[LEAPSECS] What's the point?

[Ian Batten]

On 9 Feb 2011, at 18:44, Warner Losh wrote:


> 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.


Precisely.  The daylight savings rules were subtly different between  
the UK and France for many years (fourth Sunday vs last Sunday), but  
nothing untoward happened.  The rules are markedly different between  
Europe and the US (US starts a few weeks earlier and ends a week  
later) and again, the consequences are trivial.

As a consequence of failing to incorporate leap seconds would be to  
make civil time slowly advance relative to solar time (ie, become  
progressively more "daylight-savings-y"), and in general there is a  
trend towards civil time that trades lighter evenings for darker  
mornings, many countries might be happy just to drift anyway.  I mean,  
simply failing to adopt leap seconds would solve the problem of  
getting the UK onto CET in about 5000 years, without having to get  
Bill Cash harrumping about Brussels Times or anything...

ian