ASTRONOMY A Beginner's Guide to the Universe FOURTH EDITION Eric Chaisson Tufts University Steve McMillan Drexel University PEARSON Prentice Hall Pearson Education, Inc. Upper Saddle River, New Jersey 07458
CONTENTS Preface xvii SA FOUNDATIONS PROLOGUE Charting the Heavens 2 P.I The "Obvious" View 4 P.2 Earth's Orbital Motion 7 Physlet Illustration Solar vs Sidereal Day 7 Animation The Earth's Seasons 8 P. 3 The Measurement of Distance 10 More Precisely P-l Angular Measure 10 Tutorial Stellar Parallax 12 More Precisely P-2 Measuring Distances with Geometry 13 Physlet Illustration Angular Measurements vs Distance Measurements 13 Discovery P-l Sizing up Planet Earth 14 Chapter Review 14 1 THE COPERNICAN REVOLUTION The Birth of Modern Science 16 1.1 The Orbit of the Moon 18 Physlet Illustration Lunar Phases 19 Physlet Illustration Eclipses. 21 1.2 The Motions of the Planets 22 Discovery 1-1 The Scientific Method 26 1.3 The Birth of Modern Astronomy 28 1.4 The Laws of Planetary Motion 30 More Precisely 1-1 Some Properties of Planetary Orbits 32 Physlet Illustration Kepler's 3 Laws 32 1.5 Newton's Laws 34 Physlet Illustration Universal Gravitation 36 More Precisely 1-2 Weighing the Sun 37 Chapter Review 39
LIGHT AND MATTER The Inner Workings of the Cosmos 42 a, 2.1 Information from the Skies 44 Physlet Illustration Basic Wave Properties 46 2.2 Waves in What? 46 Physlet Illustration Electromagnetic Waves 47 2.3 The Electromagnetic Spectrum 48 2.4 Thermal Radiation 51 More Precisely 2-1 The Kelvin Temperature Scale 51 Animation The Planck Spectrum 53 More Precisely 2-2 More on the Radiation Laws 54 2.5 Spectroscopy 55 2.6 The Formation of Spectral Lines 59 Animation Classical Hydrogen Atom I 61 Animation Classical Hydrogen Atom II 61 Physlet Illustration Bohr Atom and Spectra 62 2.7 The Doppler Effect 64 Physlet Illustration Doppler Effect 66 Tutorial Doppler Effect 66 Chapter Review 67 3 TELESCOPES The Tools of Astronomy 70 3.1 Optical Telescopes 72 Physlet Illustration Image Formation by Lens 73 Tutorial The Optics of a Simple Lens 73 Tutorial Chromatic Aberration 73 Tutorial Mirrors in Telescopes 73 Physlet Illustration Image Formation by Mirror 73 Physlet Illustration Telescope Designs 74 3.2 Telescope Size 75 3.3 High-Resolution Astronomy 78 3.4 Radio Astronomy 82 Discovery 3-1 The Hubble Space Telescope 82 3.5 Other Astronomies 88 Animations Light and Data Path 91 Chapter Review 94
OUR PLANETARY SYSTEM 4 THE SOLAR SYSTEM Interplanetary Matter and the Birth of the Planets 98 4.1 An Inventory of the Solar System 100 Animation An Astronomical Ruler 100 Animation Size and Scale of the Terrestrial Planets 101 Animation The Gas Giants 101 Physlet Illustration Mass of Planet from Kepler's 3 rd Law 101 4.2 Solar System Debris 104 a Discovery 4-1 What Killed the Dinosaurs? 106 Animation Comet Hale-Bopp 108 Animation Anatomy of a Comet Part I 109 Animation Anatomy of a Comet Part II 110 Animation Asteroid Comet Breakup 112 4.3 The Formation of the Solar System 114 Animation Beta Pictoris Warp 117 a More Precisely 4-1 Conservation of Angular Momentum 118 Physlet Illustration Conservation of Angular Momentum 118 Animation Solar System Formation 120 4.4 Planets Beyond the Solar System 124 Chapter Review 127 5 EARTH AND ITS MOON Our Cosmic Backyard 130 5.1 Earth and the Moon in Bulk 132 5.2 The Tides 133 a More Precisely 5-1 Why Air Sticks Around 135 5.3 Atmospheres 136 Tutorial Atmospheric Lifetimes 137 Discovery 5-1 Earth's Growing Ozone Hole 138 Physlet Illustration Escape Speed 139 Tutorial Greenhouse Effect 139 H Discovery 5-2 The Greenhouse Effect and Global Warming 140 5.4 Interiors 141 5.5 Surface Activity on Earth 144
