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ASTRONOMY TRONOASTRONOMYTODAY TODAYTODAY A01_CHAI0067_07_SE_NASTAFM.qxd 6/3/10 3:04 PM Page ii A01_CHAI0067_07_SE_NASTAFM.qxd 6/3/10 3:04 PM Page iii

ASTRONOMY TODAY

SEVENTH EDITION

ERIC CHAISSON

STEVE MCMILLAN DREXEL UNIVERSITY A01_CHAI0067_07_SE_NASTAFM.qxd 6/14/10 1:18 PM Page iv

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Library of Congress Cataloging-in-Publication Data

Chaisson, Eric. Astronomy today / Eric Chaisson, Steve McMillan.—7th ed. p. cm. Includes bibliographical references and index. ISBN 978-0-13-240085-5 (hardcover : alk. paper) 1. Astronomy. I. McMillan, S. (Stephen), 1955–II. Title. QB43.3.C48 2011 520—dc22 2010017125

ISBN 10-digit 0-13-212006-2; 13-digit 978-0-13-212006-7 (High School Binding)

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BRIEF CONTENTS

Astronomy and the Universe 1

1 Charting the Heavens: The Foundations of Astronomy 2 2 The Copernican Revolution: The Birth of Modern Science 30 PART 3 Radiation: Information from the Cosmos 56 4 Spectroscopy: The Inner Workings of Atoms 76 5 Telescopes: The Tools of Astronomy 96

1 Our Planetary System 130 6 The Solar System: An Introduction to Comparative Planetology 132 7 Earth: Our Home in Space 154 8 The Moon and Mercury: Scorched and Battered Worlds 182 9 Venus: Earth’s Sister Planet 210 10 Mars: A Near Miss for Life? 230 PART 11 Jupiter: Giant of the Solar System 258 12 Saturn: Spectacular Rings and Mysterious Moons 284 13 Uranus and Neptune: The Outer Worlds of the Solar System 312 2 14 Solar System Debris: Keys to Our Origin 332 15 The Formation of Planetary Systems: The Solar System and Beyond 360

Stars and Stellar 382

16 The Sun: Our Parent Star 384 17 The Stars: Giants, Dwarfs, and the Main Sequence 416 18 The Interstellar Medium: Gas and Dust among the Stars 444 PART 19 Star Formation: A Traumatic Birth 464 20 : The Life and Death of a Star 490 21 Stellar Explosions: Novae, Supernovae, and the Formation of the Elements 516 3 22 Neutron Stars and Black Holes: Strange States of Matter 660 Galaxies and Cosmology 570

23 The : A Spiral in Space 572 24 Galaxies: Building Blocks of the Universe 602 25 Galaxies and Dark Matter: The Large-Scale Structure PART of the Cosmos 634 26 Cosmology: The and the Fate of the Universe 660 27 The Early Universe: Toward the Beginning of Time 682 4 28 Life in the Universe: Are We Alone? 706 A01_CHAI0067_07_SE_NASTAFM.qxd 6/3/10 3:04 PM Page vi

2.4 The Birth of Modern Astronomy 39 2.5 The Laws of Planetary Motion 42 CONTENTS ■ More Precisely 2-1 | Some Properties of Planetary Orbits 44 2.6 The Dimensions of the Solar System 45 About the Authors xvi 2.7 Newton’s Laws 47 Preface xvii 2.8 Newtonian Mechanics 50 ■ More Precisely 2-2 | Weighing the Sun 52 • ANIMATION/VIDEO | Retrograde Motion of Mars 35 • ANIMATION/VIDEO | Geocentric Solar System 36 PART • ANIMATION/VIDEO | Heliocentric Solar 1 System 39 Astronomy and the Universe 1 • ANIMATION/VIDEO | Earth Captures a Temporary Moon 50 1 CHARTING THE HEAVENS Chapter Review 54 THE FOUNDATIONS OF ASTRONOMY 2 1.1 Our Place in Space 4 1.2 Scientific Theory and the Scientific Method 6 1.3 The “Obvious” View 8 ■ More Precisely 1-1 | Angular Measure 11 1.4 Earth’s Orbital Motion 12 1.5 The Motion of the Moon 16 1.6 The Measurement of Distance 23 ■ More Precisely 1-2 | Measuring Distances with Geometry 26 • ANIMATION/VIDEO | Summer Solstice 14 • ANIMATION/VIDEO | Winter Solstice 15 • ANIMATION/VIDEO | The Earth’s Seasons 15 • ANIMATION/VIDEO | The Equinoxes 15 • TUTORIAL | Phases of the Moon 17 • ANIMATION/VIDEO | Solar Eclipse in Indiana 19 • TUTORIAL | Stellar Parallax 24 Chapter Review 27

2 THE COPERNICAN REVOLUTION THE BIRTH OF MODERN SCIENCE 30 2.1 Ancient Astronomy 32 2.2 The Geocentric Universe 34 2.3 The Heliocentric Model of the Solar System 37 ■ Discovery 2-1 | Foundations of the Copernican Revolution 38 A01_CHAI0067_07_SE_NASTAFM.qxd 6/3/10 3:04 PM Page vii

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RADIATION 5.5 Radio Astronomy 114 3 5.6 Interferometry 118 INFORMATION FROM THE COSMOS 56 5.7 Space-Based Astronomy 120 3.1 Information from the Skies 58 5.8 Full-Spectrum Coverage 126 3.2 Waves in What? 61 • TUTORIAL | The Optics of a Simple Lens 99 3.3 The Electromagnetic Spectrum 63 • TUTORIAL | Chromatic Aberration 99 TUTORIAL | Reflecting Telescopes 101 ■ Discovery 3-1 | The Wave Nature of Radiation 65 • ANIMATION/VIDEO | in Orbit 104 3.4 Thermal Radiation 66 • • ANIMATION/VIDEO | Deployment of the James Webb Space ■ More Precisely 3-1 | The Kelvin Temperature Scale 67 Telescope 105 ■ More Precisely 3-2 | More About the Radiation Laws 70 • ANIMATION/VIDEO | Gemini Control Room 106 3.5 The Doppler Effect 71 • ANIMATION/VIDEO | Speckle Imaging 107 ■ More Precisely 3-3 | Measuring Velocities with • ANIMATION/VIDEO | Adaptive Optics 113 the Doppler Effect 73 • ANIMATION/VIDEO | Chandra Light and Data • ANIMATION/VIDEO | Fresnel Diffraction 65 Paths 124 • TUTORIAL | Continuous Spectra and Blackbody Chapter Review 127 Radiation 66 • ANIMATION/VIDEO | Solar Eclipse Viewed in X rays 70 • ANIMATION/VIDEO | Multispectral View of Orion Nebula 70 • ANIMATION/VIDEO | Earth Aurora in X rays 70 • ANIMATION/VIDEO | Shoemaker-Levy 9 Impact at 2.15 Microns 71 • TUTORIAL | Doppler Effect 71 Chapter Review 74

4 SPECTROSCOPY THE INNER WORKINGS OF ATOMS 76 4.1 Spectral Lines 78 4.2 Atoms and Radiation 82 4.3 The Formation of Spectral Lines 84 ■ More Precisely 4-1 | The Hydrogen Atom 86 ■ Discovery 4-1 | The Photoelectric Effect 88 4.4 Molecules 89 4.5 Spectral-Line Analysis 90 • TUTORIAL | Emission Spectra 80 • TUTORIAL | Absorption Spectra 80 • ANIMATION/VIDEO | Classical Hydrogen Atom I/Classical Hydrogen Atom II 86 • ANIMATION/VIDEO | Photon Emission 87 Chapter Review 94

