Two Teams Build First Functional Thorium-229 Nuclear Clocks, Opening Path Beyond 70-Year Atomic Standards
Updated
Updated · ScienceAlert · Jun 15
Two Teams Build First Functional Thorium-229 Nuclear Clocks, Opening Path Beyond 70-Year Atomic Standards
3 articles · Updated · ScienceAlert · Jun 15
Summary
Two independent teams in Europe and China have built the first functional thorium-229 nuclear clocks, turning a long-theoretical concept into working devices described in arXiv preprints.
Thorium-229 enables the advance because its unusually low-energy nuclear transition can be driven by lasers, letting researchers track nuclear rather than electronic energy shifts for potentially greater stability.
The European team ran a stand-alone clock, stabilized a laser against the thorium signal, benchmarked it against an ytterbium-ion atomic clock, and used it to set new constraints on some ultralight dark-matter models.
The Chinese team tested two separately produced calcium-fluoride crystals and found nearly identical frequencies, easing concerns that crystal environments would force device-by-device calibration.
The clocks still do not beat the best atomic clocks, but researchers say the nucleus's lower sensitivity to environmental noise could make nuclear clocks more precise within a few years.
How soon could this revolutionary nuclear clock technology fit inside an everyday device?
Can a clock powered by an atomic nucleus finally unmask dark matter?
Will nuclear clocks make today's ultra-precise atomic timekeeping obsolete?
2026 Thorium-229 Nuclear Clock Breakthrough: Ushering in a New Era of Ultra-Precise Timekeeping
Overview
On June 15, 2026, the nuclear clock made a historic leap from theory to reality, as confirmed by the scientific community. This breakthrough was made possible by over a decade of dedicated research from the UCLA group led by Eric Hudson, who developed a practical way to probe the nuclear transition in thorium. Their work paved the way for the first functioning thorium-229 nuclear clocks, marking a fundamental shift in how we measure time. The successful operation of these clocks opens the door to a new era of precision timekeeping, with the potential to revolutionize science and technology.