Just a Second

December 31, 2008

Everyone's posting their year-end round-ups as 2008 draws to a close, but I prefer to look forward -- the past is prologue, as a wise man once observed. There's going to be a slight hiccup in that forward movement come midnight, though: as folks around the world count down to the new year, clocks will pause for exactly one extra second -- a leap second, if you will. Kind of like that extra day that gets added every four years during leap year, except we've gotten so nitpicky that we're adjusting to a mere second here and there.

Why do we need that extra second? Well, it's partly the moon's fault, per Matt Springer at Built on Facts:

"Tides rise and fall because the moon's gravity pulls the water into a tidal bulge which the earth rotates under. This results in friction, which slows down the planet very gradually. Every year the rotation of the earth slows by about 17 microseconds. Over time, this lag builds up and eventually the keepers of the various international standard clocks have to add a second in order to keep the clocks in synchronization with the spinning planet. It's not a smooth slowing, however, so the corrections come irregularly."

Of course, we might not even care about this, if it weren't for atomic clocks. Atomic clocks were first introduced in 1949, ushering in the modern era of ultra-precision time-keeping. Unlike other clocks, these devices have no swinging pendulums or vibrating quartz crystals to keep time, which can easily slip out of calibration. Instead, it relies on the radiation emitted by -- most commonly -- cesium atoms. One second equals roughly 9,192,631,770 "cycles" (the ticks and tocks of all that emitted microwave energy).

They're so precise that an atomic clock only loses or gains a second very 60 million years or so. So if a second goes missing here and there, an atomic clock will notice. Over time, those tiny discrepancies add up. Ergo, this year we get one extra second before plunging into the great unknown of 2009.

I plan to use that extra time to dispel any lingering vestige of anxiety over what the new year might hold -- because by almost anyone's standards, I've been luckier than most, and gratitude over that good fortune is a more appropriate response than apprehension of whether that luck will hold. What will you do with your extra second?

Photo: A cesium fountain atomic clock housed at the National Institute of Standards and Technology. Source: NIST.

Comments

[Rikk Flohr]

So, do I gain an extra second of life or lose one? Perceptually, I mean.

[FFFearlesss]

So is it entirely possible, given an eternal universe, and supposing we don't get blown up by an errant comet... that eventually the earth will just stop rotating altogether?