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"It is better to be drunk with loss and to beat the ground, than to let the deeper things gradually escape."

- I. Compton-Burnett, letter to Francis King (1969)

"Cynical realism – it is the intelligent man’s best excuse for doing nothing in an intolerable situation."

- Aldous Huxley, "Time Must Have a Stop"

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Wednesday, 21 September 2005

Topic: Science

Follow Up: The Other Great Debate

At the end of July in these pages, in Counting the Seconds, or Not, there was a discussion of a controversy - the real problem with adding "leap seconds" in determining what was the actual, precise time at any place on the planet.

Say what?

Of course, it is a bit hard to explain. The July item discussed the heated argument between the Americans who wanted it one way, the British who wanted it another, and some folks at the Paris Observatory who had other thoughts. (By the way, "Our Man in Paris," Ric Erickson, editor of MetropoleParis, has a photo of the Paris Observatory, as of last weekend, here.)

This is arcane stuff.

We have offered a proposal at the UN, to an obscure committee on such matters that meets behind closed doors - a very pro-business proposal - but astronomers hate it. And Britain sees it as a threat to its revered standard, Greenwich Mean Time. Our plan would simplify the world's timekeeping by making each day last exactly twenty-four hours. But you see, since the moon's gravity has been slowing down the Earth, it takes slightly longer than those twenty-four hours for the big ball to rotate completely on its axis. So every few years a group that helps regulate global timekeeping, the International Earth Rotation and Reference Systems Service, tells governments, telecom companies, satellite operators and others to add in an extra second to all clocks to keep them synchronized - an adjustment made on New Year's Eve or the last day of June. But this just screws up all kinds of hyper-accurate computer systems, and GPS systems, even if it helps astronomers to point their telescopes precisely.

So what to do? There seem to be three choices:

You have your International Atomic Time, or "absolute timekeeping," based on atomic clocks. You have your Universal Time, the "classic system" based on the rotation of the earth. Since International Atomic Time was introduced in 1958, "atomic time" has run, now, thirty-two seconds ahead of "ordinary time" - it's those damned fluctuations in the rate of the earth's rotation, of course. And you have the compromise system to manage the divergence - that would be what came out of the International Telecommunication Union in 1971 - a system called "Coordinated Universal Time," a system uses the leap-second idea to keep everyday time accurate within 0.9 seconds. Close enough? We say "no" at the UN meetings. (Note: Leap seconds normally are declared every few years, but because of a recent stabilization in the earth's rotation, which no one is explaining, there have been no leap seconds since 1998.)

So what? See this from the Associated Press, Wednesday, September 21 -British Group Wants Debate on Leap Seconds - they're not happy at all:
Hold on a second! Britain's Royal Astronomical Society on Wednesday called for a public debate on the proposed abolition of leap seconds, a tiny end-of-year adjustment to keep clocks in synch with the earth's rotation.

The International Telecommunication Union (ITU) will meet in Geneva in November to debate a proposal to abolish leap seconds after 2007. The next leap second comes at the end of this year.

Mike Hapgood, secretary of the Royal Astronomical Society, said the debate has practical implications for computers, global positioning systems and for those who study phenomena - such as tides - which are related to the earth's rotation.

"The debate has been rather closed, mainly among timing experts," Hapgood said in a telephone interview. ...
So, should the debate be opened up? That might be fun, and a break from all the talk of war and politics and natural disasters, and oil running out and economic woes and global warming and coming pandemics. On the one side you have the purists, the business folks and the United States government arguing for absolute precision, for good reason, but ignoring the natural world with its imperfections. On the other side you have the realists, the folks who study the tides and stars, and this imperfect earth, and these people need a timekeeping system that matches actual, observable phenomena.

The purists versus the realists? Wait a second (no pun intended). That's the same debate as on all the other matters.

Posted by Alan at 10:53 PDT | Post Comment | Permalink

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