Atomic Clock -

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

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

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: Atomic Clock

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.

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

You likely interact with atomic clocks every day without realizing it: When atoms are exposed to specific frequencies of

Scientists use these clocks to detect tiny changes in gravity (General Relativity) and to search for dark matter. Precision Limits