An old jeweler’s trick could change nuclear timekeeping
A centuries-old metal-plating trick may unlock ultra-precise nuclear clocks that work without GPS and could redefine how we measure time.
Last year, researchers led by UCLA achieved a milestone that physicists had pursued for half a century. They succeeded in making radioactive thorium nuclei absorb and release photons in a controlled way, similar to how electrons behave inside atoms. The idea was first proposed by the team in 2008, and its realization is expected to open the door to a new generation of extremely precise clocks. These advances could dramatically improve navigation systems and may even help scientists test whether some of nature's fundamental constants change over time. Despite the breakthrough, a serious limitation remained. The specific isotope required for nuclear clocks, thorium-229, is found only in weapons-grade uranium. As a result, scientists estimate that only about 40 grams of this material exist worldwide for clock research, making efficiency a critical challenge.
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