From 5329fbf89e70270cc37c322f33984c5356b3c270 Mon Sep 17 00:00:00 2001 From: aiju Date: Mon, 15 Jun 2015 16:27:27 +0200 Subject: [PATCH] there's plenty of room in /lib --- lib/plentyofroom | 668 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 668 insertions(+) create mode 100644 lib/plentyofroom diff --git a/lib/plentyofroom b/lib/plentyofroom new file mode 100644 index 000000000..08ec10dda --- /dev/null +++ b/lib/plentyofroom @@ -0,0 +1,668 @@ +There's Plenty of Room at the Bottom + +An Invitation to Enter a New Field of Physics + +by Richard P. Feynman + +This transcript of the classic talk that Richard Feynman gave on December +29th 1959 at the annual meeting of the American Physical Society at +the California Institute of Technology (Caltech) was first published in +Caltech Engineering and Science, Volume 23:5, February 1960, pp 22-36. + +__________________________________________________________________ + +I imagine experimental physicists must often look with envy at men like +Kamerlingh Onnes, who discovered a field like low temperature, which +seems to be bottomless and in which one can go down and down. Such a +man is then a leader and has some temporary monopoly in a scientific +adventure. Percy Bridgman, in designing a way to obtain higher pressures, +opened up another new field and was able to move into it and to lead +us all along. The development of ever higher vacuum was a continuing +development of the same kind. + +I would like to describe a field, in which little has been done, but in +which an enormous amount can be done in principle. This field is not quite +the same as the others in that it will not tell us much of fundamental +physics (in the sense of, "What are the strange particles?") but it is +more like solid-state physics in the sense that it might tell us much +of great interest about the strange phenomena that occur in complex +situations. Furthermore, a point that is most important is that it would +have an enormous number of technical applications. + +What I want to talk about is the problem of manipulating and controlling +things on a small scale. + +As soon as I mention this, people tell me about miniaturization, and how +far it has progressed today. They tell me about electric motors that are +the size of the nail on your small finger. And there is a device on the +market, they tell me, by which you can write the Lord's Prayer on the +head of a pin. But that's nothing; that's the most primitive, halting +step in the direction I intend to discuss. It is a staggeringly small +world that is below. In the year 2000, when they look back at this age, +they will wonder why it was not until the year 1960 that anybody began +seriously to move in this direction. + +Why cannot we write the entire 24 volumes of the Encyclopaedia Brittanica +on the head of a pin? + +Let's see what would be involved. The head of a pin is a sixteenth of an +inch across. If you magnify it by 25,000 diameters, the area of the head +of the pin is then equal to the area of all the pages of the Encyclopaedia +Brittanica. Therefore, all it is necessary to do is to reduce in size all +the writing in the Encyclopaedia by 25,000 times. Is that possible? The +resolving power of the eye is about 1/120 of an inch – that is roughly +the diameter of one of the little dots on the fine half-tone reproductions +in the Encyclopaedia. This, when you demagnify it by 25,000 times, +is still 80 angstroms in diameter – 32 atoms across, in an ordinary +metal. In other words, one of those dots still would contain in its area +1,000 atoms. So, each dot can easily be adjusted in size as required by +the photoengraving, and there is no question that there is enough room +on the head of a pin to put all of the Encyclopaedia Brittanica. + +Furthermore, it can be read if it is so written. Let's imagine that +it is written in raised letters of metal; that is, where the black is +in the Encyclopedia, we have raised letters of metal that are actually +1/25,000 of their ordinary size. How would we read it? + +If we had something written in such a way, we could read it using +techniques in common use today. (They will undoubtedly find a better way +when we do actually have it written, but to make my point conservatively +I shall just take techniques we know today.) We would press the metal +into a plastic material and make a mold of it, then peel the plastic off +very carefully, evaporate silica into the plastic to get a very thin film, +then shadow it by evaporating gold at an angle against the silica so that +all the little letters will appear clearly, dissolve the plastic away from +the silica film, and then look through it with an electron microscope! + +There is no question that if the thing were reduced by 25,000 times in +the form of raised letters on the pin, it would be easy for us to read +it today. Furthermore, there is no question that we would find it easy +to make copies of the master; we would just need to press the same metal +plate