Astronomers have determined that our universe is 13.7 billion years old. How exactly did they come to this precise conclusion? How Old Is the Universe? tells the incredible story of how astronomers solved one of the most compelling mysteries in science and, along the way, introduces readers to fundamental concepts and cutting-edge advances in modern astronomy.
The age of our universe poses a deceptively simple question, and its answer carries profound implications for science, religion, and philosophy. David Weintraub traces the centuries-old quest by astronomers to fathom the secrets of the nighttime sky. Describing the achievements of the visionaries whose discoveries collectively unveiled a fundamental mystery, he shows how many independent lines of inquiry and much painstakingly gathered evidence, when fitted together like pieces in a cosmic puzzle, led to the long-sought answer. Astronomers don't believe the universe is 13.7 billion years old – they know it. You will too after reading this book. By focusing on one of the most crucial questions about the universe and challenging readers to understand the answer, Weintraub familiarizes readers with the ideas and phenomena at the heart of modern astronomy, including red giants and white dwarfs, cepheid variable stars and supernovae, clusters of galaxies, gravitational lensing, dark matter, dark energy and the accelerating universe – and much more. Offering a unique historical approach to astronomy, How Old Is the Universe? sheds light on the inner workings of scientific inquiry and reveals how astronomers grapple with deep questions about the physical nature of our universe.
Chapter 1 Introduction: 13.7 Billion Years 1
PART I. The Age of Objects in Our Solar System
Chapter 2 4004 bce 9
Chapter 3 Moon Rocks and Meteorites 16
Chapter 4 Defying Gravity 27
PART II. The Ages of the Oldest Stars
Chapter 5 Stepping Out 43
Chapter 6 Distances and Light 55
Chapter 7 All Stars Are Not the Same 61
Chapter 8 Giant and Dwarf Stars 78
Chapter 9 Reading a Hertzsprung-Russell (H-R) Diagram 94
Chapter 10 Mass 101
Chapter 11 Star Clusters 111
Chapter 12 Mass Matters 126
Chapter 13 White Dwarfs and the Age of the Universe 133
Chapter 14 Ages of Globular Clusters and the Age of the Universe 159
PART III. The Age of the Universe
Chapter 15 Cepheids 175
Chapter 16 An Irregular System of Globular Clusters 191
Chapter 17 The Milky Way Demoted 202
Chapter 18 The Trouble with Gravity 209
Chapter 19 The Expanding Universe 217
Chapter 20 The Hubble Age of the Universe 235
Chapter 21 The Accelerating Universe 245
Chapter 22 Dark Matter 261
Chapter 23 Exotic Dark Matter 282
Chapter 24 Hot Stuff 301
Chapter 25 Two Kinds of Trouble 319
Chapter 26 The WMAP Map of the CMB and the Age of the Universe 333
Chapter 27 A Consistent Answer 360
David A. Weintraub is professor of astronomy at Vanderbilt University. He is the author of Is Pluto a Planet?: A Historical Journey through the Solar System".
"This detective story is magnificently presented. The professional astronomer-author writes in an interesting, organized, and very readable way, presenting this chronology of the quest to answer one of the most challenging questions in astronomy."
"Weintraub, an astronomer at Vanderbilt University, offers a patient tour of the new data-rich landscape."
- David Kaiser, London Review of Books
"It's all very well for astronomers to say that the universe is 13.7 billion years old, but you have to wonder just how they figured that out. Vanderbilt University astronomer Weintraub (Is Pluto a Planet?) explains it all for astronomy buffs in an enthusiastic way. . . . Weintraub guides readers on a winding journey through history, explaining various dating approaches and illustrating the determination of astronomers to find the answer to one of the most basic questions about our universe."
- Publishers Weekly
"Astronomer David Weintraub explains . . . how we know that the Universe is 13.7 billion years old, a finding that has had an impact on science, philosophy and religion. By looking at the various ways in which the age of the cosmos has been established over the centuries--from the lifecycles and pulsations of stars to galactic structures and cosmology--he reveals the process of scientific enquiry and shows how astronomers gather evidence to grapple with deep questions."
"Weintraub has a gift for presenting complicated matters in a lucid and understandable way by employing clever analogies. . . . How Old Is the Universe? is a welcome contribution to the popular literature on astronomy. . . . It offers a scientifically competent and impressively informative account of how astronomers and physicists have unveiled the secrets of the universe."
- Helge Kragh, American Scientist