New York, Jan 01:
If life is often a matter of split seconds - the train door that closes in your face, the chance encounter with the love of your life, the near-collision with an oncoming truck - then the universe has just bestowed upon us a generous gift: the leap second.
Just before midnight Greenwich Mean Time on New Year's eve, one second was 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. Since the days of Sir Isaac Newton, scientists have understood the time it takes for the earth to make a full rotation is getting longer. The gradual deceleration is caused by the gravitational pull of the moon.
The same force that brings the tides is putting the brakes on the earth, albeit very slowly.
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, which measure time using the resonant frequency of a cesium atom.
When a 24-hour day, as measured by the world's atomic clocks, becomes more than 9/10th's of a second shorter than a solar day, those in charge add the leap second.