The atomic clock was invented at Columbia University by Professor Charles H. Townes, left, with the assistance of J.P. Gordon, right
In an era when millions of Americans are chained to computers, handcuffed to BlackBerrys and plugged into iPods, something as simple as knowing the current time should be easy. But here's the snag: none of these devices ever seem to sync up with each other. Why is accurately keeping time so tricky?
There is an official U.S. time, determined concurrently by the National Institute of Standards and Technology and the U.S. Naval Observatory. Both operate atomic clocks, which are capable of calculating the exact time within an infinitesimally small degree through a process that uses microwaves to manipulate cesium atoms. These clocks are publicly available, both at time.gov and over radio airwaves. GPS systems also carry on-board, constantly updated atomic clocks.
But it turns out that despite all their strengths, computers and cell phones are lousy timekeepers. Most computers carry an on-board clock powered by a separate battery. As the battery drains over time, the computer's timekeeping becomes less accurate. To sidestep this problem, most computers use the Internet to sync with an external server. (Both Microsoft and Apple operate external time servers synced to the atomic clocks carrying the official U.S. time.) But if a computer doesn't have an active Internet connection, or if time-synching is somehow turned off, a computer's clock can run askew. In addition, there's often a short but significant lag that occurs when a computer queries a distant time server, which is mainly a problem on company computers. While many companies have tried operating their own time servers as a way to increase accuracy, in many cases they don't do enough to maintain them.
Mobile devices are beset by timekeeping problems of their own. Most phones receive the time from cell-phone towers. But there's no guarantee the time servers sync up between different providers. Smart devices receive time information in a number of different ways. For a BlackBerry, the time is synched with the data network when activated, but it receives a second time feed when it's connected to a computer — so if the computer's time is off, the BlackBerry's clock gets distorted.
With so many different servers and so much room for error, there's little chance all your devices will sync up. According to a study conducted at James Madison University, more than 25% of Web servers are off by 10 seconds or more. So while the atomic clocks keep ticking away with scientific precision, it's a good bet that not all of your devices will agree with them.