Post by londontube on Nov 9, 2005 13:54:18 GMT
Taken from - 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?"
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?"
