Promise and Perils

In a commentary written for The Globe and Mail, Canada's leading newspaper, environmental lawyer David R. Boyd says:

Proponents of nanotechnology describe a future straight out of science fiction. Ultramicroscopic cameras flow through your bloodstream to identify constrictions or blockages. Supercomputers the size of a grain of salt with unprecedented speed, memory and power. Limitless, pollution-free energy. Deserts transformed into lush gardens with cheaply desalinated sea water. Bulletproof clothing the thickness of spandex. . .

Have we opened Pandora's box by manipulating material at the molecular level? Will the dystopian vision portrayed in Michael Crichton's science-fiction novel Prey come to pass, where self-replicating nanorobots develop independent intelligence and rebel against their human makers? Or will nanotechnology deliver the utopian future promised by its proponents, including human lifespans of 200 years and beyond?

These are good questions and they deserve serious answers. Let's take them one at a time:

(1) Have we opened Pandora's box by manipulating material at the molecular level?

Yes, we have, or at least we are in the process of doing so. Researchers have not yet achieved the full capabilities of molecular manufacturing -- using high-performance nanotech machines to manufacture high-performance nanotech-based products on a large scale -- but it's only a matter of time until they do. Once that point is reached, probably in the next 10-15 years, then we will indeed face a future of unprecedented potential for destruction, domination, and disruption, as well as new opportunities for health, prosperity, and abundance.

It will not be possible, nor even desirable in our view, to prevent this research from going forward. What we must do now is set a high priority on understanding the profound societal and environmental implications of advanced generation nanotechnology, and begin developing strategies and policies to maximize the benefits and avert the most dangerous risks.

(2) Will the dystopian vision portrayed in Michael Crichton's science-fiction novel Prey come to pass, where self-replicating nanorobots develop independent intelligence and rebel against their human makers?

No, because what Prey depicts is strictly fiction, not science-based, and what the book presents could not actually happen. (Read an extensive critique of Prey by CRN's Chris Phoenix here.) Having said that, we should not dismiss the possibility that advanced nanotechnology could contribute to expanded machine intelligence, and we should acknowledge that some scenarios of runaway systems are plausible. These risks must be accounted for, but they also must be placed in the context of more probable and more imminent dangers, such as an unstable nano-based arms race.

(3) Or will nanotechnology deliver the utopian future promised by its proponents, including human lifespans of 200 years and beyond?

A good deal of the hype associated with nanotechnology is plausible and should be taken seriously. The potential benefits of this technology are extreme, but so are the risks. A utopian future will not be reached unless mankind is successful at handling the enormous challenge of navigating a safe and responsible transition into the nano era.

Boyd concludes:

Given the profound implications of nanotechnology, it is imperative that we do our best to get it right the first time.

We could not agree more.

Mike Treder

Tags: nanotechnology nanotech nano science technology ethics weblog blog

Comments

[Phillip Huggan]

One subtle danger that just occured to me is that we will really have to keep an eye on our environmental footprint with many MNT engineering projects. This is a danger we are only starting to grasp with the issue of pollutants.
For example, suppose everyone in the world on average gets 1 tonne annually of diamondoid products. The world's known reserves of pure Boron are just over 400 million tonnes. Assuming all diamond products are doped with Boron (I don't know what % of product mass will need to be semiconductive) at a 1% weight, the world's supply of Boron would only last 4 years. That is a burn-rate close to some internet stocks of the past.

Will low footprint Boron extraction on Earth outweigh the risks of robotic replicators in space? Can nitrogen be doped instead? Think dope.

[Chris Phoenix, CRN]

Non-active (structural) diamond shouldn't need much doping. Active structure is limited by heat. Freitas computes a "hypsithermal limit" (to avoid climate change) of 10^15 watts worldwide. If nanomachines dissipate 10^7 W/m^3 (e.g. 99% efficient gears with power density of 10^9 W/m^3), then there can only be ~10^8 tons of active nanomachinery on earth (embedded in ~10^10-10^14 tons of structure). If doped at 1%, that's 10^6 tons of dopant.

Of course, all these numbers are +/- one or two orders of magnitude.

Remember that buckytubes--pure carbon--can be semiconducting.

It is certainly possible that the ability to do planet-scale engineering in months will lead to us destroying the environment. OTOH, we're not living sustainably now, so we're definitely "damned if we don't" develop MM (or something equivalent (if there is anything equivalent)).

Chris

[Tom Craver]

Also, as MM products can be much lighter, I doubt the average person will possess more than a ton of products (on average) at any moment.

While it may be convenient to built homes using nanotech, most of the weight will probably simply be dirt or sand excavated on site. And people don't only build out of the most convenient material. I expect we'll still have plenty of wood an brick homes, for reasons of tradition and ego.

Finally, recycling - even if one got a ton of new products each year, one wouldn't simply accumulate it indefinitely. It'll be recycled at some point.

[Chris Phoenix, CRN]

I once figured a good two-person home (2BR/2bath, about 1200 square feet/100 square meters) would require about 100 kg of diamondoid, mostly inert structure, inflated. That's with double-paned vacuum-insulated walls.

I think water is better than dirt or sand to add weight. It's a lot easier to remove when you want to deflate the product. It's less dense, but that doesn't matter for a house--just make the walls or floor a bit thicker.

Chris

[NanoEnthusiast]

One question I have is, without ballast would a nanohome or nanochair naturally float on air? I read somewhere that it would. Maybe you would want that sometimes. Imagine a chair that floats up to the ceiling when not being used, thus leaving more floor space.

