Re: Freitas on Gray Goo

Date: Mon May 15 2000 - 09:14:07 MDT

Robert B. writes, quoting Hal:

> > Assume that the goo seeds are spread widely before beginning their
> > growth phase. Robert F. suggests dispersal by airplane. Perhaps it
> > would work to spread rock-coated nanites in the form of dust released
> > into the atmosphere from a few locations over a period of many months.
> > We now have potentially billions or even trillions of nucleation sites.
> Ok, so here you are talking about an intentionally designed terrorist
> weapon using "advanced" nanotech.

What part of this is "advanced"? The ability to make trillions
of particles? The ability to cover them with rock? The ability to
disperse them by airplane? Or is it the goo itself which requires
"advanced" nanotech?

> > Each of these begins to grow simultaneously, not caring about local
> > thermal pollution, but limited by some constraining temperature, such
> > as the boiling point of water. (We cook our food before eating it;
> > perhaps the goo will find it more tender that way as well.)
> I dealt with this as well in my comments to Robert. You simply *do not*
> have the resources around the globe (energy or matter) to have uniform
> growth rates. Not enough biomass in deserts, arctic regions or under
> the ocean. Probably not enough energy in arctic regions or the ocean
> as well.

It doesn't necessarily have to be uniform to produce destructive local
and global heating. Even if many goo seeds fall in unproductive regions,
they can be preferentially seeded towards high biomass targets and you
could still be dealing with hundreds of billions of seed sites.

> > According to Robert F.'s figures, this will not cause a noticeable (4
> > degree) global increase in temperatures until something like 0.0001%
> > of total biomass has been converted. Due to the wide dispersal,
> > localized hot spots may not be detectable either. At this point the
> > global temperature will rapidly increase to 100 degrees C.
> No, only in regions where the energy and material resources are
> sufficiently dense will they be able to grow at the most rapid rates.
> There are huge regions of the planet where they will have a difficult
> time replicating at all. So you get local hot spots that can be
> detected and eradicated from space or using ground based weapons.
> The standard precaution against this would be to have defense systems
> in places where biomass consuming nanobots cannot grow.

You could still have many billions of seeds within the regions where
growth is possible. That's a lot of "hot spots". Zapping localized
hot spots might make sense if you are talking about a few dozen or a
few hundred, but a few million, billion, or trillion? That's out of
the question.

The big problem remains the exponential growth. You go from power
sufficient to raise the global temperature 4 degrees, to power levels
sufficient to raise it 100 degrees C in just ten minutes, under Robert F's
scenario. Even if you have better detection equipment that can do better
than the 4 degree point, still with exponential growth the goo will be
at undetectable levels if you go back a few minutes or an hour previously.

> Yes, if your goal is the destruction of life on the planet then this
> would be a good way to accomplish it except for the reasons I've cited
> above. However, the probability that individuals who are that irrational
> would have the resources to develop the advanced nanotech and delivery
> systems required to produce the scenario you describe seems very low
> to me. Their resources would certainly be far less than the resources
> of the groups developing the monitoring and defense systems.

Well, Robert F's paper necessarily and properly does not get into the
motivations of the various groups involved. It is meant to be a technical
analysis of whether there exists a potential threat which cannot be
reasonably countered. It seems that the paper concluded that there was no
such threat, but my reading of the details suggests exactly the opposite.


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