Scientists from Austria and China have independently developed the first two operational nuclear clocks, marking a major milestone in timekeeping technology and opening new possibilities for research into fundamental physics and the mysteries of the universe.
According to two separate studies published in the scientific journal Nature, researchers at the Vienna University of Technology and China’s Tsinghua University achieved similar results using different technical approaches. Both clocks currently perform at a level comparable to the most advanced atomic clocks.
Despite their name, nuclear clocks are not related to nuclear power or nuclear fusion. Unlike conventional atomic clocks, which measure time using changes in the energy levels of electrons surrounding an atom, nuclear clocks rely on energy transitions within an atom’s nucleus.
Both research teams used a rare isotope of thorium-229 embedded in solid calcium fluoride crystals. Professor Thorsten Schumm, who led the Austrian team, said scientists had been exploring the concept of a nuclear clock for nearly half a century, while his team began working on the project in 2008.
Chinese team leader Shi Qian Ding said that two independent teams reaching similar results through different technical methods strengthened confidence in the scientific concept.
Conventional atomic clocks use elements such as caesium or strontium to measure time through changes in electron energy levels. Nuclear clocks instead use transitions involving protons and neutrons inside the atomic nucleus.
Because the nucleus is much smaller than the electron cloud surrounding it, it may be less sensitive to certain external electromagnetic influences and temperature variations. This could eventually allow nuclear clocks to become more stable, compact and precise than existing technologies.
Modern atomic clocks are already extraordinarily accurate, losing or gaining roughly a second over billions of years. Precise timekeeping is essential for satellite navigation systems such as GPS, internet infrastructure, telecommunications networks and financial systems.
If nuclear clocks can ultimately surpass existing atomic clocks in accuracy and stability, they could improve these technologies further. Scientists also expect the technology to support sensitive experiments in fundamental physics, more precise tests of general relativity and investigations into dark matter.
The development therefore represents more than a new way to measure time. It could provide researchers with a powerful tool for exploring the fundamental laws governing the universe.