Get the background you need to understand how scientists know what they do about the past with these 24 lectures that cover an astonishing range of cases in which physics has helped to redefine history â€“ in astronomy, archaeology, geology, climatology, art history, and other fields. Your amazing voyage begins with five lectures on elementary atomic and nuclear physics. Professor Helfand then builds on this background with a series of lectures dealing with mysteries on Earth. He rounds out the voyage with a group of lectures that take on the problems of the cosmos, including the radical adjustment in our view of time and space required by Einstein's theory of relativity. Immensely rewarding and enlightening, these lectures will enhance your appreciation of both science and history by addressing questions such as these: How did corn spread across the New World? When did the extinction of the dinosaurs occur? How old is the Earth? In answering these and other questions, youâ€™ll explore the resources scientists use to investigate the past, including radioactivity, tree rings, ice cores, and ocean sediments. Here is an insightful feast that will undoubtedly satisfy your curiosity about some of the most profound discoveries in the history of humanity â€“ and the universe. With the wealth of information contained in these lectures, the next time you hear about a breakthrough scientific finding in the news, you'll be better equipped to answer the question: How did they do that?