An Etymological Dictionary of Astronomy and Astrophysics

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فرهنگ ریشه‌شناختی اخترشناسی-اخترفیزیک

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Terrestrial Time
  زمان ِ زمینی  
zamân-e zimini
Fr.: temps terrestre  

The modern astronomical standard for the passage of time on the surface of the Earth. It is
the → coordinate time scale consistent with the theory of general relativity for an observer on the surface of the Earth. TT was renamed from Terrestrial Dynamical Time (TDT)
in 1991. The fundamental unit of TT is the day of 86,400 SI seconds. It is related to the International Atomic Time by the relation: TDT = TAI + 32.184 sec.

See also: → terrestrial; → time.