Astronomy is written in clear non-technical language, with the occasional touch of humor and a wide range of clarifying illustrations. It has many analogies drawn from everyday life to help non-science majors appreciate, on their own terms, what our modern exploration of the universe is revealing. The book can be used for either aone-semester or two-semester introductory course (bear in mind, you can customize your version and include only those chapters or sections you will be teaching.) It is made available free of charge in electronic form (and low cost in printed form) to students around the world. If you have ever thrown up your hands in despair over the spiraling cost of astronomy textbooks, you owe your students a good look at this one.

Coverage and Scope
Astronomy was written, updated, and reviewed by a broad range of astronomers and astronomy educators in a strong community effort. It is designed to meet scope and sequence requirements of introductory astronomy courses nationwide.

Chapter 1: Science and the Universe: A Brief Tour
Chapter 2: Observing the Sky: The Birth of Astronomy
Chapter 3: Orbits and Gravity
Chapter 4: Earth, Moon, and Sky
Chapter 5: Radiation and Spectra
Chapter 6: Astronomical Instruments
Chapter 7: Other Worlds: An Introduction to the Solar System
Chapter 8: Earth as a Planet
Chapter 9: Cratered Worlds
Chapter 10: Earthlike Planets: Venus and Mars
Chapter 11: The Giant Planets
Chapter 12: Rings, Moons, and Pluto
Chapter 13: Comets and Asteroids: Debris of the Solar System
Chapter 14: Cosmic Samples and the Origin of the Solar System
Chapter 15: The Sun: A Garden-Variety Star
Chapter 16: The Sun: A Nuclear Powerhouse
Chapter 17: Analyzing Starlight
Chapter 18: The Stars: A Celestial Census
Chapter 19: Celestial Distances
Chapter 20: Between the Stars: Gas and Dust in Space
Chapter 21: The Birth of Stars and the Discovery of Planets outside the Solar System
Chapter 22: Stars from Adolescence to Old Age
Chapter 23: The Death of Stars
Chapter 24: Black Holes and Curved Spacetime
Chapter 25: The Milky Way Galaxy
Chapter 26: Galaxies
Chapter 27: Active Galaxies, Quasars, and Supermassive Black Holes
Chapter 28: The Evolution and Distribution of Galaxies
Chapter 29: The Big Bang
Chapter 30: Life in the Universe
Appendix A: How to Study for Your Introductory Astronomy Course
Appendix B: Astronomy Websites, Pictures, and Apps
Appendix C: Scientific Notation
Appendix D: Units Used in Science
Appendix E: Some Useful Constants for Astronomy
Appendix F: Physical and Orbital Data for the Planets
Appendix G: Selected Moons of the Planets
Appendix H: Upcoming Total Eclipses
Appendix I: The Nearest Stars, Brown Dwarfs, and White Dwarfs
Appendix J: The Brightest Twenty Stars
Appendix K: The Chemical Elements
Appendix L: The Constellations
Appendix M: Star Charts and Sky Event Resources