atomic time

atomic time

      timescale generated by atomic clocks (atomic clock), which furnish time more accurately than was possible with previous astronomical means (measurements of the rotation of the Earth and its revolution about the Sun). International Atomic Time (TAI) is based on a system consisting of about 270 laboratory-constructed atomic clocks. Signals from these atomic clocks are transmitted to the International Bureau of Weights and Measures in Sèvres just outside Paris, which uses them to form TAI. Since 1972, leap seconds have been added to the TAI timescale in order to produce Coordinated Universal Time, the timescale used globally and most closely linking atomic time to Earth's actual timescale. The need for additions of leap seconds is determined by the International Earth Rotation and Reference Systems Service, located at the Paris Observatory. Cesium fountain clocks now provide the International System of Units second to an unprecedented level of accuracy. These clocks are predicted to be off by less than one second in more than 50 million years.

Jonathan D. Betts
 

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Universalium. 2010.

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  • atomic time — noun Time whose unit is the atomic second • • • Main Entry: ↑atom * * * atomic time, time as measured by an atomic clock: »An atomic time standard…would define the second in [terms of] the number of energy waves given off by an atom of cesium… …   Useful english dictionary

  • atomic time — atominis laikas statusas T sritis Standartizacija ir metrologija apibrėžtis Ypač tiksli ir tolydi laiko matavimo skalė, kurios pagrindinis matavimo vienetas yra atominė sekundė. atitikmenys: angl. atomic time vok. Atomzeit, f rus. атомное время,… …   Penkiakalbis aiškinamasis metrologijos terminų žodynas

  • atomic time scale — atominio laiko skalė statusas T sritis automatika atitikmenys: angl. atomic time scale vok. Atomzeitskala, f rus. шкала атомного времени, f pranc. échelle de temps atomique, f …   Automatikos terminų žodynas

  • atomic time standard — atominis laiko etalonas statusas T sritis radioelektronika atitikmenys: angl. atomic time standard vok. Atomzeitnormal, n rus. атомный эталон времени, m pranc. étalon atomique de temps, m …   Radioelektronikos terminų žodynas

  • atomic time scale — atominė laiko skalė statusas T sritis Standartizacija ir metrologija apibrėžtis Laiko skalė, sudaryta pagal atominės sekundės apibrėžimą. atitikmenys: angl. atomic time scale vok. Atomzeitskala, f rus. атомная шкала времени, f pranc. échelle de… …   Penkiakalbis aiškinamasis metrologijos terminų žodynas

  • Atomic Time —    The time according to a cesium clock, based on the atomic second. An atomic second is the time required for 9,192,631,770 cycles of the radiation emitted or absorbed in a particular transition of an atom of cesium 133 …   The writer's dictionary of science fiction, fantasy, horror and mythology

  • atomic time — noun Time, as measured by an atomic clock …   Wiktionary

  • International Atomic Time — ( [http://www.bipm.org/en/scientific/tai/tai.html TAI] , from the French name Temps Atomique International) is a high precision atomic time standard that tracks proper time on Earth s geoid. It is the principal realisation of Terrestrial Time,… …   Wikipedia

  • international atomic time — a system of measuring time based on atomic clocks that measure the second as defined as the SI unit of time. Abbr.: IAT * * * International Atomic Time noun An international standard of time synchronized by atomic clocks (abbrev TAI) • • • Main… …   Useful english dictionary

  • International Atomic Time —   [ɪntə næʃnl ə tɔmɪk taɪm, englisch], Abkürzung IAT [aɪeɪ i:], die internationale Atomzeit (Zeitmessung) …   Universal-Lexikon

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