QUESTION:
As I understand it, the difference in atmosphere affects our perception of
sensory information (such as depth perception).  Is this true, and if so,
how different is what we see in the photos of Mars from reality?

ANSWER from Jim Murphy on July 15, 1997:
The atmosphere can distort our view, but that usually requires a long
line-of-site through the atmosphere between our eye and what we are seeing. 
Stars appear to twinkle because their light 'bounces' around with the air
molecules between the top of the atmosphere and our eye before striking our
eye.

The perception we all are gaining from looking at the terrific images being
returned by Mars Pathfinder's IMP do a good job of showing us what the
surface would look like if we were there.  There are some variations between
what the camera sees and what we see (we see across the entire visible
wavelength spectrum, while IMP looks at only specific wavelengths, for
instance).  ALso, with dust in the atmosphere, the light striking the
surface appears different than if the atmosphere were clear, and as a result
some features might have more intense colors if seen in direct sunlight.

Jim Murphy
Mars Pathfinder ASI/MET Science Team