The Cosmos...3.8 How Can You See the Invisible? 57 3.8a X-ray and Gamma-ray Telescopes 57 3.8b Telescopes for Ultraviolet Wavelengths 60 3.8c Infrared Telescopes 60 3.8d Radio Telescopes

Cambridge University Press978-1-108-43138-5 — The Cosmos5th EditionFrontmatterMore Information

www.cambridge.org© in this web service Cambridge University Press

The CosmosAstronomy in the New Millennium

F IFTH EDIT ION

The Fifth Edition of The Cosmos: Astronomy in the New Millennium provides you with the fundamentals of

astronomical knowledge that have been built up over decades, with an expanded discussion of the incredible

advances that are now taking place in this fast-paced field, such as New Horizons’ flyby of Pluto, exoplanets,

“dark matter,” and the direct detection of gravitational waves by LIGO.

Written in a clear and easily understandable style, this textbook has been thoroughly revised to include

(among other things) updated data and figures, new images from recent space missions and telescopes, the

latest discoveries on supernovae, and new observations of the region around the four-million-solar-mass

black hole at the center of our Milky Way Galaxy.

Jay M. Pasachoff, Field Memorial Professor of Astronomy at Williams College, teaches the astronomy

survey course. He is also Director of the Hopkins Observatory there. He received his undergraduate and grad-

uate degrees from Harvard and then had postdoctoral fellowships at the Harvard College Observatory and

the California Institute of Technology, where he has also had recent sabbatical leaves. He now has a visiting

appointment at the Carnegie Observatories.

He has observed 70 solar eclipses. He also studies occultations of stars by Pluto and other objects in the

outer Solar System.

Pasachoff is Chair of the Working Group on Eclipses of the International Astronomical Union and was

Chair of the American Astronomical Society’s Historical Astronomy Division. He is also co-editor of Teaching

and Learning Astronomy (2005) and Innovation in Astronomy Education (2008).

He received the American Astronomical Society’s Education Prize (2003); the Janssen Prize from the

Société Astronomique de France (2012); and the Richtmyer Memorial Lecture Award, American Association

of Physics Teachers (2017). Asteroid (5100) Pasachoff is named after him.

Alex Filippenko is a Professor of Astronomy, and the Richard & Rhoda Goldman Distinguished Professor

in the Physical Sciences, at the University of California, Berkeley. He received his undergraduate degree

from the University of California, Santa Barbara (1979) and his doctorate from the California Institute of

Technology (1984).

His primary areas of research are exploding stars, gamma-ray bursts, active galaxies, black holes, and obser-

vational cosmology. Filippenko was the only person to have been a member of both teams that revealed the

Nobel-worthy accelerating expansion of the Universe. He is one of the world’s most highly cited astronomers

and was elected to the National Academy of Sciences (2009).

Filippenko has won many prestigious teaching awards, including the Carnegie/CASE National Professor of

the Year among doctoral institutions (2006). He has appeared frequently on science newscasts and television

documentaries, especially The Universe series. He received the Carl Sagan Prize for Science Popularization

(2004). He enjoys world travel and observing total solar eclipses (16, all successfully).

www.cambridge.org/9781108431385www.cambridge.org



An artist’s conception of two black holes, GW170104, as they merged, similar to the ones detected by the Laser Interferometer Gravitational-wave

Observatory (LIGO).

Credit: LIGO/Caltech/MIT/Sonoma State (Aurore Simonnet)




The CosmosAstronomy in the New Millennium

F IFTH EDIT ION

Jay M. PasachoffWilliams College, Massachusetts

Alex FilippenkoUniversity of California, Berkeley




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© Jay M. Pasachoff and Alex Filippenko 2019

This publication is in copyright. Subject to statutory exception

and to the provisions of relevant collective licensing agreements,

no reproduction of any part may take place without the written

permission of Cambridge University Press.

Fourth edition published in 2013. The previous edition (The Cosmos, 3rd Edition) was

published in 2007 by Brooks/Cole Cengage.

Printed and bound in Great Britain by Clays Ltd, Elcograf S.p.A.

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accurate or appropriate.




v

Contents

Preface xix

1. A Grand Tour of the Heavens 1

2. Light, Matter, and Energy: Powering the Universe 23

3. Light and Telescopes: Extending Our Senses 41

4. Observing the Stars and Planets: Clockwork of the Universe 75

5. Gravitation and Motion: The Early History of Astronomy 107

6. The Terrestrial Planets: Earth, Moon, and Their Relatives 133

7. The Jovian Planets: Windswept Giants 189

8. Pluto, Comets, Asteroids, and Beyond 225

9. Our Solar System and Others 263

10. Our Star: The Sun 289

11. Stars: Distant Suns 317

12. How the Stars Shine: Cosmic Furnaces 357

13. The Death of Stars: Recycling 381

14. Black Holes: The End of Space and Time 415

15. The Milky Way: Our Home in the Universe 447

16. A Universe of Galaxies 479

17. Quasars and Active Galaxies 523

18. Cosmology: The Birth and Life of the Cosmos 553

19. In the Beginning 589

20. Life in the Universe 623

Epilogue 644

Appendix 1/2. Measurement Systems/Basic Constants 645

Appendix 3. Planets and Dwarf Planets 647

Appendix 4. The Brightest Stars 649

Appendix 5. The Nearest Stars 651

Appendix 6. The Messier Catalogue 654




vi Contents

Appendix 7. The Constellations 656

Appendix 8. Star Names 658

Selected reading 661

Glossary 668

Index 685




vii

Preface xix

1. A Grand Tour of the Heavens 1 1.1 Peering Through the Universe: A Time Machine 2

1.2 How Do We Study Things We Can’t Touch? 2

Figure It Out 1.1 Keeping Track of Space and Time 3

Figure It Out 1.2 Scientific Notation 3

1.3 Finding Constellations in the Sky 5

1.3a The Autumn Sky 6

Star Party 1.1 Using the Sky Maps 7

1.3b The Winter Sky 9

1.3c The Spring Sky 10

1.3d The Summer Sky 10

1.4 How Do You Take a Tape Measure to the Stars? 11

A Closer Look 1.1 A Sense of Scale: Measuring

Distances 12

1.5 The Value of Astronomy 14

1.5a The Grandest Laboratory of All 14

1.5b Origins 15

1.6 What Is Science? 16

1.7 Why Is Science Far Better Than Pseudoscience? 17

2. Light, Matter, and Energy: Powering the Universe 23

2.1 Studying a Star Is Like Looking at a Rainbow 24

Figure It Out 2.1 The Nature of Light 24

2.2 “Blackbodies” and Their Radiation 26

Figure It Out 2.2 Blackbody Radiation and Wien’s

Law 26

Figure It Out 2.3 Blackbody Radiation and the

Stefan–Boltzmann Law 27

2.3 What Are Those Missing Colors and Where Are They? 28

2.4 The Story Behind the Bohr Atom 30

2.5 The Doppler Effect and Motion 33

Figure It Out 2.4 Temperature Conversions 35

3. Light and Telescopes: Extending Our Senses 41 3.1 The First Telescopes for Astronomy 41

3.2 How Do Telescopes Work? 43

3.3 Modern Telescopes 46

3.3a Current Large Telescopes Around the World 46

Figure It Out 3.1 Light-Gathering Power of a

Telescope 47

Figure It Out 3.2 Changing Units 47

3.3b The Next Generation of Optical and Infrared

Ground-Based Telescopes 51

3.4 The Big Picture: Mapping the Sky 52

Detailed Contents

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Asteroid trails, curved because of parallax across an image

of a cluster of galaxies in Hubble Frontier Field Abell 370.

