Atomic Clock May 2026

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

Cesium atoms are sprayed into a vacuum chamber and hit with microwaves. Atomic Clock

High-speed data transfers and cellular networks require perfectly synchronized "stamps" to ensure packets of data arrive in the correct order. Stock exchanges use atomic time to log trades

An atomic clock is the world’s most accurate timekeeping device. While a grandfather clock relies on a swinging pendulum and a digital watch relies on a vibrating quartz crystal, an atomic clock uses the ultra-stable vibrations of atoms—usually cesium or strontium—to measure the passage of time. How It Works An atomic clock is the world’s most accurate

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:

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.

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