In this revised and updated Sixth Edition, Mike Seeds has two goals. First, he wants to show students their place in the universe - not just their location, but their role as planet dwellers in an evolving universe. His second goal is to show them how science works. Essentially, "Horizons" can be understood by a principle, organizing theme: the interplay of evidence and hypothesis. Through a discussion of this interplay, Seeds provides not just a series of facts, but a conceptual framework for understanding the logic of astronomical knowledge. A good example of this is how a survey of the solar system in Chapter 16 leads to theories that explain the origin of the solar system, which is followed by further evidence in Chapters 17 through 20 that helps students test and generalize theories. Students reading "Horizons" will not only learn about the vast reaches of the universe, they will gain new insight into the human quest to understand it. To enhance students' learning experience, each new copy of the book includes two CD-ROMs: "The Sky[trademark] Student Edition CD-ROM" and "Voyage Through the Solar System CD-ROM", creating the most complete media package available for an astronomy text.

Table of Contents:
PART 1: THE SKY 1. THE SCALE OF THE COSMOS Summary / New Terms / Review Questions / Problems / Critical Inquiries for the Web 2. THE SKY The Stars / The Celestial Sphere / Summary / New Terms / Review Questions / Discussion Questions / Problems / Critical Inquiries for the Web 3. CYCLES OF THE SKY The Cycle of the Sun / The Cycles of the Moon / Astronomical Influences on Earth's Climate / Summary / New Terms / Review Questions / Discussion Questions / Problems / Critical Inquiries for the Web 4. THE ORIGIN OF MODERN ASTRONOMY Pre-Copernican Astronomy / Copernicus / Tycho Brahe / Johannes Kepler / Galileo Galilei / Isaac Newton and Orbital Motion / Summary / New Terms / Review Questions / Discussion Questions / Problems / Critical Inquiries for the Web 5. ASTRONOMICAL TOOLS Radiation: Information from Space / Optical Telescopes / Special Instruments / Radio Telescopes / Space Astronomy / Summary / New Terms / Discussion Questions / Problems / Critical Inquiries for the Web PART 2: THE STARS 6. ATOMS AND STARLIGHT Atoms / The Interaction of Light and Matter / Stellar Spectra / Summary / New Terms / Review Questions / Discussion Questions / Problems / Critical Inquiries for the Web 7. THE SUN - OUR STAR The Solar Atmosphere / Solar Activity / Summary / New Terms / Review Questions / Discussion Questions / Problems / Critical Inquiries for the Web 8. THE PROPERTIES OF STARS Measuring the Distances to Stars / Intrinsic Brightness / The Diameters of Stars / The Masses of Stars / The Family of Stars / Summary / New Terms / Review Questions / Discussion Questions / Problems / Critical Inquiries for the Web 9. THE FORMATION AND STRUCTURES OF STARS The Birth of Stars / How Stars Generate Nuclear Energy / Stellar Structure / Main-Sequence Stars / The Orion Nebula / Summary / New Terms / Review Questions / Discussion Questions / Problems / Critical Inquiries for the Web 10. THE DEATHS OF STARS Giant Stars / The Deaths of Low- and Medium-Mass Stars / The Deaths of Massive Stars / The Evolution of Binary Systems / Summary / New Terms / Review Questions / Discussion Questions / Problems / Critical Inquiries for the Web 11. NEUTRON STARS AND BLACK HOLES Neutron Stars / Black Holes / Summary / New Terms / Review Questions / Discussion Questions / Problems / Critical Inquiries for the Web PART 3: THE UNIVERSE OF GALAXIES 12. THE MILKY WAY GALAXY The Discovery of the Galaxy / The Origin of the Milky Way / Spiral Arms and Star Formation / The Nucleus / Summary / New Terms / Review Questions / Discussion Questions / Problems / Critical Inquiries for the Web 13. GALAXIES Three Types of Galaxies / Measuring the Properties of Galaxies / The Evolution of Galaxies / Summary / New Terms / Review Questions / Discussion Questions / Problems / Critical Inquiries for the Web 14. GALAXIES WITH ACTIVE NUCLEI Active Galactic Nuclei / Quasars / Summary / New Terms / Review Questions / Discussion Questions / Problems / Critical Inquiries for the Web 15. COSMOLOGY The Structure of the Universe / The Big Bang / Refining the Big Bang: Theory and Observation / Summary / New Terms / Review Questions / Discussion Questions / Problems / Critical Inquiries for the Web PART 4: THE SOLAR SYSTEM 16. THE ORIGIN OF THE SOLAR SYSTEM The Great Chain of Origins / A Survey of the Solar System / The Story of Planet Building / Summary / New Terms / Review Questions / Discussion Questions / Problems / Critical Inquiries for the Web 17. THE EARTHLIKE PLANETS The Early History of Earth / The Moon / Mercury / Venus / Mars / Summary / New Terms / Review Questions / Discussion Questions / Problems / Critical Inquiries for the Web 18. WORLDS OF THE OUTER SOLAR SYSTEM Jupiter / Saturn / Uranus / Neptune / Pluto / Summary / New Terms / Review Questions / Discussion Question / Problems / Critical Inquiries for the Web 19. METEORITES, ASTEROIDS, AND COMETS Meteorites / Asteroids / Comets / Summary / New Terms / Review Questions / Discussion Questions / Problems / Critical Inquiries for the Web PART 5: LIFE 20. LIFE ON OTHER WORLDS The Nature of Life / The Origin of Life / Communication with Distant Civilizations / Summary / New Terms / Review Questions / Discussion Questions / Problems / Critical Inquiries for the Web / AFTERWORD / APPENDIX A: UNITS AND ASTRONOMICAL DATA / APPENDIX B: OBSERVING THE SKY / GLOSSARY / ANSWERS TO EVEN-NUMBERED PROBLEMS / INDEX