The Measure of the Universe: A History of Modern Cosmology

466 Pages·1965·23.633 MB·English

by  John David North

THE MEASURE OF THE UNIVERSE

THE MEASURE OF THE
UNIVERSE
A HISTORY OF MODERN COSMOLOGY
BY
J. D. NORTH
CLARENDON PRESS•OXFORD
1965
Oxford University Press, Amen House, London E.C.4
GLASGOW NEW YORK TORONTO MELBOURNE WELLINGTON
BOMBAY CALCUTTA MADRAS KARACHI LAHORE DACCA
CAPE TOWN SALISBURY NAIROBI IBADAN ACCRA
KUALA LUMPUR HONG KONG
© Oxford University Press 1965
PRINTED IN GREAT BRITAIN AT THE PITMAN PRESS, BATH
PREFACE
The main concern of this book is with the development of cosmology
dining the first half of this century. It is divided into two parts. The
first is a fairly straightforward historical and theoretical narrative. The
second is the sort of thing Lucretius might have had in mind when he
spoke of ‘the outer view of the inner law’: it is a discussion of con¬
ceptual problems which are to be found at various points in the first
part of the book.
Modern theories of cosmology were almost all prompted by theories
of gravitation, and such peripheral subjects as relativistic thermo¬
dynamics and theories of a unified field are here barely touched upon.
The methods of radio astronomy are to some extent ignored, falling
largely outside our period. It might appear inconsistent that Part I
begins with three chapters dealing briefly with some of the historical
antecedents of modern gravitational cosmology. On the other hand,
without such an excursion into earlier centuries, some of the curious
convolutions of later history would appear meaningless. Speaking
generally, it is the language of cosmology to which most attention is
paid. Not that I am unmindful of the overwhelming importance of the
methods of the observatory, but that they are simply not the prime
concern of this book.
It is surprising that no historical study of the sort has been attempted
before; for the subject abounds in controversies of a kind relevant to the
whole of physical science. Perhaps there is a general feeling that the
scientist’s intellectual arrogance has carried him too far in his pretend¬
ing to study the universe. (‘It’s a great deal bigger than I am’, as
Carlyle remarked, adding that ‘People ought to be modester’.) Perhaps
it is rather that scientific historians are reluctant to comment upon
matters which are almost as controversial today as thirty years ago.
Or perhaps it is that the body of cosmological writing is so very exten¬
sive, and its boundaries so ill-defined. At all events, if an apology for
the book is needed, it must simply be that the ‘great dust heap called
history’ will not be much the worse for a new kind of dust.
For assistance and criticism I owe a great deal to Professor G. Temple,
Dr. A. C. Crombie, Mr. H. R. Harre, Dr. G. J. Whitrow, and, not least,
my wife. I must thank not only them, but also those who, at the Claren¬
don Press and elsewhere, are taking so much care in producing this
volume. Lastly I must thank the Nuffield Foundation, whose award
59300
PREFACE
VI
of a Fellowship allowed me the time needed to complete this work,
which was written for the most part during my spare moments of the
past five years.
Oxford J’ -D-
October 1964.
CONTENTS
PREFACE v
ABBREVIATIONS xi
NOTATION xix
INTRODUCTION xxiii
Part I. ORIGINS OF MODERN COSMOLOGY
Chapter 1. NINETEENTH-CENTURY ASTRONOMY:
THE NEBULAE 3
1. The apparent structure of the Milky Way and the nebulae 3
2. The Island Universe theory established 10
Chapter 2. COSMOLOGICAL DIFFICULTIES WITH THE
NEWTONIAN THEORY OF GRAVITATION 16
1. Seeliger’s and Neumann’s objections to a Newtonian infinite 17
2. Charlier’s hierarchic hypothesis 13
Chapter 3. FIELD THEORIES AND THE WISH TO RE¬
PHRASE NEWTON’S THEORY OF GRAVITA¬
TION 24
1. Gravitation and the field concept 2 5
2. Gravitation and the hydrodynamical analogues 32
3. The Le Sage-Thomson explanation of gravitation 38
4. Reasons for wishing to revise the Newtonian theory. Reality and
the field theories 44
5. The attempts to amend Newton’s law 43
