What is atomic time and how does it work?

International Atomic Time (TAI - Temps Atomique International) measures the electromagnetic signal that electrons in atoms emit when they change energy levels.

The atomic time scale was introduced in 1955 when the scientists discovered ultra-stable frequency standards based on quantum jump between the energy levels of atoms and molecules.

An atomic clock is a physical reproduction of the ET (ephemeris time) scale. Atomic time has neither secular nor diurnal variations. It does not get old and it is distinguished by sufficient accuracy, certainty and reproducibility.

How Do Atomic Clocks Work?

It's trite to say so but atomic time is used in atomic clocks. The operating principle is as follows - the clock receives an electrical impulse, which brings the oscillatory system out of equilibrium.

Such accuracy is needed for several reasons, GPS navigation is one of them. GPS navigation system consists of Earth-orbiting satellites. For example, a smartphone uses four satellites - thus, the device determines the exact location of the owner. One satellite shows the location of the gadget, while three others calculate the time it takes for the signal to reach the device. Due to the high accuracy of the atomic clock, satellites can easily determine your current location.