under the topic of reality, though (rather than comparing global-scale images in different wavelengths and getting excited about observed differences), I did recently read an article on the apparent wet streaks on Mars (the ones that appear to come out of a crater wall and run down into the bottom, and are darker than the surrounding terrain).

They've found a number of new ones that have occurred since close up images were taken from orbit. So whatever mechanism causes them is still happening. The scale of these, though, is much smaller than Valles Marineris or Olympus Mons

There is still some debate about whether it is water or whether it is a dust flow.

Now I have to remember where I read it. Mercury? S&T? Anyone else see the article?

Edited to add a link to a similar article:

http://mars.jpl.nasa.gov/gallery/mar...6subs_100.html