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U.S. proposes to abolish leap-seconds

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Abolish leap seconds?

yes
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No votes
no
4
67%
don't care
2
33%
 
Total votes : 6

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dot matrix

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U.S. proposes to abolish leap-seconds

Post28 Sep 2005, 20:49

Earlier this year there was a proposal to extend daylight savings time in the U.S., now the U.S. government is trying to further its grasp and get the international community to abolish leap seconds, which would throw "official" time out of synchronization with solar time, leading to much confusion and hassle for scientists, satellites, etc.

The article is here

http://news.bbc.co.uk/2/hi/science/nature/4271810.stm
Last edited by dot matrix on 18 Jan 2019, 22:07, edited 1 time in total.
LED watches are quiet and polite. No ticking, no tocking, no beeping, no buzzing; they will only tell you the time when you ask to see it and they will do so instantly with no attention-seeking animations. A more civilized watch for a more civilized age.
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Re: U.S. proposes to abolish leap-seconds

Post29 Sep 2005, 11:38

from a purely scientific point of view, any calculations or measurements can be corrected, perhaps with dificulty, to compensate for this proposal, if it is adopted. However, I didn't actually see any real justification for WHY the US wanted to make the change? I don't think changing something if it only benefits some users, at the expense of others, is a reasonable excuse.

The scientific community has an obsession with using absolute constants to define various internationaly used SI units. For example, the definition of a Metre is - the length of the path travelled by light in vacuum during a time interval of 1/299 792 458 of a second - where it was originaly defined as the length of a specific object (ref: http://www.gordonengland.co.uk/conversion/sidef.htm) The new, constant based, measurements remove the potential variations that could occur in the old, physical, standards, caused by changes in temperature, air preasure etc..

So now it appears that the US scientists would like to define a standard day. However, I don't really see the need to abolish leap seconds. I have no use of them in my work, but the fact is days HAVE been getting progressively longer for millions of years, as the rotation of the earth gradually slows down. If the new standard is adopted, will this mean that it has to be applied in retospective calculations on prehistoric events? Surely not, because the whole evolution of the planet, and it's natural resources, is heavily infuenced by these variable solar times in a range of ways,collectively known as Milankovitch cycles http://en.wikipedia.org/wiki/Milankovitch_cycles.

I can see the need to have a more regulated time for telecommunications or military purposes, but such a precise system is, I think, essentially artificial. Nature is just not so precise. Maybe there will have to be both a standard (solar), and absolute time measurement, in a similar way to the different 'true, magnetic, and geographical' north, that people use in navigation, and map reading :?
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Re: U.S. proposes to abolish leap-seconds

Post29 Sep 2005, 19:59

You lost me at the milankovitsch cycles. And the link doesnt work.

Wikipedia does not have an article with this exact name
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Re: U.S. proposes to abolish leap-seconds

Post30 Sep 2005, 00:46

Yeah, replace leap seconds with leap hours :D
Here is an extensive article on this topic.
Backgrounder: About Time Scales, briefly and at great length.

I'd rather like to keep the leap seconds. Life follows the rotation of Earth, and I think it's better to keep civil time in track with this (solar time, UTC). For applications demanding high accuracy, there is TAI (atomic time). The difference between UTC and TAI is the sum of all of leap seconds, currently 32. IIUC.

The leap seconds create some problems in calendar calculations on computers. Most operating systems count seconds since a given point of time (the epoch). Now try to calculate the system time (seconds) for a given date: you can't just multiply the number of days since the epoch with 86400 to get the seconds, but you have to take the leap seconds into account.
How many seconds will pass from 2005-29-09 22:00:00 to 2006-29-09 22:00:00? You think 365x86400? No, because there will be a leap-second at the end of 2005.
Take 2005-29-09 22:00:00, convert this to system time (seconds since the epoch), add 365x86400 seconds, and convert this back to date/time, you get 2006-09-29 21:59:59. Adding 1 second to 2005-12-31 23:59:59 results in 2005-12-31 23:59:60, another second finally gives 2006-01-01 00:00:00 - always provided the system takes leap seconds into account.
Try this with Excel and past leap seconds - as you might have expected, it does not work :wink:.

Anyway, we'll soon have the opportunity to watch a leap second.
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Re: U.S. proposes to abolish leap-seconds

Post30 Sep 2005, 03:11

fronzelneekburm wrote:You lost me at the milankovitsch cycles. And the link doesnt work.

Wikipedia does not have an article with this exact name


Sorry. I thought I cut and pasted the link, having done a google search. Must have done something wrong :oops: If anyone has any interest in the subject, just do a search for 'Milankovitch cycles'. I did also rant on a bit. Sorry bout that too.

What I was essentially saying is that the days of the week, and the natural cycles (Milankovitch cycles) that, on a far longer timescale, regulate such events as glacial periods, and climate change, are controled by solar time ( along with the orbit, tilt and wobble of the earth). All these are by nature, not absolutely constant.

As the BBC article points out, the longer the timscale under consideration, the wider the gap will be between the figure for solar time, and absolute time. So, besides interfering with astronomical observaions, this adoption of 'constant' time might also interfere with the accurate dating of the natural cycles produced by solar time, which are identifyable in rocks. Well so far as I know anyway, and as what i've said has nothing at all to do with LED's, I think it's best I shut up now :?
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Re: U.S. proposes to abolish leap-seconds

Post30 Sep 2005, 17:51

abacus wrote:Well so far as I know anyway, and as what i've said has nothing at all to do with LED's, I think it's best I shut up now :?


The whole article has nothing to do with LEDs, I know its hard to believe, but I can live for a few seconds without thinking about LEDs... :D

No seriously - really no reason to shut up, I found your info pretty interesting. And back to the leap seconds - I really dont care, I was aware they exist, but I thought they are used like every hundred years or so. I really ask myself why the US care about such stuff. I really thought they got more serious problems at the moment. And who really cares about the leap seconds? I mean even if you must add a second a year or so, then what does a phone company or so lose when they "miss" the right moment or forget about it? In worst case they will bill you for 1 second less or more in a year - I really cant understand who could care about this.

Or is it scientists that "need" the leap second, like when an experiment runs over a year they lose 2 seconds and they're all like "Argh, now the result is wrong we need to do the experiment again! "

And whats the stuff with satellites, they just say it would be a problem for sattelite operators. I just dont get it - now they need to adjust their clocks all 6 month, and when the leap second is obeyed they just never again need to adjust their watches. I wasnt aware satellites have built-in a clock (I hope its an LED clock).

In sum I dont get the problems the article refers to.

Another quote from the article:

"It's a problem for telecommunications network operators - who have a large number of atomic clocks dotted around in their network - and for the military." Why dont they tell us which problems? I really thought the atomic clocks would even work fine when you dont adjust them a second all 6 months.

I guess worst scenario would be that evening will come an hour later or so in a million years.

Maybe someone could explain to me why the world will stop spinning without the leap seconds. I really dont get it.
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re: U.S. proposes to abolish leap-seconds

Post19 May 2007, 16:15

And now the earth is starting to spin faster, according to some scientists, due to the polar ice melting and more,heavy seawater moving to the poles. Who gives a milli-poop?
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