This article traces the history of timekeeping from ancient methods like tracking the Moon’s phases to the development of highly accurate atomic clocks. Early humans used natural phenomena like the Moon and water clocks to measure time, while mechanical clocks improved over centuries with innovations like pendulums and quartz oscillators. These mechanical and quartz-based clocks, though increasingly precise, were still affected by environmental factors like temperature and vibration.
The breakthrough came with the invention of the atomic clock in the mid-20th century. Scientists realized that the natural vibrations of atoms, particularly cesium, could serve as a stable and unchanging standard for time. In 1967, the second was officially redefined based on the frequency of a specific microwave radiation cycle in a cesium atom. This new standard allowed for incredibly accurate timekeeping, with modern atomic clocks losing or gaining only a second over thousands or even millions of years. These precise clocks are now essential for technologies like GPS, which relies on synchronized atomic clocks to provide accurate location data.
Source: https://www.nist.gov/si-redefinition/second-past
Keywords: atomic clock, cesium atom, microwave radiation
