Horizons: Exploring the Universe

Cover
Contents
Part I: The Sky
	Chapter 1: Here and Now
		1-1 Where Are We?
		1-2 When Is Now?
		1-3 Why Study Astronomy?
		How Do We Know? The Scientific Method
	Chapter 2: A User’s Guide to the Sky
		2-1 The Stars
		Reasoning with Numbers: Magnitudes
		2-2 The Sky and Its Motions
		Concept Art Portfolios: The Sky Around You
		How Do We Know? Scientific Models
	Chapter 3: Cycles of the Sun and Moon
		3-1 Cycles of the Sun
		Concept Art Portfolios: The Cycle of the Seasons
		3-2 Astronomical Influences on Earth’s Climate
		How Do We Know? Pseudoscience
		How Do We Know? Evidence As the Foundation of Science
		3-3 The Changeable Moon
		How Do We Know? Scientific Arguments
		Concept Art Portfolios: The Phases of the Moon
		Reasoning with Numbers: The Small-Angle Formula
	Chapter 4: The Origin of Modern Astronomy
		4-1 Classical Astronomy
		4-2 the Copernican Revolution
		Concept Art Portfolios: An Ancient Model of the Universe
		How Do We Know? Scientific Revolutions
		4-3 Planetary Motion
		How Do We Know? Hypothesis, Theory, and Law
		4-4 Galileo Galilei
		4-5 Isaac Newton and Orbital Motion
		How Do We Know? Cause and Effect
		Reasoning with Numbers: Circular Velocity
		Concept Art Portfolios: Orbits
		How Do We Know? Testing A Hypothesis By Prediction
	Chapter 5: Light and Telescopes
		5-1 Radiation: Information From Space
		5-2 Telescopes
		How Do We Know? Resolution and Precision
		Reasoning with Numbers: The Powers of a Telescope
		5-3 Observatories on Earth: Optical and Radio
		Concept Art Portfolios: Modern Optical Telescopes
		5-4 Airborne and Space Observatories
		5-5 Astronomical Instruments and Techniques
Part II: The Stars
	Chapter 6: Atoms and Spectra
		6-1 Atoms
		How Do We Know? Quantum Mechanics
		6-2 Interactions of Light and Matter
		Reasoning with Numbers: Blackbody Radiation
		6-3 Understanding Spectra
		Concept Art Portfolios: Atomic Spectra
		Reasoning with Numbers: The Doppler Forumla
	Chapter 7: The Sun
		7-1 The Solar Atmosphere
		Celestial Profile 1: The Sun
		7-2 Solar Activity
		Concept Art Portfolios: Sunspots and the Solar Magnetic Cycle
		How Do We Know? Confirmation and Consolidation
		7-3 Nuclear Fusion in the Sun
		Reasoning with Numbers: Hydrogen Fusion
		Concept Art Portfolios: Solar Activity and the Sun-Earth Connection
		How Do We Know? Scientific Confidence
	Chapter 8: The Family of Stars
		8-1 Star Distances
		Reasoning with Numbers: Parallax and Distance
		8-2 Apparent Brightness, Intrinsic Brightness, and Luminosity
		Reasoning with Numbers: Absolute Magnitude and Distance
		8-3 Stellar Spectra
		8-4 Star Sizes
		Reasoning with Numbers: Luminosity, Radius, and Temperature
		8-5 Star Masses—Binary Stars
		Reasoning with Numbers: The Masses of Binary Stars
		How Do We Know? Chains of Inference
		8-6 A Census of the Stars
		How Do We Know? Basic Scientific Data
		Concept Art Portfolios: The Family of Stars
		Reasoning with Numbers: The Mass-Luminosity Relation
	Chapter 9: The Formation and Structure of Stars
		9-1 The Interstellar Medium
		9-2 Making Stars From the Interstellar Medium
		Concept Art Portfolios: Three Kinds of Nebulae
		How Do We Know? Separating Facts From Hypotheses
		Concept Art Portfolios: Star Formation in the Orion Nebula
		9-3 Young Stellar Objects and Protostellar Disks
		Concept Art Portfolios: Observations of Young Stellar Objects and Protostellar Disks
		9-4 Stellar Structure and Nuclear Fusion
		How Do We Know? Mathematical Models
		9-5 Main-Sequence Stars
		Reasoning with Numbers: The Life Expectancies of Stars
	Chapter 10: The Deaths of Stars
		10-1 Giant Stars
		How Do We Know? Toward Ultimate Causes
		10-2 Lower-Main-Sequence Stars
		Concept Art Portfolios: Star Clusters and Stellar Evolution
		Concept Art Portfolios: Formation of Planetary Nebulae and White Dwarfs
		10-3 The Evolution of Binary Systems
		10-4 The Deaths of Massive Stars
	Chapter 11: Neutron Stars and Black Holes
