Astronomy Today

Cover......Page 1
Title......Page 7
Copyright......Page 8
Contents......Page 10
About the Authors......Page 19
Preface......Page 21
Part One: Astronomy and the Universe......Page 30
 1 Charting the Heavens The Foundations of Astronomy......Page 33
  1.1 Our Place in Space......Page 34
  1.2 Scientific Theory and the Scientific Method......Page 36
  1.3 The “Obvious” View......Page 38
  1.4 Earth’s Orbital Motion......Page 41
   More Precisely 1-1 Angular Measure......Page 42
  1.5 The Motion of the Moon......Page 46
  1.6 The Measurement of Distance......Page 52
   More Precisely 1-2 Measuring Distances with Geometry......Page 56
  Chapter Review......Page 57
 2 The Copernican Revolution The Birth of Modern Science......Page 61
  2.1 Ancient Astronomy......Page 62
  2.2 The Geocentric Universe......Page 64
  2.3 The Heliocentric Model of the Solar System......Page 67
   Discovery 2-1 Foundations of the Copernican Revolution......Page 68
  2.4 The Birth of Modern Astronomy......Page 69
  2.5 The Laws of Planetary Motion......Page 72
   More Precisely 2-1 Some Properties of Planetary Orbits......Page 74
  2.6 The Dimensions of the Solar System......Page 75
  2.7 Newton’s Laws......Page 77
  2.8 Newtonian Mechanics......Page 80
   More Precisely 2-2 Weighing the Sun......Page 82
  Chapter Review......Page 84
 3 Radiation Information from the Cosmos......Page 87
  3.1 Information from the Skies......Page 88
  3.2 Waves in What?......Page 91
  3.3 Electromagnetic Spectrum......Page 93
   Discovery 3-1 The Wave Nature of Radiation......Page 95
  3.4 Thermal Radiation......Page 96
   More Precisely 3-1 The Kelvin Temperature Scale......Page 97
   More Precisely 3-2 More About the Radiation Laws......Page 100
  3.5 The Doppler Effect......Page 101
   More Precisely 3-3 Measuring Velocities with the Doppler Effect......Page 103
  Chapter Review......Page 104
 4 Spectroscopy The Inner Workings of Atoms......Page 107
  4.1 Spectral Lines......Page 108
  4.2 Atoms and Radiation......Page 112
   More Precisely 4-1 The Hydrogen Atom......Page 114
  4.3 The Formation of Spectral Lines......Page 115
   Discovery 4-1 The Photoelectric Effect......Page 116
  4.4 Molecules......Page 119
  4.5 Spectral-Line Analysis......Page 120
  Chapter Review......Page 123
 5 Telescopes The Tools of Astronomy......Page 127
  5.1 Optical Telescopes......Page 128
  5.2 Telescope Size......Page 133
  5.3 Images and Detectors......Page 137
  5.4 High-Resolution Astronomy......Page 139
  5.5 Radio Astronomy......Page 142
  5.6 Interferometry......Page 146
  5.7 Space-Based Astronomy......Page 149
   Discovery 5-1 The ALMA Array......Page 152
  5.8 Full-Spectrum Coverage......Page 156
  Chapter Review......Page 157
Part Two: Our Planetary System......Page 160
 6 The Solar System Comparative Planetology and Formation Models......Page 163
  6.1 An Inventory of the Solar System......Page 164
  6.2 Measuring the Planets......Page 166
  6.3 The Overall Layout of the Solar System......Page 167
  6.4 Terrestrial and Jovian Planets......Page 168
   Discovery 6-1 Gravitational “Slingshots”......Page 170
  6.5 Interplanetary Matter......Page 171
  6.6 How Did the Solar System Form?......Page 172
   Discovery 6-2 Spacecraft Exploration of the Solar System......Page 174
   More Precisely 6-1 Angular Momentum......Page 177
  6.7 Jovian Planets and Planetary Debris......Page 180
  Chapter Review......Page 184
 7 Earth Our Home in Space......Page 189
  7.2 Earth’s Atmosphere......Page 190
   More Precisely 7-1 Why Is the Sky Blue?......Page 193
