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Nanosystems 52

Posted by Hemos
from the eric's-rebuttal dept.
Chris Worth has come to me (surprise!) with a review of one of the most definitive books on nanotechnology, Nanosystems. K. Eric Drexler's response to the technical issues raised by critics to nanotechnology, the book is a technical treatise
Nanosystems
author K Eric Drexler
pages 556
publisher John Wiley & Sons
rating 10/10
reviewer Chris Worth
ISBN 0471575186
summary Dr Nano answers his critics with a technical treatise on nanotech.

About the reviewer

Chris Worth is a web creative director and nanotech junkie based in Paris. You'll find other ramblings on technology, literature, and red hot asian babes at chrisworth.com. He's looking for geeks to build a subversive website for fun and profit, supported by some of the world's top creatives and assorted rich bastards; email him at chris@chrisworth.com if you're interested.

The Scenario: bringing researchers together

So you think you know what nanotech is, huh? Maybe you read a book by Neal or Greg or William and dreamed of custom-built computing molecules blanketing cities a billion deep, of patterned flesh singing a song of networked biosentience, of hundred-storey polycarbon structures reaching skywards into the electric neon night. Maybe the concept seduced you into Unbounding the Future and its Lilliputian expeditions across molecular landscapes, or you notched up to Engines of Creation and its talk of assemblers and replicators in pages nude of math. I read them too. And they're good, believe me. But to really know nanotech, to bite through the soft pop-sci underbelly and champ down on its hard skeleton of applied physics, you've got to read Nanosystems .

Nanosystems: the first technical treatise on nanotechnology

Nanosystems, by K Eric Drexler, is the real deal: the first textbook on molecular nanotechnology. It's full of greek equations and exponential graphs and globular diagrams that'd scare your chemistry professor, walled in by dense paragraphs of dry prose that'll make your teeth itch. But somehow it's readable - because the book has a broader purpose that goes beyond Potential Energy Surfaces or spatial Fourier transforms or Born-Oppenheimer approximations. That purpose is to bring together researchers from different fields, to show them how their expertise fits into the broad patchwork of nanotechnology. And that means it's readable for any motivated geek, because Drexler assumes no in-depth knowledge of any one field; concepts are explained from first principles and many equations are derived step-by-step. In a nutshell: if you get C, you can get Nanosystems.

So that's the purpose of Nanosystems: to bring disparate researchers into a single conceptual framework and make nanotech a collaborative effort. But just what is nanotech? First, let's define what it isn't - because nanotech discussions often give out more heat than light. Like transgenic crops and human cloning, vast swaths of the argument would disappear if everyone understood the principles.

Nanotech: so what the hell is it?

First, it's not necessarily about small things; the nano prefix refers to precision at the molecular scale, not the size of the finished article. A rocket motor built bottom up from component atoms one by one is molecular nanotechnology; a train of tiny gears built top-down by hewing away at a silicon surface is not. Second, nanotechnology won't turn lead into gold; elements are defined by atomic nucleii, and nanotech isn't interested in the nuclear forces. Third, it isn't a cure for all the world's problems; hatred and bigotry are separate issues no technology can solve. Fourth, there won't be any day when sci.nanotech explodes with cries of "it's here!"; since it'll be the result of research across multiple disciplines, nanotech will arrive in fits and starts.

And finally, on the biggest misunderstanding of all: no, nanotech isn't impossible. The laws of physics don't prevent nanotech happening; in fact, they emphatically make it possible. (Mr Heisenberg isn't half the troublemaker you think he is.) Yes, there's a tad too much hero worship and holy rollerism surrounding the good-natured and approachable Dr Drexler. And that's given rise to some negative column inches by Scientific American's Gary Stix and Nature's David Jones (neither of whom backed up their assertions). But catcalls and hype don't change basic physical principles; nature doesn't give a damn how loud we shout. And since Nanosystems's first printing in 1992, even Drexler's most loudmouthed critics haven't found any showstopping fault with it.

But back to what matters: what is nanotech? Fundamentally, it's about that bottom-up capability: getting every atom where you want it. Once you can get every atom where you want it, you can build machine systems from the bottom up with atomic precision. Once you can build bottom up, you can build machine systems capable of making perfect copies of themselves, as ribosomes do with DNA. And once your machine's made a perfect copy of itself, you can tell those two to build another, and those four to build four more, and so on, meaning that in a day or two you've got enough to start doing serious work. That bottom up capability of "molecular manufacturing" - which Drexler defines as "the construction of objects to complex atomic specifications using sequences of chemical reactions directed by nonbiological molecular machinery" - would lead to a new world of wealth and abundance. And Nanosystems is about reaching it.

