The bootprints that Apollo astronauts pressed into the lunar dust between 1969 and 1972 are still there, and they will stay for a very long time. By common estimates they should survive on the order of millions of years, quite plausibly ten million or more, because there is no wind, no rain, no flowing water, and almost nothing else on the Moon to wipe them away.
It is worth being precise about that, because the popular version of the claim, that the footprints will last forever, is not quite right. They will eventually be erased. It just happens so slowly that the numbers stop meaning much to us.
Why footprints vanish on Earth but not on the Moon
On Earth a footprint is short-lived. Wind fills it with blown grains, rain softens and slumps its edges, running water carries it off, tides erase it between one cycle and the next, plants and animals disturb the ground, and the freeze and thaw of water breaks the soil apart. A print in soft earth might last days, one in beach sand only hours.
The Moon has none of that machinery. It has no real atmosphere, so there is no wind to move dust and no weather of any kind. There is no liquid water on its surface, and nothing living to trample the ground. The lunar soil, called regolith, is bone dry and made of fine, sharp, angular grains that lock together and hold a crisp impression. Press a boot into it and the shape stays exactly as it was made, down to the tread pattern, with nothing routine to blur it.
The slow erasers that remain
Almost nothing is not the same as nothing. The Moon is not truly static, and a handful of very slow processes are still at work on its surface.
The main one is a constant, microscopic sandblasting from space. The Moon is continually struck by micrometeorites, tiny particles that arrive at tens of thousands of kilometres per hour, and over long spans they churn and turn over the very top layer of soil, a process sometimes called gardening. Solar wind and cosmic rays add their own slow wear, sharp swings between scorching lunar day and frigid night stress the surface, and once in a great while a larger impact could obliterate a patch of ground outright.
These act on geological timescales. The churn amounts to only a tiny fraction of a millimetre over very long periods, so a bootprint pressed centimetres deep can survive for millions of years before it is smoothed away. That is where the estimate of roughly ten million years comes from. It is an approximation built on how fast the surface turns over, not a figure anyone has measured directly, and it should be read that way.
How we know they are still there
This is not guesswork about abandoned sites. NASA’s Lunar Reconnaissance Orbiter has photographed the Apollo landing sites from orbit and shown that they remain intact. Its cameras can pick out the descent stages the astronauts left behind, the science instruments they set up, the tracks of the lunar rover, and the discoloured paths where the crews walked back and forth.
At the Apollo 11 site the trails left by the first moonwalkers are visible, and at the Apollo 17 site the crisscrossing footpaths of the last two men to walk on the Moon can be told apart from the rover’s tracks. The orbiter cannot resolve a single bootprint from that height, but it can see the trampled ground, which is direct evidence that the record is still on the surface, decades on.
Not truly permanent, and not truly safe
Two caveats keep the picture honest. The first is that the prints are not eternal; nature will erase them, just on a timescale that dwarfs human history. The second is more immediate. The likeliest thing to disturb an Apollo footprint in the next century is not a micrometeorite but us.
The Moon is becoming busy again, with crewed missions planned and a growing number of robotic landers from various countries and companies. A landing kicks up dust and debris, and rovers or visitors near a historic site could damage it. Recognising this, efforts have begun to protect the sites, including a United States law passed in 2020 aimed at preserving the Apollo landing areas as heritage. Whether such protections hold as more players reach the surface is an open question.
Why it matters
The footprints are the physical trace of the only occasions on which human beings have walked on another world. Left alone, they will outlast essentially everything we have built on Earth, standing unchanged long after our cities, monuments and coastlines have been reshaped many times over. They are also a quiet lesson in how differently time runs on an airless world, where a single careful step can remain, sharp and undisturbed, for longer than our species has existed.
