[LEAPSECS] What's the point?

Warner Losh imp at bsdimp.com
Wed Feb 9 13:44:14 EST 2011

On 02/09/2011 10:48, Rob Seaman wrote:

>> The idea that's been put forth is that the transition would be made all at once. Eastern Time zone would go from TI-5 to TI-4, most likely by failing to fallback one year in the fall.

> Exercise for the class: Which is it? Will the governments act separately or together? How will governments north and south of the equator coordinate given that daylight saving time occurs in the local summertime during opposing seasons? Etc and so forth.

Ummm, no coordination is necessary, although some will likely naturally
occur. Eastern Time is purely a US construct that Canada also uses.
Since the central governments of US and Canada set the time for the
whole country, I'd imagine that they'd coordinate like they did with the
last round of date changes for DST. Or not, if they aren't so friendly
in a few hundred years. So what is Brazil does or doesn't follow:
that's a question for Brazil to answer when they consider the issue.
They have different DST rules anyway, including making special
exceptions to the rule when they discovered that election machines
couldn't have their time changed.

To get a good feel for the mess that the current timezones are, it might
be enlightening to go and read the various TZdata files that comprise
the Olson database. http://www.twinsun.com/tz/tz-link.htm is a good
starting point for exploration.

> The folks on this list appear to have reached consensus that some mechanism (whatever it is) is required for managing leap-second-equivalents. The ITU draft includes no planning for such. Do they disagree with all the diverse voices on this list? Or do they merely find it more expedient to ignore the whole thing - for a season or a day or a century - and to leave their mess for their grandchildren to clean up? (Current astronomers, etc., would of course have to deal with the consequences immediately since it will break all our software.)

The speculation on the list is that in the absence of a central
authority, local governments will act as their people request when it is
staying dark too late and parents can't get their kids to bed with the
sun still shining, or have to drive to work in the dark too many days of
the year. There's a natural force here that pushes the governments,
each at their own pace, to implement the change. Given this natural
push, and the complete chaos of timezones today, it is natural to think
this is a good solution to the problem.

I think there's wide consensus on that point (eg, what would likely
happen). I don't think there's anything approaching consensus on the
wisdom of this route: I like it, you don't with very few agnostic views
among the others that I've seen.


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