Life in the Universe takes non-science majors on a journey through the solar system and beyond, using a rigorous yet accessible introduction to astronomy, biology, and geology to explain natural phenomena and to explore profound scientific questions about astrobiology. The Third Edition has been thoroughly revised to include updated scientific discoveries, new Cosmic Context two-page spreads, and an updated Companion Website.   Designed for astrobiology courses but also suitable for introductory astronomy courses, Life in the Universe captures your imagination by exploring fundamental pan-scientific questions: What is life? How did life begin on Earth? What are the most extreme forms of life currently known? Is it reasonable to imagine life beyond Earth?   The text motivates you to develop basic reasoning skills and an understanding of the process of science through skillful writing and a wealth of pedagogical features, such as Learning Goals that keep you focused on key concepts. Sidebars provide optional mathematical material for courses that fulfill quantitative requirements.