Chinese superclock will be off by 1 second in 30 billion years

An optical clock has been developed in Beijing that will deviate by just one second in 30 billion years. This is not merely a scientific breakthrough. It also gives China a lead in technology and independence.

Pushing the boundaries of measurability

The current second (1967) is based on caesium atoms. These vibrate over nine billion times per second. Strontium atoms vibrate much faster: around seven hundred trillion times per second. The faster the vibration, the more precise the clock.

Optical clocks monitor the light emitted by strontium electrons as they vibrate. This allows them to keep time much more precisely than standard caesium clocks. Using this technique, researchers in Beijing have built a clock with extremely low uncertainty, high stability, and accuracy.

The race for the new second

The BIPM (International Bureau of Weights and Measures) is an organisation that coordinates global measurement systems. It works with national metrology institutes to ensure that measurements are comparable and internationally recognised for science, industry and everyday use.

Every four years, a meeting is held by the General Conference on Weights and Measures (CGPM) at which decisions are made regarding definitions relating to weights and measures. The next one is in October this year, but according to ScienceAlert, China has not yet made sufficient progress to secure a new definition of the second at the upcoming meeting.

ScienceAlert states that if China can measure the second just as precisely, to 18 decimal places, with at least three optical clocks, the definition of a second can be based on the vibrations of electrons in strontium. Two other strontium clocks and two aluminium clocks in the world have already reached this milestone.

Measurements in space

Measurements taken in space can be used, for example, to determine navigation, the Earth’s surface, gravitational waves and dark matter. Optical clocks could make these measurements more accurate.

However, because optical clocks are still large, heavy, and fragile, they cannot yet be placed on satellites. Space travel requires compact and robust systems. To meet specific requirements, China is developing optical clocks that can also be used in space in the future.

The Dutch institute SRON also works with the constraints and requirements of space technology on a daily basis. Optical clocks require powerful cooling systems to bring atoms down to near absolute zero. The Netherlands Institute for Space Research is working on a way to make the cooling systems – and ultimately the optical clocks – space-compatible.

Implications for Europe

The impact on the economy and autonomy is significant. Our infrastructure relies on extremely precise timing. Consider, for example, high-frequency trading and navigation. Europe is working on its own optical clocks, partly through the iqClock consortium. Researchers in Amsterdam are making a significant contribution to this. They have developed a continuous source of ultra-cold strontium atoms. This is crucial if researchers wish to use the clocks in space. At present, the use of these clocks in space is not yet possible.

Nevertheless, China’s lead poses a risk to Europe. If China sets the standard, Europe could become dependent on foreign technology. Given geopolitical tensions, this is undesirable. That is why investing in our own technology is necessary to retain control over infrastructure and data.

Time as a geopolitical weapon

According to sinologist Ardi Bouwers in an interview with the Atlantic Commission, timekeeping has become a geopolitical instrument. China wants to be less dependent on the West and set its own standards. The strontium clock fits into that strategy.

Development is continuing. New types of clocks, such as nuclear clocks, are also currently being researched.