Japan aims to set first new global standard for second in 63 years

Japan is nearing the adoption of a new atomic clock as the official global standard for measuring the second, marking the first update in over six decades.

The new atomic clock, developed by Japanese scientists and institutions including Shimadzu Corporation, uses optical lattice technology to achieve high precision. It is currently undergoing validation and comparison with existing standards managed by the International Bureau of Weights and Measures (BIPM).

Officials from Japan’s science community, including Shimadzu President Yasunori Yamamoto, and representatives from the BIPM, announced on May 12 that the clock has demonstrated capabilities that could justify its use as the new international standard. The current definition of the second, established in 1967, is based on the microwave cesium atomic clock.

Japan’s initiative reflects ongoing scientific advancements, as optical lattice clocks are capable of measuring time with higher accuracy than traditional cesium clocks, potentially reducing measurement uncertainties and supporting improved global synchronization systems.

Why It Matters

This development could influence global navigation, telecommunications, and scientific research by providing a more precise measurement standard. An updated definition of the second may enhance the stability and accuracy of timekeeping systems worldwide.

The change could affect industries reliant on precise timing, such as GPS navigation, financial transactions, and scientific experiments, by offering a potentially more reliable measurement unit.

Background

The current definition of the second has been unchanged since 1967, based on the cesium microwave atomic clock, which remains highly accurate but is approaching its physical limits. Advances in optical lattice clock technology have demonstrated potential for greater precision, prompting international interest in revising the standard.

Japan’s effort follows decades of research into optical atomic clocks, which use lasers to trap and measure atoms with high accuracy. The proposal is now under review by the BIPM, which oversees the International System of Units (SI).

“Our clock represents a significant step forward in time measurement technology, and we believe it can set a new global standard.”

— Yasunori Yamamoto, President of Shimadzu

“The BIPM is reviewing the data and results from Japan’s atomic clock to determine if it meets the criteria for becoming the new international standard.”

— Annette Koo, Director of BIPM

What Remains Unclear

It is not yet confirmed whether the BIPM will accept Japan’s clock as the new standard. The review process is ongoing, and international consensus has not been finalized.

What’s Next

The BIPM will continue reviewing Japan’s clock data over the coming months. A decision on adoption as the new standard is expected later in 2026, with possible implementation in 2027.

Key Questions

What is the current definition of the second?

The second is currently defined based on the vibrations of a cesium-133 atom, established in 1967, and measured with microwave atomic clocks.

Why is Japan developing a new atomic clock?

Japan aims to improve measurement accuracy and advance timekeeping technology, potentially replacing the existing standard with a more precise optical lattice clock.

What are optical lattice clocks?

Optical lattice clocks use lasers to trap atoms in a lattice, allowing highly precise measurement of atomic vibrations, surpassing traditional cesium clocks in accuracy.

When could the new standard be officially adopted?

If approved, the new standard could be adopted as early as 2027, following the final review and international consensus.