3.5 Amateurs Are Participating 53

3.6 Glorious Hubble After Initial Trouble 54

3.7 You Can’t Look at the Sun at Night 56

3.8 How Can You See the Invisible? 57

3.8a X-ray and Gamma-ray Telescopes 57

3.8b Telescopes for Ultraviolet Wavelengths 60

3.8c Infrared Telescopes 60

3.8d Radio Telescopes 62

Figure It Out 3.3 Angular Resolution of a

Telescope 63

A Closer Look 3.1 A Night at Maunakea 65

3.8e The Major New Radio Projects 66

4. Observing the Stars and Planets: Clockwork of the Universe 75

4.1 The Phases of the Moon and Planets 76

4.2 Celestial Spectacles: Eclipses 77

Star Party 4.1 Observing Total Solar Eclipses 80




viii Detailed Contents

4.2a Eerie Lunar Eclipses 81

4.2b Glorious Solar Eclipses 82

A Closer Look 4.1 Colors in the Sky 83

4.3 Twinkle, Twinkle, Little Star … 87

4.4 The Concept of Apparent Magnitude 87

Figure It Out 4.1 Using the Magnitude Scale 88

4.5 Rising and Setting Stars 88

A Closer Look 4.2 Photographing the Stars 89

Figure It Out 4.2 Sidereal Time 90

4.6 Celestial Coordinates to Label the Sky 91

4.7 The Reason for the Seasons 92

Star Party 4.2 The Paths of the Moon and Planets 95

4.8 Time and the International Date Line 95

4.9 Calendars 98

4.10 Keeping Time 100

5. Gravitation and Motion: The Early History of Astronomy 107

5.1 A Brief Survey of the Solar System 107

Star Party 5.1 Prograde and Retrograde Motions 108

5.2 The Earth-Centered Astronomy of Ancient Greece 109

A Closer Look 5.1 Ptolemaic Terms 110

A Closer Look 5.2 The Antikythera Mechanism 111

5.3 A Heretical Idea: The Sun-Centered Universe 111

Lives in Science 5.1 Copernicus 113

5.4 The Keen Eyes of Tycho Brahe 114

5.5 Johannes Kepler and His Laws of Orbits 114

5.5a Kepler’s First Law 114

5.5b Kepler’s Second Law 114

Lives in Science 5.2 Tycho Brahe 115

A Closer Look 5.3 Kepler’s Laws 116

Lives in Science 5.3 Johannes Kepler 117

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The James Webb Space Telescope being tested.




Detailed Contents ix

5.5c Kepler’s Third Law 118

5.6 The Demise of the Ptolemaic Model: Galileo Galilei 118

5.7 On the Shoulders of Giants: Isaac Newton 119

5.8 Clues to the Formation of Our Solar System 120

Figure It Out 5.1 Kepler’s Third Law 121

Lives in Science 5.4 Galileo Galilei 121

Star Party 5.2 Galileo’s Observations 124

A Closer Look 5.4 Newton’s Law of Universal

Gravitation 124

Figure It Out 5.2 Newton’s Version of Kepler’s Third

Law 125

Lives in Science 5.5 Isaac Newton 126

Figure It Out 5.3 Orbital Speed of Planets 127

6. The Terrestrial Planets: Earth, Moon, and Their Relatives 133

6.1 Earth: There’s No Place Like Home 134

A Closer Look 6.1 Comparative Data for the Terrestrial

Planets and Their Moons 134

6.1a Earth’s Interior 134

A Closer Look 6.2 Density 136

6.1b Continental Drift 138

6.1c Tides 139

6.1d Earth’s Atmosphere 139

6.1e The Van Allen Belts 143

6.2 The Moon 144

6.2a The Moon’s Appearance 145

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A double page from Galileo’s Sidereus Nuncius (1610) showing his engravings of the face of the Moon as seen through his

newfangled telescope.




x Detailed Contents

A Closer Look 6.3 The First People on the

Moon 145

6.2b The Lunar Surface 146

6.2c The Lunar Interior 151

6.2d The Origin of the Moon 152

6.2e Rocks from the Moon 153

6.3 Mercury 153

6.3a The Rotation of Mercury 154

6.3b Mercury’s History 155

6.3c Mercury Observed from Earth 155

A Closer Look 6.4 Naming the Features of

Mercury 156

6.3d Spacecraft Views of Mercury 156

6.3e Mercury Research Rejuvenated 158

6.3f Mercury from MESSENGER 158

6.3g Continuing Exploration of Mercury 160

6.4 Venus 160

6.4a Transits of Venus 161

6.4b The Atmosphere of Venus 162

6.4c The Rotation of Venus 162

6.4d Why Is Venus So Incredibly Hot? 162

6.4e Spacecraft Observations of Venus’s

Atmosphere 164

6.4f Radar Observations of Venus’s Surface 165

6.4g Venus Exploration in the Twenty-First Century 166

6.5 Mars 168

6.5a Characteristics of Mars 169

6.5b Mars’s Surface 169

6.5c Mars’s Atmosphere 172Mae Jemison and Sally Ride, NASA astronauts, in a 2017

LEGO™ set, in front of a Space Shuttle.

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NASA’s Cassini mission farewell image of Saturn and its rings. The image is the last full mosaic taken two days before the

spacecraft plunged into Saturn.

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Detailed Contents xi

6.5d Mars’s Satellites 173

A Closer Look 6.5 Mars Exploration Rovers,

Mars Phoenix, and Mars Science Lab with

Curiosity 174

6.5e The Search for Life on Mars 177

6.5f Crewed Missions to Mars 180

7. The Jovian Planets: Windswept Giants 189 7.1 Jupiter 190

A Closer Look 7.1 Comparative Data for the Major

Worlds 190

Star Party 7.1 Observing the Giant Planets 191

7.1a Spacecraft to Jupiter 191

Figure It Out 7.1 The Size of Jupiter 192

7.1b The Great Red Spot 192

7.1c Jupiter’s Atmosphere 193

7.1d Jupiter’s Interior 194

7.1e Jupiter’s Magnetic Field 194

7.1f Jupiter’s Ring 195

7.1g Jupiter’s Amazing Satellites 195

A Closer Look 7.2 Jupiter and Its Satellites in

Mythology 200

7.1h JUICE at Jupiter 201

7.2 Saturn 201

7.2a Saturn’s Rings 201

7.2b Saturn’s Atmosphere 204

7.2c Saturn’s Interior and Magnetic Field 204

7.2d Saturn’s Moon Titan 204

A Closer Look 7.3 Saturn’s Satellites in

Mythology 207

7.2e Saturn’s Other Satellites 207

A Closer Look 7.4 Saturn’s Rings and Moons from

Cassini 208

7.3 Uranus 209

A Closer Look 7.5 Uranus and Neptune in

Mythology 210

Terrain on Pluto, a close-up from NASA’s New Horizons.

