Invasion of the Worm Robots Saturday, Jan 31 2009
Consider this — a worm robot that burrows through the top layer of soil and is capable of converting it into additional modular segments of itself as quickly as possible. With an efficiency of just 1%, a worm with a 1 cm maw that tunnels through a 100 meters of earth every hour would be able to process roughly 0.785 cc of earth per hour or 1,884 cc (115 cu in) per day. Assuming 7.85 cc of soil is needed to build one robotic segment 1 cm long, we get a growth rate of 0.1 cm per hour or 2.4 cm (1 in) per day. Nothing shocking, really, but the numbers are contrived to be conservative. If the worms could divide (which would be possible if each segment or a small row of segments can be self-sustaining), then exponential replication could quickly overwhelm an ecosystem even if the growth rate is relatively slow. I doubt many predators would be interested in consuming a robot.
Why brainstorm worm robots? Well, the worm motif seems very popular in evolution, and is shared by a number of different evolutionary lineages. The worm body type is the precursor from which all bilateral and complex animals evolved! (Only cnidarians and sponges didn’t evolve from worms.) The body cavity inherent in the worm body plan provides a number of benefits that others have been over many times. So, it makes sense that a worm robot might be one of the earliest macroscopic self-replicating robots that could thrive in nature.
Where would such worms get food? The same way that regular worms do, by eating other organisms, just like that insidious fly-eating robot that was developed in 2004.
The worm robot starting point brings up a number of interesting observations and questions. First, how much of a threat could these little buggers be to an ecosystem? Of course, it depends on the growth rate and how well the robot fares in competition with the natives. But let us consider the bare minimum necessary to be an annoyance.
First off, the worm robot can prove to be a major nuisance by making sure to convert the earth into something difficult for other organisms to break down. There are probably several million types of microbes in a typical tonne of earth, but if they all fail to break something down, then it is likely to remain for a very long time. There are many examples of this decomposition-resistance in nature, notably the sponge, which defends itself not so much by aggressive means but by its manifest lack of nutritious value relative to other organisms and the caltrops-shaped calcareous or siliceous spicules that it embeds itself with. Relative to defenses that a human engineer might conjure up by probing the supra-organic design space, this is pretty boring, but it has worked for over 600 million years.
Still, without getting into anything complicated, note that significantly compressing a unit of earth would probably be enough to lower its palatability to microorganisms by a significant margin. Passing around energy currency in a form that bacteria and archaea can’t digest (i.e., not glucose or sucrose) could also potentially circumvent most efforts at consumption. Processing the earth into a state whereby an exoskeleton and set of crude membranes can physically exclude microorganisms, accompanied by local microbicidal action at interfaces, could likely make the robot much more difficult to break down, both in action and when deactivated. By thinking outside the boundaries inherent to natural biology, robotics engineers will be able to create new “species” of life capable of shoving aside obstacles and continuing on their merry way.
The problem of such robots for nature-lovers is the way that they’d entirely destroy the environment. One day, lush Amazon Rainforest, three years later, a writhing mass of robotic worms and over a million extinct species. One 1-kg worm robot that reproduces just once every ten days could convert itself into 67 billion of the little monsters (67 million tonnes worth) in just a year. Especially if it intertwined itself with the ecosystem, the only way to kill all of them would be to nuke the whole damn place. Building hunter-killer worm robots wouldn’t work, because by the time they were deployed, the original worm robots would have a major advantage.
Implausible, you might say? Negative. Rudimentary worm robots have already been built, and the chemical reactions necessary to convert soil organisms into energy-storing molecules are widely known. All that would be required are advances in MEMS (no molecular manufacturing needed) that allow the worm to distribute nutrients throughout its body and build new segments effectively. In mollusks (as well as worms), the simplest “complex” organisms, cilia are used as an all-purpose mechanism for ferrying nutrients about the body and waste out the anus. Looking at the contemporary lower mollusks, along with their ancestors in the small shelly fauna, one can see that the “concept of a mollusk” is simple at its essence, but it works very well. When the enabling technology is present, these designs will be copied by roboticists with interdisciplinary knowledge in biology.
