Saitama, May 12, 2025 (News On Japan) - The current global standard for measuring time is based on the oscillation of cesium atoms. Its margin of error—just one second every 60 million years—might seem sufficiently precise, but for one Japanese physicist, it is not enough.
Physicist Hidetoshi Katori of the University of Tokyo is developing a new timekeeping system with unprecedented accuracy: a margin of error of just one second in 30 billion years. This breakthrough in time measurement could have implications beyond timekeeping, potentially contributing to the prediction of earthquakes and volcanic eruptions.
Katori’s work is part of Japan’s broader push to pioneer next-generation industrial infrastructure. In a special interview, writer Hideo Aiba explores the implications of ultra-precise time in shaping future societies.
Accurate timing underpins modern technologies. Thanks to GPS satellites, we can determine the location of people and vehicles within a margin of just a few meters. This level of accuracy is made possible by extremely precise clocks aboard satellites—clocks that currently define the world standard, drifting only one second every 60 million years.
Yet Katori believes humanity must aim even higher. His goal is to measure time so accurately that even over twice the age of the universe—approximately 30 billion years—the system would remain off by no more than a single second.
The potential applications are revolutionary. For example, by measuring tiny variations in time caused by gravitational differences, clocks could one day be used to measure elevation more accurately than traditional methods. This concept, using time to determine height, could form the basis of next-generation social infrastructure.
The setting for this breakthrough research is RIKEN’s research center in Saitama Prefecture. There, Katori and his team are developing Japan’s first fundamentally new clock—one that uses atoms of strontium instead of cesium.
While cesium atomic clocks measure the frequency of microwave radiation absorbed by cesium atoms, Katori's optical lattice clock uses laser light to trap strontium atoms in a grid-like structure. Within this optical lattice, the atoms are bombarded with laser light to measure their oscillation.
Astonishingly, the strontium atoms—normally invisible to the human eye—can be made to appear as floating dots. Each of these dots contains around 10 million atoms, and they are held still by lasers for precise measurement.
The key difference lies in frequency. Cesium clocks operate at about 9 billion cycles per second. Strontium-based optical clocks, by contrast, operate at around 400 trillion cycles per second—four to five orders of magnitude higher. This exponential leap enables far more precise time measurement.
The current cesium clocks have a precision level of 10⁻¹⁵, corresponding to a one-second error every 60 million years. Katori's strontium optical lattice clock reaches a precision of 10⁻¹⁸, reducing that error to just one second every 30 billion years.
And even that is not the end goal. Katori continues to push for even greater precision, believing that ultra-accurate timekeeping will unlock entirely new capabilities in science, geophysics, and society at large.
Source: テレ東BIZ
