The Apollo astronauts' footprints on the Moon could stay there for 100 million years.
When the Apollo astronauts walked on the surface of the moon, they left behind footprints that will remain there for a very long time. From past studies of moon rocks collected by astronauts during the Apollo missions, researchers have learned that the rocks erode at a rate of about 0.04 inches every 1 million years.
"In human terms, it may seem like forever, but in geologic terms, probably there will be no traces of the Apollo exploration in, let's say, ten to a hundred million years," Robinson said.
The eventual disappearance of human traces on the moon could be an incentive to somehow protect the sites where the Apollo astronauts landed and explored.
"The moon doesn't have an atmosphere, so that makes it such that features seem more permanent because you don't have erosion, either by wind or water, to make those features disappear as quickly as they would on Earth," said Robert Pearlman, an expert on space history and collectibles, and editor of collectSPACE.com, a SPACE.com partner site. "But it's a dynamic environment, so nothing is forever. So, unless we take action to protect those sites, then natural forces will have their way."