Get your own Free Home PageToward an Understanding of Nano-Technology written in E-Prime Text by Swinton Roof CONTENTS 1) CONTEXT I- Discussion of spatial scale , pg.4 2) CONTEXT II- Causality, pg.6 3) CONTEXT III- Temporal scale, pg.8 4) Goals of Nano-Technology, pg.10 5) Nano-Tools and Devices 6) Current Advances 7) Warning INTRODUCTION pg3. Technology can be defined as the means whereby a society produces the various 'goods' it uses. Most of us have some familiarity with micro-technology and its breathtaking changes in our world. Nano-technology in comparison promises a truly awesome next step for mankind. This paper attempts to convey some idea of what this new technology might mean. Nano-technology proposes an engineering based upon molecular machinery capable of self-replication and controlled by either molecular or electronic information systems. In other words, a technology of minute, invisible machines programmable by humans and capable of independant action and reproduction. Eric Drexler calls nano-machines, "Engines of Creation" in his excellent book by that name. No one seemed prepared to accept the unbelievable meteoric storm of the computer-age, but I feel that nano-technology promises to truly come like "a thief in the night"!
CONTEXT I - Spatial Scale pg.4
For an initial context, consider the principle of scale.
Micro-technology concerns itself with fabrications at the scale
of microns.
A 'micron' represents one millionth of a meter.
A 'nanon' represents one billionth of a meter.
Hence nano-technology goes three orders of magnitude smaller than
micro-technology. Most of us have some familiarity with the now
ubiquitous devices produced by micro-technology, but can we really
visualize the actual size of components at the heart of these devices?
Perhaps a power-of-ten tour of familiar small things will help.
The diameter of a human hair or pollen grain covers about four
thousandths of an inch or 100 microns. An average small cell extends only
about 10 microns. The lowly bacteria breaks in at one micron. Ten bacteria
end-to-end can measure a cell. Ten cells end-to-end can measure a hair.
Three or four hundred bacteria can encircle a hair. Thirty thousand bacteria
can probably sit comfortably around a grain of pollen.
The micro-chip in the computer I used to type this paper has
millions of micro-elements. The limits of micro-technology in its present
form hover at sizes somewhat smaller than one micron. A bacteria could tour
this micro-chip like a bus in a large city and find many objects comparable
in scale to its own. I find that 'bacteria size' makes a convenient reference
point for things on the scale of microns.
Now take a deep breath and imagine a world of still smaller things.
The bacteria above measures in at 1 micron or 1000 nanos. The tiny but
news-worthy virus tops in at about one-tenth of a bacteria or 100 nanos.
Just as the 100 micron hair made a starting point for our initial downward
plunge, let the virus represent the jumping off place into the next smaller
realm. Viruses, by the way, exist at the very limits of what optical
technology can see. A single photon of visible light would probably wash
over a virus like an 'energizing wave at the beach'. We have now entered
the conceptual realm of the invisible. The reader should take the metaphors I
employ as conceptual scaling tools only. I point out, however, that these
quasi-realities have undeniably real effects in our macro-sized world.
To continue, a 100 nano long virus has a 'gut' made of DNA type
material coiled round about like one would expect. A strand of DNA or
other large molecule has a scale of about 10 nanos. Finally, the smaller
constituents of large molecules measure in at 1 nano. Small molecules,
like the ones you learn about in chemistry, compose the stuff of nano
dreams! At last we have reached the nano-level.
Recapping, we have 10 nanos to a DNA rung and 10 DNA rungs to a virus;
10 viruses to a bacteria, 10 bacteria to a cell, and 10 cells to a hair.
At the shop where I work we commonly use the term 'a hair' to represent
the smallest increment one can see with the eye.
"It's a hair off, George", an eye-slave might say.
