International Atomic Time (TAI) is measured in the SI , defined in terms of vibrations of a cesium atom. It is therefore not explicitly tied to the 's rotation, although that was of course the motivation for the original definition of the .
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Atomic Time
Time based on the atomic second (see Second). Atomic time was officially adopted 1972 January 1. From 1972 January to 1974 January 1, 3 leap seconds had to be introduced to keep atomic time within 0.7 seconds of Universal Time.
International Atomic Time
International Atomic Time is a high-precision atomic coordinate time time standard based on the notional passage of proper time on Earth's geoid....
(TAI).
International Atomic Time [LLM96]
Tail
The long streamer (about 107 km long; density about 10-18 atm) behind the comet head. Type I Tails are straight (ionic tails): Type II Tails are curved (dust tails, little or no charge).
is atomic time the basis for civil time?
How do you adjust civil time?
What is the formal definition of civil time?
What is civil time?
Wmat makes up the atmosphere on Mars?
Who was Cleomedes?
What made Cleomedes famous?
UTC is more uniform and more accurate than the UT2 system because the UTC second is based on atomic time (although the UTC year is still based on the time it takes the earth to complete one orbit).
The small tidal effect can not be observed in a short period but the cumulative effect of the Earth's actual daily rotation occurring in less than 24 hours as measured on a stable clock (ephemeris time, atomic time) even a few milliseconds every day, ...
The Mars Sol Date is defined mathematically as MSD = (Julian date using International Atomic Time - 51549.0 + k)/1.02749125 + 44796.0, where k is a small correction of approximately 0.
Time scale used in orbital computations; TDT is tied to atomic clocks (International Atomic Time, TAI), whereas Universal Time is tied to observations.
International Atomic Time (TAI)
International Celestial Reference Frame (ICFR)
International Dark-Sky Association (IDA)
International Geophysical Year (IGY)
International Quiet Sun Years (IQSY)
interplanetary magnetic field (IMF) ...
It includes routines for conversions between Universal Time (UTC), Atomic Time (TAI), and Ephemeris Time (ET). It also performs conversions between calendar dates and Julian dates, and interprets or formats dates and times in a variety of styles.
with a reference frame to report their observations in, Astrometry is also fundamental for fields like celestial mechanics, stellar dynamics and galactic astronomy. It is also instrumental for keeping time, in that UTC is basically the atomic time ...
TDT] 'scientific time' - it superseded ephemeris time in 1984, and is based on a uniform scale of time derived from atomic clocks (i.e. not subject to fluctuations in the Earth's rate of rotation). Now usually called international atomic time ...
 See also: Time, Rotation, Earth, Orbit, Solar
  
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