Lee Daniel Crocker (
Mon, 27 Jan 1997 18:11:45 -0800 (PST)

> The premise falls apart right here. Friction and curvature are not related.
> Example: the moon orbits the earth. The curvature in space is created by
> force of gravity, not friction. Even in a hypothetical friction-free
> system, curvature will occur if forces are present. Of course, it is a
> little more complicated than just this, but the bottom line is that forces
> are responsible for curvature. Friction IS a force, but it is not
> applicable in the sense you are using it.
> -James Rogers

Calling friction a force is a bit misleading. It's really an effect
of billions of little electromagnetic forces between the atoms of two
irregular surfaces that can often be averaged accurately enough to
treat it as a single vector to simplify force equations. At the small
scale, there is no such force. Gravity, electromagetism, the strong
nuclear force, and the weak nuclear force are "real" forces; the rest
can all be reduced to those (and there is some good evidence that the
electromagetic and weak forces are unifiable).