   Discovery 7-1 The Greenhouse Effect and Global Warming......Page 195
  7.3 Earth’s Interior......Page 196
   More Precisely 7-2 Radioactive Dating......Page 200
  7.4 Surface Activity......Page 201
  7.5 Earth’s Magnetosphere......Page 208
  7.6 The Tides......Page 210
  Chapter Review......Page 213
 8 The Moon and Mercury Scorched and Battered Worlds......Page 217
  8.1 Orbital Properties......Page 218
  8.2 Physical Properties......Page 219
  8.3 Surface Features on the Moon and Mercury......Page 220
  8.4 Rotation Rates......Page 223
   More Precisely 8-1 Why Air Sticks Around......Page 224
   Discovery 8-1 Lunar Exploration......Page 226
  8.5 Lunar Cratering and Surface Composition......Page 229
  8.6 The Surface of Mercury......Page 234
  8.7 Interiors......Page 236
  8.8 The Origin of the Moon......Page 238
  8.9 Evolutionary History of the Moon and Mercury......Page 239
  Chapter Review......Page 241
 9 Venus Earth’s Sister Planet......Page 245
  9.1 Orbital Properties......Page 246
  9.2 Physical Properties......Page 247
  9.3 Long-Distance Observations of Venus......Page 248
  9.4 The Surface of Venus......Page 249
  9.5 The Atmosphere of Venus......Page 256
  9.6 Venus’s Magnetic Field and Internal Structure......Page 260
  Chapter Review......Page 261
 10 Mars A Near Miss for Life?......Page 265
  10.1 Orbital Properties......Page 266
  10.3 Long-Distance Observations of Mars......Page 267
  10.4 The Martian Surface......Page 268
  10.5 Water on Mars......Page 272
   Discovery 10-1 Life on Mars?......Page 278
  10.6 The Martian Atmosphere......Page 284
  10.7 Martian Internal Structure......Page 287
  10.8 The Moons of Mars......Page 288
  Chapter Review......Page 289
 11 Jupiter Giant of the Solar System......Page 293
  11.1 Orbital and Physical Properties......Page 294
  11.2 Jupiter Atmosphere......Page 296
  11.3 Internal Structure......Page 302
   Discovery 11-2 Almost a Star?......Page 304
  11.4 Jupiter’s Magnetosphere......Page 305
  11.5 The Moons of Jupiter......Page 307
  Chapter Review......Page 315
 12 Saturn Spectacular Rings and Mysterious Moons......Page 319
  12.1 Orbital and Physical Properties......Page 320
  12.2 Saturn’s Atmosphere......Page 321
  12.3 Saturn’s Interior and Magnetosphere......Page 324
  12.4 Saturn’s Spectacular Ring System......Page 326
  12.5 The Moons of Saturn......Page 332
   Discovery 12-1 Dancing Among Saturn’s Moons......Page 334
  Chapter Review......Page 343
 13 Uranus and Neptune The Outer Worlds of the Solar System......Page 347
  13.1 The Discoveries of Uranus and Neptune......Page 348
  13.2 Orbital and Physical Properties......Page 350
  13.3 The Atmospheres of Uranus and Neptune......Page 352
  13.4 Magnetospheres and Internal Structure......Page 354
  13.5 The Moon Systems of Uranus and Neptune......Page 356
  13.6 The Rings of the Outermost Jovian Planets......Page 360
  Chapter Review......Page 363
 14 Solar System Debris Keys to Our Origin......Page 367
  14.1 Asteroids......Page 368
  14.2 Comets......Page 373
   Discovery 14-1 What Killed the Dinosaurs?......Page 378
  14.3 Beyond Neptune......Page 381
  14.4 Meteroids......Page 386
  Chapter Review......Page 391
 15 EXOPLANETS Planetary Systems Beyond Our Own......Page 395
  15.1 Modeling Planet Formation......Page 396
  15.2 Solar System Regularities and Irregularities......Page 397
  15.3 Searching for Extrasolar Planets......Page 398
  15.4 Exoplanet Properties......Page 401
   Discovery 15-1 The Closest Exoplanet......Page 404
