The world's first nuclear clock just ticked on — and it could help detect a fifth fundamental force of physics

A close up of a glass chamber with a blue glow mounted on a metal pole.

For decades, physicists have pursued a goal that sounds nearly impossible: to build a clock that keeps time using an atom's nucleus rather than the electrons orbiting it.

Now, researchers have demonstrated the first functioning nuclear clock ‪—‬ an advancement that could eventually lead to more robust timekeeping devices and new ways to search for dark matter and physics beyond the Standard Model.