Dr. Dobb's Journal March 2000
Ayear ago in this space, I briefly summarized the history of nanotechnology and reported on recent progress in the field. Since then, there have been a number of even more interesting developments. It may be, in fact, that we have seen in the past year the long-sought breakthrough that tips nanotechnology over the edge from a fascinating long shot to the most-promising technological research program of the present age. So this month, I take a look at some of the more significant nanotechnology developments of the past year.
I think it's also worth taking a closer look than I did last year at the historic founding documents of the field. The field of nanotechnology was defined and its challenges were laid down by two individuals. Their contributions were different, but nanotechnology research might still be merely a fantastic idea without them, and recent nanotech developments are best evaluated in terms of the detailed and far-seeing research program laid out by Richard Feynman and K. Eric Drexler in two historic documents.
I'd also like, right here at the beginning, to slip in a word about science fiction. Again.
Last year, I cited some science fiction writing that probed the implications of nanotechnology for humanity. This is what the best science fiction has always done: Ask the human questions raised by scientific and technological advances. Science fiction is not, science fiction writers are themselves quick to point out, about prediction. Not really. Curiously, I think that science fiction writers may be getting better at predicting the future, but not through any efforts on their part. Increasingly, I suspect, today's scientists and engineers (and software developers?) grew up on science fiction and/or read it today, and I think that their thinking about science and technology is shaped in part by the science fiction they read. Thus, the future they create may be influenced by the fiction they've read.
If so, I think that's a good thing. It's hard to imagine the impact of a new scientific discovery or technological invention without playing out fictional scenarios. "Hard" science fiction writers are often well trained in the sciences and feel professionally obligated to stay current with the latest developments. They are, I'd say, ideally equipped and motivated to explore the consequences of scientific and technological advances. And somebody's gotta think this stuff through. Neal Stephenson's Cryptonomicon (science fiction) and In the Beginning Was the Command Line (nonfiction) are new on the book shelves now, but his The Diamond Age was published in 1995 and is available in paperback. It describes a future after a nanotech revolution; if you haven't read it, you might take a look.
It is also, of course, fiction. Than which, 'tis often said, reality is stranger...
"Nanotechnology" refers to technology based on the manipulation of individual atoms and molecules to build structures to complex, atomic specifications.
The hope of nanotech is not merely that technologies can be developed to manipulate atoms precisely to build tiny, useless artifacts, but rather that mechanisms can be developed that generate vast amounts of nanostuff. Only if nanomanufacturing becomes a reality is this nano business of any practical use. But how? Tiny factories? Hybrid biomechanical systems that use biological reproductive mechanisms to produce armies of nano-cyborgs? A hierarchy of tinier and tinier lathes, each cranking out multiple smaller reproductions of itself, resulting in billions of nanoscale tools awaiting our instructions? How to get from here to there is not entirely clear.
The problems are staggering. At nanoscale, different laws apply. Quantum effects become more important than gravity. There are no smooth surfaces. Really, there are no surfaces.
But the possibilities are even more staggering:
I leave you to imagine what could be accomplished in computer technology if we could build computing devices at nanoscale.
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.
So said legendary physicist and Nobel laureate Richard Feynman on December 29, 1959, speaking at the annual meeting of the American Physical Society at Caltech. The "this direction" of which he spoke was down -- down to the world of the atom. "What would happen," Feynman asked, "if we could arrange the atoms one by one the way we want them?" His speech, entitled "There's Plenty of Room at the Bottom," (http://www.zyvex.com/ nanotech/feynman.html) was the first serious description of what would become the field of nanotechnology.
In the speech, Feynman laid out the challenges and the possibilities. How could we possibly build things at a scale where quantum effects are more important than gravity? He had some ideas. And what would be the implications for humanity? He had some ideas about that, too.
One example of his vision: Feynman saw that building things at this scale is essentially the same as writing. In casting about for a precise enough pen, he thought of the idea of turning a microscope from a reading tool into a writing tool. He was 20 years ahead of microscope technology, but he was right on target: A little over a year ago, a nanopen was invented, designed practically to Feynman's specs. Perhaps what most fired the imaginations of those who heard Feynman or read the published version of the speech, though, was the tantalizing realizability of the vision he sketched. "The principles of physics," he said, "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."