The only way I can even begin to imagine to address such problems is universal transparency and inbuilt safeguards on all “3D printers” ever manufactured. Of course, there will always be those with excessive confidence in nature to repel synthetic threats (even though microbes can’t eat plastic), and to those folks this won’t be an issue, but to others, it inspires cause for worry. (Another objection would be the even more inane, “why would someone do this?”) It may be a matter of trading privacy for security, a pill many find hard to swallow, but I think the events and pundits of the future will have an answer for you — too damn bad.
I am sympathetic to arguments about ecophagy, as I think Drexler called it, but in such discussions, you’re probably better off using less details, rather than more. I understand that concretizing thing sometimes leads to more convincing arguments, but it also leads to specific objections that aren’t germane to the larger discussion.
Mere reproduction isn’t enough to make something fearsome. The worm-robot you describe is slow, and has no offensive or defensive capabilities, besides potentially attempting to eat other threats. Even within the natural world, it would have opposition. The chemical/electrical means of digestion would require storage of chemicals, which would attract parasitic bacteria, opportunistic microbes form biofilms on any energy gradient (as any engineer in field requiring sterility like industrial food service or aerospace will tell you). Is the material the worm robot made of organic? ferro-metallic? ceramic? There are lovers of each.
And really, to suggest such a simple slow thing would be difficult to eradicate is just being naive. You’re already positing it’s the only one of it’s kind in the area, a robot in a pristine wilderness. Does it use integrated circuits? HERF weapons to destroy and infowar remote subversion to disable large areas of them without bothering the local fauna at all. Does it use magnetic motors or field effects? High power electromagnetics in anti-phase could disrupt the robots long enough to run out of power, or break their metabolic cycle. And these are the big, ugly solutions.
Your proposed anti-worm robots don’t need to out-replicate the worms. They just need to kill them fast enough to gain an advantage. Given that the worms move so slow, the robots would need to be only mildly faster, and they could track and destroy vastly more worms per day than could reproduce.
Of course all this is side issues. The fact remains that real, vastly large risks come from advanced technology, and replicator technology in particular. My preferred solutions are perhaps neccessarily less coercive than others in the community concerned, but they do require solutions if we are to avoid disasters.
Hi Michael,
I’m a sci-fi writer and I love your different scenario risk assessments! Because you take them very seriously and present a well researched and carefully considered view point they create such vivid and compelling scenarios.
I hear that the Terminator 4: Terminator Salvation movie coming out in May will have a bunch of different robots. There will snake/worm like robots.
“even though microbes can’t eat plastic”
Some of them can;
http://news.therecord.com/article/354044
Strains engineered towards increased efficiency against the worm’s hydrocarbons should at least be able to keep such a nasty bugger at bay (assuming exponential growth in a bunch of worms, but at a MUCH faster rate). Massive dumping of such specialized bacteria on rainforests probably wouldn’t even be that problematic, since there (probably) is no plasic that anyone wants there. For lack of food they would all die away rather quickly.
If, on the other hand, you put in the option of a sporulation stage (like the one present in Anthrax), that can remain in the soil for a long time (up to 70 years in the original, if I remember correctly), one could “immunize” whole areas against that particular threat.
Considering the effort: Slightly changing the metabolism of some existing bacteria is much easier than building self replicating robots. The first one is already being done on a everyday basis, even in your lab next door. So whenever you will be able to synthesize a worm that can do serious harm, stiching together some microbe that eats it, shouldn’t take nearly as long.
Justin, I agree with some of your points but part of the point of this post is to argue that reproduction coupled with in-digestability is sufficient to be a huge problem. We disagree on that. Also, there’s absolutely no historic precedent of what I’m talking about here, so to be so sure that the threat could be stopped easily, even if the worms are slow, is being overconfident. Many hundreds of square miles of rainforest could be destroyed if there are a distributed network of hard-to-get-to drop points, plus the worms stay underground, making them impossible to track from the air. This is a big deal, obviously. Also, note that the numbers are deliberately conservative, speeds increased by a factor of 5-20 are more likely.
Which microbes eat ferro-metallic or ceramic materials?
I also disagree that vivid scenarios aren’t a good idea for getting people to think about these issues.
Chris, thanks.
Wolf, I forgot about that interesting Science Fair result, but the rate of digestion is still very slow. You’re right that there are bacteria that eat plastic, though.
The same would apply for any biological creature if its activities were entirely unchecked by its environment or by predation. If the worm synthesises its body from soil this means it contains elements which are edible to microbes and other larger creatures.
