Dragaera

Time and longitude

Wed Feb 16 12:51:39 PST 2005

On Wed, 16 Feb 2005, Martin Wohlert wrote:

@> Well, what is a time zone anyway?
@>
@> Peter H. Granzeau and myself assumes/knows/thinks (strike out whatever is
@> inappropriate) that every "one hour strip" of the Earth is one time zone,
@> while others assumes/knows/thinks that each place with the same time is the
@> same time zone, regardless of wherever the sun is.
@>
@> Who's right?

What, you think it's as simple as who's right and who's wrong? Heh.

The problem here is that time is an artificial human construct that we use
to conveniently measure a certain aspect of the universe. We've made a
couple of common-sense choices (the unit called "day" is about one
rotation of our planet on its axis, and the unit called "year" is about
one orbit of our planet around the sun) and basically standardized the
size of the time units worldwide, but beyond that we're just making
stuff up. And the problem is that different countries, and in some cases
different areas in the different countries, have decided to make up
different stuff.


So the question is: what does it mean for it to be 06:00? If you want that
to mean "it's morning", then you have to make 06:00 occur at
non-simultaneous times at different points on the globe, and adjust 06:00
periodically when the day changes size. And of course you're just SOL at
the poles. This is the approach the U.S. has taken (along with most of
the civilized world).

If you just think 06:00 means "six hours after we've arbitrarily started
the day, even if we're starting the day in the afernoon here", then you
don't have to do any of that. That's basically what China has decided.

So, long story longer: which group is right depends on what you mean by
"time zone". The dictionary says a time zone has to follow both rules: it
must be one of 24 longitudinal divisions and it must keep the same time.
So I suppose, according to the Keepers of the English Language, China
doesn't have any time zones at all (since it keeps different time in those
strips than other things which share the same strip do).