[Chris Phoenix, CRN]

Not if it was air-filled. It'd still have some heavier-than-air weight from its carbon structure. Nitrogen should be slightly lighter than air, so you might in theory be able to make something light enough to float by filling it with nitrogen. Of course, you could easily make it light enough by filling with hydrogen (if you didn't care about flammability) or helium.

If I had furniture bouncing around the ceiling, I'd want higher ceilings. Even if it didn't weigh much, it could still be uncomfortable to bump my head on if it was rigid and stuck in a corner.

More useful, probably, would be collapsible furniture. When not in use, just deflate it and walk on it.

Chris

[Phillip Huggan]

Okay Chris, waste heat is an issue at least an order-in-magnitude earlier in product mass than dopant.

My above comments reference a paper stating Boron-Doped diamond is a semiconductor at a 3% dosage. The 400 million figure is for the known reserves of Borax, which is only part Boron (B2O3), so rounded to 1% from 3%.
I wonder what % of product mass will be semiconducting. Boron may still be an excellent commodities play if Nitrogen doping won't work or isn't as effective.

[Tom Craver]

Dirt or sand shouldn't be much trouble to use as filler for house walls, broken up fine enough to be moved directly, or blown in using air. And it makes a pretty good insulator.

If water were used, you'd have to deal with it freezing (potential for splitting walls) and sucking heat out of a house in winter. Those can probably be dealt with - but if dirt can be used nearly as easily, why bother?

[NanoEnthusiast]

I didn't mean it would be filled with anything. If the product is produced in a sealed nanofactory in a vacuum, the inside would be vacuum.

[Chris Phoenix, CRN]

Philip, I suspect rod logic or buckytubes will be used precisely because they don't require commodities.

Tom, dirt isn't a very good insulator; vacuum is much better, especially if you add just a little aluminum for a mirror. The other nice thing about vacuum is that it doesn't transmit sound waves. That's what I meant about dual-paned walls: two big slabs of hollow pressure-stiffened diamond, with vacuum in between.

NanoEnthusiast, a very thin product filled with only vacuum would collapse very small. You have to put something inside it to inflate and stiffen it. If you put in pure nitrogen or water, you can pump it out and collapse it again. (The water might leave a monolayer, depending on the surface.)

It's not yet clear if a vacuum-filled structure of any type can be made lighter than air. 14 pounds per square inch is a lot of force. Filling with light gas will almost certainly be more efficient.

Chris

[Phillip Huggan]

Buckytubes would be great, but they are a tougher mechanosynthetic target than is diamond. MNTed robotic mines could be used to scale up CVD furnace capacity if need be over the long run.

Is rod logic assured? I read there might be an issue with disharmonous phonons or something.

[Chris Phoenix, CRN]

I don't know that anyone has looked into mechanosynthesis of buckytubes yet. They are floppier than diamond, but there are fewer competing reaction sites and probably less reconstruction. And a mechanical collar might be used to keep them from flopping so much. So I'm not sure they are a tougher synthetic target.

I haven't heard anything about disharmonous phonons, and a quick Google didn't find anything. Can you give me a reference?

Note that the phonon strength can't be greater than the dissipated energy, which is on the order of a fraction of kT per gate and kT-plus-a-fraction per latch, while the energies involved in moving a rod are many times higher than that. There'd have to be some physical "resonant" structure that concentrated the stray phonons on a single gate--and the concentration would have to happen before the phonons were thermalized--but even if such a thing existed, it should be easy to tweak the design to make it go away--or better yet, put an energy-recovery mechanism at that spot! I don't think this would be more of a problem than clock skew or voltage ripple, and it might well be less.

Chris

[Phillip Huggan]

That's what I mean when I say tougher mechanosythetic target: there is a chance CNTs won't be MNT-able. If so, to scale up CNT production would require scaling up CVD furnace capacity, would require scaling up metals mining, would require a space economy...

I don't even know why I brought up rod logic (I can't track down the critique of Merkle's paper http://www.zyvex.com/nanotech/mechano.html
at the moment). I think my concern was about an actuator, and that a semiconductive material could be used as part of the actuator (motor), but I can't remember.

[jim moore]

Graphite (CNT) has a lower energy state than diamond. That should make it an easier target than diamond. (The pi bond network in graphite adds stability)

The dimer deposition tool should work just fine, maybe even better with CNTs.

[Chris Phoenix, CRN]

On the scale of floppy things, CNTs aren't very.

Drexler's motors use a tunneling contact of varying work function. That would seem to require doping. But as I say in my Primitive Nanofactory paper,

"A rotating electrostatic motor based on Drexler's design (Drexler, 1992, sec.11.7) can be built out of only carbon and hydrogen. Bulk diamond is an excellent insulator, but a thin layer of diamond can be a semiconductor, and graphite is an adequate conductor. The electrodes for such a motor should have varying work functions for simplicity and efficiency. The work function of graphite is 4.5 eV, while the work function for CVD diamond has been measured at 5.7 eV (Groening et al., 2003). This difference should be sufficient to place ~1 electron per (graphite) electrode in a motor similar in scale to Drexler's (50 nm)."

I don't know why I didn't point out that buckytubes can be excellent conductors as well as semiconductors.

Chris

[Phillip Huggan]

A thin layer of (undoped) diamond can be a semiconductor? How is this possible without doping of some sort?

[Chris Phoenix, CRN]

I don't know... I found the fact reported... perhaps it was contaminated. In any case, buckytubes work fine.

Chris

[Phillip Huggan]

Agreed, *if* CNTs are MNT-able... it would be a useful computer simulation to attempt. Surely this simulation will occur at some point so there is no use arguing over this point.

[master law of attraction]

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