The book's structure

Inside the blue-white cover with tantalising schematics of a molecular sorting rotor, atomic-scale bearing, and a robot arm with the 50 nanometer legend, the book's 556 pages split into three parts: "Physical principles", "Components and systems", and "Implementation strategies". What it does, what to do it with, and how to get there, backed up by 450 equations. Resist the urge to skip chapters until you've skimmed the whole book once; it has a developing structure that rewards a bit of linearity. The preface - with its famous first line "Manufactured products are made from atoms, and their properties depend on how those atoms are arranged" - sets the scene, with notes on why it's reasonable to predict tomorrow's technology with today's. ("Our ability to model molecular machines has far outrun our ability to make them...") But the meat starts with the intro:

"The following devices and capabilities appear to be both physically possible and practically realizable:

Programmable positioning of reactive molecules with ~0.1nm precision
Mechanosynthesis at >10^6 operations/device.second
Mechanosynthetic assembly of 1kg objects in <10^4 s
Nanomechanical systems operating at ~10^9 Hz
Logic gates that occupy ~10^-26m (~10^8 micro^3)
Logic gates that switch in ~0.1ns and dissipate <10^-21J
Computers that perform 10^16 instructions per second per watt
Cooling of cubic-centimeter, ~10^5W systems at 300K
Compact 10^15 MIPS parallel computing systems
Mechanochemical power conversion at >10^9W/m^3
Electromechanical power conversion at >10^15W/m^3
Macroscopic components with tensile strengths >5*10^10GPa
Production systems that can double capital stocks in <10^4s"

Yeah, I was drooling too. And just a few pages further in Drexler whacks us with a nanomechanical product: a bearing with shaft and sleeve in 6- and 14-fold prime symmetry to keep it turning. It's made of carbon with the odd silicon and oxygen atom to round it out, dangling bonds capped with hydrogen, and is made of just 206 atoms. Of course it can't be built yet, but the mind boggles anyway. As it should: this diagram is a teaser for the whole book.

The rest of the intro is comparisons: how conventional solution-phase chemistry and mechanosynthetic chemistry are different, how characteristics of different approaches differ at the nanoscale, how the carbon structures described in Nanosystems are just a subset of all covalently-bonded structures, and the scope of the book. Read this: there's no sci-fi here, no what-ifs, no assuming-thats. Nanosystems is about what's possible given today's understanding of how molecules behave - as such, it's more conservative than many papers you'll see in Nature.

Chapter by chapter

Part I - Physical Principles - is the hardest, squashing a physics course into 230 pages. Ride the hump, guys; no pain, no gain. Chapter 1 takes you down into the molecular world, exploring where classical physics scales down and where it doesn't; chapters 2 and 3 get down and dirty with how molecules are shaped and how they behave when pushed. Chapter 5 is for Heisenberg fans, explaining how thermal uncertainty's a far bigger problem than quantum uncertainty at these scales, while 6 and 7 explore how nanomachine designs will be debugged, going into problems of error-checking and heat death. So far, so painful. Work with it.

It's not until chapter 8 that Drexler starts talking about "real" nanotech: mechanosynthesis. This is 1AM stuff when you know you should be putting the book down for the night but can't. You'll be reaching for the Jolt without caring about work tomorrow. There's still plenty of alkenes and alkynes and tensile bond cleavage and Pi-bond torsion talk here, but the graphs stop for a moment as Drexler deals with what later got called "fat finger" and "sticky finger" problems - how to make your reactive tool molecule slim enough to cause one reaction with a target molecule without it getting the wrong one, and how to make sure the reaction happens when you want it to. And this chapter introduces carbon, everyone's favourite element.

Carbon is one seriously cool atom. Tetrahedral covalent carbon - diamond - is a hundred or so times stronger than steel, and its components atoms are everywhere. They do have to be joined together in a precise pattern; that's why diamond is rare today, and why p.241 includes a diagram of adding two ethyne molecules to another hydrocarbon to model a step in diamondoid formation. Peppered with other common elements like oxygen, fluorine, chlorine, hydrogen, silicon, sulfur, phosphorus, and nitrogen, carbon can be assembled into tough, stiff structures with almost any mechanical or electronic property we want. And carbon molecules are surprisingly easy to model accurately on a computer. That's why Nanosystems devotes itself principally to carbon structures.

On to part II, Components and Systems. Chapter 9 kicks off with the difference between housings and moving parts, and answers one criticism levelled at Drexler: you can't extrapolate to the nanoscale from the macroscale. With a grab-bag of molecular rods and strained-shell carbon bearings, Drexler shows where we can and where we can't. Chapter 10 does the same for moving parts, salting in what happens when two structures start interacting with each other: there are some tasty diagrams of molecular gears, rollers, belts and cams here, but watch out for the graphs and equations.

By chapter 11 the components start coming together as complete systems instead of odd toys, worm gears inserted between tube sections and drive rings threaded onto toroidal housings. Some of the drawings look clunky and Victorian to our silicon-bred eyes, until you realise the transistors we know and love are huge rough-hewn logs at this scale and gravity and friction aren't problems in the same way. Nanosystems is about mechanics, not electronics, but a funky electrostatic motor on p.337 blurs the line: at these sizes both approaches are elegant.

It's at chapter 12 that Drexler gets around to computers. Shapes reminiscent of Babbage engines and Jacquard looms parade across the pages in diagrams of rod-logic gate and register apparatus. (Yes, this is the chapter that inspired a scene in The Diamond Age.) Neal Stephenson got it wrong: this is unlikely to be how we'll build tomorrow's PCs, because Nanosystems is an exploration of engineering techniques, not a recommendation to Intel. The chapter pivots on a finite-state machine built with nanomolecular AND/OR rod logic, with text stating a million-transistor CPU would fit inside a 400nm cube, run at 1GHz, and perform at 10^16 instructions per second. Nanoelectronic designs will be many orders of magnitude faster, but they're outside the scope of this book.