  15.5 Is Our Solar System Unusual?......Page 407
  Chapter Review......Page 411
Part Three: Stars and Stellar Evolution......Page 414
 16 The Sun Our Parent Star......Page 417
  16.1 Physical Properties of the Sun......Page 418
  16.2 The Solar Interior......Page 420
   Discovery 16-1 Eavesdropping on the Sun......Page 423
  16.3 The Sun’s Atmosphere......Page 425
  16.4 Solar Magnetism......Page 428
  16.5 The Active Sun......Page 433
   Discovery 16-2 Solar–Terrestrial Relations......Page 437
  16.6 The Heart of the Sun......Page 438
   More Precisely 16-1 Fundamental Forces......Page 441
  16.7 Observations of Solar Neutrinos......Page 442
   More Precisely 16-2 Energy Generation in the Proton–Proton Chain......Page 444
  Chapter Review......Page 445
 17 The Stars Giants, Dwarfs, and the Main Sequence......Page 449
  17.1 The Solar Neighborhood......Page 450
  17.2 Luminosity and Apparent Brightness......Page 453
  17.3 Stellar Temperatures......Page 456
   More Precisely 17-1 More on the Magnitude Scale......Page 458
  17.4 Stellar Sizes......Page 460
   More Precisely 17-2 Estimating Stellar Radii......Page 461
  17.5 The Hertzsprung–Russell Diagram......Page 462
  17.6 Extending the Cosmic Distance Scale......Page 465
  17.7 Stellar Masses......Page 468
   More Precisely 17-3 Measuring Stellar Masses in Binary Stars......Page 471
  17.8 Mass and Other Stellar Properties......Page 470
  Chapter Review......Page 473
 18 The Interstellar Medium Gas and Dust Among The Stars......Page 477
  18.1 Interstellar Matter......Page 478
  18.2 Emission Nebulae......Page 481
  18.3 Dark Dust Clouds......Page 487
  18.4 18-Centimeter Radiation......Page 490
  18.5 Interstellar Molecules......Page 491
  Chapter Review......Page 493
 19 Star Formation A Traumatic Birth......Page 497
  19.1 Star-Forming Regions......Page 498
   More Precisely 19-1 Competition in Star Formation......Page 499
  19.2 The Formation of Stars Like the Sun......Page 500
  19.3 Stars of Other Masses......Page 505
  19.4 Observations of Cloud Fragments and Protostars......Page 506
   Discovery 19-1 Observations of Brown Dwarfs......Page 507
  19.5 Shock Waves and Star Formation......Page 512
  19.6 Star Clusters......Page 514
   Discovery 19-2 Eta Carinae......Page 518
  Chapter Review......Page 519
 20 Stellar Evolution The Life and Death of a Star......Page 523
  20.2 Evolution of a Sun-Like Star......Page 524
  20.3 The Death of a Low-Mass Star......Page 530
   Discovery 20-1 Learning Astronomy from History......Page 536
  20.4 Evolution of Stars More Massive than the Sun......Page 537
   Discovery 20-2 Mass Loss from Giant Stars......Page 539
  20.5 Observing Stellar Evolution in Star Clusters......Page 540
  20.6 Stellar Evolution in Binary Systems......Page 543
  Chapter Review......Page 545
 21 Stellar Explosions Novae, Supernovae, and the Formation of the Elements......Page 549
  21.1 Life after Death for White Dwarfs......Page 550
  21.2 The End of a High-Mass Star......Page 552
  21.3 Supernovae......Page 554
  21.4 The Formation of the Elements......Page 558
   Discovery 21-1 Supernova 1987A......Page 560
  21.5 The Cycle of Stellar Evolution......Page 566
  Chapter Review......Page 567
 22 Neutron Stars and Black Holes Strange States of Matter......Page 571
  22.1 Neutron Stars......Page 572
  22.2 Pulsars......Page 573
  22.3 Neutron-Star Binaries......Page 576
  22.4 Gamma-Ray Bursts......Page 580
  22.5 Black Holes......Page 583
  22.6 Einstein’s Theories of Relativity......Page 585
   Discovery 22-1 Special Relativity......Page 587
