pytz has so many timezones!

J. Clifford Dyer jcd at sdf.lonestar.org
Tue Oct 9 14:39:09 EDT 2007


On Tue, Oct 09, 2007 at 11:21:41AM -0700, mensanator at aol.com wrote regarding Re: pytz has so many timezones!:
> 
> The Earth says. It takes 24 hours to revolve.
> 
> > Why aren't they separated by 30minutes, or 20, or 10? Or 2 hours?
> 
> Why isn't an hour defined to be 30 minutes?
> 
> > Or why don't we have a global time?
> 
> Like UTC?
> 
> >
> > Your 25 timezones are an abstraction the same way
> 
> Not the same way at all. The 25 timezones I speak of are
> not merely an abstraction, but related to longitude.
> 
> > as are the 400 apparently in use by people all over the world
> 
> Where the correlation to longitude is much looser.
> Granted, it doesn't need to be for non-navigational
> purposes. And although governments can legislate things
> like DST, they can't legislate longitude.
> 
> > - and last time I checked, there was no
> > fundamental law in physics or such that limited the allowed or sensible
> > number of timezones...
> 
> Isn't there some law somewhere that says the circumference
> of a sphere is 360deg? Doesn't that same law mean that no two
> points on a sphere can be seperated by more than 180deg
> longitude? Doesn't that make GMT+13 non-sensible?
> 

You seem to be talking about time zones as if they are a scientific abstraction based on the physical layout of the earth.  They are not.  They are an abstraction away from true scientific (solar) time to give us regular 24 hour days, and to simplify calculation to make sure that trains don't run into one another for having left their respective stations at times based on locally defined solar noon.  Solar time is the only kind of time that doesn't have to take political considerations into account.  

GMT+13 is not non-sensible at all, if the major trade partners of the island in question are at GMT+12.  Imagine the confusion not being able to schedule meetings on monday or friday because your next door neighbor, one time zone away, is actually off-calendar from you by one day.  The IDL was arbitrarily placed in the middle of the pacific to limit this problem to as few people as possible, but the people of Kiribati have no reason to accept the disadvantage under which this (European) abstraction places them.  What would be non-sensible is for them to live 23 hours offset from their closest neighbors and family, while living a mere three hours offset from people that they have minimal contact with.  

Cheers,
Cliff



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