Today, time stands still ... for 1 second

Today, at exactly 2 p.m., one second will be added to our official record of time -- Coordinated Universal Time, kept by a series of atomic clocks, housed in environmentally sealed vaults in about 80 timekeeping laboratories around the world and certified by the International Bureau of Weights and Measures in Paris.

The reason for the extra second is simple: The earth is slowing down. The gradual deceleration is caused by the gravitational pull of the moon.

And because time is a function of planetary movement, our days are getting longer and, depending on how you look at it, time is slowing down. This discrepancy is something we have only recently become able to measure. That happened in 1958 with the advent of atomic clocks.

Most of us will not pause to notice the extra second. But our machines will. Our computers, mobile phones and global positioning devices will all rest for one second at the appointed time as they calibrate to Coordinated Universal Time.

For the average person wishing to witness the event, the process requires a stopwatch and a common cell phone with a time display.

At the precise moment the display reads 1:59 p.m., start the stopwatch. When the display changes to 2:00, stop the watch. It should read 61 seconds.

Your extra second will have been spent.