5 TELESCOPES THE TOOLS OF ASTRONOMY 96 5.1 Optical Telescopes 98 5.2 Telescope Size 102 ■ Discovery 5-1 | The Hubble Space Telescope 104 5.3 Images and Detectors 108 5.4 High-Resolution Astronomy 110 A01_CHAI0067_07_SE_NASTAFM.qxd 6/3/10 3:04 PM Page viii

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PART2 Our Planetary System 130

6 THE SOLAR SYSTEM AN INTRODUCTION TO COMPARATIVE PLANETOLOGY 132 6.1 An Inventory of the Solar System 134 6.2 Measuring the Planets 136 6.3 The Overall Layout of the Solar System 137 6.4 Terrestrial and Jovian Planets 138 6.5 Interplanetary Matter 140 6.6 Spacecraft Exploration of the Solar System 141 ■ Discovery 6-1 | Gravitational “Slingshots” 144 6.7 How Did the Solar System Form? 146 ■ More Precisely 6-1 | Angular Momentum 148 • ANIMATION/VIDEO | An Astronomical Ruler 137 • ANIMATION/VIDEO | Size and Scale of the Terrestrial Planets I & II, The Gas Giants 138 • TUTORIAL | Comparative Planetology Mars 139 • ANIMATION/VIDEO | Solar System Formation 150 • ANIMATION/VIDEO | Protoplanteary Disk Destruction 150 8 THE MOON AND MERCURY Chapter Review 151 SCORCHED AND BATTERED WORLDS 182 7 EARTH 8.1 Orbital Properties 184 OUR HOME IN SPACE 154 8.2 Physical Properties 185 8.3 Surface Features on the Moon and 7.1 Overall Structure of Planet Earth 156 Mercury 186 7.2 Earth’s Atmosphere 156 8.4 Rotation Rates 189 ■ More Precisely 7-1 | Why Is the Sky Blue? 159 ■ Discovery 8-1 | Lunar Exploration 190 ■ Discovery 7-1 | The Greenhouse Effect and Global ■ More Precisely 8-1 | Why Air Sticks Around 192 Warming 161 8.5 Lunar Cratering and Surface Composition 195 7.3 Earth’s Interior 162 8.6 The Surface of Mercury 200 ■ More Precisely 7-2 | Radioactive Dating 166 7.4 Surface Activity 167 8.7 Interiors 202 7.5 Earth’s Magnetosphere 174 8.8 The Origin of the Moon 204 7.6 The Tides 176 8.9 Evolutionary History of the Moon and Mercury 205 • ANIMATION/VIDEO | Earth as Seen by Galileo, NEAR Earth Swingby 158 • ANIMATION/VIDEO | Transit of Mercury 185 ANIMATION/VIDEO | Full Rotation of Moon 187 • TUTORIAL | Atmospheric Lifetimes 158 • ANIMATION/VIDEO | Lunar Flyby 187 • TUTORIAL | The Greenhouse Effect 160 • ANIMATION/VIDEO | Ranger Spacecraft Descent to • ANIMATION/VIDEO | Ozone Hole Over the Antarctic 160 • Moon 190 • ANIMATION/VIDEO | Northern and Southern Lights 176 • ANIMATION/VIDEO | First Step on the Moon 191 Chapter Review 179 • ANIMATION/VIDEO | Protoplanetary Collision 204 Chapter Review 207 A01_CHAI0067_07_SE_NASTAFM.qxd 6/3/10 3:04 PM Page ix

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9 VENUS 11 JUPITER EARTH’S SISTER PLANET 210 GIANT OF THE SOLAR SYSTEM 258 9.1 Orbital Properties 212 11.1 Orbital and Physical Properties 260 9.2 Physical Properties 213 11.2 The Atmosphere of Jupiter 262 9.3 Long-Distance Observations of Venus 214 ■ Discovery 11-1 | A Cometary Impact 268 9.4 The Surface of Venus 215 11.3 Internal Structure 268 9.5 The Atmosphere of Venus 223 ■ Discovery 11-2 | Almost a Star? 270 9.6 Venus’s Magnetic Field and Internal 11.4 Jupiter’s Magnetosphere 271 Structure 227 11.5 The Moons of Jupiter 273 11.6 Jupiter’s Ring 281 • TUTORIAL | Superspaceship—Voyage to Venus 213 • TUTORIAL | Jupiter—Differential Rotation 261 • ANIMATION/VIDEO | The Rotation of • ANIMATION/VIDEO | Jupiter’s Rotation 262 Venus 213 • ANIMATION/VIDEO | Jupiter’s Atmosphere Dynamics 265 • ANIMATION/VIDEO | Transit of Venus 214 • ANIMATION/VIDEO | Galileo Mission to Jupiter 265 • ANIMATION/VIDEO | Flight Over Alpha Regio 215 • ANIMATION/VIDEO | Jupiter’s Rotating Red Spot 266 • ANIMATION/VIDEO | Topography of Venus 216 • ANIMATION/VIDEO | The Gas Giants II 268 • ANIMATION/VIDEO | Flight Over Sif Mons • ANIMATION/VIDEO | Comet Impact with Jupiter 269 Volcano 218 • ANIMATION/VIDEO | Galilean Moons Transit Jupiter 275 • ANIMATION/VIDEO | Io Cutaway 276 Chapter Review 227 • ANIMATION/VIDEO | Galileo’s View of Europa 278 • ANIMATION/VIDEO | Galileo’s View of Ganymede 279 • ANIMATION/VIDEO | Jupiter Icy Moons Orbiter 10 MARS Mission 280 A NEAR MISS FOR LIFE? 230 Chapter Review 281 10.1 Orbital Properties 232 10.2 Physical Properties 233 10.3 Long-Distance Observations of Mars 233 10.4 The Martian Surface 234 10.5 Water on Mars 239 ■ Discovery 10-1 | Life on Mars? 248 10.6 The Martian Atmosphere 250 10.7 Martian Internal Structure 253 10.8 The Moons of Mars 253 • ANIMATION/VIDEO | Hubble View of Mars 234 • ANIMATION/VIDEO | Flight Over Tharsis 235 • ANIMATION/VIDEO | Flight Over Mariner Valley 237 • ANIMATION/VIDEO | Hubble View of Mars Polar Cap 242 • ANIMATION/VIDEO | Flight Over Columbia Hills 244 • ANIMATION/VIDEO | Flight Over Opportunity at Gustav Crater 246 • ANIMATION/VIDEO | Mars Rover Landing 246 • ANIMATION/VIDEO | Meteorites Ejected from Mars 249 • ANIMATION/VIDEO | Microscopic Martian Fossils? 249 • ANIMATION/VIDEO | Martian Moons: Phobos & Deimos 254 Chapter Review 255 A01_CHAI0067_07_SE_NASTAFM.qxd 6/3/10 3:04 PM Page x

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13.6 The Rings of the Outermost Jovian Planets 326 • ANIMATION/VIDEO | Rotation of Neptune 315 • ANIMATION/VIDEO | Rotation of Uranus 318 • ANIMATION/VIDEO | Neptune’s Dark Spot 319 • ANIMATION/VIDEO | Geysers on Triton 325 Chapter Review 329

