Dan Clemmensen wrote:
> I didn't make myself clear. I don't intend to us a few hundred comets:
> I intend to use as many as necessary to accumulate an earth-mass weapon.
> Any technology that will stop an earth-mass impactor can also
> be used directly against the earth.
> That's why I'm starting from the Oort cloud. I'll do all my accelerating
> there, probably on the individual comets, before final assembly.
You need to go back and run the numbers. The only energy source in the solar system that puts out enough power to move that much mass is the sun - and you'd need to capture a significant fraction of its output to do it. That means mega-scale engineering, which is probably impossible without SI anyway.
Now, no known technology will allow us to stop such a weapon without landing on it, building our own motive system, and spending years accelerating it to change its vector. However, no known technology will let you assemble it in secret either. Moving that much mass will produce fireworks easily visible for light-years, and it will take years to get anything done. Everyone you could threaten will know what you are up to long before the weapon is ready for use.
Also, by the time you could do something like that many, many other things will have changed. Is it really the ultimate, megascale uses of nanotech that worry you, or do you see more immediate worries?
Billy Brown, MCSE+I