again into plastic and we would have another copy. + +How do we write small? + +The next question is: How do we write it? We have no standard technique +to do this now. But let me argue that it is not as difficult as it first +appears to be. We can reverse the lenses of the electron microscope in +order to demagnify as well as magnify. A source of ions, sent through the +microscope lenses in reverse, could be focused to a very small spot. We +could write with that spot like we write in a TV cathode ray oscilloscope, +by going across in lines, and having an adjustment which determines the +amount of material which is going to be deposited as we scan in lines. + +This method might be very slow because of space charge limitations. +There will be more rapid methods. We could first make, perhaps by +some photo process, a screen which has holes in it in the form of the +letters. Then we would strike an arc behind the holes and draw metallic +ions through the holes; then we could again use our system of lenses and +make a small image in the form of ions, which would deposit the metal +on the pin. + +A simpler way might be this (though I am not sure it would work): +We take light and, through an optical microscope running backwards, +we focus it onto a very small photoelectric screen. Then electrons +come away from the screen where the light is shining. These electrons +are focused down in size by the electron microscope lenses to impinge +directly upon the surface of the metal. Will such a beam etch away the +metal if it is run long enough? I don't know. If it doesn't work for a +metal surface, it must be possible to find some surface with which to +coat the original pin so that, where the electrons bombard, a change is +made which we could recognize later. + +There is no intensity problem in these devices not what you are used +to in magnification, where you have to take a few electrons and spread +them over a bigger and bigger screen; it is just the opposite. The light +which we get from a page is concentrated onto a very small area so it +is very intense. The few electrons which come from the photoelectric +screen are demagnified down to a very tiny area so that, again, they +are very intense. I don't know why this hasn't been done yet! + +That's the Encyclopaedia Brittanica on the head of a pin, but let's +consider all the books in the world. The Library of Congress has +approximately 9 million volumes; the British Museum Library has 5 million +volumes; there are also 5 million volumes in the National Library in +France. Undoubtedly there are duplications, so let us say that there +are some 24 million volumes of interest in the world. + +What would happen if I print all this down at the scale we have been +discussing? How much space would it take? It would take, of course, the +area of about a million pinheads because, instead of there being just +the 24 volumes of the Encyclopaedia, there are 24 million volumes. The +million pinheads can be put in a square of a thousand pins on a side, or +an area of about 3 square yards. That is to say, the silica replica with +the paper-thin backing of plastic, with which we have made the copies, +with all this information, is on an area of approximately the size of 35 +pages of the Encyclopaedia. That is about half as many pages as there are +in this magazine. All of the information which all of mankind has ever +recorded in books can be carried around in a pamphlet in your hand – +and not written in code, but as a simple reproduction of the original +pictures, engravings, and everything else on a small scale without loss +of resolution. + +What would our librarian at Caltech say, as she runs all over from one +building to another, if I tell her that, ten years from now, all of the +information that she is struggling to keep track of – 120,000 volumes, +stacked from the floor to the ceiling, drawers full of cards, storage +rooms full of the older books – can be kept on just one library card! +When the University of Brazil, for example, finds that their library is +burned, we can send them a copy of every book in our library by striking +off a copy from the master plate in a few hours and mailing it in an +envelope no bigger or heavier than any other ordinary air mail letter. + +Now, the name of this talk is "There is Plenty of Room at the Bottom" +– not just "There is Room at the Bottom." What I have demonstrated +is that there is room – that you can decrease the size of things in a +practical way. I now want to show that there is plenty of room. I will +not now discuss how we are going to do it, but only what is possible +in principle – in other words, what is possible according to the laws +of physics. I am not inventing anti-gravity, which is possible someday +only if the laws are not what we think. I am telling you what could be +done if the laws are what we think; we are not doing it simply because +we haven't yet gotten around to it. + +Information on a small scale + +Suppose