Originally posted by mikesingh
ArMap, though it was a good analysis, there are still a number of question marks!
1. Notice the slope. It is very slight towards the left of the image. Not enough for the 'stone' to have travelled a distance of about a km or so.
The incline had to be much greater than that. And also notice the softness of the soil as the tracks are clearly visible. How could the 'stone' have
moved this distance over soft soil? It would have got stuck a couple of feet away from its start point.
The distance travelled by the rock, if
we use the 25cm/pixel that they say is the image resolution, is something like 100 metres, not 1,000. And I don't think that the ground is as soft as
that, from what I have seen from the ground on Mars, it usually has a thin layer of dust over rocks.
2. If the incline was toward the left of the image, how come the upper stone has gone against this incline toward the top of the image?
Because
there are two inclines. That dusty area in the middle is between two higher areas, one on the left, the other, higher, on the right.
That stone came, as all other stones, from the rocky area on the left, down the slope, through the more horizontal area until it reached the slope on
the other side.
3. How can a near perfect arc be made by this 'stone' where at some stage it has gone against the incline? What force made it do so?
Volcanic activity? I think not!
That is a perfectly common thing, let a stone or a ball run down a slope until it reaches another slope
but
not perpendicular to the face of the slope and the stone (or ball) will make an arc whose shape and radius depend on the steepness of the slope
and the angle between the initial trajectory of the stone (or ball) and the face of the slope.
The is no need for any other force than gravity to do such thing, if we disregard the initial force that unblocked the stone to let it run down the
first slope.
4. How come there are two parallel tracks by 'stones' at different locations? Must be a billiard table top for this to occur, but it
isn't.
They are not parallel, they are
almost parallel, and they are not straight. If you look closely, or even better, if you use a
graphics program where you can draw a line over those tracks, you will see the one makes an arc in one direction and the other makes an arc in the
other direction.
5. What's that ramp like structure where this 'stone' has started from? Check out Zorgon's enlargement of the ramp.
I will use my
image, if you don't mind, I don't like those colours.
That "ramp", to me, looks like two areas of the rock that are more salient than the rest of the face of the rock, in the same way as to the left of
the "ramp" there is an area where the rock is less salient than the rock face.
All said, there's more than meets the eye here. But hey, what do we know about tectonics on Mars?? 
What bothers me is that from a huge picture we are only looking at a small area and ignoring the rest just because of something that probably is only
a rock.
Do yourself a favour, if you haven't seen the complete photo, go to
this page
and download the "Full-Scale JP2".
You will need a program that can read JPG2000. Photoshop has a plug-in to read them, but I am using a plug-in from Lizardtech
(
ExpressView Browser Plug-in) that works with Netscape, Internet Explorer
and Safari web browsers.
It is worth the trouble.
PS: I hope I did make any sense in my answers, I am too tired and I did not had enough time to re-read it.
Global
warming and all! 
