Also an intriguing question, like #1. I hope JonClarke shows up before too long. I'm sure he'll have some interesting things to say about it. <br /><br />The look of mist or fog that appears in some of the images that Opportunity is taking of areas near the bottom of Endurance crater, I attribute to collected dust, which is featureless and textureless. The eye has nothing to focus on and, in this sense, it looks no different to the eye than fog. In the images I'm talking about though, the dust has been light in color, not dark as in the images you have posted links to. This may be accounted for by the use of different filters in the different images. But I don't know... <div class="Discussion_UserSignature"> </div>