Minding the Heavens; The Story of our Discovery of the Milky Way; 2

Praise for the first edition: "A terrific blend of the science and the history." Martha Haynes, Goldwin Smith Professor of Astronomy, Cornell University, New York, USA "The book is a treat… Highly recommended for public and academic libraries." Peter Hepburn, now Head Librarian, College of the Canyons, Santa Clarita, California, USA Today, we recognize that we live on a planet circling the sun, that our sun is just one of billions of stars in the galaxy we call the Milky Way, and that our galaxy is but one of billions born out of the Big Bang. Yet, as recently as the early twentieth century, the general public and even astronomers had vague and confused notions about what lay beyond the visible stars. Can we see to the edge of the universe? Do we live in a system that would look, from a distance, like a spiral nebula? This fully updated second edition of Minding the Heavens: The Story of Our Discovery of the Milky Way explores how we learned that we live in a galaxy, in a universe composed of galaxies and unseen, mysterious dark matter. The story unfolds through short biographies of seven astronomers: Thomas Wright, William Herschel, and Wilhelm Struve of the eighteenth and nineteenth centuries; the transitional figure of William Huggins; and Jacobus Kapteyn, Harlow Shapley, and Edwin Hubble of the modern, big-telescope era. Each contributed key insights to our present understanding of where we live in the cosmos, and each was directly inspired by the work of his predecessors to decipher "the construction of the heavens." Along the way, the narrative weaves in the contributions of those in supportive roles, including Caroline Herschel—William’s sister, and the first woman paid to do astronomy—and Martha Shapley, a mathematician in her own right who carried out calculations for her spouse. Through this historical perspective, readers will gain a new appreciation of our magnificent Milky Way galaxy and of the beauties of the night sky, from ghostly nebulae to sparkling star clusters. Features: Fully updated throughout to reflect the latest in our understanding of the Milky Way, from our central supermassive black hole to the prospect of future mergers with other galaxies in our Local Group. Explains the significance of current research, including from the Gaia mission mapping our galaxy in unprecedented detail. Unique and broadly appealing approach. A biographical framework and ample illustrations lead the reader by easy, enjoyable steps to a well-rounded understanding of the history of astronomy. Leila Belkora (Ph.D., Astrophysics) is a science writer. She earned her doctorate from the University of Colorado-Boulder, specializing in solar radio astronomy. She has previously taught university physics, astronomy, and communication for engineers. She lives in Southern California and enjoys local astronomy outreach activities. Minding the Heavens Cover -1 Half Title 2 Title Page 4 Copyright Page 5 Dedication 6 Contents 8 Acknowledgments 10 1. Introduction 12 Viewing the Galaxy from Within 13 The Milky Way 13 Early Theories of the Universe 16 The Theory of Island Universes 17 The Andromeda Nebula 19 Ongoing Discovery 19 Notes 19 2. Thomas Wright: Visionary of Stellar Systems 22 Background: The Age of Newton, Halley and Cassini 24 Explorations 25 Early London Years: Astro-Theological Musings 27 Man of Many Talents 31 Astronomy and Astro-Theology 33 Kant Reads Wright 40 Second Thoughts 43 Notes 45 3. William Herschel: Natural Historian of the Universe 48 A Career in Music 51 Caroline 52 From Amateur to Professional 58 The Construction of the Heavens 65 The 40-Foot Telescope 69 The Evolution of Nebulae 70 Laplace's Nebular Hypothesis 72 Infrared Radiation and Binary Stars 73 The Unfathomed Milky Way 75 Notes 78 4. Wilhelm Struve: Seeker of Parallax 80 A Classical Education 80 Bessel's Influence 84 Geodesy, Double Stars and the Search for Parallax 88 Dorpat's Great Refractor 93 Professional Contacts Support Struve in a Crisis 94 Bessel's Heliometer 