Next on Americas to do list - Take over time!

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Dave A

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Taken from - http://news.bbc.co.uk/1/hi/sci/tech/4420084.stm

Timekeeping proposal sparks row

Greenwich Mean Time would become an "irrelevance" if proposals to redefine how time is measured are accepted, an historian at the Royal Observatory Greenwich, UK, has warned.

US scientists want to change the current system, which keeps clocks in synch with solar time by adding a leap second every 18 months or so.

The proposals will be discussed at a meeting in Geneva on Wednesday.

UK scientists believe the meridian's role in timekeeping is under threat.

The Prime Meridian, which runs through Greenwich in south-east London, became the basis for the world's time keeping in 1884 after the first Astronomer Royal, John Flamstead, calculated that the Earth rotated on its axis once every 24 hours.

That discovery meant that time could be defined by the Sun's position relative to a point on the Earth - in this case the meridian running through Greenwich.

'Out of synch'


It turned out that the Earth's rotation is ever so slightly slowing down. Since 1972 that anomaly was corrected by adding a so-called leap second when necessary.

But according to the Observatory's Curator of Horology - Jonathan Betts - the meridian's role in providing the basis of time keeping across the world is now under threat.

US members of the International Telecommunications Union want to change the current system.

"They want for the first time in history to separate us from the natural rotation of the Earth, which means as the years go by we will increasingly get out of synch with astronomy and the real world," he said.

"It means in a sense, as far as time keeping is concerned, the meridian line becomes sort of an irrelevance."

Lie-in

This New Year's Day we'll have an extra second in bed - an extra leap second will be added to the pips at midnight on the first of January.

Although it doesn't make for a luxurious lie-in for most of us - it is important for astronomers such as Dr Robert Massy - who's also at the Royal Observatory.

"Astronomers are people who depend very much on accurate timescales," he said.

"For example in the field of radio astronomy we need amazingly accurate clocks to ensure that the signals from telescopes on the other side of the world come together and can be aligned correctly, so for us it matters a lot."

Without the leap second astronomers would lose track of distant stars and spacecraft. And it would even affect navigation on the Earth. But it's that leap second that some American scientists want to scrap.

UK doubts

Among those upset by the idea is Daniel Gambis who works for the intriguingly named Earth Rotation Service. His job is to decide when to add a leap second. He points out that over time the Earth would gradually get out of synch with the Sun.

"For me it would be a problem if the Sun were to rise at 4pm or at a different time like noon or midnight.

"I don't support the idea of the American delegation because I think all our human activities are linked to the rotation of the Earth first.

"And in fact it appears that 90% of our users who need precise timescales are very satisfied by the present procedures."

'Plainly unnatural'

So why do the Americans want to change the system? It's hard to say because despite repeated requests those calling for the changes have been unable to find the time to speak to us.

We've been told that the issue is so controversial in industry circles that the American delegation is lying low. Even the UK's time keeper - the National Physical Laboratory - is keeping quiet. But those who want to keep the leap second say that the American delegation wants to scrap the leap second because it is inconvenient to keep resetting their high precision clocks.

Some think it would be better to add a leap hour every few hundred years. But the Royal Observatory's Jonathan Betts says the US proposal seems "plainly unnatural".

"It really doesn't appeal does it - the idea that we're gradually slipping out of synchronisation with the Earth?

"And the idea that maybe one day a leap hour could be added is surely a joke.

"It's going to be thousands of years before such a thing would apply anyway and to allow yourself to get to the stage where you're a whole hour out of synchronisation with the Sun seems to be mad. Why can't we just leave things the way they are?"
 
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Guinness

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London Tube said:
"Astronomers are people who depend very much on accurate timescales," he said.
Well then they can stick to their timescales then. Let the rest of the world keep on using GMT......
 

yorkie

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A leap second? This IS a joke, and they really should have saved it until April :lol:

Fine, they can be 1 second out if they want to :lol:
 

TheSlash

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It works out that we'd get 20 secs out synch every 30 years, so if you lived to be 90, the world would of gotten 1 minute out synch by then
 

bluecont

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And out of interest, in high precision science where is 1 minute exactlly? We are aware that a second is a fairly long unit of time to physists?

A time difference of 1s is small, and not such that it will affect the non scientific unit. But I suspect it would be a huge problem to astronomers and the like who want to precisely record the precision of things and position satelites and such.

The debate shouldn't matter quite so much at the personal time keeping level, but Im sure world wide agreement needs to be reached.

But as something to bear in mind over 18 years a correction of 12s is needed, this is enough for light to travel 3.6million kilometers, just to indicate the scale of the problem.

Ian
 

TheSlash

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I've sure a comprisimise could be a new scientific unit of measurement. In temperature we have *K, *C, *F depending on which unit of measurement you prefer
In distance measurement, you can measure in Millimetres, Centimetres, Metres, Kilometres, inches, feet, yards, furlongs, chain, miles...
On the pway you might talk about fractions of an inch when discussing 'lift plates', feet when discussing rail length, chain when discussing locations, and miles when dicussing distance covered
 

Tomnick

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Aren't we all arguing for the same thing here? The US wants to scrap the idea of the leap second - the system we currently use to keep in synch with the Earth. Everyone seems to be moaning at the physicists - but they're just as keen as everyone else to see the US proposals rejected, because it'll make life difficult for them, without really affecting anyone else too much!
 

yorkie

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Tomnick said:
Aren't we all arguing for the same thing here? The US wants to scrap the idea of the leap second - the system we currently use to keep in synch with the Earth. Everyone seems to be moaning at the physicists - but they're just as keen as everyone else to see the US proposals rejected, because it'll make life difficult for them, without really affecting anyone else too much!
I've now re-read it, and it seems to me that yes you're right we do currently have a leap second (I didn't know that before! ), and it is this leap second that keeps the Grenwich meridian in place.

The UK scientists want that to remain the case, while the US scientists want to abolish the leap second which means that the merdian moves (towards them probably ;) , although I've not got my brain fully into gear to work it out!).
 
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