Imagine taking a walk and knowing that the footprints you left will be there for decades, or centuries, or millennia.
Photos taken by NASA’s Lunar Reconnaissance Orbiter, from heights 15 miles above the Moon’s surface, show that the tracks left by the American astronauts who explored the lunar surface between 1969 and 1972 are still there. (The descent stage of the lunar module, and some of the material left by the astronauts, also are visible in the photos.) The bootprints remain sharply etched in the dusty surface because the Moon has no atmosphere and no weather to muddle or disturb the tracks.
It’s amazing enough that photos taken from 15 miles up could show human tracks in the Moondust, but it is mind-boggling to think that those tracks could remain inviolate, and unchanged, for thousands of years — for as long, or longer, as the gulf of time that separates the days of the Pharoahs from our modern era.