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Asteroid and dwarf planet 1 Ceres, imaged from NASA’s

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7.3a Uranus’s Atmosphere 210

7.3b Uranus’s Rings 211

7.3c Uranus’s Interior and Magnetic Field 212

7.4 Neptune 212

7.4a Neptune’s Atmosphere 213

7.4b Neptune’s Interior and Magnetic Field 215

7.4c Neptune’s Rings 216

A Closer Look 7.6 Naming the Rings of

Neptune 216

7.4d Neptune’s Moon Triton 217

7.5 The Formation of the Giant Planets 218

8. Pluto, Comets, Asteroids, and Beyond 225 8.1 Pluto 226

8.1a Pluto’s Mass and Size 226

8.1b Pluto’s Atmosphere 228

8.1c What Is Pluto? 228

A Closer Look 8.1 Dwarf Planets 230

8.1d The Pluto System from New Horizons 230

8.1e Beyond Pluto 230

8.2 Kuiper-Belt Objects and Dwarf Planets 232

8.3 Comets 235

8.3a The Composition of Comets 235

8.3b The Origin and Evolution of Comets 236

8.3c Halley’s Comet 237

8.3d Comet Shoemaker–Levy 9 239

8.3e Some Bright Comets 241




xii Detailed Contents

8.3f Spacecraft to Comets 243

8.3g Rosetta Orbits Its Comet 244

8.4 Meteoroids 244

8.4a Types and Sizes of Meteorites 244

8.4b Meteor Showers 247

A Closer Look 8.2 Meteor Showers 248

Star Party 8.1 Observing a Meteor Shower 248

8.5 Asteroids 249

8.5a General Properties of Asteroids 249

A Closer Look 8.3 The Extinction of the

Dinosaurs 249

8.5b Asteroids Viewed Close-Up 250

8.5c Near-Earth Objects 254

8.5d Interstellar Visitor 256

8.5e Future Asteroid Missions 256

9. Our Solar System and Others 263 9.1 The Formation of the Solar System 264

9.1a Collapse of a Cloud 264

9.1b Models of Planet Formation 265

9.2 Extrasolar Planets (Exoplanets) 266

9.2a Astrometric Method 267

9.2b Timing of Radio Pulsars 267

9.2c Periodic Doppler Shifts: The Doppler-Wobble

Method 267

9.2d Transiting Planets: The Blink Method 269

9.2e Direct Imaging of Exoplanets 272

9.2f Gravitational Microlensing 275

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A white-dwarf star, Stein 2051 B, only 17 light-years from

Earth, seen with the Hubble Space Telescope, with a more

distant star appearing below it. The white dwarf passed

in front of the other star, providing a successful test of

Einstein’s general theory of relativity.

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A multiwavelength view of Supernova 1987A, with

green showing Hubble views of how the expanding

shock wave from the star that exploded is colliding

with material ejected previously, and the red showing

dust imaged with the ALMA millimeter/submillimeter

array. Blue is hot gas imaged with the Chandra X-ray

Observatory.

9.2g Future Observing Plans and Projects 275

9.3 The Nature of Exoplanet Systems 278

A Closer Look 9.1 Naming Stars, Exoplanets, and

Kuiper-Belt-Objects 278

9.4 Goldilocks Planets 279

9.5 Brown Dwarfs 279

9.6 Planetary Systems in Formation 280

10. Our Star: The Sun 289 10.1 What Is the Sun’s Basic Structure? 290

10.1a The Photosphere 291

A Closer Look 10.1 The Most Common

Elements in the Sun’s Photosphere 292

10.1b The Chromosphere 294

10.1c The Corona 295

10.1d The Scientific Value of Eclipses 301

10.2 Sunspots and Other Solar Activity 302

10.2a What Are Those Blemishes on the Sun? 302

Star Party 10.1 Observing Sunspots 303

10.2b The Solar-Activity Cycle 303

10.2c Fireworks on the Sun, and Space Weather 304

10.2d Filaments and Prominences 307

10.2e Decades Ahead of Solar Monitoring 307

10.3 The Sun and the Theory of Relativity 307

Lives in Science 10.1 Albert Einstein 308




Detailed Contents xiii

Star cluster R136 in the Tarantula Nebula in the Large

Magellanic Cloud, imaged with Hubble.

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The Bubble Nebula, NGC 7635, gas expanding around a

massive star. The object is 7 light-years across, and is imaged

here with Hubble.

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11. Stars: Distant Suns 317 11.1 Colors, Temperatures, and Spectra of Stars 318

11.1a Taking a Star’s Temperature 318

11.1b How Do We Classify Stars? 319

11.1c The Coolest Stars 320

11.2 How Distant Are the Stars? 320

Figure It Out 11.1 Stellar Triangulation 323

11.3 How Powerful Are the Stars? 323

A Closer Look 11.1 Using Absolute Magnitudes 325

11.4 Temperature–Luminosity Diagrams 325

Figure It Out 11.2 The Inverse-Square Law 326

11.5 How Do Stars Move? 328

11.5a Proper Motions of Stars 328

Figure It Out 11.3 A Star’s Luminosity 329

11.5b Radial Velocities of Stars 329

A Closer Look 11.2 Proxima Centauri: The

Nearest Star Beyond the Sun 331

11.6 “Social Stars”: Binaries 332

Figure It Out 11.4 Doppler Shifts 333

11.6a Pairs of Stars and Their Uses 333

Figure It Out 11.5 Binary Stars 335

11.6b How Do We Weigh Stars? 337

11.6c The Mass–Luminosity Relation 337

A Closer Look 11.3 A Sense of Mass: Weighing

Stars 338

Figure It Out 11.6 The Mass–Luminosity

Relation 339

11.7 Stars That Don’t Shine Steadily 339

11.8 Clusters of Stars 343

11.8a Open and Globular Star Clusters 343

A Closer Look 11.4 Star Clusters in Our

Galaxy 344

11.8b How Old Are Star Clusters? 345

11.8c Gaia’s Hertzsprung–Russell Diagram 346

A Closer Look 11.5 How We Measure Basic

Stellar Parameters 348

12. How the Stars Shine: Cosmic Furnaces 357 12.1 Star Birth 358

12.1a Collapse of a Cloud 358

12.1b The Birth Cries of Stars 362

12.2 Where Stars Get Their Energy 364

12.3 Atoms and Nuclei 365

12.3a Subatomic Particles 365

12.3b Isotopes 365

Figure It Out 12.1 Energy Generation in the

Sun 366

12.3c Radioactivity and Neutrinos 367

12.4 Stars Shining Brightly 367

12.5 Why Stars Shine 368

12.6 Brown Dwarfs 368

12.7 The Solar Neutrino Experiment 370

12.7a Initial Measurements 370

12.7b Further Solar Neutrino Experiments 371

12.7c Beyond Solar Neutrinos 372

12.8 The End States of Stars 374




xiv Detailed Contents

A pair of spiral galaxies, NGC 4302 and 4298, both about 55

million light-years away and imaged with the Hubble Space

Telescope.