Chapter 13 starts the segue into part III, chunking up to how all these nanomachines can be linked into a complete machine system. A sorting rotor extracts the right molecules from a mix with precisely-shaped reactants attached to a cam; a set of them washes a mix progressively cleaner and cleaner (more feedstock for Neal Stephenson's Diamond Age.) Molecular conveyor belts grab molecules from a toothed gear and take them elsewhere. But the chapter's wow-factor (wow being a relative term in Nanosystems) is the nanomanipulator, a squat robot arm of four million atoms, over a hundred moving parts yet just a hundred nanometers tall. It can pitch, roll and yaw in all six degrees of freedom, snaking up and down and round and round with a train of drives and clutches spliced together with worm gears and intersegment bearings. Imagine this arm reaching out and bonding to a single atom with a reactive tip, rotating that atom away from its surface and depositing it elsewhere. Remember that image, because it's at the core of what nanotech is.

Building on this, chapter 14 describes an exemplar molecular manufacturing system: the holy grail. Another chunk up, it gloms together all the machines described already, into a complete factory for building nanomachines. From single atoms to different parts to convergent assembly to parallel construction, the factory masses less than a kilogram. With a few simple instructions, millions of interacting nanomachines will build products in minutes, blocks of molecular sorting rotors, conveyor belts, and assemblers individually unaware of the big picture but working in parallel like any anthill or beehive. Open another can of Jolt, because you're on the home stretch now.

Part III - on Implementation Strategies - tacks away from what we can build and talks about how to build the things that build them. It turns out there's more than one way to do it. In chapters 15 and 16 Drexler discusses a range of cool STM and AFM scopes for pushing and shoving atoms around, and suggests ways reactive tips on the scanning needle could play with them; since Nanosystem's publication this has started happening in several labs. Biomolecular selfassembly and protein folding are other possible paths to those first primitive tools that can bootstrap us up to covalent-carbon nanotech. Talk of cyclic backbones, crosslinking and rigidity will answer a lot of critics' questions, with a forward- and backward-chaining analysis (a la computer science) "indicates that feasible developmental pathways link our present technology base to the technology base described in Part II." And there, save for a couple of appendices on methodology and related research, the book ends.

So drop the Jolt and fall asleep, because then you can dream - dream of nanotech's infinity of possibilities. And then we can start talking about it. Talking about it the way we talk about Linux, informed by sound technical issues instead of hype and soundbites. Because Nanosystems is a subversive book, subversive the way strong crypto and open source are subversive: developing thanks to the hacker ethic, developing to liberate the masses instead of control them. Published anywhere else, this review'd probably scare people off. But to you, it probably sounds like a challenge. So read Nanosystems. Imagine how ten thousand hyperlinked Slashdotters with a strong understanding of nanotech could influence this technology... and have so much damn fun doing it.

So go on, geek: read Nanosystems . I dare you.

FOOTNOTE: About the Foresight Institute

After first reading Nanosystems in 1996 I became a member of the Foresight Institute, which Eric Drexler and Chris Peterson founded to spread information about nanotech. Foresight works quietly and cost-effectively to influence public policy towards safe, informed development of molecular nanotechnology. (As Gayle Pergamit, Drexler and Peterson's technical writing collaborator, says, it's amazing what two people and a letter to the right office can achieve.) At the conferences it runs for its members you can rub shoulders with writers like Greg Bear, David Brin and Gregory Benford, Valley legends like Doug Engelbart, hackers the stature of Raymond and Gilmore, Old Media types from the New York Times and San Jose Mercury, real nanotechies like Ralph Merkle of Zyvex and Josh Hall of IMM, and of course Drexler and Peterson themselves. And this would take you through one bagel at breakfast. Thanks to Foresight I've learned a lot, made some excellent contacts, and several strong friends. You can learn more at www.foresight.org.

Table of Contents

1. Introduction and Overview

  • 1.1 Why molecular manufacturing?
  • 1.2 What is molecular manufacturing?
  • 1.3 Comparisons
  • 1.4 The approach in this volume
  • 1.5 Objectives of following chapters

Part I

2. Classical Magnitudes and Scaling Laws
  • 2.1 Overview
  • 2.2 Approximation and classical continuum models
  • 2.3 Scaling of classical mechanical systems
  • 2.4 Scaling of electromagnetic systems
  • 2.5 Scaling of classical thermal systems
  • 2.6 Beyond classical continuum models
  • 2.7 Conclusions
3. Potential Energy Surfaces
  • 3.1 Overview
  • 3.2 Quantum theory and approximations
  • 3.3 Molecular Mechanics
  • 3.4 Potentials for chemical reactions
  • 3.5 Continuum representations of surfaces
  • 3.6 Conclusions
  • 3.7 Further readings
4. Molecular Dynamics
  • 4.1 Overview
  • 4.2 Nonstatistical mechanics
  • 4.3 Statistical mechanics
  • 4.4 PES revisited: accuracy requirements
  • 4.5 Conclusions
  • 4.6 Further Reading
5. Positional Uncertainty
  • 5.1 Overview
  • 5.2 Positional uncertainty in engineering
  • 5.3 Thermally excited harmonic oscillators
  • 5.4 Elastic extension of thermally excited rods
  • 5.5 Elastic bending of thermally excited rods
  • 5.6 Piston displacement in a gas-filled cylinder
  • 5.7 Longitudinal variance from transverse deformation
  • 5.8 Elasticity, entropy, and vibrational modes
  • 5.9 Conclusions
6. Transistions, Errors, and Damage
  • 6.1 Overview
  • 6.2 Transitions between potential wells
  • 6.3 Placement errors
  • 6.4 Thermomechanical damage
  • 6.5 Photochemical damage
  • 6.6 Radiation damage
  • 6.7 Component and system lifetimes
  • 6.8 Conclusions
7. Energy Dissipation
  • 7.1 Overview
  • 7.2 Radiation from forced oscillations
  • 7.3 Phonons and phonon scattering
  • 7.4 Thermoelastic damping and phonon viscosity
  • 7.5 Compression of potential wells
  • 7.6 Transitions among time-dependent wells
  • 7.7 Conclusions
8. Mechanosynthesis
  • 8.1 Overview
  • 8.2 Perspectives on solution-phase organic synthesis
  • 8.3 Solution-phase synthesis and mechanosynthesis
  • 8.4 Reactive species
  • 8.5 Forcible mechanochemical processes
  • 8.6 Mechanosynthesis of diamondoid structures
  • 8.7 Conclusions

