It's gonna be a long year

Posted by Michael Bakich
on Thursday, December 11, 2008

USNO clocksIf you feel like time is dragging, you’re right, at least partly. Actually, it’s Earth that’s dragging, and its lackadaisical attitude will be responsible for 2008 being a longer year. Oh, joy. Like it hasn’t been long enough already.

On December 31, the U.S. Naval Observatory (USNO) will add a “leap-second” at its Master Clock Facility in Washington. Together with the National Institute of Standards and Technology, the USNO determines time for the United States. Countries around the world will follow suit. This is the first leap-second inserted since the last day of 2005, and the 24th since 1972.

In the good old days, the length of Earth’s two basic motions — its orbit of the Sun and the daily spin on its axis — defined time. When “techies” invented atomic clocks, however, that all changed. Scientists now can define a second independent of Earth’s motions.

Which time frame would prevail? Actually, both did. In 1970, scientists formalized two time frames, one atomic and one Earth-based. They also set up the International Earth Rotation and Reference Systems Service (no, I’m not joking) to monitor the difference between the systems.

The problem is that Earth’s rotation is slowing down, albeit at a snail's pace. This lag requires the insertion of a leap-second into the atomic timescale every now and then. The goal is to keep the two time systems within 1 second of each other.

If there’s a good part to this for those of us living in the United States, it’s that the USNO will add the second at 6:59:59 p.m. EST. Because many of us will have New Year’s Eve off, this event marks one extra second of vacation. Hey, I’ll take what I can get. Happy New Year.

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