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ephemeris time

(Encyclopedia) ephemeris time (ET), astronomical time defined by the orbital motions of the earth, moon, and planets. The earth does not rotate with uniform speed, so the solar day is an imprecise unit...

time

(Encyclopedia) time, sequential arrangement of all events, or the interval between two events in such a sequence. The concept of time may be discussed on several different levels: physical, psychological, phi...

ephemeris

(Encyclopedia) ephemeris ĭfĕm´ərĭs [key] (pl., ephemerides), table listing the position of one or more celestial bodies for each day of the year. The French publication Connaissance de Temps is t...

time

(Encyclopedia) time, in music: see tempo ; meter ; rhythm ; syncopation ; metronome and musical notation . ...

time zone

(Encyclopedia) time zone: see standard time .

solar time

(Encyclopedia) solar time, time defined by the position of the sun. The solar day is the time it takes for the sun to return to the same meridian in the sky. Local solar time is measured by a ...

civil time

(Encyclopedia) civil time, local time based on universal time . Civil time may be formally defined as mean solar time plus 12 hr; the civil day begins at midnight, while the mean solar day...

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