that, instead of trying to reproduce the pictures and all the +information directly in its present form, we write only the information +content in a code of dots and dashes, or something like that, to represent +the various letters. Each letter represents six or seven "bits" of +information; that is, you need only about six or seven dots or dashes +for each letter. Now, instead of writing everything, as I did before, +on the surface of the head of a pin, I am going to use the interior of +the material as well. + +Let us represent a dot by a small spot of one metal, the next dash by an +adjacent spot of another metal, and so on. Suppose, to be conservative, +that a bit of information is going to require a little cube of atoms 5 +x 5 x 5 – that is 125 atoms. Perhaps we need a hundred and some odd +atoms to make sure that the information is not lost through diffusion, +or through some other process. + +I have estimated how many letters there are in the Encyclopaedia, +and I have assumed that each of my 24 million books is as big as an +Encyclopaedia volume, and have calculated, then, how many bits of +information there are (10^15). For each bit I allow 100 atoms. And it +turns out that all of the information that man has carefully accumulated +in all the books in the world can be written in this form in a cube +of material one two-hundredth of an inch wide – which is the barest +piece of dust that can be made out by the human eye. So there is plenty +of room at the bottom! Don't tell me about microfilm! + +This fact – that enormous amounts of information can be carried in an +exceedingly small space – is, of course, well known to the biologists, +and resolves the mystery which existed before we understood all this +clearly, of how it could be that, in the tiniest cell, all of the +information for the organization of a complex creature such as ourselves +can be stored. All this information – whether we have brown eyes, +or whether we think at all, or that in the embryo the jawbone should +first develop with a little hole in the side so that later a nerve can +grow through it – all this information is contained in a very tiny +fraction of the cell in the form of long-chain DNA molecules in which +approximately 50 atoms are used for one bit of information about the cell. + +Better electron microscopes + +If I have written in a code, with 5 x 5 x 5 atoms to a bit, the question +is: How could I read it today? The electron microscope is not quite good +enough, with the greatest care and effort, it can only resolve about 10 +angstroms. I would like to try and impress upon you while I am talking +about all of these things on a small scale, the importance of improving +the electron microscope by a hundred times. It is not impossible; it is +not against the laws of diffraction of the electron. The wave length of +the electron in such a microscope is only 1/20 of an angstrom. So it +should be possible to see the individual atoms. What good would it be +to see individual atoms distinctly? + +We have friends in other fields – in biology, for instance. We +physicists often look at them and say, "You know the reason you fellows +are making so little progress?" (Actually I don't know any field where +they are making more rapid progress than they are in biology today.) +"You should use more mathematics, like we do." They could answer us – +but they're polite, so I'll answer for them: "What you should do in order +for us to make more rapid progress is to make the electron microscope +100 times better." + +What are the most central and fundamental problems of biology today? +They are questions like: What is the sequence of bases in the DNA? What +happens when you have a mutation? How is the base order in the DNA +connected to the order of amino acids in the protein? What is the +structure of the RNA; is it single-chain or double-chain, and how is it +related in its order of bases to the DNA? What is the organization of +the microsomes? How are proteins synthesized? Where does the RNA go? +How does it sit? Where do the proteins sit? Where do the amino acids +go in? In photosynthesis, where is the chlorophyll; how is it arranged; +where are the carotenoids involved in this thing? What is the system of +the conversion of light into chemical energy? + +It is very easy to answer many of these fundamental biological questions; +you just look at the thing! You will see the order of bases in the +chain; you will see the structure of the microsome. Unfortunately, the +present microscope sees at a scale which is just a bit too crude. Make +the microscope one hundred times more powerful, and many problems of +biology would be made very much easier. I exaggerate, of course, but +the biologists would surely be very thankful to you – and they would +prefer that to the criticism that they should use more mathematics. + +The theory of chemical processes today is based on theoretical physics. +In this sense, physics supplies the foundation of chemistry. But +chemistry also has analysis. If you have a strange substance and you +want to know what it is, you go through a long and complicated process +of chemical analysis. You can analyze almost anything today, so I am a +little late with my idea. But if the physicists wanted to, they could +also dig under the chemists in the problem of chemical analysis. It would +be very easy to make an analysis of any complicated chemical substance; +all one would have to do would be to look at it and see where the atoms +are. The only trouble is that the electron microscope is one hundred times +too poor. (Later, I would like to ask the question: Can the physicists do +something about the third problem of chemistry – namely, synthesis? Is +there a physical way to synthesize any chemical substance? + +The reason the electron microscope is so poor is that the f- value of the +lenses is only 1 part to 1,000; you don't have a big enough numerical +aperture. And I know that there are theorems which prove that it is +impossible, with axially symmetrical stationary field lenses, to produce +an f-value any bigger than so and so; and therefore the resolving power +at the present time is at its theoretical maximum. But in every theorem +there are assumptions. Why must the field be axially symmetrical? Why must +the field be stationary? Can't we have pulsed electron beams in fields +moving up along with the electrons? Must the field be symmetrical? I put +this out as a challenge: Is there no way to make the electron microscope +more powerful? + +The marvelous biological system + +The biological example of writing information on a small scale has +inspired me to think of something that should be possible. Biology is not +simply writing information; it is doing something about it. A biological +system can be exceedingly small. Many of the cells are very tiny, but they +are very active; they manufacture various substances; they walk around; +they wiggle; and they do all kinds of marvelous things – all on a very +small scale. Also, they store information. Consider the possibility that +we too can make a thing very small which does what we want – that we +can manufacture an object that maneuvers at that level! + +There may even be an economic point to this business of making things very +small. Let me remind you of some of the problems of computing machines. In +computers we have to store an enormous amount of information. The kind +of writing that I was mentioning before, in which I had everything down +as a distribution of metal, is permanent. Much more interesting to a +computer is a way of writing, erasing, and writing something else. (This +is usually because we don't want to waste the material on which we have +just written. Yet if we could write it in a very small space, it wouldn't +make any difference; it could just be thrown away after it was read. It +doesn't cost very much for the material). + +Miniaturizing the computer + +I don't know how to do this on a small scale in a practical way, but I do +know that computing machines are very large; they fill rooms. Why can't +we make them very small, make them of little wires, little elements – +and by little, I mean little. For instance, the wires should be 10 or 100 +atoms in diameter, and the circuits should be a few thousand angstroms +across. Everybody who has analyzed the logical theory of computers has +come to the conclusion that the possibilities of computers are very +interesting – if they could be made to be more complicated by several +orders of magnitude. If they had millions of times as many elements, +they could make judgments. They would have time to calculate what is +the best way to make the calculation that they are about to make. They +could select the method of analysis which, from their experience, is +better than the one that we would give to them. And in many other ways, +they would have new qualitative features. + +If I look at your face I immediately recognize that I have seen it +before. (Actually, my friends will say I have chosen an unfortunate +example here for the subject of this illustration. At least I recognize +that it is a man and not an apple.) Yet there is no machine which, +with that speed, can take a picture of a face and say even that it is +a man; and much less that it is the same man that you showed it before +– unless it is exactly the same picture. If the face is changed; if +I am closer to the face; if I am further from the face; if the light +changes – I recognize it anyway. Now, this little computer I carry +in my head is easily able to do that. The computers that we build are +not able to do that. The number of elements in this bone box of mine +are enormously greater than the number of elements in our "wonderful" +computers. But our mechanical computers are too big; the elements in +this box are microscopic. I want to make some that are sub-microscopic. + +If we wanted to make a computer that had all these marvelous extra +qualitative abilities, we