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Tuesday, December 27, 2005

'Leap second' added on 12-31-2005

Attention, digital watch fanatics: The last day of 2005 will be one second longer than usual.

The precision of atomic clocks will be reconciled with the relative variability of the Earth's rotation on Dec. 31, when an extra second will be added to the Coordinated Universal Time used to tell time across the globe.

The Earth's rotational speed changes slightly because of tides and other forces, and the National Institute of Standards and Technology recalibrates its clocks occasionally to match them to the planet's time, called the astronomical time scale. The adjustment, called a leap second, takes place whenever Coordinated Universal Time is out of synch with the planet's time by more than 0.9 seconds.

On Dec. 31, Coordinated Universal Time will change from 23:59:59 to 23:59:60 before moving to 0:00:00 on January 1.

The last time a leap second was added was 1998, but usually they're added slightly less than once each year, NIST said. The first leap second was added in 1972, and often the extra second has been added at the end of June instead of the end of December.

2 comments:

Doug said...

Let's see; If we lose one second every year or so, that means that our days are getting just a little bit longer than they were when we were kids. Not much, but they are getting longer without a doubt - because scientists keep having to add seconds like this to the clock - on average, it works out to about one second every 18 months (By the way - we never lose a leap second. We always have to add leap seconds. It's always a "positive leap second" because - according to the US Naval Observatory (they keep track of this stuff) the Moon's gravity causes tides, and the tidal drag of all that water slopping around (plus the molton core of the Earth as well) slows down the earth's rotation over time.
This means that in years past, days were shorter than they are today - right? (come on! We just worked this out together!) Not much in a few years of time, but in a bunch of years, it's got to add up - right?
Now follow me here; If evolution is supposed to have taken place over "billions and billions of years" like we were taught in school, and if we back up the clock say, to just two billion years ago - assuming one leap second every two years - why, that's one billion seconds. Right?
That means that the earth must have been rotating on it's axis much faster, two billion years ago, than it is, today. Do the math!
Think about this: if the typical day two billion years ago was just 25% shorter than it is now in modern times - that would mean that the earth was spinning 25% faster than now - right?
That would mean gravity would be 25% less (animals could be larger), ocean tides would be huge, winds would be hundreds of miles per hour (because the earth is turning faster), earthquakes would be much more severe and much more common (because of all the energy moving around beneath the surface). Capilary action in plants would allow trees to grow to be hundreds and hundreds of feet tall. Blood would pump differently; chemical reactions would act differently than we are used to, today. And of course - sunrise and sunset would come 25% faster than today.
Now - go back another couple of billions of years - the earth would be rotating 50% faster than today; all the above effects and more, would be greatly increased. Friend - could life even exist in such conditions? And if it did, would it be anything like "life" as we know it?
Surely a much different world than we have today! And surely not the ancient world that Charles Darwin envisioned in 1848 when he proposed his Theory of Evolution. The billions and billions of steady years of days just like ours today, that his concept of evolution requires, were in real life, actually much different than Darwin could possibly conceive of, during his lifetime (think about the state of "science" about the time of the Mexican War). Makes you want to re-think this ground, doesn't it?
The "Leap Second" was "discovered" in 1962, after the atomic clock was invented in 1958 and man finally could keep time with an accuracy of greater than one second per month. (Based on the decay of the Cessium atom, the atomic clock is accurate to more than one thousandth of a second per year) By 1962 scientists began to notice a one-second discrepancy between actual "noon" in the parking lot outside the laboratory, and when the atomic clock said "noon". At first they thought the atomic clocks were faulty, but two years of celestial experiments by the US Naval Observatory found the fact that the earth's rotation is slowing down (first time anyone noticed!) They decided to add one second to the atomic clock to bring the clock into synchronization with the earth's rotation. A couple of years later, they had to do it again; In all, 23 Leap Seconds have been added to all the world's atomic clocks since 1962; this December 31 at midnight, we add the 24th.
That's just in our own lifetimes - the earth is slowing down, and because the moon has been out there forever, the earth's rotation has been slowing down forever as well.
Perhaps "Evolution" is not so cut-and-dried as we were taught in seventh-grade Earth Science class, and should be rethought!
Thanks for your attention.
Doug

the Rab said...

no one's proposing that science is perfect. after all, man is an imperfect creature. good food for thought though. my head hurts.