Evolution of Timescales from Astronomy to Physical Metrology

Résumé du livre

Astronomy has provided a means to mark the passage of time throughout history. One of the repeating phenomena that makes this possible is the Earth's rotation. The basic variability in its rotational speed, however, makes astronomical techniques unsuitable for timekeeping with the precision required for modern applications. Physical metrology from the first mechanical clocks to the most sophisticated atomic standards of today has assumed a growing role in timekeeping. Along with this progress in technology, more sophisticated concepts of timescales have appeared to take advantage of those improvements.