New captioned images from HiRISE, http://hirise.lpl.arizona.edu/nea.php.

Pics, wallpaper and scrollover clips. Apparently, the Webmaster has a lot of time on his hands.

The streak subimage is particularly interesting. Notice that they all appear to originate directly underneath outcrops on the slope, dark or light...odd indeed. Almost argues for an aeolian origin, but I don't believe that either...damn strange, really.

That's a good observation nprev. I tried to get a closer view from the same image that displays the features you mention.

... or the HiRISE team are doing a FANTASTIC job of processing and releasing images from "The People's Camera" as quickly as they can, just as they promised to, which we should all be extremely grateful for.

Thanks for the very nice crop, ND!

Question: Have we seen light streaks anywhere else before? I don't recall them. I am tempted to speculate that dark streaks turn light over time via some chemical mechanism (presumably an interaction with the atmosphere), but again this looks like the first place we've seen light streaks...

EDIT: I just noticed that there are also gray streaks in ND's image! Apparently there is in fact an intermediate phase, whatever direction the process goes. What's going on here?

If wind-borne dust accumulation was responsible for changing the streaks' contrast, it would make much more sense if they just vanished into the background. I'm at an utter loss to explain why in this image they apparently become brighter then the surrounding terrain.

clink clink! swear jar is now full.

I can't imagine any other explanation of this scene than flowing and evaporating liquid. Note the point source origins and repeated flows from those points (i.e. light and dark, one likely being more recent than the other.) Note the base of the lobes, NOTHING is accumulating down there. The light and dark colors are also very telling. Occam tells me that it is what my experience says it is - wet and dry. The next image of this location will almost certainly show different shapes and locations of the dark flows.

Could this be another example of slope related processes (Avalanches ) The lighting suggests that the streaks are all on a darker (downhill sloped area) with the streaks starting as points near the presumed top of the slope and with rounded lobes near the presumed bottom. If we had a good contour map, we could see if these streaks are going directly downhill and crossing the contour lines near right angles.

The different (changing?) colors, however, are another problem.

Steve M

It may not be from a related process, but THIS is the most famous other light streak on Mars.
Click to view attachment

Yeah, my swear jar's overflowing, too; don't have to worry about quarters for laundry anytime soon. This is a weirdie.

What bugs me are the gray streaks. If the streaks are initiated by a fluid, it's presumably water, and it should evaporate really fast; mud on Mars shouldn't last very long at all. I suppose that the water could become chemically bound to the soil components, though, and cause contrast changes. The logical progression to me would be dark, gray, light as hydrates gradually became, uh, dehydrated...though I don't know why they'd appear different than before.

This might be a sort of supporting evidence: Visual observers have long noted that the North Polar plains appear distinctly darker after the outer parts of the cap melt off in northern spring...chemical change? Early in the 20th Century, this was widely regarded as "proof" that Mars had plant life.

The only thing I can think of is that in this area, at the veryleast, streak formation is an extremely frequent (possibly weekly or monthly?) occurrence. Would love to see a series of repeat imagery from MRO to test the idea.

($0.02, thanks for the reminder; I had indeed forgotten!)

I processed the image with ISIS3 in color and posted a number of them here
All of the "streaks" seem to start at small mounds. Some kind of "wind blown" event?
cartrite