would have to make it, perhaps, the size of +the Pentagon. This has several disadvantages. First, it requires too +much material; there may not be enough germanium in the world for all +the transistors which would have to be put into this enormous thing. +There is also the problem of heat generation and power consumption; TVA +would be needed to run the computer. But an even more practical difficulty +is that the computer would be limited to a certain speed. Because of its +large size, there is finite time required to get the information from one +place to another. The information cannot go any faster than the speed of +light – so, ultimately, when our computers get faster and faster and +more and more elaborate, we will have to make them smaller and smaller. + +But there is plenty of room to make them smaller. There is nothing that +I can see in the physical laws that says the computer elements cannot +be made enormously smaller than they are now. In fact, there may be +certain advantages. + +Miniaturization by evaporation + +How can we make such a device? What kind of manufacturing processes +would we use? One possibility we might consider, since we have talked +about writing by putting atoms down in a certain arrangement, would +be to evaporate the material, then evaporate the insulator next to it. +Then, for the next layer, evaporate another position of a wire, another +insulator, and so on. So, you simply evaporate until you have a block +of stuff which has the elements – coils and condensers, transistors +and so on – of exceedingly fine dimensions. + +But I would like to discuss, just for amusement, that there are other +possibilities. Why can't we manufacture these small computers somewhat +like we manufacture the big ones? Why can't we drill holes, cut things, +solder things, stamp things out, mold different shapes all at an +infinitesimal level? What are the limitations as to how small a thing +has to be before you can no longer mold it? How many times when you are +working on something frustratingly tiny like your wife's wrist watch, +have you said to yourself, "If I could only train an ant to do this!" +What I would like to suggest is the possibility of training an ant to +train a mite to do this. What are the possibilities of small but movable +machines? They may or may not be useful, but they surely would be fun +to make. + +Consider any machine – for example, an automobile – and ask about +the problems of making an infinitesimal machine like it. Suppose, in the +particular design of the automobile, we need a certain precision of the +parts; we need an accuracy, let's suppose, of 4/10,000 of an inch. If +things are more inaccurate than that in the shape of the cylinder and +so on, it isn't going to work very well. If I make the thing too small, +I have to worry about the size of the atoms; I can't make a circle out of +"balls" so to speak, if the circle is too small. So, if I make the error, +corresponding to 4/10,000 of an inch, correspond to an error of 10 atoms, +it turns out that I can reduce the dimensions of an automobile 4,000 +times, approximately – so that it is 1 mm. across. Obviously, if you +redesign the car so that it would work with a much larger tolerance, +which is not at all impossible, then you could make a much smaller device. + +It is interesting to consider what the problems are in such small +machines. Firstly, with parts stressed to the same degree, the forces go +as the area you are reducing, so that things like weight and inertia are +of relatively no importance. The strength of material, in other words, +is very much greater in proportion. The stresses and expansion of the +flywheel from centrifugal force, for example, would be the same proportion +only if the rotational speed is increased in the same proportion as +we decrease the size. On the other hand, the metals that we use have a +grain structure, and this would be very annoying at small scale because +the material is not homogeneous. Plastics and glass and things of this +amorphous nature are very much more homogeneous, and so we would have +to make our machines out of such materials. + +There are problems associated with the electrical part of the system – +with the copper wires and the magnetic parts. The magnetic properties +on a very small scale are not the same as on a large scale; there is the +"domain" problem involved. A big magnet made of millions of domains can +only be made on a small scale with one domain. The electrical equipment +won't simply be scaled down; it has to be redesigned. But I can see no +reason why it can't be redesigned to work again. + +Problems of lubrication + +Lubrication involves some interesting points. The effective viscosity of +oil would be higher and higher in proportion as we went down (and if we +increase the speed as much as we can). If we don't increase the speed so +much, and change from oil to kerosene or some other fluid, the problem is +not so bad. But actually we may not have to