Billy Brown wrote:
>
> 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.
> <snip>
> > Any technology that will stop an earth-mass impactor can also
> > be used directly against the earth.
> <snip>
> > That's why I'm starting from the Oort cloud. I'll do all my accelerating
> out
> > 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.
>
You are correct in that I didn't run the numbers. I'm simply assuming that
I can find 2 million comets with an aggregate mass of two eath masses, and
that if I am willing to use fusion-powered ion engines, I can expend half
the mass of each comet to direct the other half into the same converging
hyperbolic orbit with very low relative velocities. Since each of the million
mass drivers is "small", far away, and directing its energy away from earth,
I assumed that detection from earth was difficult. As it happens, there
are a few minor trivial loose ends on this hare-brained scheme. In particular
I'm not quite sure how to manage the heat generated as the pieces aggregate
into a single mass.
Just for fun, let's try an earth-based approach. I think your nano-based defense model pits the defending naites against the attackers directly? That is, you need to know that an attack is occurring. What if I use my attackers to build hundreds or thousands of mega-nukes at an appropriate depth in the earth's crust? I don't have to burrow the nukes, I just program the seed nanites to first burrow and then build nukes. You cannot defend against this unless you are continuously monitoring the entire target volume: IMO this defense will require an SI.