Table Of ContentEdward van den Heuvel
The Amazing
Unity of
the Universe
And Its Origin in the Big Bang
Second Edition
Astronomers’ Universe
Series Editor
Martin Beech
More information about this series at h ttp://www.springer.com/series/6960
Edward van den Heuvel
The Amazing Unity
of the Universe
And Its Origin in the Big Bang
Second Edition
Edward van den Heuvel
Astronomical Institute
University of Amsterdam
Amsterdam , The Netherlands
ISSN 1614-659X ISSN 2197-6651 (electronic)
Astronomers’ Universe
ISBN 978-3-319-23542-4 ISBN 978-3-319-23543-1 (eBook)
DOI 10.1007/978-3-319-23543-1
Library of Congress Control Number: 2016934059
© Springer International Publishing Switzerland 2016
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Original Dutch edition published by Veen Media, Amsterdam, 2012
Original Dutch title: Oerknal: Oorsprong van de eenheid van het heelal © 2012 by Edward van den
Heuvel & Veen Media, Amsterdam
Cover Image credit: Cover illustration: Star cluster Pismis 24 and the emission Nebula NGC 6357,
(c) NASA Hubble Space Telescope
Printed on acid-free paper
This Springer imprint is published by Springer Nature
The registered company is Springer International Publishing AG Switzerland
Pref ace
This book resulted from the amazing fact that human beings, with only some three
pounds of brain cells, on a small planet in an insignifi cant corner of the universe,
have been able to unravel in considerable detail how the universe is built and has
evolved with time, from a fraction of a second after its beginnings until the present.
This is possible thanks to the fact that the laws of physics that during the past
centuries were discovered here on Earth have been found to be valid throughout the
observable universe. Already in the eighteenth century, it was discovered that stars
in double-star systems orbit each other according to the laws of gravity and motion
discovered by Isaac Newton a century earlier for our solar system. It thus was found
that these laws are valid not only on Earth and for the motions of the planets but
equally well for stars at distances of hundreds of light-years. Subsequently, in the
past one-and-a-half century, spectroscopic analysis of the light of distant stars and
galaxies has shown that all stars—which in fact are ‘other suns’—and galaxies con-
sist of exactly the same chemical elements that we know here on Earth, from the
lightest, hydrogen, to the heaviest, uranium . Not more and not less. This discovery
means that matter and radiation behave exactly the same throughout the universe
and that the laws of quantum mechanics and relativity discovered by Einstein and
his successors are valid throughout the universe. This great unity of the universe,
and the universal validity of the physical laws that were discovered by laboratory
experiments on Earth, is the basis of the miraculous fact that we, as little human
beings, are able to study and understand the physical processes taking place through-
out the universe. This has enabled us to understand in large part how our cosmos and
the structures in it, from planets to stars and galaxies, are built and have developed
in the course of time.
The present thinking is—on good physical grounds—that the laws of physics
that govern everything that happens in the universe came into being during the fi rst
fraction of a second after the beginning of the Big Bang. The Big Bang, and the
many solid observational facts that show that this event has taken place, therefore
plays a central role in this book.
v
vi Preface
In the course of this story, we will encounter many facts that we already under-
stand, but also a number of important things that we do not understand, for example,
why does our universe have a fi nite age and is not infi nitely old? Although we do not
know the answers to such fundamental questions, scientists are presently speculat-
ing about the answers, and we will tell the story of such speculations and discuss the
likelihood of them being true or untrue.
The basis of this entire book is the fact that we humans with brains that in struc-
ture are not very different from those of our apelike ancestors of a few million years
ago have been able to understand in large part the physical processes that have
shaped the universe as we nowadays observe it—an absolute miracle by any account.
Acknowledgements I am particularly grateful to Professor Jaap Goudsblom and
Dr. Fred Spier of the University of Amsterdam who in the 1990s of the last century
took the initiative to organize the university-wide lecture course ‘Big History’ that
from its start every year has been followed by many hundreds of students. They
invited me to present in the fi rst 4 h of this course ‘the structure, origin and evolution
of the universe’, which I have done for a number of years, both in Amsterdam and
later also at Eindhoven’s Technical University. These lectures were my inspiration
for writing this book.