lubricate at all! We have a +lot of extra force. Let the bearings run dry; they won't run hot because +the heat escapes away from such a small device very, very rapidly. + +This rapid heat loss would prevent the gasoline from exploding, so an +internal combustion engine is impossible. Other chemical reactions, +liberating energy when cold, can be used. Probably an external supply +of electrical power would be most convenient for such small machines. + +What would be the utility of such machines? Who knows? Of course, a small +automobile would only be useful for the mites to drive around in, and I +suppose our Christian interests don't go that far. However, we did note +the possibility of the manufacture of small elements for computers in +completely automatic factories, containing lathes and other machine tools +at the very small level. The small lathe would not have to be exactly like +our big lathe. I leave to your imagination the improvement of the design +to take full advantage of the properties of things on a small scale, and +in such a way that the fully automatic aspect would be easiest to manage. + +A friend of mine (Albert R. Hibbs) suggests a very interesting possibility +for relatively small machines. He says that, although it is a very +wild idea, it would be interesting in surgery if you could swallow the +surgeon. You put the mechanical surgeon inside the blood vessel and it +goes into the heart and "looks" around. (Of course the information has +to be fed out.) It finds out which valve is the faulty one and takes a +little knife and slices it out. Other small machines might be permanently +incorporated in the body to assist some inadequately-functioning organ. + +Now comes the interesting question: How do we make such a tiny +mechanism? I leave that to you. However, let me suggest one weird +possibility. You know, in the atomic energy plants they have materials +and machines that they can't handle directly because they have become +radioactive. To unscrew nuts and put on bolts and so on, they have a set +of master and slave hands, so that by operating a set of levers here, +you control the "hands" there, and can turn them this way and that so +you can handle things quite nicely. + +Most of these devices are actually made rather simply, in that there is +a particular cable, like a marionette string, that goes directly from +the controls to the "hands." But, of course, things also have been made +using servo motors, so that the connection between the one thing and the +other is electrical rather than mechanical. When you turn the levers, +they turn a servo motor, and it changes the electrical currents in the +wires, which repositions a motor at the other end. + +Now, I want to build much the same device – a master-slave system +which operates electrically. But I want the slaves to be made especially +carefully by modern large-scale machinists so that they are one-fourth +the scale of the "hands" that you ordinarily maneuver. So you have +a scheme by which you can do things at one- quarter scale anyway – +the little servo motors with little hands play with little nuts and +bolts; they drill little holes; they are four times smaller. Aha! So +I manufacture a quarter-size lathe; I manufacture quarter-size tools; +and I make, at the one-quarter scale, still another set of hands again +relatively one-quarter size! This is one-sixteenth size, from my point of +view. And after I finish doing this I wire directly from my large-scale +system, through transformers perhaps, to the one-sixteenth-size servo +motors. Thus I can now manipulate the one-sixteenth size hands. + +Well, you get the principle from there on. It is rather a difficult +program, but it is a possibility. You might say that one can go much +farther in one step than from one to four. Of course, this has all to be +designed very carefully and it is not necessary simply to make it like +hands. If you thought of it very carefully, you could probably arrive +at a much better system for doing such things. + +If you work through a pantograph, even today, you can get much more +than a factor of four in even one step. But you can't work directly +through a pantograph which makes a smaller pantograph which then makes +a smaller pantograph – because of the looseness of the holes and the +irregularities of construction. The end of the pantograph wiggles with +a relatively greater irregularity than the irregularity with which you +move your hands. In going down this scale, I would find the end of the +pantograph on the end of the pantograph on the end of the pantograph +shaking so badly that it wasn't doing anything sensible at all. + +At each stage, it is necessary to improve the precision of the +apparatus. If, for instance, having made a small lathe with a pantograph, +we find its lead screw irregular – more irregular than the large-scale +one – we could lap the lead screw against breakable nuts that you +can reverse in the usual way back and forth until this