Little would he know, but that 'that hair' might hide 10 billion nano-ites,
each one vying for its day in the sun.
reference: "From Quark to Quasar- Notes on the scale of the Universe"
by Peter H. Cadogan
Cambridge University Press, 1985
CONTEXT II- Causality pg.6 This section focuses on how events occur on the nano scale. The previous context helped us tune our scaleable conceptuality to the proper level of spatial dimension. Now we shall consider causality. In my conversations about nano-technology with people, I have encountered remarks like "I just dont see how they can squeeze all that plasic and metal into such a small space". This entirely misses the point. Man's technology throughout history up to the present has involved fabrication of devices whose smallest elements involve myriads upon myriads of molecules. The overall behavior of such devices results from a statisical averaging of the behavior of these myriads of atoms and molecules. Even a micron-sized electronic switch might contain a billion atoms. Nano-technology, in contrast, concerns itself directly with these building-blocks-of-matter. Nano-technology does not attempt to compress objects into smaller spaces, nor does it attempt to shave objects and whittle them down into miniature versions of themselves. Nano-technology intends to directly manipulate atoms and molecules. Nano-technology, once in place, composes structures from the bottom up. I talk here not of extending our current technology into smaller realms. Nothing less than a totally new paradigm can encompass the scope of nano-technology. One must first convince oneself that atoms and molecules have orderly and useful behavior. Knowledge of chemistry and physics gives overwhelming testimony to this fact. The problem with current techniques lies in their gross manipulation of behavior. Mix a zillion molecules of 'A' and a zillion of 'B' and you get 'C'. Our knowledge, however, tells us that a one-to-one reaction between individual molecules or atoms forms the basis for this gross-level process. The chemist merely has to bring the proper elements into close proximity and a statistical number of reactions or combinations occur. If one holds an atom of carbon next to a molecule of oxygen, carbon dioxide results. The elements concerned carry all the information necessary to carry out a structural commposition. This structurally-encoded-information determines what will combine with what. So long as we provide sufficient energy or force and the correct spatial orientation, a successful synthesis occurs. Of course one must use elements whose structural-encoding allows them to combine. Present-day chemistry provides the connection rules. Molecular systems have connection rules similar to tinker-toys. The process just happens! With appropriately designed levers and grippers a person could perform the reaction directly himself. So much for causality! Nano-technolgy probably will not proceed with hand-held levers. I offered the remark merely to illustrate the simplicity of causality at this level. I talk here of the level of molecular points of contact. Large molecules of course can have increbible complexity of behavior. pg.7 To recap, this dicussion of causality focused on the points at which the elements or parts of a nano-device might be structurally attached or removed. Current efforts to model molecular-dynamics ( see reference 1. ) use very simple assumptions. Most modelers base their descriptions primarily on newtonian dynamics of charged bodies in electrostatic fields. The structurally-encoded-combination-rules must be known also. McCammon and Wolynes have concluded that quantum effects have a minimal impact on the overall dynamics of such systems. I believe this means we ultimately can operate at this level of physical reality in a causally oriented way. Machines and devices can be constructed molecule by molecule to do mechanical types of things. As the current level research suggests, no known laws prevent development of nano-technology. reference: 1. "Molecular Dynamics and the Modelers' Art" by Anne Simon Moffat per. MOSIAC Volume 22 Number 4 Winter 1991
CONTEXT III- Temporal Scale pg.8 Current research on molecular movements ( ref. 1. ) focuses on fleeting motions which may last a pico-second or less over distances of 1/10 of 1 nano-meter. 1 pico-second = 10 ^ -12 second = one thousandth of one nano-second Large molecular systems exhibit behavioral changes which occur in micro-seconds, and complex biological-scale reactions might last milli-seconds. (1/1000 sec) Lets compare these times with those of current micro-processor- technology. Chips in the computer market today have clock speeds up to 50 megacycles or so. The simplest change or micro-instruction thus takes about 20 nano-seconds or 20,000 pico-seconds. If a nano-device has a part capable of moving in 10 pico-seconds, a useable action might occur in say 10 to 100 pico-seconds. One might thus imagine a nano-device capable of operating 200 to 1000 times as fast as current micro-processors. Now prepare yourself for a real surprise. If we assume that we have created a nano-machine capable of replicating itself, how long will it take for large scale results to occur? Assume a device the size of a bacteria, say one cubic micron ( 10^-18 cubic meter in volume ). Assume replication occurs every 5 minutes. In 5 minutes, we may