The question then becomes one of whether it would be possible to create an artificial life form capable of evading predation for a sufficiently long time in order to cause significant environmental destruction. This is similar to the existing problem of introducing rabbits or goats into environments where they have no natural predators. On a geological time scale humans are precisely such an invasive species, reproducing exponentially and causing significant environmental damage.
Interesting. But I remain very skeptical that this – or any sort of self-reproducing machinery other than laboratory toys or large factories – is feasible without MNT. MEMS are currently fabricated using semiconductor-type (read: huge and expensive) processes; are there serious proposals for scaling this (plus all the ancillary infrastructure, like refinement of raw materials) down to centimeter or even meter scales?
I would like to know why the question “why would someone do this?” is inane. Why don’t more groups invest in MNT and AGI development? There are obvious scientific and military motivations for developing self-replication, but probably not so obvious as to make dismissing the question reasonable, especially if you care about convincing the uninvolved rather than preaching to the choir. Don’t overestimate aggregate intelligence, and also don’t overestimate diversity of motives. (Empirically, highly pure destructive motivations are VERY rare, and seem to anticorrelate with intelligence and organizational ability – if this weren’t the case, I doubt civilization could exist.)
Still, I agree that this is interesting, and self-replication generally is worth taking seriously as a risk (though IMHO, replicators in the wild of any sort are still a good deal less likely and less threatening than the economic and military implications of more limited self-replicating factories.)
Also, I don’t know how good my judgment is here, but I suspect sentences like
- i.e., apparently 100% confident predictions without commensurate supporting arguments – work against you. This sounds like a storytelling futurist (or a fortune-teller), not a serious rationalist. Even saying “If and when… could be copied…” would be an improvement.
First Mover advantage doesn’t even last in electronics manufacture. Why would it last any longer if you allowed the hunter-killer bots to act in an evolutionary capacity (i.e.; allow them to utilize genetic algorithm variation within specific bounds to adapt to the wormbot’s variations?) If the wormbots can be exponential in growth, so too could the hunterbots. I understand that you’re describing a “runaway” scenario, but let’s not forget that you could easily re-seed the hunter-bots and that this process would be most likely a much more highly exponential rate of growth. Why is that? Because while each worm can only be made from a certain amount of processed subsoil/organic material, your hunters could reprocess an arbitrary number of wormbots.
That, and the fact that it’s always easier and quicker to destroy than it is to create. One could imagine, for example, hunter-bots that simply go around creating randomized EM pulses that would knock out any wormbots. Or simple electroshock followed by leaving behind a partial unit to ‘reseed’ within the wormbots (much like wasps do with tarantulas), etc.
The point here being: We should all very soon expect an entire abiotic ecosystem sharing space with our traditional biological one, within the next few decades. Especially since such evolutionary methods are almost guaranteed to be utilized for technological defenses.
I am informed by private email that it was Freitas who coined the term ecophagy, which I should have really remembered, having found his Kinematic Self-Replicating Machines extremely helpful.
You’re quite right that it’s unprecedented, and requires unprecedented solutions. Very quickly self-replicating machines of any type will lead to a mildly to entirely orthogonal ecology of such machines. I am confident in the ability of natural parasites to adapt to even very unusual locales and materials, but they are unlikely to act as a direct check on them. The machines we make are simply too quick, too strong, and often designed to be cleaned and sterilized regularly, I see no reason why self-replicating designs would not follow suit.
But I think it’s dangerous to talk about things too Apocalyptically, at least without strong technical supporting arguments. There are many classes of technological threats that CAN be ameliorated after the fact, and I’d prefer if we developed those techniques. If there are things that can be positively identified as practically unstoppable, then detection efforts can be focused to greater effect on those as well.
In terms of the microbes, there is nothing that directly eats ferrous metals or ceramics that I know of, but there are microbes that catalyze rust in metals and live in the resulting cavities and environment, and alkali loving bacteria that crack open ceramics and other hard spaces to give themselves more surface area. That weathering is one of the ways they date pottery, iirc.
It’s also quite true that this is an asymmetrical weapon, and that efforts to hide it, reseeding efforts, and remote support make it exponentially harder to stop. But once you begin positing support on behalf of a third-party, the question becomes a policing problem, rather than a technological one.
is a surprisingly transparent way to gain access to more types of.