Talk:Leap second
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Is there any practical considerations with regards to leap seconds? How does it affect anything? I suppose, for example, that the Unix epoch which counts seconds starting from January 1, 1970 would be about 22 (?) seconds out of sync with UTC, right? I think that discussions on such practical aspects needs to placed in the article. --seav 06:05, Jan 3, 2004 (UTC)
- I believe it has something to do with GPS systems, airline computers and the like.... but i'm just drawing that from my head, from an article I read about the latest spin correction... I don't have enough info to add to the entry. Lyellin 06:12, Jan 3, 2004 (UTC)
- Here someone asks a few relevant questions
- * http://www.mail-archive.com/leapsecs@rom.usno.navy.mil/msg00051.html
- and here is some related discussion, I think
- * http://www.metrology.asn.au/leapseconds.htm
- Essentially, there is a tension between our convention that a day is a fixed length, and our recording devices, because it isn't quite as we wish; I expect the tension will increase as the accuracy of our recording and measuring devices increase. However, I'm far from any kind of expert on the matter! :) Kyk 06:32, 3 Jan 2004 (UTC)
- The following page has a very useful explanation of leap seconds:
The only reason for leap seconds, in fact calendars vs timekeeping is to keep the Earth's surface position, and season timings in sync with the traditional points in the sky which mark the events. The reason for the gregorian calendar adjustment was to insert days into the mix to move easter back to occuring in it's traditional relation with the sky positions. (I don't recall these exactly and the details are not relevant to my point). The leap seconds are gradually realiging the earth's position back to day alignment as the leap year days adjust the calendar.
The earths nutation has caused the slipage and it was traditionally ignored, but there is still a significant amount to be accounted for, if I recall, it is a matter of inserting the adjustments to minimize other factors.
- "Roughly 50000 years in the future, one can expect to have a day of 86401 seconds if the definition of the SI second is not eventually changed."
I'm not sure, but I think in the year 4000 the Gregorian Calendar won't work as it does now a days... so this phrase would be irrelevant... could someone check it out? I'm busy... --Henriquevicente 01:12, Apr 26, 2005 (UTC)Henrique Vicente
- You may be falling into a (popular!) intellectual trap here, namely confusing the length of the day with the length of the year. The two are independent oscillations. Changing the leap-year rule near 4000 (no serious astronomer is confident to predict the exact length of the year that far into the future) would not affect the length of the day after that.