Further I would like to thank for inspiring conversations Vincent Icke, Michiel
van der Klis, my much too early deceased colleague Jan van Paradijs, Huib Henrichs,
John Heise, Rien van de Weygaert, Ralph Wijers, Tim de Zeeuw, Simon Portegies
Zwart, Sander Bais, Karel Gaemers , Robert Dijkgraaf, Johan Bleeker, Martin Rees,
Rashid Sunyaev, Jerry Ostriker, John Bahcall, Geoffrey Burbidge, David Gross,
Marty Einhorn, Jayant Narlikar, Naresh Dadhich, Ajit Kembhavi, Ganeshan
Srinivasan, Venkataraman Radhakrishnan, Dipankar Bhattacharya and last but not
least my teachers at Utrecht University Marcel Minnaert, Kees de Jager and Nico
van Kampen.
For their help in the production of the Dutch-language version of the book,
I thank very much Tom Kortbeek, Doortje Gorissen and Eddy Echternach. For their
help in producing the English-language version, I am most grateful to Esther de Wit
of Veen Publishers and Jennifer Satten, Nora Rawn and Gnanasekhar Harish of
Springer.
T he original version of this book was written in large part when I was guest of
the Kavli Institute for Theoretical Physics at the University of California, Santa
Barbara, and I am most grateful to the director and staff of the institute for their
hospitality.
I am grateful to Johan Bleeker, Rik Gheysens, Lidewijde Stolte and Rob van de
Water for suggestions for improvements for the several Dutch editions of the book,
which have been implemented here.
Amsterdam, The Netherlands Edward van den Heuvel
April 2016
Contents
1 Our Strange Universe ............................................................................. 1
2 The Sun’s Backyard: Our Solar System ............................................... 5
Sizes and Masses of the Planets ................................................................ 11
Distances in the Solar System ................................................................... 12
Chemical Composition of the Sun and Planets ......................................... 13
Why Earth Does Not Have a Cosmic Composition .................................. 14
Moons ....................................................................................................... 17
The Age of the Solar System .................................................................... 21
The Great Bombardment ........................................................................... 24
Possible Causes of the Late Heavy Asteroid Bombardment..................... 26
How did Earth Acquire Such a Large Moon? ........................................... 28
3 How Distant Are the Stars? .................................................................... 31
The Parallax Method ................................................................................. 33
The Distance to the Nearest Star as Compared to the Distance
to the Sun .................................................................................................. 43
Far Away = Long Ago................................................................................ 43
4 The Discovery of the Structure of Our Milky Way Galaxy ................ 47
The Work of William Herschell ................................................................ 48
The Work of Kapteyn ................................................................................ 51
“Fog” in the Milky Way System ............................................................... 54
Harlow Shapley and the System of Globular Star Clusters ...................... 55
Jan Oort Discovers the Motion of the Sun ................................................ 57
Radio Astronomy Shows Us the Entire Milky Way System ..................... 61
5 The Chemical Composition of the Sun and Stars ................................ 67
Kirchhoff and Bunsen’s Discovery ........................................................... 68
Formation of Spectral Lines: Quantum Jumps of Electrons in Atoms ..... 72
The Miraculous Unity of the Universe ..................................................... 76
The Chemical Composition of the Stars ................................................... 76
vii
viii Contents
6 Other Galaxies and the Discovery of the Expansion
of the Universe ......................................................................................... 79
Distances to Other Galaxies ...................................................................... 84
The Most Distant Galaxies ........................................................................ 88
The Expansion of the Universe ................................................................. 89
Is Our Galaxy at the Centre of the Universe? The Raisin- Bread
Model of an Expanding Universe ............................................................. 93
7 Gravity According to Galilei, Newton, Einstein and Mach................. 97
Introduction ............................................................................................... 97
The Weakest Force of Nature .................................................................... 100
Inertial Mass Versus Gravitational Mass .................................................. 102
Science is a Young Man’s Game ............................................................... 103
The Special Theory of Relativity .............................................................. 104
The Quantum Explanation of the Photoelectric Effect ............................. 105
Einstein’s General Theory of Relativity.................................................... 107
The Four Classical Predictions of General Relativity
and Their Experimental Confi rmation ...................................................... 109
Defl ection of Light by the Sun .............................................................. 110
The Motion of Mercury’s Perihelium ................................................... 111
