Thorium-based nuclear clock could help unlock dark matter mystery

A team of German scientists, led by Prof. Gilad Perez’s theoretical physics group at the Weizmann Institute of Science, has proposed using thorium-229-based nuclear clocks to detect dark matter. Unlike atomic clocks that rely on electron shells, nuclear clocks use the atomic nucleus, offering greater precision due to the nucleus’s stability. Thorium-229 is a rare and radioactive isotope under intense research globally for this purpose, though its scarcity and cost pose significant challenges. Recent advances, such as physical vapor deposition techniques, may reduce the amount of thorium-229 needed to build these clocks. The researchers argue that even before a fully functional nuclear clock is developed, thorium-229’s absorption spectrum can be monitored for subtle shifts caused by dark matter’s wave-like nature. These shifts would manifest as temporary changes in the mass of atomic nuclei, altering the absorption spectrum in ways that could reveal dark matter’s influence. Their theoretical calculations suggest this method could detect dark matter effects even if they are 100