Updated edition of a popular introduction to cosmology, now with new observational data, supporting web material, and problems with solutions
An Introduction to Modern Cosmology is an accessible account of modern cosmological ideas that enables readers to understand cosmology without resorting to the mathematical apparatus of general relativity. This fully revised Fourth Edition of the bestseller takes an approach which is grounded in physics with a logical flow of chapters, leading the reader from basic ideas of the expansion described by the Friedman equations to some of the more advanced ideas about the early universe.
The Advanced Topic sections present subjects with more detailed mathematical approaches to give greater depth to discussions. Student problems with hints for solving them and numerical answers are embedded in the chapters to facilitate the readers' understanding and learning.
The new edition contains updated observational data, more detailed explanations and examples of the central-to-cosmology Friedman equations, and references to extensive online supporting material. It also incorporates up-to-date results from the Planck mission, which imaged the anisotropies of cosmic microwave background radiation over the whole sky.
Sample topics explored in An Introduction to Modern Cosmology include:
- The geometry of the universe, covering flat, spherical, and hyperbolic geometry, infinite and observable universes, and the three values of k
- Simple cosmological models, covering Hubble's law, expansion and redshift, particle number densities, and evolution including curvature
- The density of the universe and dark matter, covering galaxy cluster composition and brightness of the supernovae
- The origin of light elements in the universe, covering hydrogen and helium, problems with the Hot Big Bang, and flatness and horizon problems
Written in a clear, concise format with short, accessible chapters, An Introduction to Modern Cosmology is an essential textbook resource on the subject for advanced undergraduate and graduate students of astronomy, astrophysics, and physics.
Preface xi
About the Companion Website xv
1 A Brief History of Cosmological Ideas 1
2 Observational Overview 3
2.1 In visible light 4
2.2 In other wavebands 8
2.3 Homogeneity and isotropy 11
2.4 The expansion of the Universe 11
2.5 Particles in the Universe 14
3 Newtonian Gravity 21
3.1 The Friedmann equation 22
3.2 On the meaning of the expansion 25
3.3 Things that go faster than light 25
3.4 The fluid equation 26
3.5 The acceleration equation 27
3.6 On mass, energy, and vanishing factors of c2 28
4 The Geometry of the Universe 31
4.1 Flat geometry 31
4.2 Spherical geometry 32
4.3 Hyperbolic geometry 35
4.4 Infinite and observable universes 36
4.5 Where did the Big Bang happen? 36
4.6 Three values of k 37
5 Simple Cosmological Models 39
5.1 Hubble's law 39
5.2 Expansion and redshift 40
5.3 Solving the equations 41
5.4 Particle number densities 46
5.5 Evolution including curvature 47
6 Observational Parameters 51
6.1 The expansion rate H0 51
6.2 The density parameter 0 53
6.3 The deceleration parameter q0 55
7 The Cosmological Constant 57
7.1 Introducing 57
7.2 Fluid description of 58
7.3 Cosmological models with 60
8 The Age of the Universe 63
9 The Density of the Universe and Dark Matter 69
9.1 Weighing the Universe 69
9.2 What might the dark matter be? 76
9.3 Dark matter searches 78
10 The Cosmic Microwave Background 81
10.1 Properties of the microwave background 81
10.2 The photon to baryon ratio 83
10.3 The origin of the microwave background 84
10.4 The origin of the microwave background (optional advanced treatment) 87
11 The Early Universe 91
12 Nucleosynthesis: The Origin of the Light Elements 99
12.1 Hydrogen and helium 100
12.2 Comparing with observations 103
12.3 Contrasting decoupling and nucleosynthesis 105
13 The Inflationary Universe 107
13.1 Problems with the Hot Big Bang 107
13.2 Inflationary expansion 111
13.3 Solving the Big Bang problems 113
13.4 How much inflation? 115
13.5 Inflation and particle physics 116
14 The Initial Singularity 121
15 Overview: The Standard Cosmological Model 125
15.1 Expansion 126
15.2 Geometry 126
15.3 Age 126
15.4 Fate 126
15.5 Contents 127
15.6 Early history 128
15.7 Outlook 128
Advanced Topic 1 General Relativistic Cosmology 129
A1.1 The metric of spacetime 129
A1.2 The Einstein equations 131
A1.3 Aside: Topology of the Universe 132
Advanced Topic 2 Classic Cosmology: Distances and Luminosities 135
A2.1 Light propagation and redshift 135
A2.2 The observable Universe 138
A2.3 Luminosity distance 138
A2.4 Angular diameter distance 143
A2.5 Source counts 145
Advanced Topic 3 Neutrino Cosmology 149
A3.1 The massless case 149
A3.2 Massive neutrinos 151
A3.3 Neutrinos and structure formation 153
Advanced Topic 4 Baryogenesis 157
Advanced Topic 5 Structures in the Universe 161
A5.1 The observed structures 161
A5.2 Gravitational instability 163
A5.3 The clustering of galaxies 165
A5.4 Cosmic microwave background anisotropies 167
A5.5 The origin of structure 173
Advanced Topic 6 Constraining Cosmological Models 177
A6.1 Cosmological models and parameters 177
A6.2 Key cosmological observations 178
A6.3 Cosmological data analysis 179
A6.4 The Standard Cosmological Model: 2025 edition 181
A6.5 Tensions and hints of new physics 184
A6.6 The future 185
Bibliography 187
Numerical Answers and Hints to Problems 191
Index 197
Marina Cortês is Research Faculty at the Institute of Astrophysics and Space Science of the University of Lisbon, Portugal. She previously held positions at Lawrence Berkeley National Laboratory in the United States, Perimeter Institute for Theoretical Physics in Canada, and the Royal Observatory of Edinburgh in the United Kingdom. Her research spans observational and theoretical cosmology, including work on large-scale surveys such as SDSS-IIIs BOSS and DESI, and on fundamental questions about the nature of time and the Universe. She won the inaugural Buchalter Cosmology Prize in 2014.
Andrew Liddle is Research Faculty at the Institute of Astrophysics and Space Science of the University of Lisbon, Portugal. He held previous positions as Professor at the Universities of Edinburgh and Sussex, United Kingdom, where he was also Head of Faculty. He is interested in understanding the properties of the Universe and is best known for his work on cosmological models, in particular early Universe inflation.
