Re: Maybe just maybe (@ Boltar)(@AndyS)
Pfffff... All right, I'll bite:
1. There is drag, just less of it...
From TFA: ...but is one hundred trillionth to that of Earth at sea level – a science lab would consider the "atmosphere" on the Moon to be a pretty good vacuum.
There's A LOT LESS OF IT.
Even if that 'eventually' is years (very unlikely)
So you say. Given the way the probability of collision decreases with the amount and size of the particles involved, this doesn't seem so unlikely, does it?.
2. Mountains. If this theory was true, there would be no dust below the levels of the highest peaks.
Small fallacy here. Not all the particles will impact the highest mountain, will they?
It isn't luck, it's statistics.
...but how many bits of dust would land exactly in the orbit level which aligns to the speed they have?
All of them, obviously :-D. Now, seriously, with the conditions in the Moon's surface, most meteoric impacts will cause a small fraction of the particles to reach orbital speeds, however short lived those orbits could or couldn't be.
So the orbits would all decay, and the dust would clear.
Unless new impacts were creating more dust, as seems to be the case.
4. If this did happen (which it doesn't), there would also be rocks of all shapes and sizes doing the same. There aren't.
There are. Per the reasons stated above, a fraction of meteorites hitting the moon are ejecta from previous collisions.
If I had to place a bet, I'd say that there is a 'ring' -albeit a tenuous one- of lunar dust and debris orbiting the Moon and another one orbiting the Earth, and that the Moon is clearing a path through them, just like Saturn's moons do.