6. Gravitation and Lorentz invariance 49
Chapter 4. THE ORIGINS AND CONCEPTUAL B^4.SIS
OF EINSTEIN’S THEORY OF GRAVITATION 52
1. Gravitation and light. The Principle of Eqiiivalence 52
2. Relativity and covariance 5(5
3. The Riemannian framework and the calculus of tensors 58
4. Einstein and the concept of gravitational force 63
5. Einstein’s field equations
6. Observational tests ^
Chapter 5. EARLY RELATIVISTIC COSMOLOGi 70
1. Cosmological considerations ™
2. A closed universe. W. K. Clifford and others 72
3. The Einstein world
4. The cosmological constant 33
5. The de Sitter world and ‘Mach’s Principle’ 87
6. The de Sitter effect and Weyl’s Principle 92
7. Material content
8. The geometry of the de Sitter world 106
viii CONTENTS
Chapter 6. THE EXPANDING UNIVERSE: THE
FORMAL ELEMENT 110
1. The non-static line-element m
2. The work of Friedmann, Lemaitre, and Robertson 113
3. Eddington and the Lemaitre model 122
4. The stability of the Einstein world l25
1 9Q
5. Types of relativistic models
6. The relativistic models: further points of comparison. The expand-
1 31!
ing universe
Chapter 7. THE EXPANDING UNIVERSE: THE ASTRO¬
NOMER’S CONTRIBUTION 142
1. The A-term and Hubble’s Law 442
2. Minor revision of the recession factor 445
Chapter 8. KINEMATIC RELATIVITY AND THE
REVIVAL OF NEWTONIAN COSMOLOGY 149
1. The conceptual basis of Milne’s theories 149
2. Milne’s Cosmological Principle 156
3. The simple kinematic model. Milne on ‘gravitation
4. The development of Kinematic Relativity by Milne and Whitrow 165
5. The relatively stationary substratum 168
6. Milne on gravitation and galactic evolution 170
7. Kinematic and General Relativity 1^3
8. The neo-Newtonian cosmology of Milne and McCrea 176
9. Sources of criticism lg0
Chapter 9. THE THEORIES OF GRAVITATION OF
BIRKHOFF AND WHITEHEAD 186
1. Birkhoff’s theory of gravitation 186
2. Whitehead’s theory of gravitation and its extension by J. L.
Synge 199
3. The Rayner-Whitehead cosmology 194
Chapter 10. CONTINUAL CREATION AND THE STEAD! -
STATE THEORIES OF BONDI, GOLD, AND
HOYLE 198
1. Continual creation: some early arguments 198
2. Energy conservation. The Bondi-Gold theory 208
3. Hoyle’s steady-state theory and McCrea’s interpretation of it 212
4. Creation as a physical process 217
Chapter 11. THE RECEDING GALAXIES: APPEAR¬
ANCE AND REALITY, THEORY AND
OBSERVATION 223
1. The time-scale difficulty 223
2. The reality of the expansion. Alternative explanations of the red-
shifts 22 9
3. The decision: empirical considerations 234
CONTENTS IX
4. The theoretical (d,m) relation in relativistic cosmology, and the
Stebbins-Whitford effect 242
5. The theoretical (N,m) relation 245
6. The theoretical (N,6) relation 250
7. Other criteria 251
8. Cosmology and the formation of galaxies 255
Part II. PHILOSOPHICAL ISSUES
Chapter 12. ‘FACT’ AND THE ‘UNIVERSE’ 265
1. Basic objects 265
2. Fact 268
3. Objectivity and the uniqueness of the universe 271
Chapter 13. THE ELEMENT OF CONVENTION IN
COSMOLOGY AND SCIENCE 276
1. ‘Conventionalism’: an ambiguous term. Poincar6 and his critics 276
2. The Duhem-Quine thesis 285
Chapter 14. GENERALITY, SIMPLICITY, AND THE
COSMOLOGICAL PRINCIPLES 290
1. Simplicity 291
2. Generality 293
3. Deduction and extrapolation 296
4. Homogeneity and isotropy. The cosmological principles 300
5. Cosmological theories and models 311
Chapter 15. CONCEPTUAL PROBLEMS: (i) DISTANCE
AND COORDINATES 319
1. Distance, coordinates, and a possibly circular argument 320
2. Coordinates. Whitehead’s challenge of circularity 324
3. Concepts of distance. Operationalism 330
4. Which distance-concept is fundamental ? 337
Chapter 16. CONCEPTUAL PROBLEMS: (ii) ABSOLUTE
AND RELATIVE 349
1. Newton and Leibniz on ‘space’ 350
2. Absolute and universal time 355
3. Cosmic time and modern cosmology 357
4. The exaggerated philosophical involvement of theories of natural
cosmology 361
Chapter 17. CONCEPTUAL PROBLEMS: (iii) INFINITY
AND THE ACTUAL 371
1. The concept of a potential infinity and its inadequacy 372
2. Cantor’s transfinite cardinals 377
3. Infinities in cosmology 379