14 SOLAR SYSTEM DEBRIS KEYS TO OUR ORIGIN 332 14.1 Asteroids 334 ■ Discovery 14-1 | What Killed the Dinosaurs? 338 14.2 Comets 340 14.3 Beyond Neptune 348 14.4 Meteroids 353 • ANIMATION/VIDEO | Orbiting Eros, NEAR Descent, NEAR Landing 337 • ANIMATION/VIDEO | Sun Grazing Comets 341 • ANIMATION/VIDEO | Anatomy of a Comet Part I 341 • ANIMATION/VIDEO | Comet Hale-Bopp Nucleus Animation 342 • ANIMATION/VIDEO | Anatomy of a Comet Part 2 342 • ANIMATION/VIDEO | Deep Impact Simulation, Deep Impact 12 SATURN Probe Hits Tempel 1 347 SPECTACULAR RINGS AND MYSTERIOUS • ANIMATION/VIDEO | Historical Observations of Pluto, MOONS 284 Orbits of Neptune and Pluto 349 • ANIMATION/VIDEO | Hubble’s View of Pluto 350 12.1 Orbital and Physical Properties 286 • ANIMATION/VIDEO | Asteroid/Comet Breakup 354 12.2 Saturn’s Atmosphere 286 • ANIMATION/VIDEO | Delta Capricornid Meteor Near Orion, 12.3 Saturn’s Interior and Magnetosphere 291 Daytime Passage of Meteor Fireball 354 12.4 Saturn’s Spectacular Ring System 292 Chapter Review 357 12.5 The Moons of Saturn 299 ■ Discovery 12-1 | Dancing Among Saturn’s Moons 301 15 THE FORMATION OF • ANIMATION/VIDEO | Saturn Eclipse 287 PLANETARY SYSTEMS • ANIMATION/VIDEO | Saturn Cloud Rotation 289 THE SOLAR SYSTEM AND BEYOND 360 • ANIMATION/VIDEO | Saturn Ring Plane Crossing 293 • ANIMATION/VIDEO | Voyager Ring Spokes 297 15.1 Modeling Planet Formation 362 • ANIMATION/VIDEO | Saturn Satellite Transit 298 15.2 Terrestrial and Jovian Planets 363 • ANIMATION/VIDEO | Huygens Landing on Titan 304 15.3 Interplanetary Debris 366 Chapter Review 309 15.4 Solar System Regularities and Irregularities 368 15.5 Searching for Extrasolar Planets 369 15.6 Properties of Exoplanets 372 13 URANUS AND NEPTUNE 15.7 Is Our Solar System Unusual? 376 THE OUTER WORLDS OF THE SOLAR • ANIMATION/VIDEO | The Formation of the Solar System, SYSTEM 312 Evolution of Protoplanetary Disk, Protoplanetary Disks in the Orion Nebula, Protoplanetary Disk Destruction 363 13.1 The Discoveries of Uranus and Neptune 314 • ANIMATION/VIDEO | Hot Jupiter Extrasolar Planet 13.2 Orbital and Physical Properties 316 Evaporating 377 13.3 The Atmospheres of Uranus and Neptune 318 • ANIMATION/VIDEO | Survey for Transiting Extrasolar 13.4 Magnetospheres and Internal Structure 320 Planets 377 13.5 The Moon Systems of Uranus and Neptune 322 Chapter Review 379 A01_CHAI0067_07_SE_NASTAFM.qxd 6/3/10 3:04 PM Page xi

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• TUTORIAL | SuperSpaceship—Voyage to the Sun 386 • ANIMATION/VIDEO | Solar Granulation 392 • ANIMATION/VIDEO | Solar Chromosphere 395 • ANIMATION/VIDEO | Sunspot 397 PART • ANIMATION/VIDEO | Solar Flare 403 3 ANIMATION/VIDEO | Coronal Mass Ejections 403 Stars and Stellar Evolution 382 • • ANIMATION/VIDEO | Tritium-Helium Fusion 409 Chapter Review 413 16 THE SUN OUR PARENT STAR 384 17 THE STARS 16.1 Physical Properties of the Sun 386 GIANTS, DWARFS, AND THE MAIN 16.2 The Solar Interior 388 ■ Discovery 16-1 | SOHO: Eavesdropping on the SEQUENCE 416 Sun 391 16.3 The Sun’s Atmosphere 393 17.1 The Solar Neighborhood 418 16.4 Solar Magnetism 396 17.2 Luminosity and Apparent Brightness 421 16.5 The Active Sun 401 17.3 Stellar Temperatures 423 ■ More Precisely 17-1 | More on the Magnitude ■ Discovery 16-2 | Solar–Terrestrial Relations 404 Scale 425 16.6 The Heart of the Sun 406 17.4 Stellar Sizes 428 16.7 Observations of Solar Neutrinos 409 ■ More Precisely 17-2 | Estimating Stellar Radii 429 ■ More Precisely 16-1 | Fundamental Forces 410 17.5 The Hertzsprung–Russell Diagram 430 ■ More Precisely 16-2 | Energy Generation in 17.6 Extending the Cosmic Distance Scale 433 the Proton–Proton Chain 412 17.7 Stellar Masses 436 ■ More Precisely 17-3 | Measuring Stellar Masses in Binary Stars 438 17.8 Mass and Other Stellar Properties 438 • ANIMATION/VIDEO | The Inverse-Square Law 421 • TUTORIAL | Hertzsprung–Russell Diagram 432 • ANIMATION/VIDEO | White Dwarfs in Globular Cluster 432 • TUTORIAL | Binary Stars—Radial Velocity Curves 436 • TUTORIAL | Eclipsing Binary Stars—Light Curves 438 Chapter Review 441

18 THE INTERSTELLAR MEDIUM GAS AND DUST AMONG THE STARS 444 18.1 Interstellar Matter 446 18.2 Emission Nebulae 449 18.3 Dark Dust Clouds 455 18.4 21-Centimeter Radiation 458 18.5 Interstellar Molecules 460 • ANIMATION/VIDEO | Infrared View of Nebulae 447 • ANIMATION/VIDEO | Gaseous Pillars of Star Birth, The Eagle Nebula 452 • ANIMATION/VIDEO | Orion Nebula Mosaic 454 • ANIMATION/VIDEO | Pillars Behind the Dust, The Tarantula Nebula 455 • ANIMATION/VIDEO | Horsehead Nebula 457 Chapter Review 462 A01_CHAI0067_07_SE_NASTAFM.qxd 6/3/10 3:04 PM Page xii

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• ANIMATION/VIDEO | Binary Brown Dwarfs 475 • ANIMATION/VIDEO | Visit to Orion Nebula 477 • ANIMATION/VIDEO | Protostars 478 • ANIMATION/VIDEO | Herbig–Haro Objects 479 • ANIMATION/VIDEO | Bipolar Outflow 479 • ANIMATION/VIDEO | Triggered Star Formation 481 • ANIMATION/VIDEO | Carina Nebula 486 Chapter Review 487

