US proposal to abandon leap seconds

[VJ]

What are they thinking?

http://news.bbc.co.uk/1/hi/sci/tech/4271810.stm

Every six months, the Paris Observatory tells the world whether to add or subtract a second from atomic clocks.

This synchronises clock time with the solar time used by astronomers.

The US plan to abolish leap seconds would force astronomers to look for new ways to make sure their telescopes are pointed in the right part of the sky.

And leap seconds are not only needed for astronomy:

"When you compare UTC and the Earth's rotation, the two slowly drift apart."

But the RAS points out that the idea of clock time following solar time is also deeply embedded in contemporary technical culture. Researchers estimate that the difference between UTC and Earth time could increase to about an hour within several hundred years.

Jörg

[Nowhere]

What they're thinking? Well, I'd guess that some influencial investor, whose wealth depends on one of the systems (0,01% of all out there I'd guess) that must maintain absolutelly accurate time at all times, decided that it's cheaper for him to lobby the idea isntead of making sure his software/system will work with one 61 second minute every year or so. And apparently he found people in administration who whink that instead of letting companies wise up and write the software that takes into account leap seconds, it's better to **** with the entire way we measure time and convince the rest of the world to do it also (the rest of the world meanwhile rolls over laughing at the proposal).

Leap hour every few centuries...now that's brilliant idea . Most of the systems today can do with simply synchronising when the change occurs...it wouldn't be that easy and would require much more thought in case of 25-hour day. But that's the planning of government at its best, I guess - they won't be around. But what our descendands will think about us all? Something about beeing arrogant perhaps? (anyway...I doubt the idea would live...I doubt it will ever come into force), forcing some law that will come in effect several hundred years later? I'm sure they'll understand argumentation of leap seconds beeing "sporadic, irregular events that can cause trouble"...after all, they'll have only one GIGANTIC irregularity.

Found some humorous comment on the issue

Once there was a boy, who longed to be as well known as Julius Caesar. First he gathered his legionnaires and started some wars, but he didn't get the respect from the public he wanted. Then he had a brilliant idea. Julius had a calendar named after him, maybe he could get one too. All he had to do was come up with a plan to show those pesky scientists that time was controlled by God, not some mathematical constant, and if God wanted it to jump ahead by an hour every 5 or 6 hundred years, then dammit, that is what is going to happen. He decided to call his invention the Dubyan calendar, because if he called it Georgian, people might give his daddy credit for it, or even worse, some limey king that died last century.

PS. next new year will be somehow special for all living in GMT
better adjust your clocks so you won't open the champaigne one second too early

[Fat Tone]

A lot of my old mates at NPL are hopping mad at this

[Marshmallowman]

Obviously they don't need to be synchronised with our solar day becasue they seem to be living on a different planet

[Dr Mordrid]

It's not that cut and dried;

http://wired.com/wired/archive/11.11/start.html?pg=5

Dr. Mordrid

[Brian Ellis]

It's even kludgier than that. The problem is that the common perception is that a day is 24 hours, ie a complete rotation of the earth, so that the sun is due south at its highest point (N. hemisphere outside the tropics, of course) at noon every day. This is fine, as long as the most accurate time-measuring equipment is a clepsydra or even a quartz watch. But it makes one assumption which is a false premiss: that the rotational speed of the earth is constant. It ain't! There are differences between aphelion and perihelion and, above all, according to the phase of the moon and the distance of the moon from the earth. Then there are earthly variations, as well, due to the variable position of land masses with wobble (like an unbalanced wheel on a car). This also changed with the seasons as one hemisphere or the other warmed up and expanded. Even the Indian Ocean tsunami caused the earth's rotation to slow down by a few tens of nanoseconds/day - permanently.

As time is really an astronomical measure, it seems to me normal that all clocks should be adjusted periodically, as and when needed, to be synchronised to the "sun's position", even though it is less precise than a caesium clock, if only to avoid "noon" being too early or late.

One of my ex-customers in Switzerland was the Observatoire de Neuchâtel, which is one the international time keepers, sending out time signals for most of Europe. They had (probably still have) three caesium clocks as their standard. My interlocutors included various scientists whose conception of time was difficult to understand. In fact, they considered that time was the most accurate physical variable measurable by man, provided that by "time" you meant the caesium clock time. I think I remember they said the accuracy of the second was known to ±1 in 10^14. The next most accurate variable was length (2 orders of magnitude less), when considered as the distance that a beam of light travels in a perfect vacuum in a given length of time. However, it is the krypton 86 clock that is used for the standard. The metre is defined as 1,650,763.73 wavelengths of the radiation caused by the transition between levels 2p10 and 5d5 of the atom.

This is a very complex subject, far beyond my understanding, with many tens of scientists expanding their knowledge on a daily basis worldwide.

On a lighter note, the fact that the US is proposing to unilaterally drop the leap second is just one more proof that they are out of step with the rest of the world

[VJ]

I agree it is not all cut and dried, and complex...

But one cannot justify introducing a time system based on something not in sync with the earth. I mean, in the short term these few seconds won't matter for over 99% of the people, allthough it would be hell for the remaining portion (but if neccessary they could work with their own 'timezone' - so to speak). But in the long run it will yield problems for everybody: sunrise and sunsets shift, ...; imagine having a day job and having to go to work shortly after sunrise at 23.00 (and send the kids to school). Ok, this is an extremely long time off, but it illustrates the problem; similar problems could occur in a shorter timeframe.


Jörg