Abstract
Very early human experience has suggested a practical definition for the measurement of time: We define a unit of time by defining a standard (cyclical) process. Whenever this process completes its cycle identically, a unit of time has elapsed. This is the origin for the various measures of time in classical astronomy. Nature suggests strongly that we use as such standard processes the year (defined as a complete revolution of the earth around the Sun), the month (the completion of a revolution of the moon around the earth), and the day which again can be measured in several different ways. While the sidereal day is measured by a rotation in respect to the vernal equinox, the mean solar day is measured in respect to the mean. Sun. More recently, we have distinguished many more different ways of defining measures of time, partly in response to perceived needs of the applications, but in part also from purely aesthetic principles.
Publisher
Cambridge University Press (CUP)
Reference18 articles.
1. Time Scales: their history, definition and interpretation;Guinot;Astron. Astrophvs,1988
2. Practical implications of relativity for a global coordinate time scale
3. Thomas J. B. , “A Relativistic Analysis of Clock Synchronization.” Proceedings of the Sixth Annual Precise Time and Time Interval (PTTT) Applications and Planning Meeting pp. 425–439, 1974
4. Around-the-World Atomic Clocks: Predicted Relativistic Time Gains
5. Alley C. O. , “Relativity and Clocks,” Proceedings of the 33rd Annual Symposium on Frequency Control, pp. 4–39A, 1979.