Coordinated Universal Time


Coordinated Universal Time
n.
UNIVERSAL TIME as periodically adjusted to coordinate with atomic clocks: it serves as the official international basis for STANDARD TIME: abbrev. UTC

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      international basis of civil and scientific time, implemented in 1963. The unit of UTC is the atomic second, and UTC is widely broadcast by radio signals. These signals ultimately furnish the basis for the setting of all public and private clocks. Since Jan. 1, 1972, UTC has been modified by adding “leap seconds” when necessary.

      UTC serves to accommodate the timekeeping differences that arise between atomic time (which is derived from atomic clocks (atomic clock)) and solar time (which is derived from astronomical measurements of the Earth's rotation on its axis relative to the Sun). UTC is thus kept within an exact number of seconds of International Atomic Time and is also kept within 0.9 second of the solar time denoted UT1 (see Universal Time). Because of the irregular slowing of the Earth's rate of rotation by tidal friction and other forces, there is now about one more (atomic clock-derived) second in a solar year than there are UT1 seconds. To remedy this discrepancy, UTC is kept within 0.9 second of UT1 by adding a leap second to UTC as needed; the last minute of December or June is made to contain 61 seconds. The slowing of the Earth's rotation varies irregularly, and so the number of leap seconds by which UTC must be retarded to keep it in epoch with UT1 cannot be predicted years in advance. Impending leap seconds for UTC are announced at least eight weeks in advance by the International Earth Rotation and Reference Systems Service at the Paris Observatory, however.

Jonathan D. Betts
 

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Universalium. 2010.

Look at other dictionaries:

  • Coordinated Universal Time — n. UNIVERSAL TIME as periodically adjusted to coordinate with atomic clocks: it serves as the official international basis for STANDARD TIME: abbrev. UTC …   English World dictionary

  • Coordinated Universal Time —   [kəʊ ɔːdɪneɪtɪd juːnɪ vəːsəl taɪm, englisch], Abkürzung CUT, die koordinierte Weltzeit (UTC) …   Universal-Lexikon

  • Coordinated Universal Time — UTC redirects here. For other uses, see UTC (disambiguation). Coordinated Universal Time (abbreviated UTC) is the primary time standard by which the world regulates clocks and time. It is one of several closely related successors to Greenwich… …   Wikipedia

  • Coordinated Universal Time — Die koordinierte Weltzeit (UTC, Coordinated Universal Time[1]) ist die aktuelle Weltzeit. Sie hat in dieser Funktion die Mittlere Greenwichzeit (Greenwich Mean Time – GMT) bereits 1926 abgelöst. Sie ist eine Kombination aus der internationalen… …   Deutsch Wikipedia

  • Coordinated Universal Time — An atomic time scale that is the basis for broadcast time signals. Coordinated Universal Time (UTC) differs from International Atomic Time by an integral number of seconds; it is maintained within 0.9 seconds of UT1 (see Universal Time) by… …   Military dictionary

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  • Coordinated Universal Time — suderintasis pasaulinis laikas statusas T sritis informatika apibrėžtis ↑Pasaulinis laikas, suderintas su atominio laikrodžio laiku. Suderintojo pasaulinio laiko ir pasaulinio laiko skirtumas negali būti didesnis kaip 0,9 s. Todėl ten, kur šio… …   Enciklopedinis kompiuterijos žodynas

  • coordinated universal time — noun Greenwich Mean Time updated with leap seconds • Syn: ↑UTC • Hypernyms: ↑Greenwich Mean Time, ↑Greenwich Time, ↑GMT, ↑universal time, ↑UT, ↑UT1 …   Useful english dictionary

  • Coordinated Universal Time — noun a system of time measurement used to regulate time and clocks around the world, based on International Atomic Time with leap seconds added at irregular intervals to compensate for the earth s slowing rotation; except in highly technical… …   Australian English dictionary

  • Coordinated Universal Time — noun Date: 1969 the international standard of time that is kept by atomic clocks around the world abbreviation UTC; compare Greenwich mean time, Universal time …   New Collegiate Dictionary


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