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A cluster of galaxies 10 billion light-years from Earth, with

500 trillion times the mass of our Sun. Hot gas in the middle,

imaged with the Chandra X-ray Observatory, shows as blue-

white overlaying Hubble’s visible-light image in green and

the Spitzer Space Telescope’s image in red.

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13. The Death of Stars: Recycling 381 13.1 The Death of the Sun 381

13.1a Red Giants 381

13.1b Planetary Nebulae 383

13.1c White Dwarfs 384

13.1d Summary of the Sun’s Evolution 386

13.1e Binary Stars and Novae 387

13.2 Supernovae: Stellar Fireworks! 388

13.2a Core-Collapse Supernovae 389

13.2b White-Dwarf Supernovae (Type Ia) 391

13.2c Superluminous Supernovae 393

13.2d Observing Supernovae 393

13.2e Supernova Remnants 393

A Closer Look 13.1 Searching for

Supernovae 395

13.2f Supernovae and Us 396

13.2g Supernova 1987A! 397

13.2h Cosmic Rays 401

13.3 Pulsars: Stellar Beacons 402

13.3a Neutron Stars 402

13.3b The Discovery of Pulsars 402

13.3c What Are Pulsars? 403

13.3d The Crab, Pulsars, and Supernovae 404

13.3e Slowing Pulsars and Fast Pulsars 406

13.3f Binary Pulsars and Gravitational Waves 406

13.3g A Pulsar with a Planet 408

13.3h X-ray Binaries 408

14. Black Holes: The End of Space and Time 415 14.1 The Formation of a Stellar-Mass Black Hole 416

14.2 The Photon Sphere 416

14.3 The Event Horizon 417

14.3a A Newtonian Argument 417

14.3b Black Holes in General Relativity 418

14.4 Time Dilation 419

14.5 Properties of Black Holes 419

14.5a Rotating Black Holes 419

14.5b Measuring Black-Hole Spin 420

14.6 Passageways to Distant Lands? 422

14.7 Detecting a Black Hole 422

14.7a Hot Accretion Disks 422

14.7b Cygnus X-1: The First Plausible Stellar-Mass

Black Hole 423

14.7c Other Black-Hole Candidates 424

Figure It Out 14.1 Binary Stars and Kepler’s

Third Law 424




Detailed Contents xv

An all-sky map made with the European Space Agency’s Planck spacecraft, which was also used to map the cosmic background

radiation. The image is a composite of magnetic-field, atomic “free-free,” dust, and carbon-monoxide components.

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14.7d The Strange Case of SS433 425

14.8 Supermassive Black Holes 426

14.9 Moderation in All Things 428

14.10 Gamma-ray Bursts: Birth Cries of Black Holes? 430

14.10a How Far Away Are Gamma-ray Bursts? 430

14.10b Models of Gamma-ray Bursts 431

14.11 Mini Black Holes 433

14.12 The Detection of Gravitational Waves 433

Proposal: The Maxwell–Einstein speed 440

15. The Milky Way: Our Home in the Universe 447 15.1 Our Galaxy: The Milky Way 448

Star Party 15.1 Observing the Milky Way 448

15.2 The Illusion That We Are at the Center 450

15.3 Nebulae: Interstellar Clouds 451

15.4 The Parts of Our Galaxy 453

15.5 The Center of Our Galaxy 456

15.6 All-Sky Maps of Our Galaxy 460

15.7 Our Pinwheel Galaxy 461

15.8 Why Does Our Galaxy Have Spiral Arms? 463

15.9 Matter Between the Stars 464

15.10 Radio Observations of Our Galaxy 465

15.11 Mapping Our Galaxy 466

15.12 Radio Spectral Lines from Molecules 468

15.13 The Formation of Stars 468

15.14 At a Radio Observatory 471

16. A Universe of Galaxies 479 16.1 The Discovery of Galaxies 480

16.1a The Shapley–Curtis Debate 480

16.1b Galaxies: “Island Universes” 482

16.2 Types of Galaxies 483

16.2a Spiral Galaxies 483

16.2b Elliptical Galaxies 485

16.2c Other Galaxy Types 486

16.3 Habitats of Galaxies 488

16.3a Clusters of Galaxies 488

Star Party 16.1 Observing Galaxies 488

16.3b Superclusters of Galaxies 491

16.4 The Dark Side of Matter 491

16.4a The Rotation Curve of the Milky Way

Galaxy 491

16.4b Dark Matter Everywhere 493

Figure It Out 16.1 Calculating the Mass from

the Rotation Curve 494

16.4c What Is Dark Matter? 495

16.5 Gravitational Lensing 497

16.6 The Birth and Life of Galaxies 503

16.7 The Expanding Universe 503

Figure It Out 16.2 Redshifts and the Hubble–Lemaî tre

Law 505

Figure It Out 16.3 Using the Hubble–Lemaî tre Law to

Determine Distances 506




xvi Detailed Contents

A gravitationally lensed embryonic galaxy, only half a billion years after the big bang. It is only 1% the mass of our Milky Way

Galaxy, and is revealing an early stage of galaxy formation. The lensing smeared it into an arc; other galaxies about that far

away and far back in time appear only as reddish dots. The image was taken with the Hubble Space Telescope.

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16.8 The Search for the Most Distant Galaxies 506

