You might be wondering why in the world we need such precise measures of time. Well, many systems we use everyday, such as Global Positioning Systems, require precise synchronization of time. This comes into play in telecommunications and wireless communications, also. For purely scientific reasons, we can use precise measurement of time to determine whether or not fundamental constants in the universe appear to be changing over time. Not something that keeps the average person awake at night, but a big deal to theoretical physicists. Before addressing atomic clocks, the author discusses the ways we measure time, in this month’s column.