
· It is the initial condition that needs to be fine-tuned, not the value today. No one is claiming that the expansion rate today is fine-tuned to 1016, much less that the age of the universe is fine-tuned. In fact, the age of the universe is part of the problem: as Hawking says, if Hi one second after the big bang were different by – one part in a hundred thousand million million”, the universe would have recollapsed before it reached 13.7 billion years old. [Luke A. Barnes: The Fine-Tuning of the Universe for Intelligent Life, University of Sydney, Australia, June 11, 2012. P65]. Note: Hi is the value of the Hubble parameter at the initial time.
· The universe, to the best of our knowledge, is electrically neutral. If the ratio of the number of protons to electrons in an astronomical body were different from unity by one part in α/αG ≈ 1037, then electrical repulsion would win out over gravitational attraction, and the body would not be stable. No body could be held together by gravity. [Luke A. Barnes: The Fine-Tuning of the Universe for Intelligent Life, University of Sydney, Australia, June 11, 2012. P67]
Multiverse
· Firstly, the difficulty in ruling out multiverses speaks to their unfalsifiability, rather than their steadfastness in the face of cosmological data. [Luke A. Barnes: The Fine-Tuning of the Universe for Intelligent Life, University of Sydney, Australia, June 11, 2012. P57].
· In contrast, we cannot observe any of the properties of a multiverse {M; f(m); π}, as they have no causal effect on our universe. We could be completely wrong about everything we believe about these other universes and no observation could correct us. The information is not here. The history of science has repeatedly taught us that experimental testing is not an optional extra. The hypothesis that a multiverse actually exists will always be untestable. The most optimistic scenario is where a physical theory, which has been well-tested in our universe, predicts a universe-generating mechanism. Even then, there would still be questions beyond the reach of observation, such as whether the necessary initial conditions for the generator hold in the metaspace, and whether there are modifications to the physical theory that arise at energy scales or on length scales relevant to the multiverse but beyond testing in our universe. Moreover, the process by which a new universe is spawned almost certainly cannot be observed. [Luke A. Barnes: The Fine-Tuning of the Universe for Intelligent Life, University of Sydney, Australia, June 11, 2012. P57].
· If the claim is that the laws of nature are fixed by logical and mathematical necessity, then this is demonstrably wrong | theoretical physicists find it rather easy to describe alternative universes that are free from logical contradiction (Davies, in Manson, 2003). [Manson N. A., ed., 2003, God and Design: The Teleological Argument and Modern Science. Routledge] [Luke A. Barnes: The Fine-Tuning of the Universe for Intelligent Life, University of Sydney, Australia, June 11, 2012. P63].
· Finally, it would be the ultimate anthropic coincidence if beauty and complexity in the mathematical principles of the fundamental theory of physics produced all the necessary low energy conditions for intelligent life. This point has been made by a number of authors, e.g. Carr & Rees (1979) and Aguirre (2005). [Luke A. Barnes: The Fine-Tuning of the Universe for Intelligent Life, University of Sydney, Australia, June 11, 2012. P64].
· \It is logically possible that parameters determined uniquely by abstract theoretical principles just happen to exhibit all the apparent fine-tunings required to produce, by a lucky coincidence, a universe containing complex structures. But that, I think, really strains credulity.” [Wilczek F: Physics Today (2006b), 59, 10] [Luke A. Barnes: The Fine-Tuning of the Universe for Intelligent Life, University of Sydney, Australia, June 11, 2012. P64].
[R. E. Davies and R, H. Koch, “All the Observed Universe Has Contributed to Life,” Philosophical Transactions of the Royal Society of London, Series B, 334 (1991), pp. 391-403.]
· At least 36 of the chemical elements are known to be necessary for the totality of terrestrial organisms; at least 27 of these are required for humans and l 7 for the microorganism, E. coli. [R. E. Davies and R, H. Koch, “All the Observed Universe Has Contributed to Life,” Philosophical Transactions of the Royal Society of London, Series B, 334 (1991), pp. 391-403.]
· the Sun is not a ‘second or third generation’ star but that about 3 x l09 supernovae were necessary to form the Solar System and our human chemistry. Further, virtually every star in the Milky Way Galaxy existing at or before about 8 x 109 years ago has made some material contribution to Earth and us. [R. E. Davies and R, H. Koch, “All the Observed Universe Has Contributed to Life,” Philosophical Transactions of the Royal Society of London, Series B, 334 (1991), pp. 391-403.]
· The elements phosphorous (P) and potassium (K ) are cosmically in shortest supply and the quantities of them necessary to make a human can only have come from a minimum average galactic volume of about 2 x 107 that of Sun. [R. E. Davies and R, H. Koch, “All the Observed Universe Has Contributed to Life,” Philosophical Transactions of the Royal Society of London, Series B, 334 (1991), pp. 391-403.]
· [R. E. Davies and R, H. Koch, “All the Observed Universe Has Contributed to Life,” Philosophical Transactions of the Royal Society of London, Series B, 334 (1991), pp. 391-403.]