achieve over 10 billion actions at the rate of 100 pico-seconds each. This roughly corresponds to a computer program giga-bytes long. Sounds plausible to me, even if a little shaky in logic. Anyway, assume the device manages to clone itself in 5 minutes. After 60 replicative doublings, we have 2^60 devices or approximately 10^18 units. Now 10^18 units at 10^-18 cubic meters each, yields 1 solid cubic meter of nano-stuff. This all takes place in only 5X60 = 300 minutes or 5 hours. The next few hours give enough time to cover the surface of the planet. The reader may of course have objections, but exponential doubling means extraordinary growth rates no matter how you slice it. One may add to this picture by realizing that these units must have encoded-instruction- processors, so one might have in effect a barrel-full of nano-processors all churning away in parallel with each one doing its specialty on cue at any particular point in the replication chain. If feeling a little threatened now, turn to the WARNING at the end of this paper. Goals of Nano-Technology pg.9 As stated previously, nano-technology aims to create molecular-based devices capable of self-replication and programmability. One can imagine artificial-intelligence capability also. If the devices remain in our control, we can no doubt expect marvels in the bio-medical industry. A plethora of possibilities exist for the imagination. I point out that, in a sense, nano-machines flourish everywhere life does. The 'chemistry' of life presents no inherent problems to nano-devices. Nano-machines exhibit one major difference from living creatures, however. Life evolved, while nano-ites arise, if at all, from intelligent human design and craft. We as humans must decide what goals to strive for. Nano-technology provides the leverage to move worlds.
Projections: Global information storage and retrieval Super-intelligent global mind machine Totally automated food & resource industries Deformable voice-activated convience objects Cures for all ills of the body Relative immortality Transmigration of Mind Travel to the stars Nested Virtual reality An anwser to the question "Why ask why?" Tools and Devices pg.10 Man fashions material objects in three basic ways: by machining, deformation, and fabrication. He uses his mind, hands, and senses as primary or first-order tools. With this basic assembledge, he creates second-order tools.These second-order tools consist of grippers, cutting-wedges, impact-hammers, belts, gears, pulleys, platforms etc. Second-order tools primarily originate from machined or shaved objects although deformation provides more capable versions. Third-order devices make their appearance as fabrications of second-order parts into machines with multi-functionality. Fourth-order devices come into service as engines or motors which continue in motion as long as resources are available. Fifth-order devices (computers) encode information and control other devices. Sixth-order devices (robots or assemblers or knowbots) have self-programmability. Seventh-order devices replicate. Replicators make use of all lower-order devices. Replicators evolve. Nano-technology potentially may make use of all lower-order tools to arrive at self-replicating assemblers. A first generation replicator might consist of these parts: information tape and store tape decoder or reader central processor or control unit motive engine drive linkages conveyor system assembler unit parts and tools rack raw materials bins input and output ports manipulators and sensors Fashioning all of the above parts requires much ingenuity, but please recall that a group of students once made a working computer from tinker-toys. Information plus material equals creativity. Imagine a nano-machine as large as a bacteria again. We might expect it to have about 10^12 or 1000 billion atoms. If individual working elements consist of about 100 atoms, we count about 10 billion functioning parts. This allows approximately 1,000,000 parts per functional-system division of a replicator as listed above. I think the Space Shuttle sounds rather simple in comparison. If the reader thinks 100 atoms is too few to make something out of, read the next section on current advances. reference: "Engines of Creation" by Eric Drexler, 1987? WARNING Physical reality, as we know it now, has little meaning once nano-machines take over. Objects in space-time can have no essential nature if composed of multi-programmable-replicating- universal-information-bearing-Turing-machines! Reality will probably collapse like a 'house of cards' with lot of nightmares on the way down. The funny thing IS, though, I think IT'S always BEEN that way.
"Nanotechnology is the blanket term used to describe the precision manufacture of materials and structures of molecular dimensions. Many of the goals of nanotechnology were expressed nearly 40 years ago by th renowned physicist Richard P. Feynman. Molecular-scale robots currently exist only in the imaginations of nanotechnologists and the artists who depict their ideas. But some technological visionaries, led by K. Eric Drexler, think that the dream will soon become a reality that will transform everything from health care to food production. (Drexler's ideas are outlined in his book Engines of Creation)." Scientific American on nantechnology
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