Figure It Out 16.4 Relativistic Effects 508

16.9 The Evolution of Galaxies 511

16.10 Evolution of Large-Scale Structure 514

17. Quasars and Active Galaxies 523 17.1 Active Galactic Nuclei 524

17.2 Quasars: Denizens of the Distant Past 526

17.2a The Discovery of Quasars 526

17.2b Puzzling Spectra 527

17.2c The Nature of the Redshift 528

17.3 How Are Quasars Powered? 529

17.3a A Big Punch from a Tiny Volume 531

17.3b What Is the Energy Source? 531

17.3c Accretion Disks and Jets 532

17.4 What Are Quasars? 533

17.5 Are We Being Fooled? 536

17.6 Finding Supermassive Black Holes 537

Figure It Out 17.1 The Central Mass in a Galaxy 538

17.7 The Effects of Beaming 540

17.8 Probes of the Universe 543

18. Cosmology: The Birth and Life of the Cosmos 553 18.1 Olbers’s Paradox 554

18.2 An Expanding Universe 555

18.2a The Hubble-Lemaître Law 555

18.2b Expansion Without a Center 556

18.2c What Is Actually Expanding? 558

18.3 The Age of the Universe 559

18.3a Finding Out How Old 559

Figure It Out 18.1 The Hubble Time 560

18.3b The Quest for Hubble’s Constant 560

18.3c A Key Project of the Hubble Space

Telescope 562

18.3d Deviations from Uniform Expansion 566

18.3e Type Ia Supernovae as Cosmological

Yardsticks 566

18.4 The Geometry and Fate of the Universe 567

18.4a The Cosmological Principle: Uniformity 567

18.4b No “Cosmological Constant”? 567

18.4c Three Kinds of Possible Universes 569

Figure It Out 18.2 The Critical Density and

ΩM

569

A Closer Look 18.1 Finite Flat and Hyperbolic

Universes 571

18.4d Two-Dimensional Analogues 572

18.4e What Kind of Universe Do We Live In? 573

18.4f Obstacles Along the Way 574

18.5 Measuring the Expected Deceleration 574

18.5a The High-Redshift Hubble Diagram 574




Detailed Contents xvii

18.5b Type Ia (White-Dwarf) Supernovae 575

18.5c An Accelerating Universe! 575

18.5d Einstein’s Biggest Blunder? 577

18.5e Dark Energy 578

18.5f The Cosmic Jerk 579

18.6 The Future of the Universe 581

19. In the Beginning 589 19.1 The Steady-State Theory 590

19.2 The Cosmic Microwave Background Radiation 591

19.2a A Faint Hiss from All Directions 591

19.2b Origin of the Microwave Radiation 592

19.3 Deviations from Isotropy 594

19.3a Ripples in the Cosmic Microwave

Background 594

19.3b The Overall Geometry of the Universe 595

19.3c The Wilkinson Microwave Anisotropy Probe

(WMAP) 596

19.3d The Planck Spacecraft 596

19.3e Evaluating the Cosmic Background

Radiation 596

19.3f Planck Maps Objects in Space 599

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19.3g Ground-Based Telescopes for the Cosmic

Background Radiation 599

19.3h Polarization of the Cosmic Background

Radiation 599

19.4 The Early Universe 600

19.4a Going Back in Time 600

19.4b A Brief History of the Early

Universe 602

19.4c Primordial Nucleosynthesis 604

19.5 The Inflationary Universe 606

19.5a Problems with the Original Big-Bang

Model 606

19.5b Inflation to the Rescue 607

Figure It Out 19.1 Inflation of the Early

Universe 609

19.5c Forces in the Universe 609

19.5d Supercooling the Universe 612

19.5e Successes of Inflation 612

19.5f The Ultimate Free Lunch? 613

Figure It Out 19.2 Virtual Particles 614

19.6 A Universe of Universes 614

19.7 A Universe Finely Tuned for Life? 616

20. Life in the Universe 623 20.1 The Origin of Life 624

20.2 Life in the Solar System 626

20.3 Suitable Stars for Intelligent Life 626

20.4 The Search for Extraterrestrial Intelligence 627

Figure It Out 20.1 Interstellar Travel and Einstein’s

Relativity 628

20.5 Communicating with Extraterrestrials 632

20.6 The Statistics of Intelligent Extraterrestrial Life 633

20.6a The Drake Equation 633

20.6b Where Is Everyone? 635

Figure It Out 20.2 The Drake Equation 636

20.7 UFOs and the Scientific Method 637

20.7a UFOs 637

20.7b Of Truth and Theories 639

20.8 Conclusion 639

Epilogue 644

Appendix 1/2. Measurement Systems/Basic Constants 645

Appendix 3. Planets and Dwarf Planets 647

Appendix 4. The Brightest Stars 649

Appendix 5. The Nearest Stars 651

Appendix 6. The Messier Catalogue 654

Appendix 7. The Constellations 656

Appendix 8. Star Names 658

Selected reading 661

Glossary 668

Index 685




Saturn and Mars at their closest places to Earth as they orbit, the oppositions of 2018, imaged with the Hubble Space Telescope.

Saturn’s northern-hemisphere summer triggered a large storm, seen here as it disintegrates near Saturn’s north pole. Mars’s

southern-hemisphere spring triggered a huge dust storm that eventually covered the whole planet.

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xix

Astronomy continues to flourish, with huge discoveries such as the

one that pairs of giant black holes merge, sending ripples through

space-time – so-called gravitational waves – that we can pick up on

Earth. Even the merger of a pair of neutron stars has been detected

not only from the gravitational waves – let’s say by ear, given the

“chirp” of detection – but also with ordinary telescopes, the eyes of

the Universe. So, as of 2018, we have the eyes and the ears of the

Universe working together.

The Universe’s expansion – which was long thought to be slow-

ing down – is, astonishingly, accelerating, presumably as a conse-

quence of mysterious “dark energy.” We have discovered thousands

of planets around other stars – other solar systems abound! A gen-

eration of large optical telescopes has been built on mountaintops,

and arrays of dozens of radio telescopes such as the Atacama Large

Millimeter/submillimeter Array (ALMA) at an extremely high-alti-

tude site explore their part of the spectrum at high resolution. Still

larger telescopes are being planned or built, including the Thirty

Meter Telescope, the Giant Magellan Telescope, and the European

Extremely Large Telescope, all for optical and near-infrared studies,

and the Daniel K. Inouye Solar Telescope in Hawaii for detailed

studies of the Sun. The Hubble Space Telescope, with its latest

updated set of cameras, sends down exciting data all the time, and

we anticipate the launch in 2019 of the James Webb Space Telescope

with its mirror much larger than Hubble’s. The latest space obser-

vatories transmit images made with gamma rays, with x-rays, and

with infrared radiation. The overall structure of the Universe is

being mapped and analyzed, with catalogues of millions of objects

being compiled. Cosmology has become an observationally rich

science.

In Solar System studies, NASA’s Curiosity rover triumphantly

travels around Mars, bearing instruments to investigate Mars’s past

habitability. The Cassini spacecraft that orbited Saturn for 13 years

plunged into its surface in 2017, to protect Saturn’s moons from

being contaminated with terrestrial microbes. Spacecraft recently

orbited the asteroid and dwarf planet Ceres and a comet. Another

spacecraft flew right by Pluto and its moons and is now en route to a

tiny object beyond them. Moreover, new electronic instruments and

computer capabilities, new space missions to Solar-System objects,

and advances in computational astronomy and in theoretical work

will continue to bring forth exciting results.

In this latest edition of The Cosmos: Astronomy in the New

Millennium, we describe the current state of astronomy, both the

fundamentals of astronomical knowledge that have been built up

over decades and the incredible advances that are now taking place.

We want simply to share with students the excitement and magnifi-

cence of the Universe.

We try to cover all branches of astronomy without slighting any

of them; each teacher and each student may well find special inter-

ests that are different from our own. One of our aims in writing this

book is to educate citizens in the hope that they will understand the

value and methods of scientific research in general and astronomical

research in particular.

In writing this book, we share the goals of a commission of the

Association of American Colleges, whose report on the college cur-

riculum stated:

A person who understands what science is recognizes that scientific

concepts are created by acts of human intelligence and imagination;

comprehends the distinction between observation and inference and

between the occasional role of accidental discovery in scientific inves-

tigation and the deliberate strategy of forming and testing hypoth-

eses; understands how theories are formed, tested, validated, and

accorded provisional acceptance; and discriminates between conclu-

sions that rest on unverified assertion and those that are developed

from the application of scientific reasoning.

The scientific method permeates the book.

Preface

The dot between two of Saturn’s rings is Earth, our planet. NASA’s

Cassini spacecraft orbited in the Saturn system through 2017,

when it was directed to plunge into Saturn’s atmosphere to safely

destroy it without risking contaminating any of Saturn’s moons

with terrestrial life-forms.

