Name: How Atomic Clocks Keep Perfect Time
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Modern timekeeping relies on the accuracy of atomic clocks, which revolutionized timekeeping by using the quantum behavior of atoms to measure time. Discover how these incredibly precise clocks work, and how they ensure global synchronization in everything from GPS to scientific research.

Atomic clocks use quantum physics and the resonant frequency of atoms, like cesium, to define time.

How Atomic Clocks Keep Perfect Time

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Modern timekeeping relies on the accuracy of atomic clocks, which revolutionized timekeeping by using the quantum behavior of atoms to measure time. Discover how these incredibly precise clocks work, and how they ensure global synchronization in everything from GPS to scientific research.

Atomic clocks use quantum physics and the resonant frequency of atoms, like cesium, to define time with incredible precision.

Atomic clocks use quantum physics and the resonant frequency of atoms, like cesium, to define time with incredible precision.

How Atomic Clocks Keep Perfect TimePublished: January 6, 2025Narrator: Over the centuries, we've tracked time a variety of ways. But since the 1960s, time has been officially determined using atomic clocks and the quantum characteristics of atoms. The consistency of atomic clocks arises from the very nature of atoms.Speaker 2: Atomic clocks depend crucially on the quantum physics of atoms. You have a nucleus, around which there are electrons in certain energy levels. And these energy levels of possible energy states that the electron can have inside the atom.Narrator: Since an electron can only be at certain energy levels and not in between, to get to a higher level, it needs to encounter a very specific helping hand, such as a particular photon.Speaker 2: So if it were to absorb an incoming photon, it would have to be of just the right energy to jump from one level to a higher level.Narrator: That special relationship between the electrons of a particular atom and a photon of a specific energy level is a unique signature for that atom. It's called a resonant frequency.Speaker 2: So this characteristic signature of this atom gives us a very specific frequency standard that we can use to build a timekeeping device.Narrator: Atomic clocks work in different ways, but they all use a specific type of atom or molecule as a reference to lock in the frequency of an electromagnetic wave, whose oscillations provide the ticking of the clock.Today, a second is officially defined by counting the oscillations of the primary resonant frequency of a cesium-133 atom. That's over 9 billion oscillations per second.

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How Atomic Clocks Keep Perfect Time

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