If you want to know where you are, you need a good clock. The surprising connection between time and place is explored in Time and Navigation: The Untold Story of Getting from Here to There, the companion book to the National Air and Space Museum exhibition of the same name.Today we use smartphones and GPS, but navigating has not always been so easy. The oldest "clock" is Earth itself, and the oldest means of keeping time came from observing changes in the sky. Early marin...