Part II

9. Nanoscale Structural Components
  • 9.1 Overview
  • 9.2 Components in context
  • 9.3 Materials and models for nanoscale components
  • 9.4 Surface effects on component properties
  • 9.5 Shape control in irregular structures
  • 9.6 Components of high rotational symmetry
  • 9.7 Adhesive interfaces
  • 9.8 Conclusions
10. Mobile Interfaces and Moving Parts
  • 10.1 Overview
  • 10.2 Spatial Fourier transforms of nonbonded potentials
  • 10.3 Sliding of irregular objects over regular surfaces
  • 10.4 Symmetrical sleeve bearings
  • 10.5 Further applications of sliding-interface bearings
  • 10.6 Atomic-axle bearings
  • 10.7 Gears, rollers, belts, and cams
  • 10.8 Barriers in extended systems
  • 10.9 Dampers, detents, clutches, and ratchets
  • 10.10 Perspective: nanomachines and macromachines
  • 10.11 Bounded continuum models revisited
  • 10.12 Conclusions
11. Intermediate Subsystems
  • 11.1 Overview
  • 11.2 Mechanical measurment devices
  • 11.3 Stiff, high gear-ratio mechanisms
  • 11.4 Fluids, seals, and pumps
  • 11.5 Convective cooling systems
  • 11.6 Electromechanical devices
  • 11.7 DC motors and generators
  • 11.8 Conclusions
12. Nanomechanical Computational Systems
  • 12.1 Overview
  • 12.2 Digital signal transmission with mechanical rods
  • 12.3 Gates and logic rods
  • 12.4 Registers
  • 12.5 Combinational logic and finite-state machines
  • 12.6 Survey of other devices and subsystems
  • 12.7 CPU-scale systems: clocking and power supply
  • 12.8 Cooling and computational capacity
  • 12.9 Conclusion
13. Molecular Sorting, Processing, and Assembly
  • 13.1 Overview
  • 13.2 Sorting and ordering molecules
  • 13.3 Transformation and assembly with molecular mills
  • 13.4 Assembly operations using molecular manipulators
  • 13.5 Conclusions
14. Molecular Manufacturing Systems
  • 14.1 Overview
  • 14.2 Assembly operations at intermediate scales
  • 14.3 Architectural issues
  • 14.4 An examplar manufacturing-system architecture
  • 14.5 Comparisons to conventional manufacturing
  • 14.6 Design and complexity
  • 14.7 Conclusions

Part III

15. Macromolecular Engineering
  • 15.1 Overview
  • 15.2 Macromolecular objects via biotechnology
  • 15.3 Macromolecular objects via solution synthesis
  • 15.4 Macromolecular objects via mechanosynthesis
  • 15.5 Conclusions
16. Paths to Molecular Manufacturing
  • 16.1 Overview
  • 16.2 Backward chaining to identify strategies
  • 16.3 Smaller, simpler systems (stages 3-4)
  • 16.4 Softer, smaller, solution-phase systems (stages 2-3)
  • 16.5 Development time: some considerations
  • 16.6 Conclusions
Appendix A. Methodological Issues in Theoretical and Applied Science
  • A.1 The role of theoretical applied science
  • A.2 Basic issues
  • A.3 Science, engineering, and theoretical applied science
  • A.4 Issues in theoretical applied science
  • A.5 A sketch of some epistemological issues
  • A.6 Theoretical applied science as intellectual scaffolding
  • A.7 Conclusions
Appendix B. Related Research
  • B.1 Overview
  • B.2 How related fields have been divided
  • B.3 Mechanical engineering and microtechnology
  • B.4 Chemistry
  • B.5 Molecular biology
  • B.6 Protein engineering
  • B.7 Proximal probe technologies
  • B.8 Feynman's 1959 talk
  • B.9 Conclusions
Afterword Symbols, Units, and Constants Glossary References Index
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Nanosystems

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  • by Anonymous Coward
    ...back in the day. A student group had invited him to give whatever his boilerplate nanotalk consisted of at the time. Surprisingly, a lot of professors attended.

    The problem I had, and still have with Drexler, is that he has zero practical experience with making a physical system. All his books are full of pretty tinkertoy structures made using molecular modeling software. Big deal. And most of his ideas for nano-whatevers are simply analogs of macroscopic devices (wheels, gears, robot arms, etc). Uh, most physical properties are different at that scale--why would you want mimics of macroscopic devices? A nano device that looks like a gear is not going to function as a gear, I can guarantee you.

