QUOTE (Dan-Dare @ Apr 5 2008, 01:18 PM)

MY point is.
Why is it that the dust and there is a lot of it that is thrown up by the moon buggy's wheels, just fall straight back to the moons surface.
If you look at the films of the moon buggy the dust is thrown up a lot and then settles down very fast.
If the astronauts are affected when they jump, will the dust not be effected in a similar manner and return to the surface at a slower rate than hear on earth.
Dan Dare
OK, Dan, I think I can understand what you're asking.
What you have to do is compare apples to apples first of all.
You've asked if a given quantity of dust, being tossed up to some level...let's say 4 feet...for the sake of argument, on the Earth would fall back to the surface at a faster rate than it would on the Moon, being that the gravity on the Earth is 6 times that of the Moon.
Let's take away the variable that makes the two environments radically different--that being the atmosphere of the Earth.
Now, both the Moon, with its 1/6 g (~5.33 FPS/S), and the Earth, with its 1 g (~32 FPS/S) are apples to apples.
In that case, the answer to your question is yes, the dust (or any object for that matter) will fall back to the Earth faster than it would on the Moon.
A 4 foot drop on the Moon would take about 1.2 seconds. The same 4 foot drop on Earth would only take about 1/2 second.
However, on the Earth, the atmosphere is present, and when you're talking about microfine, very light particles of pulverized dirt, like dust, those particules are going to naturally interact with the particles of air, and be profoundly effected by them.
What you see on Earth definitely resembles a slower rate of fall to the surface, which is seemingly contradictory to the gravity involved, but very much in conformance with aerodynamic effects on very light objects.
What you actually see on Earth are varying rates of fall in a given bunch of dust. Larger clumped together parts of the dust that don't completely diffuse in the atmosphere fall faster, and the diffuse material will fall at slower and slower rates, some of it actually being suspended in the air for some time (clouds). Eventually, it all settles down, but as you may have observed, a dust cloud, which can only occur in an atmosphere, can linger for some time.
The overall impression would tend to be that dust on Earth, kicked up to a given height, would fall slower than on the Moon, despite the gravity difference.
This is entirely because of the atmosphere, and the fine particles of dust interacting and mixing with molecules of air.
No such thing happens on the Moon, so everything up there falls uniformly...slower than it would on Earth if the Earth were a vacuum, but the Earth isn't a vacuum, so you can't really compare the two with diffuse objects that are subject to atmospheric drag.
You can try a little experiment to show this to yourself.
Take a pinch of some very fine substance...a tiny pinch of flour, corn strach, a piece of cigarrette ash...anything like that.
Hold it at head level in front of you, and rub your fingers together, releasing the mashed up dust you create, and watch how long it takes those fine particles to fall to the ground.
Alot longer than a half second or so--which is what they should fall at, if there was no atmosphere.
I once did this with a cigar ash, to illustrate this very thing. From about 4 feet up, particles were still descending to the ground 6 seconds after release.
If the Earth were a vacuum, these particles would've taken around a half second to drop to the ground, no matter what their size. On the Moon, they'd take about 1 1/4 seconds.
Thus--as you can prove to yourself by simple experiment--the reason dust appears to fall slower here on Earth, when logic tells you it should fall faster, is strictly because of atmospheric resistance involving very low mass tiny particles.
I hope maybe that answered your question???