Starship Asterisk*

On second thought: I went to the ESA website, where this photo originally came from. It is at http://www.esa.int/SPECIALS/Mars_Express/SEMCHPYEM4E_0.html and this photo is not like the image posted in Makc's reply. It is like the one that I have asked my original question about. The two large crater...

Makc, thank you for posting that image. The one I was confused about is inverted! I checked the original image out in the APOD archives, and it's coming up on my screen as inverted, so that's where the problem lies.

The picture on 02-28 APOD site shows what might be frozen water plates covered by dust, but there are two features I am curious about. The light source is coming from the left; there is illumination on the left side of the plates, and shadows on the right. The three small craters have shadows on the...