lead screw is, +at its scale, as accurate as our original lead screws, at our scale. + +We can make flats by rubbing unflat surfaces in triplicates together +– in three pairs – and the flats then become flatter than the thing +you started with. Thus, it is not impossible to improve precision on +a small scale by the correct operations. So, when we build this stuff, +it is necessary at each step to improve the accuracy of the equipment +by working for awhile down there, making accurate lead screws, Johansen +blocks, and all the other materials which we use in accurate machine +work at the higher level. We have to stop at each level and manufacture +all the stuff to go to the next level – a very long and very difficult +program. Perhaps you can figure a better way than that to get down to +small scale more rapidly. + +Yet, after all this, you have just got one little baby lathe four +thousand times smaller than usual. But we were thinking of making an +enormous computer, which we were going to build by drilling holes on +this lathe to make little washers for the computer. How many washers +can you manufacture on this one lathe? + +A hundred tiny hands + +When I make my first set of slave "hands" at one-fourth scale, I am +going to make ten sets. I make ten sets of "hands," and I wire them to +my original levers so they each do exactly the same thing at the same +time in parallel. Now, when I am making my new devices one-quarter again +as small, I let each one manufacture ten copies, so that I would have +a hundred "hands" at the 1/16th size. + +Where am I going to put the million lathes that I am going to have? Why, +there is nothing to it; the volume is much less than that of even one +full-scale lathe. For instance, if I made a billion little lathes, each +1/4000 of the scale of a regular lathe, there are plenty of materials +and space available because in the billion little ones there is less +than 2 percent of the materials in one big lathe. + +It doesn't cost anything for materials, you see. So I want to build a +billion tiny factories, models of each other, which are manufacturing +simultaneously, drilling holes, stamping parts, and so on. + +As we go down in size, there are a number of interesting problems that +arise. All things do not simply scale down in proportion. There is the +problem that materials stick together by the molecular (Van der Waals) +attractions. It would be like this: After you have made a part and +you unscrew the nut from a bolt, it isn't going to fall down because +the gravity isn't appreciable; it would even be hard to get it off the +bolt. It would be like those old movies of a man with his hands full of +molasses, trying to get rid of a glass of water. There will be several +problems of this nature that we will have to be ready to design for. + +Rearranging the atoms + +But I am not afraid to consider the final question as to whether, +ultimately – in the great future – we can arrange the atoms the +way we want; the very atoms, all the way down! What would happen if we +could arrange the atoms one by one the way we want them (within reason, +of course; you can't put them so that they are chemically unstable, +for example). + +Up to now, we have been content to dig in the ground to find minerals. +We heat them and we do things on a large scale with them, and we hope +to get a pure substance with just so much impurity, and so on. But we +must always accept some atomic arrangement that nature gives us. We +haven't got anything, say, with a "checkerboard" arrangement, with the +impurity atoms exactly arranged 1,000 angstroms apart, or in some other +particular pattern. + +What could we do with layered structures with just the right layers? +What would the properties of materials be if we could really arrange the +atoms the way we want them? They would be very interesting to investigate +theoretically. I can't see exactly what would happen, but I can hardly +doubt that when we have some control of the arrangement of things on a +small scale we will get an enormously greater range of possible properties +that substances can have, and of different things that we can do. + +Consider, for example, a piece of material in which we make little +coils and condensers (or their solid state analogs) 1,000 or 10,000 +angstroms in a circuit, one right next to the other, over a large area, +with little antennas sticking out at the other end – a whole series +of circuits. Is it possible, for example, to emit light from a whole +set of antennas, like we emit radio waves from an organized set of +antennas to beam the radio programs to Europe? The same thing would be +to beam the light out in a definite direction with very high intensity. +(Perhaps such a beam is not very useful technically or economically.) + +I have thought about some of the problems of building electric circuits +on a small scale, and the problem of resistance is serious. If you build +a corresponding circuit on a small scale, its natural