    Somebody oughta tell this guy that the nanotechnology problem has been solved. It's here today, it works, and it's called biology.



    BTW, sorry for the earlier blank post...
  • by Anonymous Coward
    I have read the book. It took more than one night of Jolt induced alertness to get through it (several weeks actually, without the Jolt). I highly recommend it to all geeks everywhere. Some of it is pretty heavy-going, but you can skim some of the heaviest chapters (like chapter 7) without affecting your understanding of the rest of the book. It makes most of the objections from people who have not read the book seem simplistic and ill-considered.
    The developments in technology you will see over the next few years (and which we have started seeing already) will provide concrete examples of many of the things that Drexler describes.
    "Imagine how ten thousand hyperlinked Slashdotters with a strong understanding of nanotech could influence this technology... and have so much damn fun doing it." Do you want to miss out on this?

    Read The Book!

    PS Read Engines of Creation first

    And don't forget to read The Programmers' Stone [ftech.net] and Reciprocality [melloworld.com]

    Michael Richards [mailto] (no, not the actor)
  • "If the spending that had gone into the cold war and
    defense had, say, gone into the space program instead,"

    . . . we'd be a smoking, radioactive heap of ashes, with a soviet flag at the top. (the only thing that the spending changed is that we delayed it by 20 years, and there will be a USA flag on the top of the smoking heap of radioactive ashes. Hooray for our side!)

    In fact, the only reason we even went to the moon, or even launched satellites, was due to the cold war. Or don't you know your history, about how scared the US was when the USSR launched sputnik, and demonstrated that they could put a nuke anywhere on the planet, anytime. That is what the space program was all about in that era. Now that companies like Hughes know that they can make $$$ by making and selling commmunication satellites, they do it - but would they have done it without that upfront government spending on the basic R&D?

    Really, the difference between nanotech and space technology, is that it's FAR more attractive to businesses, because the potential for profit is huge, while the up front investment is relatively small (compared to space exploitation). Not to mention, the potential is limitless. Not so in space exploitation, where the orbits are rapidly filling up with either useful satellites, or dangerous space junk.

    With space, the sky's the limit.
    With Nanotech, not even the sky is the limit. More like quantum mechanics.

    I wish I had a nickel for every time someone said "Information wants to be free".
  • This was actually the original premise proposed by Feynman way back 30 years ago or so. I forget the analogy he used at the moment (it was rather amusing to think about), but it is in a paper somewhere at http://www.foresight.org from a lecture he gave on the subject.
    EMYL,
  • So called "futurists" like Caral Sagan and other scifi/philosophers have said that we should have moon bases established and be to mars and back by now. I don't see any of that happening.

    Um, so? Some predictions pan out, some don't. In any case, Drexler seems to be pretty careful about just pointing out what could be and not saying that he knows what will be. Granted, some nano-enthusiasts get carried away and make pretty ludicrous predictions, but that's hardly Drexler's fault. In fact, he tries to discourage bogosity [rutgers.edu].

  • There are actually free HTML versions of both Engines of Creation and Unbounding the Future available on the Foresight web site, here [foresight.org].
  • Well, that's what I meant when I posted that. You'd drop a few general purpose replicators which would make the rest of the machines. But the machines wouldn't all be small, because there are economies of scale, and not all the machines would be capable of self-duplication and other 'complex' tasks.
  • Perhaps. Some jobs seem to be perfect for autonomous large machines, just as some seem perfect for millions of tiny ones.

    If you have to haul huge quantities of raw materials from one site to another, a long way away, a 'truck' would seem to make more sense than a conveyor belt. Especially since the truck would be immediately useful on a different route, where the belt would have to be moved. Also, a belt has to cover the whole distance, even if it's only in use 0.02% of the time. If you're using seperate machines, you just put less of them on the job and use them as their full, and most efficient, capacity.

    Maybe there will be improvements to trucks, and not just in the engine/fuel, but in the general structure, but wheels are a pretty basic idea and seem pretty hard to improve on.

    I can see a use for both. Why give each nanite the ability to travel hundreds of kilometers between jobsites when hundreds of millions can be carried at once, in one shipment. Large machines would probably also carry repair nanites, and larger scale bots, to fix any problems they encountered along the way.
  • Here's what I don't get about the vision of nanotechnology--why do its proponents see the coming up with self-replicating machines part as such a trivial step? People have been trying to make self-replicating macromachines for centuries with no luck. Worth writes "Once you can build bottom up, you can build machine systems capable of making perfect copies of themselves, as ribosomes do with DNA." But I'm not persuaded that the existence of self-replicating molecules proves much. People are self-replicating big machines, and that hasn't helped us toward the macro-scale goal. Are there actually factors that make independent replication of complex sturctures easier on a smaller scale?

    Come to think of it, using Worth's definition (nanotech is anything constructed molecule-by-molecule), aren't all living things (or at least all genitic manipulation) nanotech?
  • The reviewer (and others) make a point of saying that Drexler is responding to his critics with this book --- as if he is the champion of nanotech while others (traditional, stodgy old scientists) are dismissing his radical ideas.

