History of the Long Year

If it seemed like a longer year than usual, that’s because it is, by a second. The scientists who control the settings on the official clocks worldwide will add a “leap second at 11:59:59 PM GMT on New Year’s Eve, December 31.

Why? This is to justify the two different time scales we use: atomic time and Earth’s rotation.

“Surely,” you ask, “what could be more constant than the sunrise?”

Well, you might ask, and don’t call me Shirley.

Leap Second

But due to gravitational forces — much too complicated for me to explain to you — atomic clocks are actually more constant. OK, here’s a bit of detail — like the moon moving farther away and changing the Earth’s rotation, solar gravity, tidal movement, space dust, magnetic storms, and solar wind. And perhaps global warming with melting ice caps.

But we like to “rise with the Sun” at the same time each day. So, if you go to bed before midnight on New Year’s Eve (yeah, right), you’ll get a bit more sleep.

Will this cause a Y2K panic of Biblical proportions, like the one at the end of 1999 when all life as we know it came to an end?

No, we’re safe this time. Many computer time servers are set up to handle the extra second. Unlike leap years, which come pretty regularly, every four years, you may need to adjust your wristwatch, thanks to the International Earth Rotation and Reference Systems Service in Paris, who mandated this case-by-case change back in July. It hasn’t happened since 2005 (did you notice?) and has only happened 23 other times since 1972 when this practice was started. It likely won’t happen again for another 4 or 5 years.

So, you’ve got some more time on your hands this year. What are you going to do with it?

Bill Petro, your friendly neighborhood historian
billpetro.com

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