20 STELLAR EVOLUTION THE LIFE AND DEATH OF A STAR 490 20.1 Leaving the Main Sequence 492 20.2 Evolution of a Sun-like Star 493 20.3 The Death of a Low-Mass Star 498 ■ Discovery 20-1 | Learning Astronomy from History 503 20.4 Evolution of Stars More Massive than the Sun 505 ■ Discovery 20-2 | Mass Loss from Giant Stars 507 20.5 Observing Stellar Evolution in Star Clusters 508 20.6 Stellar Evolution in Binary Systems 511 • ANIMATION/VIDEO | H–R Diagram Tracks Stellar Evolution 494 • ANIMATION/VIDEO | Red Giant Evolution 495 • ANIMATION/VIDEO | Death of the Sun Part I 498 • ANIMATION/VIDEO | Death of the Sun Part II 499 • ANIMATION/VIDEO | Helix Nebula Formation 500 • ANIMATION/VIDEO | Helix Nebula, Helix Nebula White Dwarf, White Dwarf Cooling Sequence, Bi-Polar Planetary Nebula 502 • ANIMATION/VIDEO | Light Echo 507 Chapter Review 513

21 STELLAR EXPLOSIONS 19 STAR FORMATION NOVAE, SUPERNOVAE, AND THE FORMATION A TRAUMATIC BIRTH 464 OF THE ELEMENTS 516 21.1 Life after Death for White Dwarfs 518 19.1 Star-Forming Regions 466 21.2 The End of a High-Mass Star 520 ■ More Precisely 19-1 | Competition in Star Formation 467 21.3 Supernovae 522 19.2 The Formation of Stars Like the Sun 468 ■ Discovery 21-1 | Supernova 1987A 524 19.3 Stars of Other Masses 473 21.4 The Formation of the Elements 528 19.4 Observations of Cloud Fragments 21.5 The Cycle of Stellar Evolution 534 and Protostars 474 • ANIMATION/VIDEO | Recurrent Nova 519 ANIMATION/VIDEO | Shockwaves Hit the Ring of Supernova ■ Discovery 19-1 | Observations of Brown • Dwarfs 475 1987A, Composition and Structure of the Ring Around 19.5 Shock Waves and Star Formation 480 Supernova 1987A 525 • ANIMATION/VIDEO | Structure of Supernova, Supernova 19.6 Star Clusters 482 Explosion 526 ■ Discovery 19-2 | Eta Carinae 486 • ANIMATION/VIDEO | Supernova Remnant in Cassiopeia 528 • ANIMATION/VIDEO | Stellar Birth 471 Chapter Review 535 • ANIMATION/VIDEO | Evolution of a 1-Solar-Mass Star 472 A01_CHAI0067_07_SE_NASTAFM.qxd 6/3/10 3:04 PM Page xiii

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• TUTORIAL | Escape Speed and Black Hole Event Horizons 553 • ANIMATION/VIDEO | Energy Released from a Black Hole? 559 • ANIMATION/VIDEO | Black Hole and Companion Star, Black Hole Devours Neutron Star 561 • ANIMATION/VIDEO | Black Hole Geometry 562 • ANIMATION/VIDEO | Supermassive Black Hole, Black Hole in the Center of M31 563 Chapter Review 567

PART4 Galaxies and Cosmology 570

23 THE MILKY WAY GALAXY A SPIRAL IN SPACE 572 23.1 Our Parent Galaxy 574 23.2 Measuring the Milky Way 576 ■ Discovery 23-1 | Early “Computers” 580 23.3 Galactic Structure 582 23.4 The Formation of the Milky Way 585 23.5 Galactic Spiral Arms 587 ■ Discovery 23-2 | Density Waves 590 23.6 The Mass of the Milky Way Galaxy 591 23.7 The Galactic Center 595 • ANIMATION/VIDEO | Cepheid Variable Star in Distant Galaxy 578 • ANIMATION/VIDEO | Rotating Globular Cluster 593 • TUTORIAL | Gravitational Lensing 594 22 NEUTRON STARS AND • ANIMATION/VIDEO | X-ray View of Galactic Core 596 BLACK HOLES • ANIMATION/VIDEO | Black Hole in the Center of the Milky STRANGE STATES OF MATTER 538 Way? 597 Chapter Review 599 22.1 Neutron Stars 540 22.2 Pulsars 541 22.3 Neutron-Star Binaries 544 24 GALAXIES 22.4 Gamma-Ray Bursts 548 BUILDING BLOCKS OF THE 22.5 Black Holes 551 22.6 Einstein’s Theories of Relativity 553 UNIVERSE 602 ■ Discovery 22-1 | Special Relativity 555 24.1 Hubble’s Galaxy Classification 604 22.7 Space Travel Near Black Holes 557 24.2 The Distribution of Galaxies in Space 611 22.8 Observational Evidence for Black Holes 560 24.3 Hubble’s Law 615 ■ More Precisely 22-1 | Tests of General Relativity 564 ■ More Precisely 24-1 | Relativistic Redshifts and Look-Back ■ Discovery 22-2 | Gravity Waves: A New Window on the Time 618 Universe 566 24.4 Active Galactic Nuclei 618 • ANIMATION/VIDEO | Pulsar in Crab Nebula 543 • ANIMATION/VIDEO | X-ray Binary Star 545 24.5 The Central Engine of an Active Galaxy 626 • ANIMATION/VIDEO | Colliding Binary Neutron Stars 550 • ANIMATION/VIDEO | The Evolution of Galaxies 613 A01_CHAI0067_07_SE_NASTAFM.qxd 6/3/10 3:04 PM Page xiv

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• ANIMATION/VIDEO | Active Galaxy 620 • ANIMATION/VIDEO | Dark Matter 637 • ANIMATION/VIDEO | Eruption of a Supermassive Black Hole, • ANIMATION/VIDEO | Galaxy Collision I 639 M87 Jet 624 • ANIMATION/VIDEO | Starburst Galaxy 640 • ANIMATION/VIDEO | Birth of a Quasar 625 • ANIMATION/VIDEO | Galaxy Collision II 640 Chapter Review 631 • ANIMATION/VIDEO | Hubble Deep Field Zoom I, Hubble Deep Field Zoom II 643 • ANIMATION/VIDEO | Galaxy Merger 645 • ANIMATION/VIDEO | Cluster Merger 650 25 GALAXIES AND • ANIMATION/VIDEO | How a Gravitational Lens Works 654 • ANIMATION/VIDEO | Simulation of Gravitational Lens DARK MATTER in Space 656 THE LARGE-SCALE STRUCTURE • ANIMATION/VIDEO | Dark Matter Collision, Bullet Cluster OF THE COSMOS 634 Collision 657 Chapter Review 657 25.1 Dark Matter in the Universe 636 25.2 Galaxy Collisions 639 25.3 Galaxy Formation and Evolution 641 26 COSMOLOGY 25.4 Black Holes in Galaxies 646 THE BIG BANG AND THE FATE 25.5 The Universe on Large Scales 650 ■ Discovery 25-1 | The Sloan Digital Sky Survey 653 OF THE UNIVERSE 660 26.1 The Universe on the Largest Scales 662 26.2 The Expanding Universe 664 26.3 The Fate of the Cosmos 667 26.4 The Geometry of Space 669 ■ More Precisely 26-1 | Curved Space 671 26.5 Will the Universe Expand Forever? 672 26.6 Dark Energy and Cosmology 675 ■ Discovery 26-1 | Einstein and the Cosmological Constant 676 26.7 The Cosmic Microwave Background 677 • ANIMATION/VIDEO | Cosmic Structure 662 • ANIMATION/VIDEO | The Big Bang 665 • ANIMATION/VIDEO | Gravitational Curvature of Space 670 Chapter Review 679