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xx Preface

What is science? The following statement was originally drafted

by the Panel on Public Affairs of the American Physical Society, in

an attempt to meet the perceived need for a very short statement

that would differentiate science from pseudoscience. This state-

ment has been endorsed as a proposal to other scientific societies

by the Council of the American Physical Society, and was endorsed

by the Executive Board of the American Association of Physics

Teachers:

Science is the systematic enterprise of gathering knowledge about the

world and organizing and condensing that knowledge into testable

laws and theories. The success and credibility of science is anchored

in the willingness of scientists to:

Expose their ideas and results to independent testing and replica-

tion by other scientists; this requires the complete and open exchange

of data, procedures, and materials;

Abandon or modify accepted conclusions when confronted with

more complete or reliable experimental evidence. Adherence to these

principles provides a mechanism for self-correction that is the foun-

dation of the credibility of science.

Our book, through the methods it describes, should reveal this sys-

tematic enterprise of science to the readers.

Because one cannot adequately cover the whole Universe in a few

months, or even a year, we have had to pick and choose topics from

within the various branches of astronomy, while trying to describe a

wide range, to convey the spirit of contemporary astronomy and of

the scientists working in it. Our mix includes much basic astronomy

and many of the exciting topics now at the forefront.

Two examples are the currently hottest topics in astronomy: the

discovery of thousands of planets around other stars (so-called ex-

oplanets) and the discovery of gravitational waves from merging

black holes and neutron stars. Our exoplanet coverage brings the

discoveries and the new techniques and spacecrat being used up

to 2018, with a graph of the Kepler spacecrat’s discoveries, men-

tion of the K2 version of the spacecrat including an image with its

ields of view overlain, and a discussion of new instruments, such

as NASA’s Transiting Exoplanet Survey Satellite (TESS), launched

in 2018.

For the fantastic discovery of gravitational waves from collisions of

black holes over a billion light-years away, which was honored with

the 2017 Nobel Prize in Physics, we have expanded our previous cov-

erage of the Laser Interferometer Gravitational-wave Observatory

(LIGO). We include the latest update to the graph of spiraling neu-

tron stars that led to an indirect veriication of the existence of grav-

itational waves, which was recognized with the 1993 Nobel Prize in

Physics. Moreover, we discuss LIGO’s August 2017 detection of two

such neutron stars merging, and the result not only of the gravita-

tional waves themselves but also of concomitant gamma rays, visible

light, and other forms of electromagnetic waves.

For the 2017 total solar eclipse whose path crossed the United

States, we have the latest imaging and a discussion of why such ob-

servations were scientiically important.

Anyone choosing an astronomy textbook should consider the

following:

• Readability. Our prose is extremely clear and readable.

• Scientific accuracy. Our book is written by experts in the field and

has the various chapters checked by other experts.

• Up to date. Our book has sunspot numbers up to date to show the

current phase of the sunspot cycle; exoplanet lists and diagrams up

to the current situation; the latest on the Cassini mission to Saturn

and to Curiosity roaming around on Mars; images of the corona

at the 2017 total solar eclipse; a discussion of the Hubble constant

and the expansion of the Universe, with slightly different values

coming from an overall measurement of the cosmic background

radiation from the Planck spacecraft compared with the latest val-

ues of the Universe’s expansion and acceleration from supernova

observations; and more.

• Features like A Closer Look, Figure It Out, and Star Party that help

this book be useful for astronomy survey courses of one semester

or of those that spread the material out over two or more semesters.

NEW IN THIS EDITION

• Updated data (such as sunspot numbers showing the current min-

imum of the sunspot cycle) and figures throughout the text, as well

as new images from recent space missions (such as the Cassini mis-

sion to Saturn as well as Curiosity roaming around on Mars) and

ground-based telescopes (such as images of the corona at the 2017

total solar eclipse).

• Expanded discussions of the hottest current topics, such as New

Horizons’ flyby of Pluto (Chapter 8), the latest on exoplanets

(Chapter 9) and dark matter (Chapter 18), and the direct detection

of gravitational waves by LIGO (Chapter 14).

• The latest discoveries on supernovae, including pictures of the first

known strongly gravitationally lensed supernova (showing five

separate images of that supernova).

• New observations of the 4-million-solar-mass black hole at the

center of our Milky Way Galaxy.

• The latest progress on precision measurement of the Hubble con-

stant for the expansion of the Universe.

• Additional end-of-chapter questions and updated summaries and

glossary.

ORGANIZATION

The fifth edition of The Cosmos: Astronomy in the New Millennium is

generally organized in an Earth-outward approach. Chapter 1 gives

an overview of the Universe. Chapter 2 presents fundamental astro-

nomical concepts about light, matter, and energy, while Chapter 3

summarizes the various types of telescopes used to explore the

electromagnetic spectrum. In Chapter 4, we discuss easily observed

astronomical phenomena and the celestial sphere. Some professors

prefer to cover that material at the very beginning of the course or at

other points, and there is no problem with doing so.

Chapter 5 examines the early history of the study of astronomy.

Chapters 6 through 8 cover the Solar System and its occupants,




Preface xxi

although a thorough discussion of the Sun is reserved for later, in

Chapter 10. Chapter 6 compares Earth to the Moon and Earth’s

nearest planetary neighbors, Venus and Mars. Based largely on the

Voyager, Galileo, and Cassini data, Chapter 7 compares and contrasts

the Jovian gas/liquid giants – Jupiter, Saturn, Uranus, and Neptune.

Chapter 8 looks at the outermost part of the Solar System, including

Pluto and its moon, Charon, as well as other Kuiper-belt objects still

farther out; the chapter also spotlights comets and meteoroids, the

Solar System’s vagabonds. Chapter 9 discusses the formation of our

own Solar System and describes the exciting discovery of thousands

of exoplanets and exoplanet candidates around other stars.

Chapter 10 concentrates on the Sun, our nearest star, exploring

its various components and the solar activity cycle. Moving out-

ward, Chapters 11 through 14 examine all aspects of stars. Chapter

11 begins by presenting observational traits of stars – their colors

and types – and goes on to show how we measure their distances,

brightnesses, and motions. It also discusses binary stars, variable

stars, and star clusters, in the process showing how we derive stellar

masses and ages. Chapter 12 answers the question of how stars shine

and reveals that all stars have life cycles. Chapter 13 tells what hap-

pens when stars die and describes some of the peculiar objects that

violent stellar death can create, including neutron stars and pulsars.

Black holes, the most bizarre objects to result from star death, are the

focus of Chapter 14. We end the chapter by describing how the Laser

Interferometer Gravitational-wave Observatory (LIGO) detected,

several times, the tiniest possible variation in the length of a light

beam, with the waves interpreted as coming from the merger of two

black holes each containing 10−30 times as much mass as the Sun.

And in August 2017, LIGO even detected the merger of two neutron

stars simultaneously with telescopes around the world and in space

seeing the event in ordinary, electromagnetic radiation. We are in the

era of “Multi-Messenger Astronomy,” as NASA has recently put it:

“photons, gravitational waves, and particle astrophysics.”

