Thanks for the link. I will read it when I have a little time.
Its a matter of physical limits of materials. there is simply not space and energy enough to permit nanobots to do much. The “Grey Goo” scenario relies on nanobots being able to produce their own power from harvested materials, being able to replicate themselves from harvested materials, and being able to chop up nearly anything.
The first problem is not insurmountable, but much, much harder than it seems. remember, no lifeform (humans aside) on the planet earth does much besides take in energy. And, these are microrobots, which can’t hold onto significant amounts of it. Bacteria hold onto only enough to divide. And colonies of bacteria never take over the palce, because they always run into the energy limit of their environment. Nanorobots would have to get all the power they need and store it, which amounts to us humans remaking the path of life. Not an easy task.
The second problem is also more difficult than it sounds. You can’t simply find the raw materials very easily. Plus, what happens when they use up one source? They have no idea where the next one is! This makes them use of lots of power wandering around tasting for the resources they need. This is where things get tight, because the swarm MUST grow or its shrinking from power loss. Of course, it could just eats own dead, but that just uses up more power. Ergo, to replicate, it will have to be in an environment where it can constantly take in new energy and still have access to raw materials.
And that assumes that a nanobot CAN replicate itself. This is a nontrivial problem. Can you build a DNA strand that can lead to the creation of a robotic lifeform? Can you write one that makes even a simply germ? What about a virus? No? There almost certainly will have to be a factory unit of some kind.
by Eburacum45
But this doesn’t help. You now need to make and organize a whole economy, much like ants. You still didn’t say how the nanobots are going to “know” what to do. You can’t ignore this problem, and you canot simply build control systems. The only real things that can work is a chemical adapter, but that’s hardly very accurate, and further increases the already difficult task of replicating the “swarm”.
Yes, in fact it conflicts with our current understanding of the physical limits of computer systems, so I’d say that we’d have to break several laws of physics first.
The last problem is the real doozy though - how are you going to make nanobots that can take apart any structure? Even if they could take apart any chemical structure, they will be expending energy if they aren’t somehow gainig it. And how many “tools” will they need?Barring some awesom scientific discovery of a Universal Solvent, you are going to have to have some damned big nanomahcines to hold the chemical swiss army knife. take the two together, and the nanomachine also MUST have a chemical Universal Constructor to all the peices together into new nanobots. If it isn’t, they whole group of nanomachines WILL die from energy exhaustion.
And then, of course, there is the question of exactly “why” it would go cutting up everything. Unless it had some kind of impulse to do so to everything it comes into contact with, it will just sit there and die.
But at the last, a strong electromagnetic signal will simply kill them all. Theya re basically a tiny bit of metal, so pumping them full of jiuce - and they REALLY cannot take much - will kill them dead.