universal time (redirected from Universal Time Coordinated)

universal time

n. Abbr. UT

The mean solar time for the meridian at Greenwich, England, used as a basis for calculating time throughout most of the world. Also called Greenwich time, Greenwich Mean Time, Zulu time.

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universal time

n

1. (Mathematics & Measurements / Units) (from 1928) name adopted internationally for Greenwich Mean Time (measured from Greenwich midnight), now split into several slightly different scales, one of which (UT1) is used by astronomers Abbreviation UT

2. (Mathematics & Measurements / Units) Also called universal coordinated time an internationally agreed system for civil timekeeping introduced in 1960 and redefined in 1972 as an atomic timescale. Available from broadcast signals, it has a second equal to the International Atomic Time (TAI) second, the difference between UTC and TAI being an integral number of seconds with leap seconds inserted when necessary to keep it within 0.9 seconds of UT1 Abbreviation UTC

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universal time

The mean time for the meridian at Greenwich, England (0° longitude), which runs through the former site of the Royal Observatory. It is based on the sidereal period of Earth's rotation and is used as a basis for calculating standard clock time throughout most of the world. Also called Greenwich Mean Time. Compare coordinated universal time.

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A measure of time that conforms, within a close approximation, to the mean diurnal rotation of the Earth and serves as the basis of civil timekeeping. Universal Time (UT1) is determined from observations of the stars, radio sources, and also from ranging observations of the moon and artificial Earth satellites. The scale determined directly from such observations is designated Universal Time Observed (UTO); it is slightly dependent on the place of observation. When UTO is corrected for the shift in longitude of the observing station caused by polar motion, the time scale UT1 is obtained. When an accuracy better than one second is not required, Universal Time can be used to mean Coordinated Universal Time. Also called ZULU time. Formerly called Greenwich Mean Time.

Thesaurus

Noun

1.

universal time - the local time at the 0 meridian passing through Greenwich, England; it is the same everywhere GMT, Greenwich Mean Time, Greenwich Time, UT, UT1 time - the continuum of experience in which events pass from the future through the present to the past coordinated universal time, UTC - Greenwich Mean Time updated with leap seconds