    The fact is that scientists have been doing nanotechnology for decades; its just that they call it chemistry, biochemisty, or solid state physics. If a chemist is annoyed by Drexler, its because he gets away with drawing ridiculous molecular structures (gears, levers, tiny espresso machines, etc.), ignoring very basic physics. One can criticize some of Drexler's specific examples without being against nanotech, just as one can criticize the "warp drive" in Star Trek without being against space travel.

    Drexler's book Engines of Creation does a great service in that it eloquently raises awareness about the implications of tiny self-replicating machines. But the book is obviously not a scientific reference, and doesn't have enough of a plot to qualify as science fiction. I've not read the nanosystems book, but to anyone out there who wants to really get into nanotech, you've got to start by getting a good grounding in thermodynamics, statmech, quantmech and basic chemistry. At a bare minimum, you've got to get a good understanding of Brownian motion and other aspects of thermal noise. Then you'll see why chemists are annoyed by Drexler's ridiculous gears and such.

    Its not just that things getting tinier; its not just that we need waldos manipulating smaller and smaller waldos. When you get down to the atomic level the rules change.

  • I was not commenting on Nanosystems, I was commenting on some of the molecular designs present in Drexler's earlier works, and commenting on the fact that "nanotechnology" is nothing more and nothing less than hard core chemistry and physics. If Drexler is the father of nanotech, then I guess he's the father of applied physics and chemistry, and all the people out there busting their ass in the lab trying to get protein to hang together are merely implementing his vision.

    I like his older book, funny molecules and all, and this newer one looks great too, with much more background material, and I appreciate the review.

  • I admit I haven't checked into nanotech very deeply, but every time I see it mentioned I have the same questions.

    The review mentions that nanotech is building machines up atom by atom (or molecule by molecule). Is anyone working on going the other way, i.e. creating something that can replicate itself, only slighty smaller. THen that one can build yet a smaller version, etc, until you get something really small?

    These articles always mention that these machines can replicate themselves, i.e. on machine copies itself, then two machines make 4 copies, etc. It seems that if you wanted to build a machine to do something useful, other than just copy itself, you would need to spend a lot of effort to include the copy functionality. I mean, do you want a simple machine that can repair a heart valve, or a more complicated one that can repair a heart valve AND copy itself?
  • Anybody interested in this topic can join the Foresight Institute, [foresight.org] which is dedicated to nanotechnology. They hold several conferences during the year, where you can meet Drexler and other luminaries in the field.

    -stern
  • Nanotechnology will move fast precisely because it isn't big science like the space race and fusion. It can be done relatively cheaply in a distributed way. The human genome project is a good model for it and I think it will come a lot sooner than people think.

    Tom
  • Guess that attempt at comic book humor didn't meet that moderators approval... drat... hehe
  • Just to correct a somewhat misleading impression there - Prof. Smalley is actually a strong nanotech advocate. (Or, perhaps we are thinking of different people?) E.g. see his 1996 talk [rice.edu] on the social and environmental necessity of nanotechnology:

  • And I would subscribe, but $840/yr is a little rich for my blood. At least when for the time being this is just an object of (intense) personal curiosity.

    pth
    My name is not spam, it's patrick
  • So called "futurists" like Caral Sagan and other scifi/philosophers have said that we should have moon bases established and be to mars and back by now. I don't see any of that happening.
  • There are multiple paths to take here. First of all, the nanomachine will simply be following instructions on how to copy itself. The assembler itself will be a very simple device, much like RNA, simply taking instructions and following them. Whether those instructions are a tape for building another assembler, or for building larger special purpose devices that, for instance, repair a heart valve, is inconsequential. A machine that can repair a heart valve would mostly likely consist of many different types of machines, all of them much more complicated then a simple assembler. I would suspect you could simply have a vat of assemblers that are instructed to produce the heart valve repair machines, and then inject these machines into your body. One molecular structure building a copy of itself is not that complicated. One that has knowledge of biology is MUCH more complicated. The copy functionality would actually be the most basic function of an assembler. The highly complex instructions for large medical devices would be a more time consuming task for it to process. And the medical devices themselves would be an order of magnitude more complex then an assembler. In fact they might have assemblers working within them, millions of assemblers, repairing and modifying functionality. Something that repairs heart valves might be the size of a human blood cell, which is itself a huge environment filled with many many specialized nano-machines. A nano device such as this would have a power plant, repair assemblers, a computer, input and output devices, sensors, a chemistry lab, a factory for producing appendages, etc. etc. An assembler just has a few tiny arms that grasp atoms and create chemical bonds to build molecular structures.
  • Self replication becomes very easy when its just a molecular structure. What does the assmebler care if its a diamond lattice or if its another assembler? If an assembler can create any 3 dimensional precise molecular structure, then self-replication is a given. Macro technology has nothing to do with it, given that there must be processed raw materials, etc. that go into self-replication. I'm sure it could be done on the macro scale, but since a machine contains plastics, metal alloys, computer chips, etc. etc. you would have to duplicate every single one of these items from the raw resource on up. Not an easy task. But with nanotechnology, the raw resource is the basic building block. And you are right, all living things are nanotech. If a whale can be constructed from a single fertilized cell, its definitely a self-replicating nanotech creation.
  • Nanotech machines dont have to be "small" but even a truck will have nanoscale devices. Its simply the scale at which the basic level of work gets carried out. But why have trucks driving around when you could just have big thick umbilicals with trillions of tiny robotic arms moving material a particle at a time. Large modern pumps do a good job at pumping everything from water to sand and peanut butter. A nano pump could haul material very fast and very efficiently, distributing it where it needs to go for raw materials or where ever. Modern machinery will probably not have very many equivilants in a nano world, since there are much more far out and efficient devices that could be constructed. But of course there will be large "machines" however, they will have nano-scale devices doing the low down dirty work, even if its just constant repair of the machine itself.
  • Are there any less textbook-like books on the subject out there? I'm interested, but don't have the time to invest in trying to decipher a book of this stature.
  • This was a good, if rather belated review. Certainly, much that seemed rather improbable at the time of publication has turned out to be quite practical. Drexler's book is a visionary work, and a great place to start looking for nanotech concepts. Since someone put in a plug for Foresight Institute, which holds a series of very useful meetings through the year, I thought I'd just mention that Wiley's Technical Insights unit also publishes a weekly E-mail-delivered news briefing on developments in the field. It's called Nanotech Alert. There's also a multiclient report available -- items culled from its first year of publication -- called, not surprisingly, "Nanotechnology." Neither are cheap treats, because they are not consumer publications. But for researchers, business people wondering where this research will lead us, and industry decisionmakers who need to stay on top of what people are recognizing as "one of the key industries of the 21st Century", Nanotech Alert is pretty much the only focused source of nanotech news available. And yes, we're always interested in input or news of developments from the field, if you have any tips. Get more details at http://www.wiley.com/technical_insights. Or e-mail us at insights@wiley.com.