  22.7 Space Travel Near Black Holes......Page 589
  22.8 Observational Evidence for Black Holes......Page 592
   More Precisely 22-1 Tests of General Relativity......Page 594
   Discovery 22-2 Gravity Waves: A New Window on the Universe......Page 596
  Chapter Review......Page 599
Part Four: Galaxies and Cosmology......Page 602
 23 The Milky Way Galaxy A Spiral in Space......Page 605
  23.1 Our Parent Galaxy......Page 606
  23.2 Measuring the Milky Way......Page 607
   Discovery 23-1 Early “Computers”......Page 612
  23.3 Galactic Structure......Page 614
  23.4 The Formation of the Milky Way......Page 617
  23.5 Galactic Spiral Arms......Page 619
   Discovery 23-2 Density Waves......Page 622
  23.6 The Mass of the Milky Way Galaxy......Page 623
  23.7 The Galactic Center......Page 627
  Chapter Review......Page 631
 24 Galaxies Building Blocks of the Universe......Page 635
  24.1 Hubble’s Galaxy Classification......Page 636
  24.2 The Distribution of Galaxies in Space......Page 643
  24.3 Hubble’s Law......Page 647
  24.4 Active Galactic Nuclei......Page 650
  24.5 The Central Engine of an Active Galaxy......Page 658
  Chapter Review......Page 663
 25 Galaxies and Dark Matter The Large-Scale Structure of the Cosmos......Page 667
  25.1 Dark Matter in the Universe......Page 668
  25.2 Galaxy Collisions......Page 671
  25.3 Galaxy Formation and Evolution......Page 673
   Discovery 25-1 The Sloan Digital Sky Survey......Page 679
  25.4 Black Holes in Galaxies......Page 680
  25.5 The Universe on Large Scales......Page 684
  Chapter Review......Page 691
 26 Cosmology The Big Bang and the Fate of the Universe......Page 695
  26.1 The Universe on the Largest Scales......Page 696
  26.2 The Expanding Universe......Page 698
  26.3 The Fate of the Cosmos......Page 701
  26.4 The Geometry of Space......Page 703
   More Precisely 26-1 Curved Space......Page 705
  26.5 Will the Universe Expand Forever?......Page 706
  26.6 Dark Energy and Cosmology......Page 708
   Discovery 26-1 Einstein and the Cosmological Constant......Page 709
  26.7 The Cosmic Microwave Background......Page 711
  Chapter Review......Page 713
 27 The Early Universe Toward the Beginning of Time......Page 717
  27.1 Back to the Big Bang......Page 718
  27.2 Evolution of the Universe......Page 721
   More Precisely 27-1 More on Fundamental Forces......Page 722
  27.3 Formation of Nuclei and Atoms......Page 725
  27.4 The Inflationary Universe......Page 728
  27.5 Formation of Structure in the Universe......Page 733
  27.6 Cosmic Structure and the Microwave Background......Page 735
  Chapter Review......Page 739
 28 Life in the Universe Are We Alone?......Page 743
  28.1 Cosmic Evolution......Page 744
   Discovery 28-1 The Virus......Page 745
  28.2 Life in the Solar System......Page 750
  28.3 Intelligent Life in the Galaxy......Page 752
  28.4 The Search for Extraterrestrial Intelligence......Page 757
  Chapter Review......Page 761
 Appendix 1 Scientific Notation......Page 765
 Appendix 2 Astronomical Measurement......Page 766
 Appendix 3 Tables......Page 767
 A......Page 773
 B......Page 774
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Answers to Check Questions......Page 797
Answers to Self-Test Questions......Page 802
Photo Credits/Text Permissions......Page 805
 C......Page 809
 D......Page 810
 G......Page 811
 I......Page 812
 M......Page 813
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 R......Page 815
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 T......Page 817
 Z......Page 818
Star Charts......Page 819