The Gravitational Redshift of Light ...................................................... 112
A Fourth Classical Effect: The Shapiro Time Delay ............................ 113
Navigation with GPS ................................................................................ 114
The Origin of Inertia ................................................................................. 115
Can Newton’s Theory of Gravity now go into the Garbage Bin? ............. 116
8 Einstein, de Sitter, Friedmann, Lemaître and the Evolution
of the Universe ......................................................................................... 117
The Cosmological Principle ...................................................................... 118
De Sitter’s Discovery ................................................................................ 121
Friedman’s Solutions ................................................................................ 123
Einstein’s Reactions to Friedman’s Discoveries ....................................... 127
Einstein’s “Biggest Blunder” .................................................................... 128
Lemaître’s Hypothesis of the Big Bang .................................................... 128
The Origin of the Name Big Bang ............................................................ 131
The Hubble Time ...................................................................................... 132
The Cosmological Redshift ....................................................................... 133
Can Galaxies Move Away from us with Velocities Larger
than the Speed of Light? ........................................................................... 136
How Large is the Universe? ...................................................................... 136
9 The Big Bang as Origin of the Universe ................................................ 137
Radiation in the Early Universe ................................................................ 141
The Prediction of the Cosmic Microwave Background Radiation ........... 144
The Discovery of the Cosmic Microwave Background Radiation
from the Big Bang ..................................................................................... 146
Contents ix
Further Proofs of the Big Bang ................................................................. 150
The Abundances of Light Isotopes ....................................................... 150
The Evolution of Galaxies .................................................................... 150
Olbers’ Paradox: Why Is It Dark at Night?........................................... 158
Cosmology as a Real Science ................................................................... 158
10 The Origin of the Matter in the Universe ............................................. 161
Why Is There Matter in the Universe? ...................................................... 163
Brief Summary of the History of the Universe ......................................... 165
Planck Time, Planck Length and Planck Mass ......................................... 165
The Unifi cation of All Forces of Nature ................................................... 168
11 We Are Made of Stardust; Timescales of the Universe and of Life .... 171
Stellar Populations in Galaxies ................................................................. 172
Star Cluster Ages and the Cycle of Enrichment of the Gas
of Galaxies with Heavier Elements ........................................................... 176
Once More the Cosmic Timescale ............................................................ 180
The Development of Life on Earth ........................................................... 181
The Origin of the Eukaryotes .................................................................... 184
The Timescales of Earth and of the Universe ........................................... 185
12 Is the Universe Open, Closed or Flat? The Horizon Problem,
the Flatness Problem and Inflation ....................................................... 189
The Horizon Problem ................................................................................ 190
Infl ation ..................................................................................................... 193
The Flatness Problem ................................................................................ 194
13 Dark Matter and Dark Energy: Our Strange Universe ...................... 197
Gravitational Lenses ................................................................................. 199
What Is Dark Matter? ................................................................................ 199
Does Dark Matter Really Exist? ............................................................... 202
Dark Energy: From Greatest Blunder to a Genial Stroke ......................... 204
Vacuum Energy ......................................................................................... 211
The Perfect Free Lunch ............................................................................. 213
14 Ripples in the Cosmic Microwave Background Radiation.................. 215
Structure Formation in a Static Universe .................................................. 220
Structure Formation in an Expanding Universe ........................................ 221
The Cosmic Web: Further Confi rmations of the Existence
of Dark Matter and Energy ....................................................................... 223
15 Time in the Universe ............................................................................... 227
What Happened Before the Big Bang? ..................................................... 231
About the Direction of Time ..................................................................... 231
Universal Clocks of the Universe.............................................................. 234
