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 19th
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 (3rd 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-20th 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?