27 THE EARLY UNIVERSE TOWARD THE BEGINNING OF TIME 682 27.1 Back to the Big Bang 684 27.2 The Evolution of the Universe 687 ■ More Precisely 27-1 | More on Fundamental Forces 688 27.3 The Formation of Nuclei and Atoms 690 27.4 The Inflationary Universe 694 27.5 The Formation of Structure in the Universe 698 27.6 Cosmic Structure and the Microwave Background 701 • ANIMATION/VIDEO | The First Stars Reionize the Universe 690 • ANIMATION/VIDEO | Cosmic Evolution, Cosmic Structure 699 • ANIMATION/VIDEO | Ripples in the Early Universe 701 • ANIMATION/VIDEO | COBE and WMAP View of Cosmic Microwave Background 702 Chapter Review 703 A01_CHAI0067_07_SE_NASTAFM.qxd 6/3/10 3:05 PM Page xv

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28 LIFE IN THE UNIVERSE Appendices A-1 ARE WE ALONE? 706 Appendix 1: Scientific Notation A-1 Appendix 2: Astronomical Measurement A-2 28.1 Cosmic Evolution 706 Appendix 3: Tables A-3 ■ Discovery 28-1 | The Virus 709 28.2 Life in the Solar System 714 28.3 Intelligent Life in the Galaxy 716 28.4 The Search for Extraterrestrial Intelligence 723 Glossary G-1 • ANIMATION/VIDEO | Icy Organics in Planet-Forming Disc 711 Answers to Concept Check Questions AK-1 • ANIMATION/VIDEO | Earth’s Biosphere in Action: Answers to Self-Test Questions AK-6 Plankton Bloom 714 Index I-1 • ANIMATION/VIDEO | Asteroid Impacting the Earth 720 Star Charts S-1 Chapter Review 725 A01_CHAI0067_07_SE_NASTAFM.qxd 6/3/10 3:05 PM Page xvi

ABOUT THE AUTHORS

Eric Chaisson Eric holds a doctorate in astrophysics from , where he spent ten years on the faculty of Arts and Sciences. For several years thereafter, he was a senior scientist and director of educational programs at the Space Telescope Science Institute and adjunct pro- fessor of physics at . For the past decade, Eric has been at Tufts University, where he is a research professor in the Department of Physics and in the School of Education, and director of the Wright Center for Innovative Science Education. He has written 12 books on astronomy, which have received such liter- ary awards as the Phi Beta Kappa Prize, two American Institute of Physics Awards, and Harvard’s Smith-Weld Prize for Literary Merit. He has published more than 100 scientific papers in professional journals and has also received Harvard’s Bok Prize for original contribu- tions to astrophysics.

Steve McMillan Steve holds a bachelor’s and master’s degree in mathe- matics from Cambridge University and a doctorate in astronomy from Harvard University. He held post- doctoral positions at the University of Illinois and Northwestern University, where he continued his research in theoretical astrophysics, star clusters, and high-performance computing. Steve is currently Distinguished Professor of Physics at Drexel University and a frequent visiting researcher at Princeton’s Institute for Advanced Study and Leiden University. He has pub- lished more than 70 scientific papers in professional journals.

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PREFACE

stronomy is a science that thrives on new discoveries. information. Several chapters have also seen significant reor- Fueled by new technologies and novel theoretical ganization in order to streamline the overall presentation, Ainsights, the study of the cosmos continues to change strengthen our focus on the process of science, and reflect our understanding of the universe. We are pleased to have new understanding and emphases in contemporary astron- the opportunity to present in this book a representative sam- omy. Among the many changes are: ple of the known facts, evolving ideas, and frontier discover- ● The Big Picture feature on each chapter opening spread ies in astronomy today. explains how chapter content fits in with an overall per- We present a broad view of astronomy, straightfor- spective on introductory astronomy, helping students wardly descriptive and without complex mathematics. The see how each chapter is connected to a broad under- absence of sophisticated mathematics, however, in no way standing of the universe. The theme is then called out prevents discussion of important concepts. Rather, we rely again in selected figures throughout the chapter. on qualitative reasoning as well as analogies with objects and phenomena familiar to the student to explain the com- ● Streamlined coverage—a reduction of over 50 pages— plexities of the subject without oversimplification. We have keeps students focused on the essentials they need to learn. tried to communicate the excitement we feel about astron- ● Further emphasis throughout on the process of science omy and to awaken students to the marvelous universe and how astronomers “know what they know.” around us. ● Updates on the Hubble Space Telescope, James Webb We are very gratified that the first six editions of this text Space Telescope, Spitzer Space Telescope, and Fermi have been so well received by many in the astronomy educa- Gamma-Ray Space Telescope in Chapter 5. tion community. In using those earlier texts, many teachers ● and students have given us helpful feedback and construc- A more complete account of the condensation theory of tive criticisms. From these, we have learned to communicate solar system formation in Chapter 6. better both the fundamentals and the excitement of astron- ● Coverage of the Lunar Reconnaissance Orbiter (LRO) omy. Many improvements inspired by these comments have and Lunar Crater Observation and Sensing Satellite been incorporated into this new edition. (LCROSS) missions in Chapter 8. ● New data and imagery from the Messenger mission on Focus of the Seventh Edition Mercury’s atmosphere, plains, and magnetosphere in From the first edition, we have tried to meet the challenge of Chapter 8. writing a book that is both accurate and accessible. To the ● New material on Mars’s Borealis Basin and NASA’s student, astronomy sometimes seems like a long list of unfa- Phoenix lander in Chapter 10. miliar terms to be memorized and repeated. Many new ● Updates on the 2009 comet collision with Jupiter and terms and concepts will be introduced in this course, but we new “red spot” storms on the planet in Chapter 11. hope students will also learn and remember how science is ● done, how the universe works, and how things are connected. Updates throughout Chapter 12 reflecting new Cassini In the seventh edition, we have taken particular care to show data and imagery, including discussion of storms on how astronomers know what they know, and to highlight Saturn, surface conditions on Titan and the other both the scientific principles underlying their work and the moons, and new discoveries in Saturn’s ring system. process used in discovery. ● Updates on new discoveries in the Kuiper belt in Chapter 14. New and Revised Material ● Rewritten and expanded coverage in Chapter 15 of Astronomy is a rapidly evolving field and, in the three years extrasolar planets, with new discussion of hot Jupiters, since the publication of the sixth edition of Astronomy super-Earths, exoplanetary properties, and the search for Today, has seen many new discoveries covering the entire Earth-like planets orbiting in the habitable zones of spectrum of astronomical research. Almost every chapter in their parent stars. the seventh edition has been substantially updated with new ● Updated discussion of brown dwarfs in Chapter 19.

