Earth’s Tidal Brake Pushes Moon Away, Extending Our Day

Tidal friction is slowly transferring Earth's rotational energy to the Moon, lengthening our days by about two milliseconds per century and pushing the Moon outward by roughly 3.8 centimeters per year, a drift measured for decades with lasers reflecting off Apollo-era lunar mirrors. The mechanism, rooted in gravity and corroborated by geological and historical records, will continue to alter the Earth–Moon dynamic, with long-term implications for day length, eclipses, and climate-linked sea-level changes in coming centuries.