Scientists in Austria and China have independently developed the world’s first two functional nuclear clocks, marking a major breakthrough in timekeeping technology.
Scientists in Austria and China have independently developed the world’s first two functional nuclear clocks, marking a major breakthrough in timekeeping technology. The achievement could pave the way for ultra-precise time measurement and open new avenues for exploring fundamental physics and the mysteries of the universe.
According to two separate research papers published in the prestigious scientific journal Nature, scientists at the Vienna University of Technology in Austria and Tsinghua University in China achieved the breakthrough independently at almost the same time. Researchers say that both clocks currently perform at a level comparable to that of the most advanced atomic clocks. Experts have clarified that nuclear clocks should not be confused with nuclear energy, nuclear fusion or other atomic energy projects. They are called “nuclear” clocks because they measure time by tracking changes in the energy levels of an atomic nucleus rather than those of electrons in the outer regions of an atom.
Both research teams used a rare isotope of thorium known as thorium-229, embedded in a solid calcium fluoride crystal. Professor Thorsten Schumm, who leads the Austrian team, said scientists had been exploring the concept of a nuclear clock for nearly half a century, while his team formally began working on the project in 2008. Shiqian Ding of Tsinghua, head of the Chinese research team, said that two independent teams achieving similar results at almost the same time through different technical approaches provided strong evidence that the scientific concept was robust and reliable. Conventional atomic clocks, based on a concept introduced in 1949, measure time by tracking changes in the energy levels of electrons in atoms of elements such as caesium and strontium. Lasers or microwaves move electrons between different energy states, and the resulting characteristic frequency is used to measure time with extraordinary precision.
Nuclear clocks follow a similar principle but use energy-level transitions within an atom’s nucleus, which contains protons and neutrons, instead of relying on its outer electrons. Because the nucleus is extremely small compared with the surrounding electron cloud, it is relatively less susceptible to external electromagnetic influences and minor temperature fluctuations. This property could enable future nuclear clocks to become more stable, compact and exceptionally accurate. Modern atomic clocks are already remarkably precise, accumulating an error of approximately one second over billions of years.
Highly accurate timekeeping is essential for satellite navigation systems, including GPS, as well as the internet, communications networks and financial systems. If nuclear clocks eventually surpass existing atomic clocks in accuracy and stability, they could help improve these technologies even further. Scientists believe the significance of this development extends far beyond timekeeping. Highly sensitive nuclear clocks could support experiments in fundamental physics, enable more precise tests of Einstein’s general theory of relativity and help researchers search for possible traces of dark matter, one of the universe’s greatest mysteries. The development of the first functional nuclear clocks could therefore represent more than a new way to measure time. It may mark the beginning of a new era in the scientific effort to understand the fundamental laws governing the universe.
