Atomic Clock – Real

If the microwave frequency is exactly right, the atoms change states.

The best modern atomic clocks are so stable that they wouldn't lose or gain a single second in —a span of time longer than the age of the universe. Atomic Clock

At the heart of the clock is a physical constant: the "resonant frequency" of an atom. When atoms are exposed to specific frequencies of microwave or light energy, their electrons jump between energy levels. In a standard cesium atomic clock: If the microwave frequency is exactly right, the

Since 1967, the International System of Units (SI) has defined one second as exactly 9,192,631,770 oscillations of the radiation produced by this transition in a cesium-133 atom. Why It Matters When atoms are exposed to specific frequencies of

Stock exchanges use atomic time to log trades down to the microsecond, preventing fraud and ensuring a fair "first-come, first-served" system.

High-speed data transfers and cellular networks require perfectly synchronized "stamps" to ensure packets of data arrive in the correct order.

GPS satellites carry atomic clocks. Because radio signals travel at the speed of light, even a billionth of a second of error could result in your GPS being off by several miles.