Davies, P. (1990) God and the new physics. London: Penguin. (Original 1983)

 

Davies, P. (1990) God and the new physics. London: Penguin. (Original 1983)

 

Preface.

·       1900 – 1925: the theory of relativity and quantum theory forced physicists to reform their view of reality fundamentally. They now refer to a ‘self-creating universe’ – a cosmos that erupts into existence spontaneously, much as a sub-nuclear particle sometimes appears spontaneously in certain high-energy processes.

·       This book’s foundations are ‘the Big 4 questions of existence’:

‘Why are the laws of nature what they are?

‘Why does the universe consist of the things it does?

‘Who did those things arise?

‘How did the universe achieve its organization?’ (p. viii)

 

1. Science and religion in a changing world

·     For most of human history, people have asked religions fundamental questions of existence (e.g. How was the universe created and how will it end? What is the origin of life and humanity?). Only in the last few centuries has science offered answers to them.

·     Physics is now accommodating ‘mind’ at a time when the life sciences are trying to abolish it. Physicists are rejecting strictly mechanical models of the universe in favour of a view that the mind plays an integral role in all physical events; while biologists – who once privileged the human mind in nature’s hierarchy - are moving towards the materialism characteristic of 19^th century physics.

 

2. Genesis

·     ‘This chapter deals with the origin of the universe as a whole.’ (p. 9) (!!)

·     Either the universe has always existed (in some form or another) or it began (in some way or another) at some particular moment.

·     Most contemporary cosmologists believe that the physical universe burst into existence in a ‘Big bang’ some 18 billion years ago. Most of the evidence is encompassed by ‘the most universal law of physics known – the second law of thermodynamics’ (p. 10); this is supplemented by the theories of gravity and of the expanding universe

·     The second law of thermodynamics

-      The universe is steadily becoming more disordered/chaotic/entropic (buildings fall down, landscape is eroded, natural resources depleted).

M. C.: Why are these processes of disorder/chaos/entropy?

-      Phenomena that apparently counter this law do so only if you fail to see the universe as a whole, where an increase of order in one area is always accompanied by a decrease in another. E.g. new buildings are erected … but only by depleting the total stock of energy and of material resources. ‘When a full balance sheet is drawn up, disorder always wins.’ (p. 10), i.e. entropy never decreases.

-      If a system is isolated from its surroundings, its entropy will increase remorselessly until it can increase no further – it will have reached thermodynamic equilibrium. It can be returned to its original state, but only by replacing the depleted energy and resources from another system … which will increase that system’s entropy accordingly.

-      If the universe has a finite stock of order and is moving irreversibly towards disorder (ultimately to thermodynamic equilibrium), then:

a) The universe will end eventually in complete thermodynamic equilibrium (aka ‘heat death’)

b) The universe did not always exist, or it would have reached its end-state (thermodynamic equilibrium) an infinite time ago.

E.g. the earth would have cooled down, the sun would have burnt out.

-      The creation of our solar system is but one event in a continuing process that has occurred hundreds of billions of times in the Milky Way alone, but this continuous ‘birth-life-death’ process isn’t infinite – the material of burnt-out stars can’t be recycled fully, some is lost to black holes and the energy of a star’s creation is dissipated as starlight over aeons.

·     Isaac Newton’s theory of gravity

-      Gravity is a universal force, acting between all material bodies in the universe – each star and each galaxy exerts a gravitational force on every other one.

-      Left to themselves, they would collapse together through gravity. At the sub-cosmos level, gravity is countered by centrifugal force (the planets revolve around the sun; the galaxy rotates); but there is no evidence that the cosmos as a whole rotates, so the present arrangement of the galaxies can’t have existed infinitely.

-      The conundrum has been known since Newton’s time, but wasn’t resolved until the 1920s by Hubble.

·     Edwin Hubble’s theory of the expanding universe

-       A moving light source can stretch or compress light waves emanating from it, just as a moving vehicle stretches the sound waves emanating from it – the Doppler effect.

-       The light from galaxies is distorted in colour – shifted to the red end of the spectrum – suggesting that its source is receding from us at many thousand of miles per second.

-       Distant galaxies are receding faster than closer ones, so the gaps between galaxies are expanding also – i.e. the universe is expanding.

-       Rather than the galaxies moving apart through space, each one’s gravitational pull stretches space, so the universe is expanding without having to expand into some space. (Einstein argued that gravity stretches time and space - the sun’s gravity bends starlight grazing its surface; clocks run faster in a gravity-free environment than on earth.)

·     The ‘big bang’

-       The ‘big bang’ created space (a physicist regards space as an elastic medium, rather than just an emptiness. ‘Nothing’ is ‘no space’, as well as no matter.) and time (as space stretches and shrinks, so does time).

-       Aristotle (3^rd century BC) rejected the idea that time was created, because it implied a first event without a cause. Most physicists reject a notion of time flowing or moving in favour of a notion of time as just ‘there’, like space.

