[time-nuts] How can it be :05 in one place and :30 in another
magne at samfundet.no
Sun Oct 26 11:35:26 UTC 2008
Gretchen Baxter wrote:
> I went to http://www.timeanddate.com/worldclock/
> I saw that it was 10:35 in New York but in Adelaide it was 1:05 PM and in
> New Delhi 8:05.
> How can that be?
I take it the question really is why there are time zones which are not
an integral number of hours offset from UTC ? I guess there is mostly
two reasons for this, one of geography and one of politics.
Let's look at India: The republic of India spans from
approx 68 deg. east to 89 deg. east, somewhat more than a full
time zone span. The start longitude for UTC+5 is at 60 east,
UTC+6 at 75 east and UTC+7 at 90 east. There are good reasons
for a country to have a single time zone (just think of trains, flights,
tv broadcasts etc., but there are a lot of other reasons), but for India
choosing an integral offset could be inconvenient as you want the
solar day to coincide with the clock day as much as possible.. So they
decided to go for UTC+5:30 as a working compromise.
When you look at other examples, like Nepal and Venezuela, I think
you will find that political reasons have been more important.
Not going into details here, but I guess the honorable mr. Chavez
found it important to be on "venezuelan time" instead of the
atlantic standard time (or even worse, eastern time :)
I suspect some of the same goes for Nepal (at UTC+05:45)..
Indian standard time (UTC+05:30) would suit them just fine, but
somehow having your very own time can be, eh, positive for
The other neighbour of Nepal, China, has taken another direction.
China, spanning 50 degrees of latitude (more than 3 complete time
zones), has chosen one common time zone. Interestingly enough, this is
the Beijing time zone. Beijing is located in the eastern part of
China, so the western regions of China observe noon at closer to 15:00
(that's 3pm for you USians).
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