Coordinated world time

of these articles describes the coordinated world time UTC; for other meanings of UTC see UTC (term clarifying).
UTC time belts in Europe

the coordinated world time (UTC) is the current world time, and has in the function the middle Greenwichzeit Greenwich Mean Time (GMT) replaced. It is a combination of the international atomic time TAI and the universal time UT. The time belts are indicated as positive or negative deviation from UTC (z. B. UTC + 2 corresponds the Central European Summer Time).

ThoseUTC combines the physical atomic time (TA) with the astromomischen time (UT) and therefore also civil time is called.

UTC is the reference time for numerical data:

  • in aviation
  • for the scientific use, as far as he does not take part directly in time measurementor more special requirements places for
  • international projects, over several time belts partly extends in
  • the Internet , and also than system time for computers in
  • the amateur radio on
  • the international space station (EAT) table of contents



the coordinated world time one shortens internationally as UTC. UTC is not an initial word, the initial letters fits neither for the French expression Temps Universel Coordonné still for the English-language variant Coordinated universal Time. Rather those is UTC a name variant of the universal time UT with the added, modifying C, which stands for coordinated. Sometimes UTC is falsely expressed as universal Time code.


map of the world with time belts

of the coordinated world timethe times in the different time belts of the earth are derived.

The UTC a general time belt is assigned, on the basis of the 0 (zero) Meridian, which runs by Greenwich. This general time belt becomes in particular in aviation and within the military range alsothe letter designates Z. Z stands here for Zero (=Null). Therefore one speaks also of Z-time or Zulu time (in accordance with the word Zulu assigned in the I.C.A.O. alphabet the letter Z).

The universal time in Germany, Austria, Switzerland and Italy is those Central European time (MEZ, or also CET for cent ral European Time), which is equal the UTC plus one hour. While the Central European summer time ( MESZ/CEST) applies for the summer time, which corresponds the UTC plus two hours. A date in the form 14:52 UTC+1: 00 means thus 14:52 clock of Central European time (MEZ).

regulation and correction

time measurement take place on basis of the SI second. The SI second is firm since 1956 no longer coupled to the earth rotation, thus in particular no more thanthe 86.400. Part middle sun tags defines. Today the SI second is time-normally defined by an atomic. A date on basis of the SI second is called therefore atomic time.

Since the speed of the earth rotation is not constant, it comes to deviations betweenthe atomic time and the Sonnenzeit. For this reason those was introduced UTC. It is derived from the international atomic time (TAI ) and synchronized if necessary by insertion of switching seconds with the universal Sonnenzeit (UT1), i.e. the deviation between UTC andUT1 is kept ever smaller than 0.9 seconds.
(S. in addition major items: Switching second)

of administration

the administration of the UTC takes place world-wide via different institutes for time, for example via the Federal Standards Laboratory (Germany), the Federal Office for metrology andAccreditation (Switzerland), the Federal Office for calibration and surveying (Austria). Their representations become then z. B. UTC (PTB) calls. The co-ordination of the UTC is task of the international office for weights and mass (BIPM). This ensures for the fact that those UTC world-wide everywhereis alike.

Web on the left of

Wiktionary: UTC - Word origin, synonyms and translations

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