Moon Footprints Will Last Tens of Thousands of Years

Because the Moon has no atmosphere, there’s no wind, rain, or erosion to wipe away marks on its surface. The footprints left by Apollo astronauts in the 1960s and ’70s are still there, almost perfectly preserved. But the Moon isn’t completely static: a steady rain of micrometeoroids, and the debris they kick up, slowly churns the surface. New Lunar Reconnaissance Orbiter data suggest the astronaut tracks will be gone in tens of thousands of years—about 81,000 years for 99 percent of the surface to be churned—still far longer than any human monument on Earth.