Leap second to remain for another three years

Leap second to remain for another three years


Posted on January 20, 2012 - 04:24 by Emma Woollacott


The ITU Radiocommunication Assembly has decided to hang on to the leap second for three more years, keeping the world's atomic clocks in synch with the Earth's rotation.
http://img.tgdaily.com/sites/default...stic/clock.jpgThe reason the leap second is needed is that the rotation of the Earth is - very gradually - slowing. Without the occasional addition of a leap second to the year, 'clock time' would eventually lose its relationship with the cycle of day and night.
The leap second was first introduced in 1972, and is managed by the International Bureau of Weights and Measures (BIPM).
Measurements from timing centres around the world are used to determine Coordinated Universal Time (UTC), which is adjusted to within 0.9 seconds of Earth rotation time, as determined by the International Earth reference and Rotation Service (IERS).
However, some countries, in particular the US, had wanted to eliminate leap seconds because of the difficulties they create for computer communications.
And the reason the decision's been deferred is to allow time to consider all the technical options and implications, says the ITU.
"The suppression of the leap second would make continuous time scale available for all the modern electronic navigation and computerized systems to operate with and eliminate the need for specialized ad hoc time systems," the committee reports.
"This, however, may have social and legal consequences when the accumulated difference between UT1 – Earth rotation time – would reach a perceivable level (two to three minutes in 2100 and about 30 minutes in 2700)."
The committee will debate the issue again at its next meeting in 2015 - a little later than would have been the case if the decision had gone the other way, as a new leap second's due to be added this June.

All I care about is being able to do the math, given a clock on my ship and my sextant to figure out where the hell I am.

I know WHEN I am 99% of the time.

I know where I am about 37% of the time.

hahaha

Oh wait... there's more.

Corrections: January 20

Published: January 19, 2012






FRONT PAGE
Because of an editing error, an article on Thursday about disagreement among countries over whether to abolish the leap second omitted an element of the leap year cycle. The leap year adds a day to February in a familiar four-year cycle, as the article noted — except in century years not divisible by 400. Thus, although 2000 was a leap year, 2100 will not be. The article also misidentified, in some editions, the point at which noon would strike at sunrise if the leap second is eliminated. That depends on the rate at which the Earth’s spin slows down, which is not precisely predictable. Whatever the timing, the event would occur many thousands of years from now, but probably not “more than 100,000 years from now.”

Just for the record (and for anyone who really gives a crap) ... Noon is 12:00 local time.

However, that's not really noon where you are. Almost no one reading this will be exactly on the meridian for their time zone.

So there is something called "Local Area Noon" which is based on the time that the sun crosses your meridian.

Essentially, this is the point where the sun has reached its highest point in the sky, to the south of you (if you're in the Northern Hemisphere, which the majority reading this will be).

That position is noon for that DAY. The next day it will be at a different time.

If you think that is complex, try figuring out precisely where you are if you know what time it is from UTC (assuming you don't know EXACTLY where you are).

You can calculate your exact Longitude once a day from that "noon sight" (a reading you take with your sextant, if you were so inclined).

You know, this would be a great plot device for a futuristic science fiction novel. Advance to a time when the day is an hour longer.

LOL

The only thing it does (adding seconds) is messes up the clocks on your boat so you can't figure out to the exact second when the sun crosses your meridian. lol