posted on Aug, 27 2014 @ 08:12 PM
originally posted by: St Udio
here's a bit of info. the responses seem to overlook in explaining the sand movement by the Martian winds...
Jun 05, 2008 · The gravity on Mars is much lower than it is here on Earth, 62% lower to be more precise.
That means that Martian gravity is 38% of Earth’s...
therefore more sand mass can be more easily transported by less than Earthlike winds of a thin atmosphere
The point is some
sand is moved and some is not. Obviously the wind does not blow everywhere and some areas get less than others. For example
the lee areas behind rocks would get less and the windward side would get more, yet there is only some evidence of this and given that we are talking
millions of years, there are not many buried rocks.
Some of the points above have been argued by those who believe the data and opinions given by NASA, and from them there are 'official' opinions both
ways. On one hand the wind is strong enough to blow sand into sandstorms and block out the light and to have dust devils whizzing about at up to
70kph. On the other hand, the wind is so weak that it barely lift the normal earth-sized sand grains because they are too heavy.
It seems that the Martian wind-blown sand dunes are composed of very find dust and the pattern of them would suggest that the shape has been built up
over a long time rather like the shifting sands in our deserts. If these are wind-blown sand dunes, this indicates to me that there IS dust being
carried by the winds so why do we not see extensive evidence in all other places which have been photographed by the rovers.
However, water also produces sand-dune-like shapes on the landscape, particularly when the water is shallow and has been evaporated leaving the same
marks behind. OK, this is a stretch of the imagination, but it might explain why there are 'dunes' in some areas and not so much evidence in others.
We have seen ripple-like effects in the sand at the bottom of craters, well over millions of years since the water has left, isn't it likely that the
wind would have blown small particles of sand to fill these up and make the landscape smooth?