frequency goes up, +since the wave length goes down as the scale; but the skin depth only +decreases with the square root of the scale ratio, and so resistive +problems are of increasing difficulty. Possibly we can beat resistance +through the use of superconductivity if the frequency is not too high, +or by other tricks. + +Atoms in a small world + +When we get to the very, very small world – say circuits of seven +atoms – we have a lot of new things that would happen that represent +completely new opportunities for design. Atoms on a small scale behave +like nothing on a large scale, for they satisfy the laws of quantum +mechanics. So, as we go down and fiddle around with the atoms down +there, we are working with different laws, and we can expect to do +different things. We can manufacture in different ways. We can use, not +just circuits, but some system involving the quantized energy levels, +or the interactions of quantized spins, etc. + +Another thing we will notice is that, if we go down far enough, all of our +devices can be mass produced so that they are absolutely perfect copies +of one another. We cannot build two large machines so that the dimensions +are exactly the same. But if your machine is only 100 atoms high, you +only have to get it correct to one-half of one percent to make sure the +other machine is exactly the same size – namely, 100 atoms high! + +At the atomic level, we have new kinds of forces and new kinds of +possibilities, new kinds of effects. The problems of manufacture and +reproduction of materials will be quite different. I am, as I said, +inspired by the biological phenomena in which chemical forces are used +in a repetitious fashion to produce all kinds of weird effects (one of +which is the author). + +The principles of physics, as far as I can see, do not speak against the +possibility of maneuvering things atom by atom. It is not an attempt +to violate any laws; it is something, in principle, that can be done; +but in practice, it has not been done because we are too big. + +Ultimately, we can do chemical synthesis. A chemist comes to us and says, +"Look, I want a molecule that has the atoms arranged thus and so; make +me that molecule." The chemist does a mysterious thing when he wants to +make a molecule. He sees that it has got that ring, so he mixes this +and that, and he shakes it, and he fiddles around. And, at the end of +a difficult process, he usually does succeed in synthesizing what he +wants. By the time I get my devices working, so that we can do it by +physics, he will have figured out how to synthesize absolutely anything, +so that this will really be useless. + +But it is interesting that it would be, in principle, possible (I think) +for a physicist to synthesize any chemical substance that the chemist +writes down. Give the orders and the physicist synthesizes it. How? Put +the atoms down where the chemist says, and so you make the substance. The +problems of chemistry and biology can be greatly helped if our ability to +see what we are doing, and to do things on an atomic level, is ultimately +developed – a development which I think cannot be avoided. + +Now, you might say, "Who should do this and why should they do it?" +Well, I pointed out a few of the economic applications, but I know that +the reason that you would do it might be just for fun. But have some +fun! Let's have a competition between laboratories. Let one laboratory +make a tiny motor which it sends to another lab which sends it back with +a thing that fits inside the shaft of the first motor. + +High school competition + +Just for the fun of it, and in order to get kids interested in this field, +I would propose that someone who has some contact with the high schools +think of making some kind of high school competition. After all, we +haven't even started in this field, and even the kids can write smaller +than has ever been written before. They could have competition in high +schools. The Los Angeles high school could send a pin to the Venice +high school on which it says, "How's this?" They get the pin back, +and in the dot of the 'i' it says, "Not so hot." + +Perhaps this doesn't excite you to do it, and only economics will do +so. Then I want to do something; but I can't do it at the present moment, +because I haven't prepared the ground. It is my intention to offer a +prize of $1,000 to the first guy who can take the information on the +page of a book and put it on an area 1/25,000 smaller in linear scale +in such manner that it can be read by an electron microscope. + +And I want to offer another prize – if I can figure out how to phrase +it so that I don't get into a mess of arguments about definitions – of +another $1,000 to the first guy who makes an operating electric motor – +a rotating electric motor which can be controlled from the outside and, +not counting the lead-in wires, is only 1/64 inch cube. + +I do not expect that such prizes will have to wait very long for +claimants. +