		11-1 Neutron Stars
		Concept Art Portfolios: The Lighthouse Model of Pulsars
		How Do We Know? Hypotheses, Theories, and Proofs
		11-2 Black Holes
		How Do We Know? Checks on Fraud in Science
		11-3 Compact Objects With Disks and Jets
Part III: The Universe of Galaxies
	Chapter 12: The Milky Way Galaxy
		12-1 Discovery of the Galaxy
		How Do We Know? Calibration
		12-2 Structure of the Galaxy
		12-3 Spiral Arms and Star Formation
		12-4 The Nucleus of the Galaxy
		How Do We Know? Nature As Processes
		Concept Art Portfolios: Sagittarius A
		12-5 Origin and History of the Milky Way Galaxy
	Chapter 13: Galaxies: Normal and Active
		13-1 The Family of Galaxies
		How Do We Know? Classification in Science
		Concept Art Portfolios: Galaxy Classification
		13-2 Measuring the Properties of Galaxies
		Reasoning with Numbers: The Hubble Law
		13-3 The Evolution of Galaxies
		13-4 Active Galactic Nuclei and Quasars
		Concept Art Portfolios: Interacting Galaxies
		How Do We Know? Statistical Evidence
		Concept Art Portfolios: Galaxy Jets and Radio Lobes
		13-5 Disks, Jets, Eruptions, and Galaxy Evolution
	Chapter 14: Modern Cosmology
		14-1 Introduction to the Universe
		How Do We Know? Reasoning By Analogy
		14-2 The Big Bang Theory
		Reasoning with Numbers: The Age of the Universe
		How Do We Know? Science: A System of Knowledge
		14-3 Space and Time, Matter and Gravity
		Concept Art Portfolios: The Nature of Space-Time
		14-4 Twenty-First-Century Cosmology
		How Do We Know? Wishing Doesn’t Make It So
Part IV: The Solar System
	Chapter 15: Origin of the Solar System and Extrasolar Planets
		15-1 The Great Chain of Origins
		How Do We Know? Two Kinds of Hypotheses: Catastrophic and Evolutionary
		15-2 A Survey of the Solar System
		Concept Art Portfolios: Terrestrial and Jovian Planets
		How Do We Know? Reconstructing the Past From Evidence and Hypotheses
		15-3 The Story of Planet Building
		15-4 Planets Orbiting Other Stars
	Chapter 16: Earth and Moon: Bases For Comparative Planetology
		16-1 A Travel Guide to the Terrestrial Planets
		How Do We Know? Understanding Planets: Follow the Energy
		16-2 Planet Earth
		Concept Art Portfolios: The Active Earth
		How Do We Know? Scientists: Courteous Skeptics
		Celestial Profile 2: Earth
		Celestial Profile 3: The Moon
		16-3 The Moon
		Concept Art Portfolios: Impact Cratering
	Chapter 17: Mercury, Venus, and Mars
		17-1 Mercury
		Celestial Profile 3: The Moon
		Celestial Profile 4: Mercury
		How Do We Know? Hypotheses and Theories Unify the Details
		17-2 Venus
		Concept Art Portfolios: Volcanoes
		17-3 Mars
		Celestial Profile 5: Venus
		Celestial Profile 6: Mars
		How Do We Know? The Present Is the Key to the Past
		Concept Art Portfolios: When Good Planets Go Bad
	Chapter 18: The Outer Solar System
		18-1 A Travel Guide to the Outer Solar System
		18-2 Jupiter
		Concept Art Portfolios: Jupiter\'s Atmosphere
		18-3 Saturn
		Celestial Profile 7: Jupiter
		Celestial Profile 8: Saturn
		How Do We Know? Funding For Basic Research
		Concept Art Portfolios: The Ice Rings of Saturn
		18-4 Uranus
		18-5 Neptune
		Concept Art Portfolios: Uranus\'s and Neptune\'s Rings
		Celestial Profile 9: Uranus
		Celestial Profile 10: Neptune
		18-6 Pluto and the Kuiper Belt
	Chapter 19: Meteorites, Asteroids, and Comets
		19-1 Meteoroids, Meteors, and Meteorites
		How Do We Know? Selection Effects
		19-2 Asteroids
		Concept Art Portfolios: Observations of Asteroids
		19-3 Comets
		Concept Art Portfolios: Observations of Comets
		19-4 Asteroid and Comet Impacts
Part V: Life
	Chapter 20: Astrobiology: Life on Other Worlds
		20-1 the Nature of Life
		How Do We Know? The Nature of Scientific Explanation
		Concept Art Portfolios: DNA: The Code of Life
		20-2 Life in the Universe
		20-3 Intelligent Life in the Universe
		How Do We Know? UFOs and Space Aliens
Afterword
Appendix A: Units and Astronomical Data
Appendix B: Observing the Sky
Glossary
Answers to Even-Numbered Problems
Index