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What is an Atomic Clock?

The whole concept of time is man-made. But did you ever wonder how clocks evolved from hourglasses and reading shadows cast by the sun using a sundial?  Thanks to a simple invention, we can tell time more efficiently. 

An atomic clock or a quantum logic clock is a type of time-telling device that is known for its accuracy. One iteration is the quantum logic clock known to be so accurate. It would only lose one second after 33 billion years.

The Atomic Clock

A Columbia University professor named Isidor Rabi could be credited as the starting proponent that led to creating the atomic clock. In the 1930s, he developed the atomic beam magnetic resonance technique. This method allowed the measurement of the magnetic properties of atoms and further on measuring the spin of protons in the atom’s core. (Source: NCBI)

Rabi’s technique allowed for a deeper understanding of how atoms worked. This technique led to the creation of the first atomic clock in 1949. The National Bureau of Standards, now called the National Institute of Standards and Technology or NIST, created the first atomic clock.

An atomic clock works wherein the number of vibrations of certain atoms is measured. This is then converted into a measure of time. The reason why atomic clocks are accurate is that the resonance frequencies of specific atoms are incredibly consistent. Frequencies are not influenced by outside forces such as temperature changes. (Source: How Stuff Works)

Many versions of the atomic clock were created using different atomic particles. The first one utilized ammonia particles, while the NBS-1, built-in 1952, used cesium atoms. In 1968, the NBS-4 was created. It was the most accurate atomic clock that the NIST used all the way into the 1990s.

In 1999, the NBS-4 was replaced by NIST-F1, boasting the accuracy of losing one second after 20 million years. Into the 2010s, scientists have developed a different clock that is more accurate than the atomic clock.

The quantum-logic clock boasts the accuracy of losing one second after 3.7 billion years. It’s saying it will only lose one second after 2.5 universes are created and become extinct. This clock utilizes only a single aluminum ion, compared to the atomic clock’s cesium atom. (Source: Wired)

Practical Uses of the Atomic Clock

There are several practical uses of the atomic clock that we are not entirely familiar with


All GPS satellites have multiple atomic clocks to aid them in providing precise locations. This is important for space navigation and also communications between the GPS satellites.


Banks need accurate clocks to ensure time and date stamps of high-frequency transactions. Imagine if the stock market didn’t have highly accurate clocks. The stock market wouldn’t be as thriving as it is now without the help of atomic clocks.

Telco Providers

Have you noticed an option on your mobile phone to set the time to service provider time? Telco providers use atomic clocks to ensure they provide accurate time to their users regardless of what region in the world they are in. (Source: Online Sciences)

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