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● New coverage in Chapter 20 of the evolution of low- tions that adorn the text, and we have sought to present the mass stars and the discovery of multiple stellar popula- best and latest imagery of a wide range of cosmic objects. Each tions in globular star clusters. illustration has been carefully crafted to enhance student learn- ● Updates on gamma-ray burst observations and models ing; each is pedagogically sound and tied tightly to the nearby in Chapter 22. discussion of important scientific facts and ideas. This edition contains more than 100 revised figures that show the latest ● Updated discussion of Hubble’s constant in Chapter 24 imagery and the results learned from them reflecting the recent convergence of measurement techniques. Full Spectrum Coverage and Spectrum Icons. ● Further emphasis in Chapter 24 on active galaxies as Increasingly, astronomers exploit part of a continuum with normal galaxies, and quasars RIV UX Gthe full range of the electromag- as a type of active galaxy. netic spectrum to gather information about the cosmos. ● Updated description of the standard model of active Throughout this book, images taken at radio, infrared, ultra- galactic nuclei in Chapter 24. violet, X-ray, or gamma-ray wavelengths are used to supple- ment visible-light images. As it is sometimes difficult (even ● Update on the Sloan Digital Sky Survey and successor for a professional) to tell at a glance which images are surveys in Chapter 25. visible-light photographs and which are false-color images created with other wavelengths, each photo in the text is The Illustration Program accompanied by an icon that identifies the wavelength of electromagnetic radiation used to capture the image. Visualization plays an important role in both the teaching and the practice of astronomy, and we continue to place strong emphasis on this aspect of our book. We have tried to combine aesthetic beauty with scientific accuracy in the artist’s concep-

Compound Art It is rare that a single image, be it ᮤ FIGURE 22.4 Crab Pulsar In the core of the Crab Nebula (a), the Crab pulsar (c) blinks on and off about 30 times each second. In this pair of optical a photograph or an artist’s conception, can capture images, the pulsing can be clearly seen. In the right frame, the pulsar (arrow) is on; in the left frame, it is off. (b) This more recent Chandra X-ray image of the all aspects of a complex subject. Wherever possible, Crab, superimposed on a Hubble optical image, shows the central pulsar, as well as rings of hot X-ray-emitting gas in the equatorial plane, driven by the multiple-part figures are used in an attempt to pulsar wind and moving rapidly outward. Also visible in the image is a jet of hot gas (not the beam of radiation from the pulsar) escaping perpendicular convey the greatest amount of information in the to the equatorial plane. (d) The light curve shows the main pulse and its precursor. (The latter is probably related to the beam directed away from most vivid way: Earth.) (ESO; NASA) ● Visible images are often presented along with their counterparts captured at other wave- (a) lengths. RIV UX G ● Interpretive line drawings are often superim- posed on or juxtaposed with real astronomi- Jet cal photographs, helping students to really Disk “see” what the photographs reveal. OFF ON ● Breakouts—often multiple ones—are used to (c) RIV UXG zoom in from wide-field shots to close-ups so Pulsar that detailed images can be understood in their larger context. Jet Intensity

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Interactive FIGURE Interactive Figures and Photos Icons throughout Penumbra: Sun partly 1.24 Types of Solar visible, partial Eclipse eclipse seen Earth (a) The Moon’s the text direct students to dynamic versions of art Moon shadow consists of two Sun parts: the umbra, where no and photos on Mastering Astronomy®. Using Umbra: Sun completely sunlight is seen, and the obscured, total penumbra, where a portion of eclipse seen the Sun is visible. (b) If we are online applets, students can manipulate factors (a) in the umbra, we see a total eclipse; in the penumbra, we such as time, wavelength, scale, and perspective to increase see a partial eclipse. (c) If the Partial Moon is too far from Earth at eclipse Sun the moment of the eclipse, the their understanding of these figures. umbra does not reach Earth To and there is no region of Sun totality; instead, an annular Corona eclipse is seen. (Note that Moon (Sun these figures are not drawn behind) to scale.) (Insets: NOAA; Total G. Schneider) eclipse Moon (b)

Annular eclipse To Sun Moon

Moon Sun (c)

Other Pedagogical Features CONCEPT CHECK As with many other parts of our text, teachers have helped ✔ In what ways might observations of extrasolar planets help us guide us toward what is most helpful for effective student understand our own solar system? learning. With their assistance, we have revised both our in- chapter and end-of-chapter pedagogical apparatus to Process of Science Checks. Each chapter now also increase its utility to students. includes one or two “Process of Science Checks,” similar to Learning Goals. Studies indicate that some students have the Concept Checks but aimed specifically at clarifying the trouble prioritizing textual material. For this reason, a few questions of how science is done and how scientists reach (typically five or six) well-defined Learning Goals are pro- the conclusions they do. Answers to these in-chapter ques- vided at the start of each chapter. These help students struc- tions are also provided at the back of the book. ture their reading of the chapter and then test their mastery of key concepts. The Learning Goals are numbered and PROCESS OF SCIENCE CHECK keyed to the items in the Chapter Summary, which in turn ✔ How do Newton’s and Einstein's theories differ in their refer back to passages in the text. This highlighting of the descriptions of gravity? most important aspects of the chapter helps students prior- itize information and also aids in their review. The Learning Concept Links. In astronomy, as in many scientific disci- Goals are organized and phrased in such a way as to make plines, almost every topic seems to have some bearing on them objectively testable, affording students a means of almost every other. In particular, the connection between the gauging their own progress. astronomical material and the physical principles set forth early in the text is crucial. Practically everything in Chapters The Big Picture. The Big Picture feature on every chapter 6–28 of this text rests on the foundation laid in the first five THE BIG opening spread encapsulates the overarching message PICTURE chapters. For example, it is important that students, when that each chapter imparts, helping students see how they encounter the discussion of high-redshift objects in chapter content is connected to a broad understanding of Chapter 25, recall not only what they just learned about the universe. The feature is then called out again in selected Hubble’s law in Chapter 24 but also refresh their memories, chapter figures that explore the big picture. if necessary, about the inverse-square law (Chapter 17), stel- Concept Checks. We incorporate into each chapter a lar spectra (Chapter 4), and the Doppler shift (Chapter 3). number of “Concept Checks”—key questions that require Similarly, the discussions of the mass of binary-star compo- the reader to reconsider some of the material just presented nents (Chapter 17) and of galactic rotation (Chapter 23) or attempt to place it into a broader context. Answers both depend on the discussion of Kepler’s and Newton’s laws to these in-chapter questions are provided at the back of in Chapter 2. Throughout, discussions of new astronomical the book. objects and concepts rely heavily on comparison with topics introduced earlier in the text. A01_CHAI0067_07_SE_NASTAFM.qxd 6/3/10 3:05 PM Page xx

