QUESTION:
Recently, I have looked at Mars with a telescope.  Surprisingly, Mars was
white!  Isn't Mars red?  If so, why was it this color?

ANSWER from Mike Mellon on April 22, 1997:
The human eye is not good at detecting colors at low levels of light. 
However, photographic film is much better at sensing the the colors. So, 
many things that you look at in telescopes look greyish when pictures 
of them in books are brightly colored. It's kinda disappointing, I know,
but you might try photographing Mars to see if the colors come out better.

It also depends on the size of the telescope; A large apeture and low
magnification will concentrate the light for you eye to detenct colors 
more easily. Although Mars is already pretty bright, and you should be 
able to detect some redness without a telescope at all. It may not be
as striking as you expect.