Posted by
timothy
on from the seconds-all-taste-the-same dept.
ygslash writes "The IERS has announced today that, after seven years, there will once again be a leap second this year. On December 31, 2005, the time 12:59 will last for 61 seconds."
Re:Shouldn't that be...
by
dextr0us
·
· Score: 4, Informative
A positive leap second will be introduced at the end of December 2005.
The sequence of dates of the UTC second markers will be:
2005 December 31, 23h 59m 59s 2005 December 31, 23h 59m 60s 2006 January 1, 0h 0m 0s
Actually, its 12:00:00 then another 12:00:00.
-- "Martha Stewart can lick my Scrotum......do i have a scrotum?" -- Sharon Osbourne
Re:Should we really bother?
by
B.D.Mills
·
· Score: 5, Interesting
It depends on your definition of "significant".
I have calculated[1] that in 1000 years a leap second will be required about every two months. It's likely that at that time we would still be using time standards similar to those in use now.
On the other hand, in 1 million years, about 15 leap seconds will be required each day. Therefore, at some point timekeeping must necessarily divide the day into units that are not an integral number of seconds. We would have a situation where the record for the 100 metres dash is expressed in seconds, but the length of the second used for dividing up the day is not the same length. Such "stretched time" has already been used for the Spirit and Opportunity rovers on Mars.
[1] A common formula for approximating the evolution of delta-T over time is 31 * Cy^2, where Cy is expressed in centuries.
--
The only thing necessary for the triumph of evil is for good men to do nothing. - Edmund Burke
Re:Star Trek has it figured out.
by
toddbu
·
· Score: 4, Interesting
The only problem is that no one knows how its supposed to work.
They work much like warp speed - start out low and end high. The higher the epsiode number, the higher the range. I think that it's derived from fishing, where "the big one that got away" gets bigger each time the story is told.
-- If you don't want crime to pay, let the government run it.
Re:Two questions
by
Mudd+Guy
·
· Score: 5, Informative
Actually, it's not calculable farther in advance. The Earth's rotation is inconsistent enough that leap seconds are sometimes needed, but the need can't be predicted more than about a year in advance [1]. In other words, there is noise in the Earth's rotation period of about 1 second per year. Atomic clocks are a lot better than this (good to ~50 ns per year [2]!!!), so it's pretty easy to detect the problem.
Re:These guys must not be real nerds
by
VernonNemitz
·
· Score: 4, Interesting
The thing that bothers me is, when that big quake in Indonesia went off last year and caused that big tsunami, they talked about how the Earth's rotation SPEEDED UP. If it has already slowed down again in only one year, such that a leap second is needed, then that implies some other place has been bulging and may be about to give way. So, any Slashdotters who can pass this inference on to the geology folks, please do so pronto! Thanks!
Slashdot Mirror
What AM I going to do with all that extra time?
A positive leap second will be introduced at the end of December 2005.
The sequence of dates of the UTC second markers will be:
2005 December 31, 23h 59m 59s
2005 December 31, 23h 59m 60s
2006 January 1, 0h 0m 0s
Actually, its 12:00:00 then another 12:00:00.
"Martha Stewart can lick my Scrotum......do i have a scrotum?" -- Sharon Osbourne
It depends on your definition of "significant".
I have calculated[1] that in 1000 years a leap second will be required about every two months. It's likely that at that time we would still be using time standards similar to those in use now.
On the other hand, in 1 million years, about 15 leap seconds will be required each day. Therefore, at some point timekeeping must necessarily divide the day into units that are not an integral number of seconds. We would have a situation where the record for the 100 metres dash is expressed in seconds, but the length of the second used for dividing up the day is not the same length. Such "stretched time" has already been used for the Spirit and Opportunity rovers on Mars.
[1] A common formula for approximating the evolution of delta-T over time is 31 * Cy^2, where Cy is expressed in centuries.
The only thing necessary for the triumph of evil is for good men to do nothing. - Edmund Burke
They work much like warp speed - start out low and end high. The higher the epsiode number, the higher the range. I think that it's derived from fishing, where "the big one that got away" gets bigger each time the story is told.
If you don't want crime to pay, let the government run it.
Actually, it's not calculable farther in advance. The Earth's rotation is inconsistent enough that leap seconds are sometimes needed, but the need can't be predicted more than about a year in advance [1]. In other words, there is noise in the Earth's rotation period of about 1 second per year. Atomic clocks are a lot better than this (good to ~50 ns per year [2]!!!), so it's pretty easy to detect the problem.
Sorry, I can't help with the second question.
[1] See this Wikipedia article.
[2] See this Wikipedia figure.
The thing that bothers me is, when that big quake in Indonesia went off last year and caused that big tsunami, they talked about how the Earth's rotation SPEEDED UP. If it has already slowed down again in only one year, such that a leap second is needed, then that implies some other place has been bulging and may be about to give way. So, any Slashdotters who can pass this inference on to the geology folks, please do so pronto! Thanks!