Preface xi
PART I
Understanding Astronomy 1
CHAPTER 1 Discovering the Night Sky 5
WHAT IF… Earth’s Axis Lay on the Ecliptic? 40
CHAPTER 2 Gravitation and the Motion of the Planets 41
CHAPTER 3 Light and Telescopes 69
WHAT IF… Humans Had Infrared-Sensitive Eyes? 104
CHAPTER 4 Atomic Physics and Spectra 105
PART II
Understanding the Solar System 127
CHAPTER 5 Formation of the Solar System and Other Planetary Systems 131
CHAPTER 6 Earth and the Moon 157
WHAT IF… The Moon Didn’t Exist? 191
CHAPTER 7 The Other Terrestrial Planets 193
CHAPTER 8 The Outer Planets 231
WHAT IF… We Lived on a Metal-Poor Earth? 274
CHAPTER 9 Vagabonds of the Solar System 275
CHAPTER 10 The Sun: Our Extraordinary Ordinary Star 311
PART III
Understanding the Stars 337
CHAPTER 11 Characterizing Stars 341
CHAPTER 12 The Lives of Stars from Birth Through Middle Age 369
WHAT IF… Earth Orbited a 1.5-M⊙ Sun? 404
CHAPTER 13 The Deaths of Stars 405
WHAT IF… A Supernova Exploded Near Earth? 433
CHAPTER 14 Black Holes: Matters of Gravity 435
PART IV
Understanding the Universe 457
CHAPTER 15 The Milky Way Galaxy 461
CHAPTER 16 Galaxies 481
WHAT IF… The Solar System Were Located Closer to the Center of the Galaxy? 512
CHAPTER 17 Quasars and Other Active Galaxies 513
CHAPTER 18 Cosmology 529
CHAPTER 19 Astrobiology 557
APPENDICES
A Powers-of-Ten Notation A-1
B Guidelines for Solving Math Problems and Reading Graphs A-1
C Key Formulas A-4
D Temperature Scales A-5
E Data Tables A-7
F Periodic Table of the Elements A-17
G Largest Optical Telescopes in the World A-18
H Buying a Telescope A-20
Glossary G-1
Answers to Selected Questions ANS-1
Index I-0
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