by astro_uk » Mon Dec 11, 2006 11:00 pm
It looks to me like there is some dust to be seen, in the rocks there are regions that look exactly the same as the surface dust, as if dust has collected in cracks in the rocks.
I think the answer is that the rocks that you can see do not have flat tops, they are pretty much all inclined so even without the effect of quakes which occur periodically I would expect that the dust would simply slide down off the rocks. Especially as the dust is very fine, once one thin layer has filled in the rough parts of the rock, I would guess any additional layers would tend to slide down the sides. Any quakes or impacts would tend to increase the slippage.
I also wonder if the effect of the sun could be important. The difference in temperature between night and day is considerable and could lead to a change in the size of particles, perhaps slight changes in particle size could also make layers of dust unstable to slippage.
Not being a planetary scientist they are my best guesses, I'm sure someone will be along soon to put us straight.
It looks to me like there is some dust to be seen, in the rocks there are regions that look exactly the same as the surface dust, as if dust has collected in cracks in the rocks.
I think the answer is that the rocks that you can see do not have flat tops, they are pretty much all inclined so even without the effect of quakes which occur periodically I would expect that the dust would simply slide down off the rocks. Especially as the dust is very fine, once one thin layer has filled in the rough parts of the rock, I would guess any additional layers would tend to slide down the sides. Any quakes or impacts would tend to increase the slippage.
I also wonder if the effect of the sun could be important. The difference in temperature between night and day is considerable and could lead to a change in the size of particles, perhaps slight changes in particle size could also make layers of dust unstable to slippage.
Not being a planetary scientist they are my best guesses, I'm sure someone will be along soon to put us straight.