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It is important to remind students of these links so that Discovery Boxes. Exploring a wide variety of interesting they recall the principles on which later discussions rest and, supplementary topics, Discovery boxes provide the reader if necessary, review them. To this end, we have inserted “con- with insight into how scientific knowledge evolves and cept links” throughout the text-symbols that mark key intel- emphasizes the process of science. lectual bridges between material in different chapters. The links, denoted by the symbol• together with a section ref- End-of-Chapter Questions and Problems. Many ele- erence, signal that the topic under discussion is related in ments of the end-of-chapter material have seen substantial some significant way to ideas developed earlier, and provide reorganization: direction to material to review before proceeding. ● Each chapter incorporates Review and Discussion Questions, which may be used for in-class review or for Key Terms. Like all subjects, astronomy has its own special- assignment. As with the Self-Test Questions, the material ized vocabulary. To aid student learning, the most important needed to answer Review Questions may be found astronomical terms are boldfaced at their first appearance in within the chapter. The Discussion Questions explore the text. Boldfaced Key Terms in the Chapter Summary are particular topics more deeply, often asking for opinions, linked with the page number where the term was defined. In not just facts. As with all discussions, these questions addition, an expanded alphabetical glossary, defining each usually have no single “correct” answer. Questions Key Term and locating its first use in the text, appears at the identified with a POS icon encourage students to end of the book. explore the Process of Science. ● H-R Diagrams and Acetate Overlays. All of the book’s Each chapter also contains Conceptual Self-Test H-R diagrams are drawn in a uniform format, using real Questions in a multiple choice format, including select data. In addition, a unique set of transparent acetate overlays questions that are tied directly to a specific figure or dramatically demonstrates to students how the H-R diagram diagram in the text, allowing students to assess their helps us to organize our information about the stars and understanding of the chapter material. These questions track their evolutionary histories. are identified with a VIS icon. Answers to all these questions appear at the end of the book. More Precisely Boxes. These boxes provide more quanti- ● The end-of-chapter material includes Problems, based tative treatments of subjects discussed qualitatively in the on the chapter contents and requiring some numerical text. Removing these more challenging topics from the main calculation. In many cases the problems are tied directly flow of the narrative and placing them within a separate to quantitative statements made (but not worked out in modular element of the chapter design (so that they can be detail) in the text. The solutions to the problems are not covered in class, assigned as supplementary material, or sim- contained verbatim within the chapter, but the informa- ply left as optional reading for those students who find them tion necessary to solve them has been presented in the of interest) will allow teachers greater flexibility in setting text. Answers to odd-numbered Problems appear at the the level of their coverage. end of the book.

Chapter Review Summaries. The Chapter Review CHAPTER REVIEW Summaries, a primary review tool, are linked to the Learning SUMMARY

1 The scientific method (p.7)is a revolution (p.13)around the Smaller Light Light Larger ground area from from ground area Goals at the beginning of each chapter. All Key Terms methodical approach employed by Sun, we see different stars at covered Sun Sun covered Observation Theory Vernal equinox N scientists to explore the universe night at different times of the (Mar. 21)

around us in an objective manner. A year, and the Sun appears N introduced in each chapter are listed again, in context and in N Sun theory (p.6)is a framework of ideas to move relative to the stars. Summer Winter solstice N (June 21) solstice and assumptions used to explain some The Sun’s apparent yearly path (Dec. 21)

Autumnal set of observations and construct around the celestial sphere (or the equinox (Sept. 21) boldface, along with key figures and page references to the text Prediction theoretical models (p.6)that make predictions plane of Earth’s orbit around the Sun) about the real world. These predictions in turn are amenable to is called the ecliptic (p.14).We experience seasons (p.15)be- discussion. further observational testing. In this way, the theory expands and cause Earth’s rotation axis is inclined to the ecliptic plane. At the science advances. summer solstice (p.14),the Sun is highest in the sky and the North celestial pole length of the day is greatest. At the winter solstice (p.15),the Sun 2 Early observers grouped the thou- Apparent rotation Polaris of the celestial sphere is lowest and the day is shortest. At the vernal (p.15)and sands of stars visible to the naked eye CASSIOPEIA DIPPER into patterns called constellations autumnal equinoxes (p.15),Earth’s axis of rotation is perpendi- LYRA GEMINI (p.8),which they imagined were VIRGO cular to the line joining Earth to the Sun, so day and night are of North Pole equal length. The interval of time from one vernal equinox to the attached to a vast celestial sphere Earth Equator (p.10)centered on Earth. Constella- ORION next is one tropical year (p.15). PISCES Polaris Vega (pole star tions have no physical significance, 4 In addition to its rotation SAGITTARIUS (current pole star) in A.D. 14,000) but are still used to label regions of the about its axis and its revolution Thuban SOUTHERN CROSS (pole star in sky. The points where Earth’s axis of rota- around the Sun, Earth has many 3000 B.C.) 23.5° Celestial sphere tion intersects the celestial sphere are called other motions. One of the most Earth's axis South celestial pole of rotation the north and south celestial poles (p.10).The important of these is precession

line where Earth’s equatorial plane cuts the celestial sphere is the (p.15),the slow “wobble” of Ecliptic Equator celestial equator (p.11). Earth’s axis due to the influence plane 3 The nightly motion of the stars across the sky is the result of of the Moon. As a result, the sidereal year (p.15)is slightly longer Earth’s rotation (p.10)on its axis. The time from one noon to the than the tropical year, and the particular constellations that happen next is called a solar day (p.12).The time between successive ris- to be visible during any given season change over the course of thou- ings of any given star is one sidereal day (p.12).Because of Earth’s sands of years. A01_CHAI0067_07_SE_NASTAFM.qxd 6/3/10 3:05 PM Page xxi

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Teacher Resources Test Bank. (Available for download) An extensive file of MasteringAstronomy® approximately 2500 test questions, newly compiled and www.masteringastronomy.com revised for the seventh edition by Lauren Jones (Ohio MasteringAstronomy is the most widely used and most Department of Education, Office of Curriculum and advanced astronomy tutorial and assessment system in the Assessment). The questions are organized and referenced world. By capturing the step-by-step work of students by chapter section and by question type. The sixth edition nationally, MasteringAstronomy has established an unpar- Test Bank has been thoroughly revised and includes many alleled database of learning challenges and patterns. Using new Multiple Choice and Essay questions for added con- this student data, a team of renowned astronomy education ceptual emphasis. This Test Bank is available in both researchers has refined every activity and problem. The Microsoft® Word and TestGen® formats (see description of result is a library of activities of unique educational effec- Instructor Resource DVD). tiveness and assessment accuracy. MasteringAstronomy provides students with two learning systems in one: a Instructor Resource DVD. This DVD provides virtually dynamic self-study area and the ability to participate in every electronic asset teachers will need in and out of the class- online assignments. room. The disc contain all text figures in jpeg and PowerPoint MasteringAstronomy provides teachers with a fast and formats, as well as the animations and videos from the effective way to assign uncompromising, wide-ranging MasteringAstronomy Study Area. The IR-DVD also contains online homework assignments of just the right difficulty and TestGen®,an easy-to-use, fully networkable program for creat- duration. The tutorials coach 90 percent of students to the ing tests ranging from short quizzes to long exams. Questions correct answer with specific wrong-answer feedback. from the Test Bank are supplied, and teachers can use the Powerful post-diagnostics allow teachers to assess the Question Editor to modify existing questions or create new progress of their class as a whole or to quickly identify an questions. This disc set also contains chapter-by-chapter lec- individual student’s areas of difficulty. Tutorials built around ture outlines in PowerPoint and conceptual "clicker" questions text content and all the end-of-chapter problems from the in PowerPoint. text are available in MasteringAstronomy. A media-rich self- study area is included that students can use whether the Most of the teacher supplements and resources are available teachers assigns homework or not. A complete eText is also electronically for download on the Instructor Resource included in MasteringAstronomy. Center (IRC). Please go to www.PearsonSchool.com/ High School teachers can obtain preview or adoption Access_Request and select “access to online instructor access in the following ways: resources.”You will be required to complete a one-time reg- Preview Access istration subject to verification before being emailed access ● Ask your sales representative for a Preview Access Code information for download materials. Card (ISBN 0-13-111589-8). Adoption Access Student Resources ● Register online at www.PearsonSchool.com/ MasteringAstronomy® Access_Request, using Option 3 www.masteringastronomy.com This homework, tutorial, and assessment system is OR uniquely able to tutor each student individually by provid- ● Ask your sales representative for an Adoption Access ing students with instantaneous feedback specific to their Code Card (ISBN 0-13-214300-3). wrong answers, simpler subproblems upon request when they get stuck, and partial credit for their method(s) used. Instructor Guide. (Available for download) Revised by Students also have access to a self-study area that contains James Heath (Austin Community College), this online guide practice quizzes, self-guided tutorials, animations, videos, provides: sample syllabi and course schedules; an overview and more. Students receive access to MasteringAstronomy of each chapter; pedagogical tips; useful analogies; sugges- through their teacher. A complete eText is also included in tions for classroom demonstrations; writing questions, MasteringAstronomy. selected readings, and answers/solutions to the end-of-chap- ter Review and Discussion Questions and Problems; and additional references and resources. A01_CHAI0067_07_SE_NASTAFM.qxd 6/3/10 3:05 PM Page xxii