-       ‘These bizarre ideas can only be fully grasped by appeal to mathematics. … By employing mathematics as a language, science can describe situations which are completely beyond the power of human beings to imagine. Indeed, most of modern physics falls into this category. Without the abstract description provided by mathematics, physics would never have progressed beyond simple mechanics. … In fact, it may be logically impossible for anyone to be able to correctly visualise certain physical systems, such as atoms, because they contain features that simply do not exist in the world of our experience.’ (p. 18)

-       In the mid-1960s, background cosmic radiation was discovered that is a relic of the big bang; and knowing the temperature of the present radiation, we can compute its value at any epoch (each time a part of the universe doubles in size, its temperature falls by half).

-       Contemporary physicists use particle accelerators to create high-energy collisions that simulate for an instant the conditions at a mere million-millionth of a second after the big bang (when the temperature was a million billion degrees). Consequently, they can model with confidence many of the physical processes (e.g. hydrogen nuclei fusing to form helium and some deuterium) that must have occurred after that first searing moment. (Models predict that the ratio of hydrogen to helium should be 1:3, which is close to the ratio in the contemporary cosmos – indicating that the basic ideas of the big bang are correct.)

·     The ‘solid state’ theory of the universe (Bondi, Gold & Hoyle)

-       The universe is infinite in age and the continual creation of new, low-entropy matter avoids thermodynamic ‘heat death’. Overall, the universe remains the same: as the universe expands and the density of existing matter is decreased, newly-created matter fills the gaps, maintaining a constant density; as galaxies are dispersed, new galaxies are created in the widening void. (In the ‘big bang’ model, the density of galaxies declines steady and the universe evolves in structure and arrangement.)

-       Advances in astronomy disproved any simple version of the theory; and the discovery of cosmic background radiation in 1965 finished it.

 

3. Did God create the universe?

·       Creating matter

-        Pre-20^th century, theologians and scientists believed that matter cannot be created (or destroyed) by natural means – only by god. Thus, scientists believed that the universe was eternal, thus avoiding the need for a creation.

-        In 1933, Carl Anderson created matter in the laboratory for the first time, building on theories by Einstein and Dirac. While studying the absorption by metal sheets of cosmic rays (high energy particles from space), he observed Dirac’s antielectron. (Dirac and Anderson shared a Nobel Prize for this prediction and discovery.)

-        Subsequently, the production of electrons and antielectrons (aka ‘positrons’) became common in a range of laboratory processes; and post-1945 the development of subatomic particle accelerators enabled the production of antiprotons and antineutrons. Today, positrons and antiprotons can be made in large quantities and stored; and ‘antimatter’ (antiparticles) is made routinely in physics laboratories.

·     Albert Einstein’s equation E = mc²

-        Expresses the idea that mass has energy and energy has mass. In a sense, mass is ‘locked up’ energy and if it is unlocked, mass will disappear amid a burst of energy. Conversely, if enough energy is concentrated in a spot, it will create matter.

-        The energy of a body’s motion ought to result in an increase in its mass (it appears heavier). At ordinary speeds, the effect is minute, because a little mass is equivalent to enormous amounts of energy; but modern particle accelerators can make electrons and protons travel close to the speed of light, where their masses have been seen to increase dozens of times.

-        Increasing mass increases the weight of existing matter – it doesn’t create matter.

·         Paul Dirac’s equation (not given here)

-        Attempted to reconcile Relativity Theory with Quantum Theory (concerned with the behaviour of atomic and sub-atomic matter):

‘A unified relativistic quantum theory is needed to describe subatomic particles moving at near the speed of light, such as occurs as a result of energetic radioactive emissions.’ (p. 27)

-        Its successful explanation of the behaviour of ordinary electrons implied the existence of ‘antielectrons’ – identical to electrons in mass and spin, but carrying a positive (not a negative) charge and reverse spin, i.e. a mirror image of electrons.

-        Dirac predicted that if enough energy could be concentrated, it would create an ‘antielectron’ where none existed before; and that it would be accompanied by an electron, so that electrical charge would be ‘conserved’ (sic). Thus, energy would create matter in the form of an electron-antielectron pair.

·         Creating matter in/through the ‘big bang’

-        Anderson’s and Dirac’s work suggested a natural (not ‘supernatural’) explanation of the origin of all matter: in the big bang, huge amounts of energy caused the incoherent production of vast amounts of matter and anti-matter which, when cooled sufficiently, cohered into stars and planets; and the universe should be a fifty-fifty mix of matter and anti-matter. BUT …

-        Observations disprove the expectations of a 50-50 mix; and anyway, only a trifling amount of anti-matter can exist in the universe without it exploding, because matter and anti-matter annihilate each other with a violent release of energy (the reverse of matter-creation). However …

-        While in the laboratory the creation of matter and antimatter is a symmetrical process, the conditions of the ‘big bang’ were so extreme that a slight excess of matter was created. The current levels of background cosmic radiation match very closely the level predicted by this explanation (and, therefore, we can extrapolate the temperatures of the moments in the ‘big bang’ when this excess of matter was created).

-        The processes described here do not represent the creation of matter out of nothing, but the conversion of pre-existing energy into matter. But whence the energy?