Earth’s days drift longer as the planet slows under lunar pull
Earth’s day is gradually lengthening—about 1.7 milliseconds per century—primarily due to tidal braking by the Moon, which is gradually moving away from Earth (~3.8 cm/year). Additional tiny effects come from shifts in Earth’s interior, winds, and ocean currents, including climate-driven glacier melt that redistributes mass. Scientists track these minute changes with atomic clocks and techniques like VLBI. A full stop would take tens of billions of years, well beyond the Sun’s red-giant era.
