Atomic time

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The Atomic Time ( TA for French Temps Atomique ) is a time scale on the atomic second is based. At numerous time institutes around the world, atomic time is usually implemented using cesium atomic clocks . In Germany the atomic time is determined by the Physikalisch-Technische Bundesanstalt (PTB). The atomic time of PTB is called TA (PTB). The atomic times of different time institutes are compared using GPS time comparisons, now increasingly using two-way time and frequency comparisons (TWSTFT). The results are sent to the International Bureau of Weights and Measures (BIPM), which uses them to form a weighted average which is the basis of International Atomic Time (TAI) published by BIPM.

Both Earth's rotation and orbital period are subject to the earth around the sun, according to human time scales, minor fluctuations and can not be measured with sufficient accuracy. In order to achieve the accuracy of time measurement required in technology and natural science, the fundamental unit of time, the second , is based today on an atomic natural constant . On the other hand, time scales that run synchronously with mean solar time are of interest in everyday life , i.e. H. based on the earth's rotation. Due to certain irregularities in the rotation of the earth, solar and atomic time are not synchronized. The deviation is so small that it does not appear in everyday life. Coordinated universal time ( UTC) applies here , which, like atomic time, is based on the second and, if necessary (based on observations of the earth's rotation ), is synchronized with the universal solar time ( UT1 ) by leap seconds .

Time / time
( second )
Atomic time scale
( second ) 		Astronomical timescale
Solar time
( solar second ) 		Orbital time
( ephemeris second )
Atomic time (TA)
International Atomic Time ( TAI )
Mean solar time  (local time)
Universal solar time  (UT1)
World time  (UT)
Coordinated Universal Time  (UTC)

literature

  • Tony Jones: Splitting the second: the story of atomic time . Institute of Physics Pub., Philadelphia, PA 2000, ISBN 0-7503-0640-8 (English, content and review , National Library Board Singapore 2009).
  • Atomic time scales. Physikalisch-Technische Bundesanstalt, accessed on April 14, 2011 .

Web links

  • Atomic time Displays the atomic time of the Physikalisch-Technische Bundesanstalt