As we explore further, Chapter 15 describes the parts of the Milky

Way Galaxy and our place in it. Chapter 16 pushes beyond the Milky

Way to discuss galaxies in general, the fundamental units of the

Universe, and evidence that they consist largely of dark matter. Ways

in which we are studying the evolution of galaxies are also described.

Chapter 17 looks at quasars, distant and powerful objects that shine

because gigantic black holes are swallowing gas in the central regions

of galaxies.

Chapters 18 and 19 consider the ultimate questions of cosmo-

logical creation by analyzing recent findings and current theories.

Evidence that the expansion of the Universe is currently speeding

up with time (probably propelled by a mysterious “dark energy”),

possibilities for the overall geometry and fate of the Universe, rip-

ples in the cosmic background radiation, the origin and early expo-

nential growth of the Universe, and the idea of multiple universes

are among the fascinating (and sometimes very speculative) topics

explored. Lastly, Chapter 20 discusses the always-intriguing search

for extraterrestrial intelligence.

FEATURES

The Cosmos: Astronomy in the New Millennium offers instructors a

concise overview of a wide range of astronomical topics. An early

discussion of the scientific method stresses its importance in the ver-

ification of observations. The text presents up-to-date coverage of

many important findings and theories as well as the latest images,

including observations of Jupiter and Saturn from the Cassini–

Huygens mission (including the landing on Titan), close-up obser-

vations of Mars, images of stars in formation and of gas near them

from the largest telescopes in space, and coverage of recent total

solar eclipses and of the pair of transits of Venus – the like of which

will not be seen on Earth until the year 2117, in the twenty-second

century.

We provide, as well, a sampling of the many significant find-

ings from the Hubble Space Telescope. Numerous images from the

Chandra X-ray Observatory, the Spitzer Space Telescope, the Planck

spacecraft that studied the cosmic background radiation, and the

Gaia spacecraft that is mapping a billion of the nearest stars, also

appear, as do results from the Swift spacecraft that is monitoring

gamma-ray bursts, among the most powerful and violent phenom-

ena in the Universe (the origin of one type of which is now proven

by observations of the merging neutron stars). Of particular interest

is the recent advance in our understanding of the age and expansion

of the Universe, both through better measurements of the current

expansion rate and through the discovery that the Universe’s expan-

sion is now speeding up with time. We also present the recent excit-

ing measurements that allow astronomers to determine the overall

geometry of the Universe and the early appearance of large-scale

structure through detailed observations of the cosmic background

radiation.

PEDAGOGY

1. Chapteropener. Each chapter includes the following features:

• Origins. NASA has chosen Origins as one of its major themes

for the organization of its missions and has several spacecraft

in the Origins program. Inspired by this choice, each chapter

piques the reader’s interest with some of the discoveries, tools,

and theories behind our effort to understand the Universe and

its relationship to us.

• Chapter introduction, summarizing the main topics discussed

in each chapter and how these fit into the rest of the book.

• Aims, setting out what students should expect to learn from

the material that follows.

2. StarParties. An occasional feature that shows students how to

find things in the sky. These include observing exercises and links

to the star maps that appear on the inside covers of the book. For

example, Star Party 5.1 explains how to sketch the position of

Mars or Jupiter in relation to the stars near them, repeating this

exercise every 6–9 days over the course of 2–3 months. Students

examine their results to see the planets in their prograde and ret-

rograde motions, which are important to understand in order to




xxii Preface

properly comprehend the work of Copernicus and how it super-

seded the model of Ptolemy.

3. FigureItOut. In some astronomy courses, it may be appropri-

ate to elaborate on equations. Because we wrote The Cosmos:

Astronomy in the New Millennium to be a descriptive presenta-

tion of modern astronomy for liberal-arts students, we kept

the use of mathematics to a minimum. However, we recognize

that some instructors wish to introduce their students to more

of the mathematics associated with astronomical phenomena.

Consequently, we provide mathematical features, numbered so

they can be assigned or not, at the instructor’s option. Figure It

Out 5.1, for example, gives a mathematical treatment of Kepler’s

third law that can be included in a course in a way that is easy to

mark on a syllabus; similarly, Figure It Out 5.2 gives professors the

option of introducing Newton’s formulation of Kepler’s third law

to find masses.

4. LivesinScience. These boxes provide biographies of important

historical figures like 5.1 Copernicus, 5.2 Tycho, 5.3 Kepler, 5.4

Galileo, and 5.5 Newton. Lives in Science 10.1 discusses Albert

Einstein.

5. ACloserLook. Using these boxes, students can further explore

interesting topics, such as size scales in the Universe, observing

with large telescopes, various celestial phenomena, mythology,

and naming systems. For example, we are pleased to supply some

exciting new close-up views of Mars from NASA’s Curiosity rover

that is now on its surface in A Closer Look 6.5, whereas in A Closer

Look 5.1 we specifically define the main features of the Ptolemaic

system: deferent, epicycle, and equant.

6. Keywordsandglossary. New vocabulary is boldfaced in the text

and in the expanded summaries that are given at the end of each

chapter, and defined in the glossary.

7. Chaptersummary. Each chapter includes the following features:

• Concept Review, summarizing the main topics discussed.

• Questions. An expanded set of end-of-chapter questions cov-

ers a range of material and includes some that are straight-

forward to answer from the text and others that require more

thought.

• Topics for Discussion. A list of themes and questions aimed at

engaging students in deeper explorations of the material dis-

cussed in each chapter.

8. Appendices for additional coverage. Appendices at the end of

the book provide additional information on planets, stars, con-

stellations, and nonstellar objects.

9. SkyMaps. Inside the covers of the book, students will find the

exceptionally beautiful sky maps by Wil Tirion to help them find

their way around the sky when they go outside to observe the

stars.

ONLINE RESOURCES

Adopters of The Cosmos, 5th edition, can access a rich array of teach-

ing and learning resources at http://thecosmos5.com. The website

(together with the authors’ personal website http://www.solarcorona

.net) is regularly updated to include the latest discoveries and photo-

graphs from various sources. It features the following:

• Multiple-choice self-tests and other useful information such as lists

of typographical errors, updates to various new scientific discov-

eries since the publication of the textbook, and links to websites

such as those with new discoveries as yet unknown at the time of

this printing.

• “Misconceptions.” Recent educational research has shown that stu-

dents often need to unlearn incorrect ideas in order to understand

the correct ones. A list of these misconceptions – as well as the

correct alternatives – is available on our website.

• Links to relevant websites on a wide variety of astronomical mate-

rial, such as http://photojournal.jpl.nasa.gov for planetary images;

http://sidc.oma.be/silso for the latest sunspot cycle plots; http://

spaceweather.com for the latest on daily sunspots or auroras;

and http://hubblesite.org for a wide range of new Hubble Space

Telescope observations.

