Updated and expanded to include the many exciting developments in modern astronomy and experimental observations, "Astronomy: Structure of the Universe, Fourth Edition" explores the observable features of the universe and contains new information derived from recent experiments and space missions. The first part describes our solar system and its members, giving special attention to the Sun, Earth, and Moon. The second section treats the nature of matter and its behavior in stellar bodies and interstellar matter under a wide range of physical conditions. The third part discusses our galaxy in detail before considering external galaxies and ending with questions of cosmology and cosmogony. The book also includes many worked examples, problems with answers, and a selection of practical projects. This fourth edition of Roy and Clarke's classic textbook is one of two textbooks written to meet the current need for a comprehensive and systematic treatment of astronomy, including the physical and mathematical groundwork so often omitted from other textbooks.