On Fri, 25 Sep 2009 08:08:57 -0400, Tom Francis - SWSports
wrote:

He estimated that a single sail, six miles across, could
boost an object the size of our moon out of orbit and complete one
grav of acceleration in ten years.

Not to be argumentative, but since the moon already has a surface area
far larger than 6 miles across, why isn't it being boosted out of
orbit as we speak ?