• People in Astronomy. A series of interviews presenting a famous

contemporary astronomer engaged in conversation about a

variety of topics, such as: current and future work in astron-

omy, what led that person to study and pursue astronomy as

a career, and why learning about astronomy is an important

scientific and human endeavor. We interviewed a diverse set

of astronomers – diverse both personally and in astronomical

field of study. We discussed Saturn with Carolyn Porco, the

head of the Saturn imaging team on the Cassini spacecraft;

brown dwarfs and exoplanet astronomy with Gibor Basri and

how he got interested in astronomy; space astronomy with Jeff

Hoffman, a former astronaut who helped upgrade the Hubble

Space Telescope in orbit; and Sandra Faber about galaxies. We

hope that students enjoy reading their comments as much as

we enjoyed speaking with them and learning about their varied

interests and backgrounds.

STAR CHARTS

Pasachoff ’s Peterson Field Guide to the Stars and Planets is a suggested

accompaniment for those wanting monthly star maps, star charts,

and other detailed observing aids; see http://www.solarcorona.com.

Quarterly star maps, improved and redrawn for us for The Cosmos:

Astronomy for the New Millennium by the foremost celestial cartog-

rapher, Wil Tirion of The Netherlands, appear on the inside covers

in The Cosmos, 5th edition.

ACKNOWLEDGMENTS

The publishers join us in placing a heavy premium on accuracy, and

we have made certain that the manuscript and past editions have

been carefully read and considered. As a result, students will find that

the statements in this book, brief as they are, are authoritative.

This fifth edition of The Cosmos benefited from new and updated

photographs and comments on text from Seth Shostak (SETI Institute)




Preface xxiii

on SETI, Daniel Wertheimer (University of California, Berkeley) on

SETI, Lynn Cominsky (Sonoma State University) on gamma-ray astron-

omy, Leon Golub (Harvard-Smithsonian Center for Astrophysics) on

heliophysics, Joel Weisberg (Carleton College) on gravitational waves

from the double pulsar, Richard Manchester (CSIRO, Australia) on

pulsars, Rosemary Killen (NASA’s Goddard Space Flight Center)

and Carl Schmidt (University of Virginia) on Mercury, Augustin

Sanchez Lavega (Valencia) on the winds of Jupiter and Saturn, Laura

Brenneman (Harvard-Smithsonian Center for Astrophysics) on future

x-ray missions, Alan Guth (MIT) and Adrienne Erickcek (University

of North Carolina) on the inflationary universe, and Eric Nash

(NASA’s Goddard Space Flight Center) on the ozone hole. We also

thank William Graham for useful comments. The fourth edition of

The Cosmos benefited from the advice and special images provided

by Lynn Cominsky (Sonoma State University), Leon Golub (Harvard-

Smithsonian Center for Astrophysics), Joel Weisberg (Carleton

College), Daniel Seaton (Royal Observatory of Belgium), John Johnson

(Harvard-Smithsonian Center for Astrophysics), Robert Simmon

(NASA’s Goddard Space Flight Center), Richard McCray (University of

Colorado), Richard Manchester (CSIRO, Australia), Daniel Stern (Jet

Propulsion Laboratory), Daniel Mortlock (Imperial College, London),

Matthew Templeton and Arne Hernden (AAVSO), Stefan Fichtel

(Ixtract), Federica Bianco (Las Cumbres Observatory Global Telescope

Network and the University of California, Santa Barbara), Gareth

Williams (Harvard-Smithsonian Center for Astrophysics), Lorne

McKee (National Resources Canada), Jens Vellev (Aarhus University),

Gerard van Belle (Lowell Observatory), Geoff Marcy (University of

California, Berkeley), Wayne Hammond (Chapin Library of Williams

College), and Axel Mellinger (Central Michigan University).

At the time of proof for the fifth edition, we benefitted from

additional consultations with Gerald Williger (U. Louisville; cur-

rently a Fulbright Scholar at Konkoly Observatory) on the full

set of chapters; Mark Showalter (SETI Institute), Jupiter’s moons;

Carolyn Porco (Southwest Research Institute), Cassini/Saturn;

Imke de Pater (U. California, Berkeley), outer planets; Lindy Elkins-

Tanton (Arizona State U.), lunar minerals and water; Beatriz

Garcia (Pierre Auger Observatory, Argentina), cosmic rays; David

Ehrenreich (U. Geneva), exoplanets; Bruce Elmegreen (IBM) and

Clare Dobbs (U. Exeter), M51 modeling; Mansi Kasliwal (Caltech),

Palomar Transient Factory and Zwicky Telescope Facility; Doug Gies

(Georgia State U.), CHARA; Howard Bond (Penn State and STScl),

V838 Cygni; Lorenzo Reynard (South African Radio Astronomy

Observatory), Square Kilometer Array; Marek Demianski (Williams

College and University of Warsaw), supernovae and cosmology;

Alan Stern and Cathy Olkin (SwRI), Dale Cruikshank (NASA Ames),

Rick Binzel (MIT), Bill McKinnon (Washington U.), Pluto; and

Eric Mamajek (NASA’s JPL-Caltech), planetary and stellar data and

names.

For her extensive editorial consulting, we thank Madeline Kennedy

in Williamstown. For additional assistance, we thank Michele Rech

in Williamstown.

At Cambridge University Press, we thank our commissioning

editor Vince Higgs, and Ilaria Tassistro and her editorial team, as well

as Charlie Howell and his production team.

J.M.P. thanks various members of his family, who have pro-

vided vital and valuable editorial services in addition to their gen-

eral support. His wife, Naomi, has always been very helpful both

personally and editorially. He is grateful for the family support of

Deborah Pasachoff/Ian Kezsbom/Lily Kezsbom/Jacob Kezsbom/

Xander Kezsbom and of Eloise Pasachoff/Tom Glaisyer/Samuel

Glaisyer/Jessica Glaisyer.

A.F. thanks his children, Zoe, Simon, Caprielle, and Orion

Filippenko, for the long hours they endured while he was busy work-

ing on this book rather than spending time with them; they mean

the universe to him. A.F. also thanks his wife, Noelle Filippenko, for

her incredible patience, advice, and support; he could not have suc-

ceeded without her, and he looks forward to sharing more of the

wonders of the cosmos with her.

We are extremely grateful to all the individuals named above for

their assistance. Of course, it is we who have put this all together,

and we alone are responsible for the content. We would appreciate

hearing from readers with suggestions for improved presentation

of topics, with comments about specific points that need clarifi-

cation, with typographical or other errors, or just to tell us about

your astronomy course. We invite readers to write to us, respec-

tively, at Williams College, Hopkins Observatory, 33 Lab Campus

Drive, Williamstown, MA 01267–2565, [email protected], and

Department of Astronomy, University of California, Berkeley, CA

94720–3411, [email protected], or through the book’s web-

sites. We promise a personal response to each writer.

Jay Pasachoff

Alex Filippenko




A close-up view of the surface of dwarf planet Pluto, taken as NASA’s New Horizons spacecraft lew by on July 14, 2015, along with a full-disk view taken as the spacecraft

approached. The heart-shaped region is Sputnik Planitia. At bottom right, in enhanced color, we see features that rise 1.5 miles high, scarred by clusters of pits 5–8 miles across and

up to 1.5 miles deep, deeper than our Earth’s Grand Canyon.

NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

Documents

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