5.6 The Surface of the Moon 146 5.7 Magnetospheres 150 Physlet Illustration Magnetic Field of Planet 150 5.8 v History of the Earth-Moon System 153 Chapter Review 155 O THE TERRESTRIAL PLANETS A Study in Contrasts 158 6.1 Orbital and Physical Properties 160 6.2 Rotation Rates 161 Physlet Illustration Rotation of Mercury 162 Animation The Phases of Venus 162 6.3 Atmospheres 163 Animation The Rotation of Venus 164 6.4 The Surface of Mercury 165 Physlet Illustration Meteor Energy 165 6.5 The Surface of Venus 166 6.6 The Surface of Mars 170 """ Video Mars North Pole 171 Video Rotation of Mars 171 Discovery 6-1 Martian Canals? 172 Discovery 6-2 Life on Mars? 174 6.7 Internal Structure and Geological History 180 Animation Terrestrial Planets 180 6.8 Atmospheric Evolution on Earth, Venus, and Mars 182 Tutorial Greenhouse Effect 184 6.9 The Moons of Mars 184 Chapter Review 185 7 THE JOVIAN PLANETS Giants of the Solar System 188 7.1 Observations of Jupiter and Saturn 190 Animation Galileo Mission to Jupiter 190 More Precisely 7-1 Gravitational "Slingshots" 191 Physlet Illustration Gravitational Slingshot 191 7.2 The Discoveries of Uranus and Neptune 192 7.3 Bulk Properties of the Jovian Planets 193 7.4 Jupiter's Atmosphere 196 7.5 The Atmospheres of the Outer Jovian Worlds 198 Video Saturn Storm 200
7.6 Jovian Interiors 203 Animation The Gas Giants Part II 204 Discovery 7-1 A Cqmetary Impact 207 Chapter Review 208 8 MOONS, RINGS, AND PLUTO Small Worlds Among Giants 210 8.1 The Galilean Moons of Jupiter 212 Animation Io Cutaway 215 Animation Galileo Flyby of Io 215 Video Jupiter's Moon Europa 216, Video Jupiter's Moon Ganymede 217 8.2 The Large Moons of Saturn and Neptune 218 8.3 The Medium-Sized Jovian Moons 220 8.4 Planetary Rings 223 Physlet Illustration Tidal Forces vs. Self-Gravity 226 8.5 Pluto and Its Moon 229 Animation Orbits of Neptune and Pluto 230 Video Historical Observations of Pluto 230 Animation Mutual Eclipses of Charon and Pluto 231 8.6 Is Pluto a Planet? 232 Chapter Review 234 THE STARS 9 THE SUN Our Parent Star 238 9.1 The Sun in Bulk 240 Tutorial SuperSpaceship Voyage to the Sun 241 9.2 The Solar Interior 242 Discovery 9-1 SOHO: Eavesdropping on the Sun 244 Physlet Illustration Random Walk 244 9.3 The Solar Atmosphere 246 9.4 The Active Sun 249 Physlet Illustration Rotation by Sunspots 250 Video May 12 1997 Solar Flare Event 254 Animation Coronal Mass Ejection 255 9.5 The Heart of the Sun 255 More Precisely 9-1 The Strong and Weak Nuclear Forces 259 Chapter Review 259
10 MEASURING THE STARS Giants, Dwarfs, and the Main Sequence 262 10.1 The Solar Neighborhood 264 10.2 Luminosity and Apparent Brightness 267 Discovery 10-1 Naming the Stars 267 Animation The Inverse-square Law 268 More Precisely 10-1 More on the Magnitude Scale 269 10.3 Stellar Temperatures 270 Physlet Illustration Blackbody and Stellar Temperature 271 10.4 Stellar Sizes 273 More Precisely 10-2 Estimating Stellar Radii 274 10.5 The Hertzsprung-Russell Diagram 275 Tutorial Hertzsprung-Russell Diagram 276 10.6 Extending the Cosmic Distance Scale 277 10.7 Stellar Masses 279 Tutorial Binary Stars-Radial Velocity Curves 279 Tutorial Eclipsing Binary Stars-Light Curves 280 Chapter Review 283 11 THE INTERSTELLAR MEDIUM Star Formation in the Milky Way 286 11.1 Interstellar Matter 288 11.2 Interstellar Clouds 290 Discovery 11-1 Ultraviolet Astronomy and the "Local Bubble" 292 Animation M16 Eagle Nebula 293 Video Gaseous Pillars of Star Birth 293 Physlet Illustration Spin Flip and 21-cm Radiation 297 11.3 The Formation of Stars Like the Sun 298 Video Orion Nebula Mosaic 302 Animation Bi-Polar Outflow 304 11.4 Stars of Other Masses 306 11.5 Star Clusters 307 Chapter Review 310 1 2 STELLAR EVOLUTION The Lives and Deaths of Stars 312 12.1 Leaving the Main Sequence 314 12.2 Evolution of a Sun-like Star 315 Animation Death of a Sun 318 Animation Death of a Sun Part II 318 12.3 The Death of a Low-Mass Star 319 Animation Bi-Polar Planetary Nebula 320 (
