The first ticking ‘nuclear clocks’ are here

Two research teams, one in Europe and one in China, have made the world’s first ‘nuclear’ clocks. These clocks derive their ‘tick’ from the energy that makes protons and neutrons inside the nucleus of thorium-229 shift to a higher energy level. The groups used similar approaches to solve the problem that’s hindered nuclear-clock development in the past: how to keep the clock’s tick speed from drifting over time. Creating a nuclear clock is “a dream come true”, says atomic physicist Thorsten Schumm, a member of the European team. “Now we have a fierce but friendly global competition.”