J. D. Barrow: Fitness of the Cosmos for Life: Biochemistry and Fine-Tuning,
· Today, it is particularly striking to many scientists that cosmic constants, physical laws, biochemical pathways, and terrestrial conditions are just right for the emergence and flourishing of life. It is not surprising, of course, that, as life exists, the cosmic and chemical conditions for it had to have been formatted for such an emergence. It would be remarkable, however, if the format could have been otherwise, and hence not right for life. [J. D. Barrow : Fitness of the Cosmos for Life: Biochemistry and Fine-Tuning, Cambridge University Press. Cambridge University Press 2007. p31]
· During the universe’s history, it now seems that only a very restricted set of physical conditions operative at several major junctures of emergence could have opened the gateways to life. (Hogan, 2000). [J. D. Barrow : Fitness of the Cosmos for Life: Biochemistry and Fine-Tuning, Cambridge University Press. Cambridge University Press 2007. p31]
· Paul Dirac argued that even if this approach were to work for smaller numbers roughly of the order of unity, it could not possibly suffice for the very large dimensionless numbers that characterize cosmology (Dirac, 1937; see also Barrow, 2002, pp. 106–12). He had been struck by a coincidence between three such numbers, each an integral power of a very large number,N, of the order of 1040: (1) the ratio of the gravitational to the electric force is ∼N−1; (2) the ratio of the mass of the universe to the mass of the proton is ∼N2; and (3) the Hubble age of the universe in atomic units is ∼N. Dirac was convinced that the occurrence of N in these apparently unrelated cosmic features could not possibly be a coincidence. However, one of the three, the Hubble age, is a variable. Assuming the coincidence to be significant, the other two would therefore also have to be variables in order to maintain equality. The consequences would be that the numbers of protons and neutrons would have to increase over time, and the gravitational “constant” would have to decrease, both troubling implications for theory. Dirac focused on the latter of the two consequences, proposing that the gravitational factor should weaken over time. (Although he did not note this, such a revision would have the benefit of explaining the enormous value of N, the feature that had puzzled Dirac most. It would simply reflect the great age of the universe at this point.) [J. D. Barrow : Fitness of the Cosmos for Life: Biochemistry and Fine-Tuning, Cambridge University Press. Cambridge University Press 2007. P71]
· In many instances, even a small percentage change in the value of a single physical constant, holding the other constants unchanged, would yield a universe that is not hospitable to life. It became, indeed, a sort of parlor game among physicists to work out consequences of this sort. Some of their conclusions: If the electromagnetic force were to be even slightly stronger relative to the other fundamental forces, all stars would be red dwarfs, and planets would not form. Or if it were a little weaker, all stars would be very hot, and thus short-lived. Other thought experiments bore on the chemical constitution of the imagined universe: If the strong nuclear force were to be just a little stronger, all of the hydrogen in the early universe would have been converted into helium. If it were to be slightly weaker in percentage terms, helium would not have formed, leaving an all-hydrogen universe. If the weak nuclear force were to have been just a little weaker, supernovas would not have developed, and thus heavier elements would not have been created. And so on. [J. D. Barrow: Fitness of the Cosmos for Life: Biochemistry and Fine-Tuning, Cambridge University Press. Cambridge University Press 2007. pp74-75]
· As far back as 1953, Hoyle pointed to a striking “what if?” involving carbon (Hoyle, 1954). For carbon to form within stars from the fusion of beryllium and helium and for it not to convert too rapidly into oxygen, he predicted that the relevant nuclear resonance level would have to lie within a very narrow range of values (Dunbar et al., 1953a,b; Barrow and Tipler, 1986, pp. 252–4). Later experimental work confirmed this prediction, although there has been some debate recently about how “fine” that tuning actually is. Just as important is that the carbon not convert too rapidly into oxygen; here the resonance level in oxygen that would have led to rapid conversion is barely avoided.Were the values to be slightly different in either of the two cases, there would not be enough carbon to sustain the chemistry of life (Hoyle, 1965). [J. D. Barrow : Fitness of the Cosmos for Life: Biochemistry and Fine-Tuning, Cambridge University Press. Cambridge University Press 2007. P79]
· in the case of carbon, recent calculations seem to indicate that the fine-tuning first apparent in the chemistry of the various nuclei involved carries over to the level of basic physics: were the strong force to be greater by as little as 5 percent, or the electromagnetic force to be greater by perhaps 4 percent, the production of carbon and oxygen in the infant universe could have shut down. [J. D. Barrow : Fitness of the Cosmos for Life: Biochemistry and Fine-Tuning, Cambridge University Press. Cambridge University Press 2007. P80]
· Biological considerations play an indispensable role in all discussions of cosmic fine-tuning. But in this role they are not part of the fine-tuning claim itself. Typically, as we have seen, proponents of fine-tuning allege that an unexpected degree of constraint on some physical parameter or basic constant is necessary if some other physical condition is to be realizable in the universe. Then, in a separate argument, this latter condition is held to be necessary for the universe’s being open to the development of complex life. [J. D. Barrow: Fitness of the Cosmos for Life: Biochemistry and Fine-Tuning, Cambridge University Press. Cambridge University Press 2007. P80]
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