The nuclear clock: the most accurate time measurement ever

Mankind has always striven for ever more precise ways to measure time. From sundials and mechanical clocks to the atomic clock, and now a new breakthrough: the nuclear clock. But what exactly is this clock, what makes the nuclear clock so accurate and how does it differ from the already highly accurate atomic clock?

What exactly is a nuclear clock?

A nuclear clock is a hyper-accurate timekeeper that, unlike the atomic clock, works not on the basis of the electrons in an atom, but on the vibrations of the atomic nucleus. This makes the nuclear clock (currently) the most accurate and purest way of timekeeping. provides an even more stable and precise basis for timekeeping. So precise that in a billion years you will measure almost no deviation. We previously wrote about the atomic clock and how accurate it is, so the nuclear clock goes one step further.

What can the nuclear clock be used for?

While atomic clocks are already the norm in scientific research and GPS systems, for example, the nuclear clock goes one step further. The possibilities of the nuclear clock are enormous. For applications that require extreme precision, such as basic physics research, space travel and advanced navigation systems, this clock could be a true revolution. In addition, the clock could help investigate new physical phenomena, such as dark matter and gravitational waves, by allowing us to better observe subtle changes in time and space.
As technology advances, the nuclear clock might help us unravel new mysteries of the universe - and deepen our understanding of time even further.

How does the nuclear clock work?

The technology behind the nuclear clock is relatively new and is still being refined. Scientists discovered that the core of the thorium-229 isotope exhibits very regular vibrations, which are ideal for time measurements. These vibrations are extremely stable and allow time measurement at an unprecedented level of accuracy. As you may know, a quartz watch works by measuring vibrations from a quartz crystal. These vibrations work well in a watch but are far too irregular and inaccurate for scientific time measurement.

What makes the nuclear clock unique is that the core vibrations of the thorium isotope are virtually insensitive to external influences such as electromagnetic fields, temperature or gravity. As a result, the clock remains unprecedentedly precise, regardless of conditions.

The difference from the atomic clock

Atomic clocks, like those used for time measurement in many watches and clocks, measure the vibrations of electrons as they change energy levels. This method is already very accurate and is used for important applications such as navigation and communication. The margin of error of an atomic clock is only one second per million years. Some of our Citizen watches also use timekeeping with atomic clock. And no, there is no atomic clock in these watches: they receive the radio signal emitted by the atomic clock and indicate the correct time based on this signal.

Nuclear clock: margin of error of only 1 second per billions of years

It's a rather technical story but the nuclear clock takes time measurement to an even higher level. Whereas atomic clocks work with the relatively small energy differences between electrons, the nuclear clock uses the much more stable energy differences within the atomic nucleus itself. This makes the clock even less prone to disturbances, theoretically giving it a margin of error of just one second per billion years!

Nuclear clock in your watch?

While these technological advances are impressive, chances are slim that we will see nuclear clocks in our wristwatches anytime soon. This is due to a number of practical limitations.

1. Complexity and size
A nuclear clock is a very complex device. It requires highly sophisticated technology to measure the vibrations of atomic nuclei, which is currently only possible in laboratories. Reducing this technology to a size that fits in a wristwatch is a huge challenge.

2. Energy consumption
A nuclear clock consumes a lot of energy because it has to constantly take highly accurate measurements. However, watches run on small batteries, which are unable to support this energy demand. Moreover, watches need to last for months or years without needing battery replacement, something that is not feasible with a nuclear clock.

3. Accuracy vs. daily requirement
The precision of a nuclear clock, with a margin of error of only one second per billion years, is impressive, but unnecessary for daily use. For most people, a quartz- or atomic-controlled watch already provides more than enough accuracy.

4. Cost
Developing nuclear clocks is extremely expensive. This technology is still in its infancy and is mainly used for scientific and specialised applications. Even if it were possible to downsize the clock, the cost would be prohibitive for the average consumer.

5. Reliability of existing technology
Current technologies, such as quartz and atomic timekeeping (Atomic Time Keeping) watches, are already very reliable and accurate. GPS watches and radio-controlled watches already synchronise with atomic clocks worldwide, eliminating the need to integrate nuclear clocks into watches.

Although the nuclear clock is a fascinating breakthrough, this technology will not be available for our wristwatches for the time being. Its complexity, cost, energy requirements and redundant precision for daily use simply make it impractical. For now, quartz and atomic watches remain more than adequate for our daily timekeeping.