Peter Ness wrote:
This picture may be of a liquid on Mars - because the reflections of the creeks are almost perfectly mirror imaged in the water below, which takes coincidence a little far.

Alex writes:
FWIW, without precise orientations supplied by you it's difficult locate your "reflection[s]." Nevertheless, I'll assume, as Mike F did, that you are referring to the area of the crater rim towards the middle of the swath. If so, bear in mind that your "reflection[s]" are occuring on a crater SLOPE (see MOLA altimetry trace) and not a flat surface. IMO the high albedo contact between the crater rim and slope merely represents a layer between the more resistent caprock of the upper plateau and the material subjacent. Any appearance of a liquid surface is illusory.

As I noted previously, the dendritic gullies at the crater rim (merging into polygonal terrain) suggest some sort of erosive process IN THE PAST, maybe even involving a liquid volatile, but positing that the image in question depicts an existing surficial liquid surface is a fairly extraordinary claim requiring extraordinary evidence, which I have yet to see.

Peter Ness wrote:
I have some idea of what the fluid could be.

Alex writes:
Perhaps you might share your thoughts. At any rate, it would have to be a fairly exotic fluid, especially given the prevailing temperature and pressure conditions.

Alex R. Blackwell
University of Hawaii