Scientists report world’s first working nuclear clocks

Atomic clocks are the world’s gold standard for timekeeping, at the heart of everything from GPS navigation to synchronised networks. A ytterbium atomic clock is so precise it misses one second every 23 billion years.

Yet scientists are interested in more precise clocks to detect infinitesimal changes in fundamental forces and further advance navigation.

In two papers in Nature , scientists from Europe and China have now reported the world’s first working nuclear clocks.

While, in an atomic clock, an atom’s electrons are easily disturbed by electric or magnetic fields and temperature changes in a room, the nucleus is shielded by the electron cloud.

Exciting a nucleus usually requires energetic X-rays or gamma rays, which are difficult to harness. However, the thorium-229 isotope’s nucleus has a transition energy low enough to be triggered by an ultraviolet laser.