The world clock

Imagine a world without time, no time would be total chaos, everyone would do something without knowing what it does, or how long it is.
Time is a feature of this world, and he is counted the clock. The clock shows hours, minutes, seconds passing again and again. Everyone asked at least once in life time is it?
What if, over tt this globe would be the same time? There is something wrong? You know it's 3 am in you, and in another corner of the world at 3 am would be the day. It would be nonsense. Therefore it was common for every country to have a time zone by time zone where they are.
This is because when we travel somewhere, always be midnight at 24 or at 0.

 A world clock is the area of ​​the surface of the earth, which clocks show the same time (this time in "Time" has been named as opposed to "local time" with that of the longitude of the location determined). In theory, each world clock bounded by meridians of longitude, but in reality for political reasons, they are adapted to the country's borders. In the past, people used solar noon local time relative to that outpost settlements varied widely. The hours of constant travel claims quicker and more accurate world clocks becomes more and more a problem.

Dividing the world into 24 equal ball exactly two corner so arise ideal 24 world clocks. These extend across each 7 ½ degrees of longitude on either side of the reference meridian, which is ideally an integer multiple of 15 ° with respect to the internationally agreed prime meridian. This has the following advantages:

    The world clock is different at the zone boundaries from only ± ½ hour of the mean solar time.
    The time difference from the adjacent world clock is ± 1 hour.

Most states have chosen one of the 24 world clocks as statutory time (or more world clocks in states with a large east-west extension). An actual world clock is the sum of all states or parts with the same selected world clock and in areas of the oceans, which are always part of an ideal world clock.

Such an actual world clock differs firstly from an ideal world clock because the western and eastern borders of the states on the borders of an ideal world clock to fall, and generally follow any longitude. In addition, the binding to the solar time often not a priority for traditions, economic considerations or cultural ties with neighboring states. Consequently, the world clock of a neighboring or more distant ideal world clock to be selected as the official time. An actual world clock already frayed edges is therefore offset occasionally in east-west direction, and is not always a continuous north-south strip. Most likely it is over the oceans a longer part of the ideal Kugelzweiecks because they not for domestic purposes, but the shipping and aviation and the military (for example, by NATO: see DTG) is defined and used.

Colloquially, the term world clock can only be meant the territory of a state, rather than the area described as a world clock belongs. Further confusion arises when the terms timezone and world clock are used as synonyms.

Some countries do not use one of the 24 "ideal" world clock which differ by an hour of each other. Choose between a time, thereby creating a ending on its southern and northern borders timezone (eg India).

States with a large east-west distance usually have multiple world clocks (for example, U.S. and Russia). They divide their territory more or less in line with the "ideal" world clocks. It can double or more broad national world clocks can be formed (as in Russia), or in the nation has only one world clock is used (as in China).

The world clocks are relative to the general Coordinated Universal Time (UTC, Coordinated Universal Time), such as UTC +1 h Central European Time (CET) or UTC-3: 30pm (Newfoundland Standard Time). Because the usage is not always clear, one world clock UTC ± x is sometimes referred to as a world clock.

In some countries, in addition, about every six months and normal zone (normal time, English Standard Time) and DST (English DST, Daylight Saving Time) is changed.

The date changes in each world clock, if there is midnight (24 clock / 00 clock), or when crossing the International Date Line (change between world clocks, UTC +12 h or 12 h UTC). Thus, a world clock is also characterized by the same valid date.

All times are in Coordinated Universal Time (UTC) are compared. The point of reference to the zero meridian (0 longitude) that is located near London Greenwich Royal observatory through the circle, so the earlier Coordinated Universal Time in Greenwich Mean time (GMT) was called. world clocks of Agreement of the International Meridian Conference was taken.


The zone from UTC time to the hour are usually different from and less frequently compared to the whole half-hour, two hours, four cases there is a difference. The second number is the same everywhere. Large-scale east-west countries (such as China), the case that a single standard time is used; occur in other specialties.