First ticking nuclear clocks arrive
Scientists have built the first functioning nuclear clocks , a long-pursued advance in precision timekeeping. Unlike atomic clocks, which count oscillations in the electrons orbiting an atom, a nuclear clock relies on a transition within the atomic nucleus itself.
That difference is the point. A nucleus is far smaller and far less sensitive to stray electric and magnetic fields than the surrounding electrons, so a clock built on a nuclear transition can in principle be more stable and easier to operate outside the laboratory. Beyond setting new records for precision, such clocks could become tools for testing fundamental physics — including whether the constants of nature are truly constant — and for applications from navigation to geology that depend on exquisitely accurate timing.