Moon drifting away at 3.8 cm per year, confirmed by millimetre-precision laser ranging
Laser pulses bounced off Moon retroreflectors left by Apollo and Lunokhod missions measure the Moon’s recession from Earth at about 3.8 cm per year with millimetre accuracy, a result that tests general relativity and informs Earth–Moon dynamics; the rate depends on ocean tides and continental layout, and future reflectors from Artemis missions will enable sharper measurements.