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Edmund Scientific Star and Planet Locator The famous 10-15 minutes, challenges students with a series of carefully rotating roadmap of the heavens shows the location of the designed questions that spark classroom discussion, engages stars, constellations, and planets relative to the horizon for the students in critical reasoning, and requires no equipment. exact hour and date you determine. This 8 square star chart Available for purchase. was plotted by the late astronomer and cartographer George ISBN 0-13-239226-7 Lovi. The reverse side of the locator is packed with additional data on the planets, meteor showers, and bright stars. Observation Excercises in Astronomy This workbook contains Included with each star chart is a 16-page, fully illustrated, a series of astronomy exercises that integrate technology from pocket-size instruction booklet. Available for purchase. planetarium software such as Stellarium, Starry Night College, ISBN 0-13-140235-8 WorldWide Telescope, and SkyGazer. Using these online prod- ucts adds an interactive dimension to students’ learning. Lecture Tutorials for Introductory Astronomy, 2nd Edition Available for purchase. Edward E. Prather, University of Arizona ISBN: 0-321-63812-3 Timothy F. Slater, University of Arizona Jeffrey P. Adams, Montana State University Gina Brissenden, NASA Center for Astronomy Education Acknowledgments (CAE) at the University of Arizona Throughout the many drafts that have led to this book, we CAPER, Conceptual Astronomy and Physics Education have relied on the critical analysis of many colleagues. Their Research Team suggestions ranged from the macroscopic issue of the book’s Funded by the National Science Foundation, Lecture- overall organization to the minutiae of the technical accuracy Tutorials for Introductory Astronomy are designed to help of each and every sentence. We have also benefited from make large-lecture-format courses more interactive. The sec- much good advice and feedback from users of the first six ond edition features new Tutorials on the Doppler Shift, editions of the text. To these many helpful colleagues, we Extrasolar Planets, Kepler’s 2nd Law, and Seasons. Each of the offer our sincerest thanks. 38 Lecture-Tutorials is presented in a classroom-ready for- mat, asks students to work in groups of 2-3, takes between Reviewers of the Seventh Edition Nadine G. Barlow Kristine Larsen John Scalo Northern Arizona University Central Connecticut State University University of Texas at Austin Thomasanna Hail Steve Mellema Jie Zhang Parkland College Gustavus Adolphus College George Mason University Lynn Higgs University of Utah Reviewers of Previous Editions Stephen G. Alexander Elizabeth P. Bozyan Kimberly Engle Miami University of Ohio University of Rhode Island Drexel University William Alexander Malcolm Cleaveland Michael N. Fanelli James Madison University University of Arkansas University of North Texas Robert H. Allen Anne Cowley Richard Gelderman University of Wisconsin, La Crosse Arizona State University Western Kentucky University Cecilia Barnbaum Bruce Cragin Harold A. Geller Valdosta State University Richland College George Mason University Peter A. Becker Ed Coppola David Goldberg George Mason University Community College of Southern Nevada Drexel University Timothy C. Beers David Curott Martin Goodson University of Evansville University of North Alabama Delta College William J. Boardman Norman Derby David G. Griffiths Birmingham Southern College Bennington College Oregon State University Donald J. Bord John Dykla Donald Gudehus University of Michigan, Dearborn Loyola University, Chicago Georgia State University A01_CHAI0067_07_SE_NASTAFM.qxd 6/3/10 3:05 PM Page xxiii

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Clint D. Harper Fred Marschak Vicki Sarajedini Moorpark College Santa Barbara College University of Florida Marilynn Harper Matthew Malkan Malcolm P. Savedoff Delaware County Community College University of California, Los Angeles University of Rochester Susan Hartley Chris Mihos John C. Schneider University of Minnesota, Duluth Case Western Reserve University Catonsville Community College Joseph Heafner Milan Mijic Larry Sessions Catawaba Valley Community College California State University, Los Angeles Metropolitan State College of Denver James Heath Scott Miller Harry L. Shipman Austin Community College Pennsylvania State University University of Delaware Fred Hickok Mark Moldwin C. G. Pete Shugart Catonsville Community College University of California, Los Angeles Memphis State University Darren L. Hitt Richard Nolthenius Stephen J. Shulik Loyola College, Maryland Cabrillo College Clarion University F. Duane Ingram Edward Oberhofer Tim Slater Rock Valley College University of North Carolina, Charlotte University of Arizona Steven D. Kawaler Andrew P. Odell Don Sparks Iowa State University Northern Arizona University Los Angeles Pierce College William Keel Gregory W. Ojakangas George Stanley, Jr. University of Alabama University of Minnesota, Duluth San Antonio College Marvin Kemple Ronald Olowin Maurice Stewart Indiana University-Purdue University, Saint Mary’s College of California Williamette University Indianapolis Robert S. Patterson Jack W. Sulentic Mario Klairc Southwest Missouri State University University of Alabama Midlands Technical College Cynthia W. Peterson Andrew Sustich Kristine Larsen University of Connecticut Arkansas State University Central Connecticut State University Lawrence Pinsky Donald Terndrup Andrew R. Lazarewicz University of Houston Ohio State University Boston College Andreas Quirrenback Craig Tyler Robert J. Leacock University of California, San Diego Fort Lewis College University of Florida Richard Rand Stephen R. Walton Larry A. Lebofsky University of New Mexico California State University, Northridge University of Arizona James A. Roberts Peter A. Wehinger Matthew Lister University of North Texas University of Arizona Purdue University Gerald Royce Louis Winkler M. A. Lohdi Mary Washington College Pennsylvania State University Texas Tech University Dwight Russell Robert Zimmerman Michael C. LoPresto Baylor University University of Oregon Henry Ford Community College Phillip Lu Western Connecticut State University

The publishing team at Addison-Wesley/Benjamin We would also like to express our gratitude to Kelly Cummings has assisted us at every step along the way in creat- Reed for updating and maintaining the media resources in ing this text. Many thanks to Tema Goodwin, who managed the MasteringAstronomy® Study Area. the many variables that go into a multifaceted publication Finally, we would like to express our gratitude to such as this. Production managers Crystal Clifton and Mary renowned space artist Dana Berry for allowing us to use many O’Connell have done an excellent job of tying together the of his beautiful renditions of astronomical scenes, and to Lola threads of this very complex project, made all the more com- Judith Chaisson for assembling and drawing all the H–R dia- plex by the necessity of combining text, art, and electronic grams (including the acetate overlays) for this edition. media into a coherent whole. Special thanks are also in order to cover and interior designer Derek Bacchus for making the Eric Chaisson seventh edition look spectacular. Steve McMillan