universal time

noun

universal time

(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 UT
Also calleduniversal 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 UTC

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

universal time

The measure of time obtained from the rotation of the Earth , also known as Greenwich mean time, after the Greenwich Observatory in England. The world's time standard today is Coordinated Universal Time, which is kept by atomic clocks . The two universal times are kept in synchronization by the occasional insertion of leap seconds into the year.

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First recorded in 1885–90

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The longitude is to be added to the universal time if it is positive, and subtracted if it is negative.

You got the universal time equal to the local time, minus the longitude, plus twelve hours.

But the use of universal time will not necessarily involve a change; it will rather be something added to what all now possess.

When the geological record is thus obtained it may be used as a universal time scale for geological history.

Now refer to Fig. 46, in which Greenwich is taken as universal time.

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