HORIZONS: EXPLORING THE UNIVERSE, Enhanced Thirteenth Edition, will help you understand your place in the universe—not just your location in space but your role in the unfolding history of the physical universe. To achieve this goal, they focus on two central questions: "What Are We?" which highlights your place as a planet dweller in an evolving universe, guiding you to a better understanding of where we came from and how we formed; and "How Do We Know?" which provides insights into how science works and how the process of science can teach us more about what we are. In this edition, all end-of-chapter material is available online in the MindTap homework system, and there is a MindTap Reader version available to students.