The Marvels of the Atomic Clock
The Atomic Clock is a core component of the engineering marvels of today, such as satellite communication, the Internet, GPS technology and interplanetary travel. It is the sophisticated technology of this clock which allows for precise synchronization of timing across the earth and into space. It uses the oscillation inherent in the structure of atoms to function like the pendulum of a mechanical clock.
The introduction of the atomic clock was made possible by the research advancements of the 1930’s and 1940’s as radio communications improved as an aid to the military during World War II. In 1945, the concept of a clock based on vibrations of molecules (atomic beam magnetic resonance) was introduced by Isidor Rabi of Columbia University. Four years later the National Bureau of Standards (now called the National Institute of Standards and Technology) announced the world’s first (atomic) clock based on the vibrations of the ammonia molecule.
During the 1950’s a number of these clocks were built that allowed for advanced standardization of time. In 1952, the first clock based on the cesium atom was built. The National Bureau of Standards introduced the NBS-1 (atomic) clock as the national standard for time. Meanwhile, Dr. Louis Essen at the National Physics Laboratory in the UK continued research into (atomic) clocks based upon ammonia. Through the 1960’s the National Bureau of Standards regularly replaced and advanced the models of (atomic) clocks regulating time in the United States.
During the 1960’s, the clocks were based upon the cesium-133 atom and in 1967 the second was officially defined as 9,192,631,770 oscillations of resonant frequency of the cesium-133 atom. The current standard clock for the United States called NIST-F1 by the National Institute of Standards and Technology was introduced in 1991 and this atomic clock is accurate to 1 second every 20 million years.
Besides the U.S. standards, world time is standardized by 80 clocks that are scattered across 24 countries. Coordinated Universal Time, as this standardization is called, is maintained by the Bureau International de l’Heure in Paris. With the highly accurate technology available through the use of these clocks, astronomers discovered the interesting fact that the earth is slowing down at rate of about one second per year and that the earth is drifting slightly in its relationship with the stars.
If you are not concerned about astronomy but have the desire or need for accurate time measurement, affordable clocks, which are actually radio controlled clocks, are readily available for purchase by consumers. These clocks made for home and office use received signals from the U.S.
and automatically set the correct time, date, and year.
Need more information?
Back to Clock History.