[texhax] default length of a space

[Gerard E. Seibert]

This is probably a dumb question; however, I have not been able to find a
definitive answer. Exactly how wide is a "space" in LaTeX? I found that the
default for a line was "0.4pt", or at least that is what it states in one
publication. I want to know what the length of a "space" is. Is it dependent
on the font size? If so, how would I compute it? Is there a list anywhere
that shows all of the common lengths and their measurements?

One last question. I tried using "\the \rightmargin" and it always displays
"0"; however "\the \leftmargin" shows the margin size. Why is the
"\rightmargin" not shown?

Thanks!

-- 
Jerry