Every second counts: Scientists link 10 clocks across 6 nations to redefine timekeeping

Scientists from six countries conducted the largest comparison of optical clocks, linking 10 clocks via satellite and fiber connections over 45 days. They performed 38 frequency ratio measurements with unprecedented consistency, demonstrating the feasibility of a global optical time scale and improving clock precision. This experiment brings us closer to redefining the second by 2030 using optical clocks, which are far more accurate than current cesium-based atomic clocks, potentially revolutionizing timekeeping and enabling new physics tests.