Terrestrial Dynamical Time zamân-e tavânik-e zamini Fr.: temps dynamique terrestre A uniform atomic time scale for apparent geocentric ephemerides defined by a 1979 IAU resolution, which replaced Ephemeris Time. TDT is independent of the variable rotation of the Earth, and the length of the tropical year is defined in days of 86,400 seconds of international atomic time. In 1991 it was replaced by Terrestrial Time. → terrestrial; → dynamical; → time. |