    Peter Savage/Editor-in-Chief/Technical Insights

  • Nanosystems is truly excellent, but I'd hesitate to recommend it to anyone that doesn't benefit from a solid engineering background. This is a real textbook, not a lay read.

    It's not an occasional read either. I've spent about 18 months on it so far and I'm about halfway through, plus a few occasional excursions into parts further on. It won't be less than another year or so before I've finished my first pass. What you get back from this book is proportional to the effort that you put into understanding it, ie. as in any other scientific or engineering field.

    For people that don't fit the above category of readers, I wholeheartedly recommend Engines of Creation, also by Drexler, the popular book which opened up the possibilities of the field to the masses. It's extremely, wonderfully good, but without the maths.
  • I know I was oversimplifying. I know I left out all the fun stuff about how enzymes are a sloppy part of evolution. I know that nanites would be implicitly more accurate and controlled than enzymes. I was just stating that heisenberg shouldn't ever have been seen as an issue, since if enzymes can do it, so can anything else operating on that scale with nearly zero relative velocity, and that nanorobots would be functionally similar to enzymes.
    ---
    "'Is not a quine' is not a quine" is a quine.
  • Although I haven't read the book, I feel that I need to comment on something the reviewer said. As the reviewer pointed out, Heisenburg isn't nearly as problematic for nanotech as people love to point out. In fact, we already have nanotech assemblers and their ilk, and have had them for well over two billion years; they're called enzymes. We have enzymes all over the place, unzipping our DNA apart and reassembling it into two copies by finding matching proteins and bonding them to the other half of the stepladder. Basically, a nanomachine can be thought of as an artificial enzyme.

    Heisenburg uncertainty only really becomes an issue when something is moving at a high relative velocity or is at very high temperature, and when that's the case, you definitely don't want to be twiddling the atoms anyway (not that you'd be able to, since you (the enzyme/nanobot) wouldn't even be close enough to the atoms to manipulate them anyway and/or would have its own atoms knocked out of place due to the sheer kinetic energy).
    ---
    "'Is not a quine' is not a quine" is a quine.

  • I've not read the nanosystems book ...

    Obviously. RTFB.

    One of the reasons Drexler wrote Nanosystems was to respond to just this sort of comment from people who insisted on commenting on the topic without understanding it. And no doubt one of the reasons Chris wrote the review was that he was dead-tired of Slashdotters commenting on the topic without understanding it.

    Go read the book. Read the related stuff being published by chemists, biochemists, physicists, etc, etc. Then comment on it.

  • Try Drexler's own "The Engines of Creation". Or "Nano" by Ed Regis. Of the two I'd say that "Engines" is the one to go for, but they're both eminently readable.
    A good thing to read is nano-based fiction. Try "The Bohr Maker" by Linda Nagata, "The Diamond Age" by Neal Stephenson or "Nanodreams" a collection of short stories edited by Elton Elliott.
  • Well, at least the reviewer found it amusing.
    Chris Worth
  • ...set of nano items that's actually been made. A pair of nano gears (spinning at terahertz) is the most modelled structure in the field, and one lab has (accidentally) made a sleeve and shaft bearing at the nanscale, bottom up.

    The reason mech properties at the nanoscale'd be nice is that bio is squishy, wet, and not very strong in general. Covalent diamond, by contrast, is a dream engineering material.
  • The book contains detailed sections on Pi-bond torsion and strained aromaticity - yes they're problems, but not insurmountable. Gears simulated using the conservative MM2 model appear to stay stable up to 1THz.

    I suspect you've worked with Prof Smalley, who, while a brilliant chemist, perhaps lacks the engineering insight to see these problems as engineering challenges, not showstoppers.
  • Yup, I believe it WAS a typo - it should be cubic m, not m. Apologies.
  • Mr. Worth has a fun, breezy style--readable to a fault (when do Jolt references cease to be hip and start to be annoying?). However, this piece sometimes reads more like an ad than a review, and more like an ad for the movement than an ad for the book. What are we supposed to take away from a sentence like "Carbon is one seriously cool atom?" Knowledge about Drexler's book? About Nanotech? About physics?