Video Formation of Helix Nebula 320 Animation H-R Diagram Tracks Stellar Evolution 321 Animation Recurrent Nova 323 12.4 Evolution of High-Mass Stars 324 12.5 Supernova Explosions 326 Physlet Illustration Supernova 326 Animation Supernova Explosion 328 n Discovery 12-1 Supernova 1987A 330 Animation Shockwaves Hit the Ring Around Supernova 1987A 331 Animation Composition and Structure of the Ring Around Supernova 1987A 331 12.6 Observing Stellar Evolution in Star Clusters 332 n More Precisely 12-1 The Cycle of Stellar Evolution 335 Animation Evolution of a 1-Solar-Mass Star 335 Chapter Review 335 13 NEUTRON STARS AND BLACK HOLES Strange States of Matter 338 13.1 Neutron Stars 340 13.2 Pulsars 341 13.3 Neutron-Star Binaries 343 Physlet Illustration Period of Pulsar 343 13.4 Gamma-Ray Bursts 346 n Discovery 13-1 Gravity Waves 348 13.5 Black Holes 349 a More Precisely 13-1 Einstein's Theories of Relativity 350 Physlet Illustration Equivalence Principle 351 Tutorial SuperSpaceship 351 13.6 Gravity and Curved Space 352 More Precisely 13-2 Tests of General Relativity 353 13.7 Space Travel Near Black Holes 354 13.8 Observational Evidence for Black Holes 357 Animation Black Hole Geometry 358 Chapter Review 360 GALAXIES AND THE UNIVERSE 14 THE MILKY WAY GALAXY A Grand Design 364 14.1 Our Parent Galaxy 366 14.2 Measuring the Milky Way 367 Animation Cepheid Star in Distant Galaxy 369 a Discovery 14-1 Early Computers 371
14.3 Galactic Structure 372 14.4 The Formation of the Milky Way 375 14.5 Galactic Spiral Arms 376 Discovery 14-2 Density Waves 378 14.6 The Mass of the Milky Way Galaxy 380 Physlet Illustration The Mass of a Galaxy 380 14.7 The Galactic Center 383 Chapter Review 387 15 NORMAL AND ACTIVE GALAXIES Building Blocks of the Universe 390 15.1 Hubble's Galaxy Classification 392 15.2 Clusters of Galaxies 399 Animation Cluster Merger 402 15.3 Active Galactic Nuclei 403 Discovery 15-1 Colliding Galaxies 404 Animation Collision of Two Spiral Galaxies 404 Animation Birth of a Quasar 411 15.4 The Central Engine of an Active Galaxy 412 Animation Active Galaxy 413 Animation Cosmic Jets 413 Animation Black Hole in Galaxy M87 414 Animation Supermassive Black Hole 415 15.5 Supermassive Black Holes in Galactic Nuclei 416 Chapter Review 417 1 6 HUBBLE'S LAW AND DARK MATTER The Large-Scale Structure of the Cosmos 420 16.1 Cosmic Expansion 422 More Precisely 16-1 Relativistic Redshifts and Look-Back Time 424 Physlet Illustration Hubble's Law-Doppler Shift & Distance 425 16.2 Dark Matter in the Universe 426 Animation Dark Matter 428 16.3 Large-Scale Structure 429 Animation Gravitational Lensing 432 16.4 Galaxy Formation and Evolution 434 Video Hubble Deep Field Zoom Sequence 435 Animation Starburst Galaxy 436 Physlet Illustration Active Galactic Nuclei 440 Chapter Review 441
17 COSMOLOGY The Big Bang and the Fate of the Universe 444 17.1 The Universe on the Largest Scales 446 17.2 The Expanding Universe 447 Animation Big Bang 449 17.3 The Fate of the Cosmos 450 Discovery 17-1 The Cosmological Constant 454 17.4 The Geometry of Space 456 More Precisely 17-1 Curved Space 457 Physlet Illustration Creation and Annihilation and Temperature 458 17.5 The Early Universe 458 17.6 The Formation of Nuclei and Atoms 460 17.7 Cosmic Inflation 462 17.8 The Formation of Large-Scale Structure in the Universe 465 Animation Cosmic Structure 465 Chapter Review 467 18 LIFE IN THE UNIVERSE Are We Alone? 470 18.1 Cosmic Evolution 472 18.2 Life in the Solar System 475 18.3 Intelligent Life in the Galaxy 477 Physlet Illustration Drake Equation and Number of Intelligent Civilizations 482 18.4 The Search for Extraterrestrial Intelligence 482 Chapter Review 486 Appendices A-l Appendix 1: Scientific Notation A-l Appendix 2: Astronomical Measurement A-2 Appendix 3: Tables A-3 Glossary G-l Answers to Concept Check Questions AK-1 Answers to Self-Test Questions AK-4 Index 1-1