time zones

[arrymong]

according to the song "it's only half past twelve but i don't care, it's five o clock somwhere"
is this correct? I thought that the time zones were multiples of an hour. But can it be true is there a time zone that is working with an extra half hour!!!! Ta very much in advance

[ChuckFickens]

there are several

French Polynesia -9:30
Venezuela -4:30
Canada (NST) -3:30
Iran +3:30
Afghanistan +4:30
Republic of India and Sri Lanka +5:30
Nepal +5:45 (OK not half hour, but worth a mention)
Cocos Islands and Myanmar +6:30

There are more!

[stevepj]

In the vast majority of countries the 1 hour rule applies, but there are places around the world that don't fit that rule, see attached link.

http://www.timeanddate.com/worldclock/

[vascop]

In a purely scientific sense,ANY two DIFFERENT lines of Longitude represent different times, but in practice, to make things simple, we divide the world into zones.
Otherwise your friend who lives 30 miles east or west of you would be using a different time to you - of course if you cross a time zone, as you can in America for instance, then your friend could well be using a different time.

[ChuckFickens]

vascop is quite correct,

strictly speaking time differences around the globe are analogue, so just by simply stepping 1 inch east or west you are altering you're timezone.

It's just we tend to measure it in 1 hour blocks because its easier to deal with

[R1Geezer]

Actual time zones are one hour.What we are talking about is how nations fiddle with their clocks. We offset ours by 1 hour in the summer because it suits us. There is no reason why it has to be an hour, it's just more common. India etal no doubt find that half an hour or indeed an hour and a half are more convenient.

[wildwood]

Yes, you are correct. Time zones are a manmade invention and in some places they even run horizontal like in the states of Australia you can go from South Australia, drive due north into Queensland and be in an different time. Who says time travel is not possible?.

[arrymong]

good answers thank you all.

[New Judge]

As an aside, standard times across a country or time zone were introduced comparitively recently.

Until the early 1800s each town, city or area kept its own “local time” which was synchronised only with the time indicated by sunrise/sunset. So noon in London would occur about twenty minutes before noon in, say, Exeter. “Leeds time” was six minutes behind London.

This presented no problems when journeys of any significant distance could be measured in many hours or even days. Then came the railways and as they expanded “local time” caused enormous problems with timetabling and scheduling.

In 1840 the Great Western Railway was the first railway company to standardise its time to Greenwich Mean Time. Others soon followed and the adoption of GMT by the railways led to the entire country using GMT as the standard time for the UK. There were pockets of resistance, mainly from the church and some church and cathedral clocks were fitted with two minute hands, one showing local time and the other GMT. In 1880 the Statutes (Definition of time) Act was passed and a unified standard time the whole of Great Britain was finally given legal status. In 1884 GMT was agreed as the universal reference for setting time around the globe.

Other countries followed a similar pattern, with the railways driving the need to adopt a standard time. Standard time in India was not adopted until 1906. Nonetheless some parts of the country refused to comply. Calcutta and Bombay continued to some degree with local times until 1945 and 1955 respectively.

[north star]

As a further aside despite China's size it has no 'time zones' and is the same time wherever.

[jno]

all Russian railway stations have clocks set to Moscow time; apparently they never quite got the hang of time zones, in spite of studying the English system. They were very impressed with Vauxhall station, however, and 'voxzal' is Russian for 'train station'.

[ABerrant]

Despite R1Geezer's assertion, "actual" time zones are not "one hour". Presumably "actual" is meant to refer to "standard" time zones, of which there are 40 (not the expected 24) due to fractional hour offsets and zones with offsets larger than 12 hours near the International Date Line.

http://en.wikipedia.org/wiki/List_of_time_zones

If "actual" is meant to convey "in reality" i.e. relative to Sun's position in the sky, then there are an infinite (or an immeasurable finite) number of time zones.

[R1Geezer]

I'm talking about the 24 longitude divisions that indicate the progress of the day in offset to the prime meridan. Yes there are an infinite number if you want to get your rocks off on some pedatry high!

[fredpuli47]

Further to New Judge's answer, there's an old jeweller's shop in Galway, whose very old clock (c 1800) outside is headed by a sign reading 'Galway Time' . That is a reminder that times were once different in different parts of the same country.Time has no meaning in Ireland but nowadays this clock shows the time in Dublin .