95 Crises and New Directions for Struve 97 Parallax 97 The Etudes 101 Final Years 104 Notes 105 5. William Huggins: Pioneer of the New Astronomy 108 An Informal Education 109 Attraction to Astronomy 111 The Beginnings of Spectroscopy 114 Collaboration with Miller 116 Spectra of the Nebulae 120 The Motions of the Stars 123 The 15-Inch Telescope 125 Margaret 127 Competition 129 Later Years 132 Notes 135 6. Jacobus Kapteyn: Mastermind without a Telescope 140 A Start in Leiden 142 An Inauspicious Start at Groningen 144 Sky Surveys 145 Stellar Distances and Motions 149 Star Streaming and the Plan of Selected Areas 152 Mount Wilson and the Problem of Interstellar Absorption 154 Hertzsprung 156 New Ways to Estimate Distances 158 Searching for a Synthesis 161 World War I 162 Later Years: The Kapteyn Universe 163 Notes 166 7. Harlow Shapley: Champion of the Big Galaxy 170 A Missouri Childhood 171 Undergraduate Years in Missouri 172 Eclipsing Binaries at Princeton 173 Arrival at Mount Wilson 175 Globular Cluster Distances 177 The "Big Galaxy" Hypothesis 179 Elucidating the Sidereal Structure 181 "Formicid" and Other Adventures 183 Shapley Marshals His Arguments 185 Heber Curtis 186 The Great Debate 186 Shapley to Harvard 188 Lingering Questions from the Great Debate 191 The Magellanic Clouds and Other Metagalactic Subjects 192 World War II and Its Aftermath 193 An Unpopular Internationalist Stance 194 Later Years 194 Notes 195 8. Edwin Hubble: Redeemer of Island Universes 200 Early Interest in Astronomy 200 A Reluctant Student of Law 202 Graduate Study in Astronomy 204 Military Service and a Stay in Cambridge 206 Early Mount Wilson Years 207 Classifying the Nebulae 209 Jeans's Nebular Theory 211 Breakthrough 214 A Return to Classification 217 The Milky Way and the Andromeda Nebula: Cosmic Twins 219 Hubble's Expanding Universe 220 Lemaître and a Renewal of Interest in Cosmology 223 Einstein's Visit in 1931 225 The Distribution of the Nebulae 226 Second World War 227 New Telescopes 230 Notes 231 9. The Milky Way Revealed 234 The Quest for Dark Matter 237 The Disk 238 The Bulge 242 The Galactic Center 243 Journey to the Heart of the Galaxy 245 Gaia and Future Surveys 247 The Local Group, the Milky Way's Neighborhood 248 Conclusion 248 Notes 249 References 254 Index 266 globular;,cluster;,stellar;,system;,andromeda;,nebula;,orion;,planetary;,island;,universe;,Herschel;,dark,matter;,galaxy;,Hubble;,history,of,science;,popular,science;,solar,system; globular,cluster,stellar,system,andromeda,nebula,orion,planetary,island,universe,Herschel,dark matter,galaxy,Hubble,history of science,popular science,solar system Today, we accept that we live on a planet circling the sun, that our sun is just one of billions of stars in the galaxy we call the Milky Way, and that our galaxy is but one of billions born out of the big bang. Yet as recently as the early twentieth century, the general public and even astronomers had vague and confused notions about what lay beyond the visible stars. Minding the Heavens: The Story of Our Discovery of the Milky Way is about how scientists discovered that we lived in a galaxy, in fact, a universe full of galaxies. This fascinating story of the discovery of our own and other galaxies is told through the lives of seven astronomers: Thomas Wright, William Herschel, Wilhelm Struve, William Huggins, Jacobus Kapteyn, Harlow Shapley, and Edwin Hubble. Each contributed greatly to our present understanding of where we live in the cosmos. Through the science and lives of these seven people, each shaped by their family, friends, and contemporaries, we follow this amazing story of discovery. From the mid 1700s with Thomas Wright through to the mid 20th century with the more familiar names of Shapley and Hubble, each character bringing us nearer to our present understanding of the Universe. This fully updated second edition of Minding the Heavens: The Story of Our Discovery of the Milky Way explores how we learned that we live in a galaxy, in a universe of composed of galaxies and unseen, mysterious dark matter.