Dan Clemmensen wrote:
> If we are willing to believe that nanotech permits at least some way to
> build large structures using multi-generation assembler production
> then it should be possible to send arobotic probe to the Oort cloud and
> a very large comet or a bunch of smaller comets, aggregate them into a
> large mass, add reaction engines, and direct the resulting mass into a
> cometary orbit that intersects the earth. Just how do you intend to defend
> against this? There are a great many alternative attacks: this is just
> the first one I happened to think of.
By using the same technology, of course. While your robots are journeying to the Oort cloud and diverting comets, mine are mining the moon to build defensive systems in high orbit. A multi-gigaton warhead will convert a comet into a cloud of gas quite nicely. If you build missile defenses on the comet, we can use directed energy weapons instead (burn one side of the comet to push it off course - or just shoot off your missile defenses and nuke it). I have far more mass to play with than you do, which lets me build bigger and better hardware.
The fundamental point is that the contest between offense and defense is far from over. Nuclear weapons and ICBMs gave offense a temporary edge because the size of the Earth and the speed of human reflexes used to be important limitations. The same automation that lets us actually do something with assemblers will completely change that equation, and it is not easy to predict how.
Billy Brown, MCSE+I