Coordinated Universal Time
CUT
ITU-T X.680
leap second
UTC
World Time
Zulu time
(UTC, World Time) The standard time common to
every place in the world. UTC is derived from International
Atomic Time (TAI) by the addition of a whole number of "leap
seconds" to synchronise it with Universal Time 1 (UT1), thus
allowing for the eccentricity of the Earth's orbit, the
rotational axis tilt (23.5 degrees), but still showing the
Earth's irregular rotation, on which UT1 is based.
Coordinated Universal Time is expressed using a 24-hour clock
and uses the Gregorian calendar. It is used in aeroplane
and ship navigation, where it also sometimes known by the
military name, "Zulu time". "Zulu" in the phonetic alphabet
stands for "Z" which stands for longitude zero.
UTC was defined by the International Radio Consultative
Committee (CCIR), a predecessor of the ITU-T. CCIR
Recommendation 460-4, or ITU-T Recommendation X.680 (7/94),
contains the full definition.
The language-independent international abbreviation, UTC, is
neither English nor French. It means both "Coordinated
Universal Time" and "Temps Universel Coordonné".
<BIPM>.
<The Royal Observatory Greenwich>.
<History of UTC and GMT>.
<U.S. National Institute of Standards & Technology>.
<UK National Physical Laboratory>.
<US Naval Observatory>.
<International Telecommunications Union>.
Earth's irregular rotation (/pub/misc/earth_rotation).
(2001-08-30)
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