    I wish the review had been more specific. The section on Chapter 9 ends with "With a grab-bag of molecular rods and strained-shell carbon bearings, Drexler shows where we can and where we can't [extrapolate to the nanoscale from the macroscale]." I'd love a few examples, or a brief explanation of the principles at work. I realze that Chris was trying to write a review, not the Cliff Notes, but I was disappointed that I came away from the piece without my knowledge of the field being increased.
  • These articles always mention that these machines can replicate themselves, i.e. on machine copies itself, then two machines make 4 copies, etc. It seems that if you wanted to build a machine to do something useful, other than just copy itself, you would need to spend a lot of effort to include the copy functionality. I mean, do you want a simple machine that can repair a heart valve, or a more complicated one that can repair a heart valve AND copy itself?

    They usually are talking about the assembler when they talk about this. The assembler is a machine that can build things on the nano- scale, and is programmable. The idea is that it will first be programmed to copy itself, so that a very large number of assemblers can be created.

    Once the assembler is done, then they'll start playing with it, programming it to build other things. Most of these other, non-assembler, machines will not have the ability to copy themselves, for various reasons. Perhaps a few will be made by taking the functionality of the assembler and adding on.

    They aren't planning to make every nanomachine able to replicate itself. As you pointed out, that would add much more to the machine than is necessary in almost all cases, and add the worries about a badly-designed one, or flawed one, replicating out of control.
    ---
  • I own this book, and while I've started to read it, I've realized that it is probably not the best book to read as an introduction into nanotechnology. I've seen a number of others available at The Foresight Institute [foresight.org] that appear to be better ones to start out with, and I plan to purchase those before coming back to this one.

    It's more technical, and definately a good one for people who have more than just a passing interest in molecular nanotechnology, but not the one you'll try and get your friends and family to read.

    Anyone know the names of some better introductory ones? I think there are two or three mentioned in the review, but I believe there are more than that available.
    ---
  • In fact, we already have nanotech assemblers and their ilk, and have had them for well over two billion years; they're called enzymes. We have enzymes all over the place, unzipping our DNA apart and reassembling it into two copies by finding matching proteins and bonding them to the other half of the stepladder. Basically, a nanomachine can be thought of as an artificial enzyme.

    That's true, but there's also one teeny little problem, which is the very different behavior of biological vs. engineered systems. Biology is a lot like that spaghetti code many of us wrote when we started out.

    To use your example: DNA replication. It is true that one enzyme unzips the DNA and that there's another (polymerase) which brings in nucleotides that glom on. However, it is a very common event (it's happened to you a couple times while you're reading this) that a copy error is made --- a base gets left out, or the wrong one gets added. This isn't a machine --- it can't perfectly repeat the steps every time. So, there are other enzymes which check the DNA, try to detect mutations, and then try to fix them or delete the strand. If the bad copy gets expressed into protein, there are other enzymes which check the protein and send it off for destruction if it's bad. If the bad protein still makes it into cellular function, your immune system can try to recognize the cell as defective and kill it. If none of that works... time to call your primary care provider.

    Your body is making millions of errors at the molecular level every second. It's just that those errors get lost in the huge stream of stuff that manages to work out correctly. There's no machine I know of that works anything like a biological system; some of Rodney Brooks' subsumptionist architectures come close, but no human can build something of the same complexity as the machinery which makes even a single cell pathway work. There are things we can still learn from the biological model, but I'd be very surprised if we ended up doing nanotech using the same architecture. I'd be similarly surprised if we ended up doing AI by making a neural net that simulated the brain. IMHO, we need electronics and nanoengineering to do those things which a biological system can't do well --- the rest can be left up to the wetware.

    Alik
    (Currently reviewing lipids for the next biochem exam...)

  • Have you or your professors read Nanosystems? The purpose of that book was to explain some of these questions. Drexler gets very specific about how to possibly achieve highly reactional chemistry in a controlled manner. And remember, Nanosystems was written many years ago, its not the current state of the art. But its the first, and only, book that attempts to deal with the actual practicalities of nanotechnology instead of just saying "some day we will be able to..." it says "here is how we might be able to achieve this.." Drexler and Merkle spent a lot of time researching the hows of possible nanotechnology.
  • by Chris Worth (18843) on Tuesday November 02, 1999 @09:18AM (#1569985) Homepage
    Hey BearPaw - yup, you almost hit the nail on the head: I wrote the review to get some facts into the debate. But it's principally to appeal to regular geeks who might be interested - after all, a lot of geeks have done the same for me. (See The Microsoft Matrix [chrisworth.com])
  • So called "futurists" like Caral Sagan and other scifi/philosophers have said that we should have moon bases established and be to mars and back by now. I don't see any of that happening.

    The thing is... those should have happened by now. If the spending that had gone into the cold war and defense had, say, gone into the space program instead, we'd probably already have a big space station in orbit, have a small base on the moon, and have a ship with people en-route to Mars.

    The technology is there, and has been for a while. It's the social issues that have kept it from happening, and those are much more unstable and unpredictable.

    They predict nanotech will be here in 20-30 years. And if it's not here then, I bet it's not the science and technology that's not up to it, but the social issues that influence it that have kept it from occuring.
    ---

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