Learn more physics!
How long will astronauts' footprints on the Moon's surface remain there?
If you were to walk along a beach on Earth, your footprints would
be washed away quickly by the tide. And if you took a walk in the
desert, the wind would soon blow them away. But on the moon, there's no
air or water at all. In fact, there's not even an atmosphere. Without
Earth-like atmospheric erosion to rub them out, the astronauts'
footprints should remain on the Moon's surface forever. Or at least
until they get hit by a meteor from space, making a new lunar crater.
(published on 10/22/2007)
Follow-up on this answer.