Ring laser tracks Earth's axial wobble 100 times more accurately

Scientists at the Technical University of Munich (TUM) and the University of Bonn have developed a highly sensitive underground ring laser capable of tracking Earth's axial wobble with unprecedented precision—100 times more accurate than previous ring lasers or gyroscopes. Located at the Geodetic Observatory in Wettzell, Bavaria, this instrument recorded Earth's subtle rotational fluctuations, including precession and nutation, continuously over 250 days without relying on telescopes, satellites, or external reference signals. Unlike traditional methods such as Very Long Baseline Interferometry (VLBI), which require complex, multi-continental radio telescope networks and take days or weeks to process data, the ring laser provides near real-time measurements with updates every hour or less. Earth’s axis experiences constant motion due to gravitational forces from the Moon and Sun and its equatorial bulge, resulting in slow precession cycles (~26,000 years) and shorter nutation oscillations (notably an 18.6-year cycle, plus weekly and daily fluctuations