Martian Enigma - Slope Streaks

Martian slope streaks - they've been a topic of disussion and research for a while now, but a recently shared Mars Reconnaissance Orbiter (MRO) image spurred me on to create this thread.

Here's the image page: www.uahirise.org...

A nearly true-colour version:



A full-scale closeup of where the streaks start:



and where they end:



Are these streaks created by wet sand trickling down the slope? Or are they just dry dark basaltic sand, which shows up in many other photos of Mars?





To me, they look like dry sand, but who knows, maybe somewhere on Mars, there are indeed some wet soil streaks. It would be cool if MRO or some other orbiter were able to detect liquid water in martian soil if there is any. (we already know there is some water ice there) It seems like scientists have been going back and forth on whether water is involved in these streaks at all: en.wikipedia.org...

Do you think one of the future mars rovers could be sent to such a streak and study it?

a reply to: wildespace

I'm always wary of trusting my own senses with some of these images. Do you know what I mean? The concave versus convex and also the way topography can appear flat when it really isn't. In this one, the vertical streaks seem to be driven by gravity and our senses see them as beginning at the top and 'falling' down. Whether those streaks are a heavier, darker sand is hard to say. Of course, there's a lingering temptation to see them as liquid stains.



The topography puzzles me because the snip below appears to show three of the streaks running horizontally. Does that rule out my automatic interpretation of up, down and gravity?

originally posted by: Kandinsky
a reply to: wildespace
The topography puzzles me because the snip below appears to show three of the streaks running horizontally. Does that rule out my automatic interpretation of up, down and gravity?

It looks like the end of a ridge. hirise-pds.lpl.arizona.edu...

a reply to: wildespace

Yes, and the fact that the streaks predominate on just one side of the outcrop's skirting hillside could be significant, in that if it receives more sunlight than the other side (with far fewer streaks) then that could strengthen the presumption that this is meltwater.

a reply to: wildespace


Ummm...there's oil in them thar hills...

To me...it appears as if something is leaking out from beneath the surface...A submartian X-filey black goo...

Or some other more mundane explanation...

I like my answer better though...it throws a little fiction into the science...





YouSir

a reply to: wildespace

Here's a good one from your link. I snipped it to highlight the significant differences in shades. The darkness could support your idea of basaltic sands because there are almost black sands high up on the plains of retired volcano, Mount Teide. They're very dark indeed. The black 'spills' could be interpreted as being the youngest ones and the others possibly lightened by aeolian processes over greater time spans.



Foil cap on...they do look like a fluid something or other is regularly flowing down the slopes.

originally posted by: wildespace
Are these streaks created by wet sand trickling down the slope? Or are they just dry dark basaltic sand, which shows up in many other photos of Mars?

What is this a picture of? It looks a gouge in a stucco wall. Or maybe a boot-print. And what is causing that shadow?

a reply to: Kandinsky

Foil cap on...they do look like a fluid something or other is regularly flowing down the slopes.

Could be darker sand under the top layer, too. Or liquid volatile gasses, refreezing, or evaporating. There is permafrost there, it surely melts under the right conditions.

The rover uncovers it all the time. As well as the whats under the red 'top soil'.

a reply to: wildespace

Your images seem to reflect, in this case, its shading. See the small ripples across the streaks?

a reply to: Shadoefax

It's a hole dug by, I think, the Curiosity rover.

a reply to: wildespace

I think it was 2 or 3 years ago those streaks made,major news as water.

OP, I'd say that in pictures 2 and 3, you can see it is some kind of liquid that went down as you can see the sand's texture is continuous from the wet part to the dry part. Had it been sand sliding down, the sand would have made a little depression at the top and it would bulge at the bottom of the streak due to sand accumulation.

And a few years ago, there were pictures of a rover in what looked like fresh mud. I think a few months later NASA said there were unfrozen liquids on Mars. But then, here on ATS, many saw the mud and were surprised NASA was silent about it.

originally posted by: Crumbles
a reply to: wildespace

I think it was 2 or 3 years ago those streaks made,major news as water.

Yeah, it was, and I was wondering why this thread was suddenly revisiting the story. I guessed that OP wanted to use photos other than the ones used by NASA to test this hypothesis elsewhere on Mars.