Then came the Renaissance and with it Copernicus, Galileo, Kepler, Huygens, and Newton: giants who courageously remade the world into an earth which actually moves 100,000 feet a second while revolving 1,000 miles an hour around an object 93,000,000 miles away. And yet birds perch unruffled and an apple will fall straight down All of this we think we know. But how well do we know it? In the twenty-five years since its first publication, The Birth of a New Physics has become a classic in the history of science. Here expanded by more than one-third and fully updated, it not only offers us the best account of the greatest scientific revolution but also tells us how we can know we live in a dynamic universe.