Intended for undergraduate non-science majors, satisfying a general education requirement or seeking an elective in natural science, this is a physics text, but with the emphasis on topics and applications in astronomy. The perspective is thus different from most undergraduate astronomy courses: rather than discussing what is known about the heavens, this text develops the principles of physics so as to illuminate what we see in the heavens. The fundamental principles governing the behaviour of matter and energy are thus used to study the solar system, the structure and evolution of stars, and the early universe. The first part of the book develops Newtonian mechanics towards an understanding of celestial mechanics, while chapters on electromagnetism and elementary quantum theory lay the foundation of the modern theory of the structure of matter and the role of radiation in the constitution of stars. Kinetic theory and nuclear physics provide the basis for a discussion of stellar structure and evolution, and an examination of red shifts and other observational data provide a basis for discussions of cosmology and cosmogony.

1. Watchers of the Heavens.- 1.1. Celestial Motions.- 1.2. Early Astronomy.- 1.3. The Copernican Revolution.- Exercises.- 2. The Stuff Moves Around.- 2.1. Fundamental Properties.- 2.2. Derived Quantities.- 2.3. Scalars and Vectors 21 Exercises.- 3. Eyes on the Skies.- 3.1. Wave Phenomena.- 3.2. Reflection and Refraction of Light.- 3.3. The Doppler Effect.- Exercises.- 4. Newton Puts It All Together.- 4.1. Newton's Laws of Motion.- 4.2. Linear Momentum.- 4.3. Weight.- Exercises.- 5. Running the Machine.- 5.1. Mechanical Work.- 5.2. Energy.- 5.3. Collisions.- 5.4. Power.- Exercises.- 6. Off the Straight and Narrow.- 6.1. Uniform Circular Motion.- 6.2. Centripetal Force.- Exercises.- 7. The Gravity of It All.- 7.1. Early Speculations.- 7.2. Newton's Law of Universal Gravitation.- 7.3. Measurement of the Force Constant.- 7.4. Escape Velocity.- 7.5. Planetary Atmospheres.- Exercises.- 8. Round and Round She Goes.- 8.1. Orbital Motion.- 8.2. Artificial Satellites in Earth Orbit.- Exercises.-9. As the World Turns.- 9.1. Mechanical Equilibrium.- 9.2. The Origin of the Solar System.- Exercises.- 10. Let There Be Light!.- 10.1. Electricity.- 10.2. Magnetism.- 10.3. Induced Electric Currents.- 10.4. Electromagnetic Radiation and Light.- 10.5. The Earth's Magnetic Field.- 10.6. Electric Potential Energy.- Exercises.- 11. What's the Matter?.- 11.1. Thomson's Model of the Atom.- 11.2. The Discovery of Radioactivity.- 11.3. The Geiger-Marsden Experiment.- 11.4. Rutherford's Model of the Atom.- Exercises.- 12. Hot Stuff.- 12.1. Radiation from Hot Matter.- 12.2. The Failure of Classical Physics.- 12.3. Planck's Quantum Hypothesis.- Exercises.- 13. Einstein's Bundles.- 13.1. The Photoelectric Effect.- 13.2. Momentum of Light.- 13.3. Equivalence of Mass and Energy.- Exercises.- 14. The Great Dane.- 14.1. The Structure of the Atom.- 14.2. The Man from Copenhagen.- 14.3. Comets.- Exercises.- 15. Sugar and Spice and Everything Nice.- 15.1. The Many-Electron Atom.- 15.2. Atomic Spectra.-15.3. The Periodic Table of the Elements.- Exercises.- 16. The Starry Messenger.- 16.1. Intrinsic Brightness.- 16.2. Stellar Spectra.- 16.3. The Hertzsprung-Russell Diagram.- 16.4. Binary Stars.- Exercises.- 17. The Sun Is a Gas.- 17.1. Boyle's Law.- 17.2. A Molecular Model of the Gas.- 17.3. The Ideal Gas Law.- 17.4. Absolute Temperature.- Exercises.- 18. The Sun Is a Nuclear Furnace.- 18.1. The Structure of the Atomic Nucleus.- 18.2. Nuclear Reactions.- Exercises.- 19. No More to Wonder What You Are.- 19.1. The Evolution of a Star Like the Sun.- 19.2. The Evolution of a Heavier Star.- 19.3. The Stuff Between the Stars.- 19.4. Solar Neutrinos.- Exercises.- 20. The Flight of the Galaxies.- 20.1. The Nebulae.- 20.2. Variable Stars and Cosmic Distances.- 20.3. Hubble's Discovery.- 20.4. The Structure of a Spiral Galaxy.- Exercises.- 21. The Big Picture.- 21.1. The Cosmological Principle.- 21.2. The Quasars.- 21.3. The Cosmic Background Radiation.- 21.4. A Final Word.- Exercises.- Appendix A. Linear Graphs.- Exercises.- Appendix B. Physical and Astronomical Data.- Appendix C. Useful Formulas.- Appendix D. The Chemical Elements.- Appendix E. The Brightest Stars in the Sky.