Blue goo can be manufactured ahead of time and stored inactive until it's needed. This might be a useful thing to do with all the megatons of extra carbon in the atmosphere. Then while the gray goo is trying to replicate and avoid the blue goo, the blue has only one thing on its mind: killing gray.

Robert Freitas has shown that a gray goo trying to convert the biosphere would have a very hard time of it: it couldn't run at anything near full speed because of the heat it would generate.

A blue goo design that self-replicated in the wild would in fact face the problem of how to grow without doing damage. But what if we converted the U.S. Strategic Petroleum Reserve into blue goo, and distributed caches worldwide for fast response?

Also, goo is not very good as a military weapon, or even a terrorist weapon. I'm mainly worried about script kiddies, and a pre-made blue goo would probably be adequate to deal with that.

Of course, today we don't deal with computer infections nearly as well as we could.

Chris

The link in the main message has been corrected – Thanks, Tom, for catching this.

The URLs in the main message didn't work for me. http://www.sciencefriday.com/ works for Science Friday, and http://www.sciencefri day.com/pages/2000/Aug/hour2_081100.html works for the particular episode.

Assemblers running amuck are a concern in the same way alien abductions are a concern. It is trivially simple to design fail-safe systems to prevent such disasters; I suspect that is why Richard Smalley refers to such concerns as "silly". This is perhaps the wrong word, since it is also trivially simple to design fail-safe systems to prevent Chernobyl-style meltdowns, and yet they happen – in every instance to date not because there was a problem with the carefully designed procedures, but outside (e.g. human) factors. Since human sloppiness, incompetence and unwillingness to RTFM will not really enter into the nanofabrication process, it is much less of a concern, IMHO. That is, good fail-safe systems could form part of the design of the nanomachines themselves, as well as the fabrication unit making them. We can, for example, prevent a hegemonising nano-swarm using principles similar to those which Nature uses to prevent the entire globe being covered in E.Coli…

This is very much true. For you Americans, consider how many of the educated people you know are obsesed with having children. Not many is likely to be the answer. Many people who have been educated have come to see children as a burden (they saw themsleves as burdens, if that helps), so don't have them and leave it to someone else. Of course, once we're post human, we can have as many kids as we want!

Warning: there were some pretty broad generalizations above. So, if you don't find them to be true, that's okay, but they have been for me.

I agree. "In those hours, we would develop anti grey goo" just doesn't hold water. A period of hours isn't an acceptable design window for *ANY* assemblers, let alone defensive self-replicators. We're talking about a self-replicating machine to seek out and alter *ALL* instances of some molecular profile, anything less is only a delay. It would have to repoduce, saturate an environment, *stop reproducing at some point*(so as not to become just an alternative grey goo), determine which matter it encounters needs to be dissasembled or pacified, perform the defensive action, and then just loiter in the environment with all it's inherently-menacing complexity unless disposed of somehow. It would have to be several orders of complexity greater than the simple doubling-machine it's pitted against. That means it would require more time to reproduce, more complex building blocks, and hopefully a great deal of peer review in it's design process. It seems pretty likely that even if the rushed cure isn't unintentionally more damaging than the disease, it would be unable to compete for the resources available even without the offensive nanites having a headstart. I know, I'm jstsumschmuck, and not an authority on anything I've just written about, but I live here too. And I'd like to survive to see mnt's potential payoffs.

You assert: " Currently there are 6.3 billion people alive in a world that can only support half that." Perhaps you'd like to clarify what you mean by "support"?

If you are interested in empirical data and theoretical analysis about what level of population the world could support, I highly recommend Julian Simon's book, The Ultimate Resource 2, which thoroughly refutes common misconceptions about "limits to growth." More generally, most current estimates suggest that improvements in education, health, wealth and other factors will lead to population stabilizing through a voluntary process at some point in the next century or so.

Well, I do agree with most of your comments, but the dreaded 'grey goo' already exists in the world today, and therefore, I believe this is an important issue to address. What is the 'grey goo' which exists today in the modern world, you ask? The answer is: PEOPLE. Currently there are 6.3 billion people alive in a world that can only support half that – in contrast to this, the population in 2003 is expected to be 8.1 billion, and by the year 2012, an estimated 12 billion people. Is this not a problem? From what it looks like to me, people are acting just like nanites would, except they don't reproduce as fast.

(a cure for this would simply be to release nanites in the atmosphere, making every woman/man/child involutarily inhale these little machines, which, upon consumption, would go to the reproductive organs and either 1) Shut them off OR 2) Limit them to 1 Reproduction period.)

This method would EASILY fix the very big population problem we have now, though I am quite sure it would cause quite a controversy, but who cares – we are no longer in the Dark Ages afterall, and anyone who thinks that it is mandatory to reproduce is a nutcase who should be disposed of.

I believe the same method can be used for Nanites, as well, thus halting the Grey Goo Effect.

I think that it is useful to distinguish a couple of different scenarios:

1. grey goo today:

   Smalley is quite right. No one can build an MNT replicator yet.

2. grey goo accident during first steps of MNT replicator research:

   I bet that Smalley is right, because I'll bet that the first MNT replicator looks like a molecule in an intensive care unit, strapped to the equivalent of a ventilator, IVs, etc.

3. mature MNT, grey goo industrial accident

   It takes a pretty stupid design to get this to happen, the equivalent of building self-replicating vinyl siding and managing to disable all the "off" switches. I suspect that this will happen on rare occasions, but I also suspect that something which is originally intended to produce a useful product will probably be sufficiently slow growing that most of these accidents will look more like bad jokes than like catastrophes. I think that the Foresight guidelines are a reasonable approach to avoiding this.

4. mature MNT, intentional grey goo from an individual

   I think that this will be a problem, and will require something like active shields. We've got a while till this is a problem.

5. mature MNT, intentional grey goo from a State or competent terrorists

   See the whole arms control discussion. This is one of a very broad class of MNT weapons (others are likely to be more useful…). A lot of these are hard to control.

A potential run-away grey-goo scenario is anything but silly.

Assuming somebody actaully creates a general purpose environmentally powered self-replicator, the results are likely to be catastrophic. I know fo at least two reasons:

1) The power of doubling can be deceptively misleading. Assuming a doubling time of one hour, and an intial 1 kg. of grey-goo, that would yield over 4000 kilos in 12 hours. The weight of a large truck. In another 12 hours, you will have the wieght of 4000 trucks; aprox: 1.7 million kilos. 36 hours after intitial release: 7 billion kilos, 48 hours: 3 Trillion Kilos!!

So in less than 2 days after intial release we running rampant in the bioshpere, and doubling every hour. In less than a week, assuming these replicators can operate in cold and hot environments and are powered by the sun, the entire earth including the crust would be consumed by grey goo.

2) Engineering a response to a grey-goo outbreak would be next to impossible. The anti-grey goo would have to replicate faster than the grey goo in order to catch up. This is unlikely since grey-goo is not picky in what matter it decides to digest, where anti-grey-goo would have to be in order not to further the destruction. So what matter will anti-grey goo go use? It can't consume people, grass, trees or anything, unless you feel the threat od grey goo is greater than the potential loss of millions of people.

So as far as I can see, the only adequate defense against grey goo, is creating super-sophisticated anti-grey goo assemblers and release them into the bioshpere as a pre-cautionary measure. You could see this as bossting the biosphere's immune system. The equivalernt of biospheric 'white blood cells'.