Others took up the challenge.
The field was an obscure one then, the clients tended to be large research institutions, and practical applications seemed far away.
-- Neal Stephenson, The Diamond Age.
One of those inspired by Feynman's challenge was K. Eric Drexler. Feynman may have laid down the challenge, but it was Drexler who articulated the program. (In The Diamond Age, Stephenson honors Feynman and Drexler by painting them into a Michelangelo-like ceiling painting in Merkle Hall, named after nanotechnologist Ralph Merkle, the third member of the nanotech pantheon.)
Eric Drexler published the first scientific paper on nanotechnology in 1981. He received the first doctorate in the field, from MIT, in 1991. He taught the first courses in nanotechnology, at Stanford. He started the Foresight Institute (http:// www.foresight.org/) and the Institute for Molecular Manufacturing to promote and explore nanotechnology. He has written seminal books and papers on nanotechnology, starting with Engines of Creation (http://www.foresight.org/EOC/).
In Engines, Drexler lays out the program and, with characteristic thoroughness, explores the ways in which nanotechnology could improve man's lot and the ways in which it could really screw things up. Drexler is no less ambitious than Feynman. The necessary tool for nanotechnology to take off is what Drexler calls an assembler: "the greatest production tool in history, a truly general fabrication system able to make anything that can be designed."
The book makes it clear that useful nanotechnology depends on automation. Building individual artifacts on the scale of one billionth of a meter is of no practical use; whatever we build at that scale, we'll need a lot of them to make them even noticeable. Feynman pointed out that nature has some nice tools and techniques for producing many copies of something from a single blueprint, and Drexler describes how molecular factories might use biological mechanisms to pump out a product. He sketches a program for the nanofactory: replicators churning out new assemblers at an exponential rate, the assemblers processing raw material and churning out a finished product in volumes greater than any assembly line in existence today.
An obvious area of application of nanotechnology is to make very tiny computers. Drexler spends little time in this book on the technological challenges of nanocomputing, which are significant. Instead, he more or less takes it for granted that nanoelectronics can take us farther in the direction of artificial intelligence, and considers some implications of that. (The book probably shows its age in this section more than in others.)
On the "wet" side of nanotechnology, Drexler anticipates drug design, cell repair machines, effective cryonics, and a cure for aging. So far, nanoscience has only chipped away at the drug design possibility, but it appears that some of the most useful developments in the near term will be coming from the wet side -- from biological applications of nanotechnology -- with "dry" side advances in nanoelectronics and the manufacture of new materials proceeding somewhat more slowly.
Drexler also spends a surprising amount of space in Engines talking about what most might consider peripheral or even irrelevant issues -- space travel and the structure of communication. Well, Drexler is a lumper. Botanists characterize their colleagues as either lumpers or splitters; those who see the connections or those who see distinctions. Truly inspired lumpers can seem pretty crazy, seeing connections everywhere, writing meticulously argued massive tomes with details that can't be understood until you understand them in their totality (like Joe Firmage with his essays on everything, or like Ted Nelson, with whom Drexler once worked on the Xanadu project and who captured the lumper's manifesto as "everything is deeply intertwingled").
But don't get me wrong: Drexler is to be taken very seriously. His writing and his work with the Foresight Institute have inspired a generation of nanopioneers. This past year, that inspiration seems to have paid off especially well.
I am not afraid to consider the final question as to whether, ultimately...we can arrange the atoms the way we want; the very atoms, all the way down!
-- Richard Feynman, "There's Plenty of Room at the Bottom."
So what has been accomplished?
First, nanotechnology researchers have answered Feynman's final question: We can indeed place atoms where we want them, building molecules atom by atom. We've done it.
But what may prove to be the breakthrough technology for nanotechnology operates at the level of a few molecules (still definitively nanoscale). A little over a year ago, researchers at Northwestern University built a nanopen, capable of drawing a line a few nanometers wide with a single type of molecule (http:// www.sciencedaily.com/releases/1999/ 10/991015075640.htm). Last October, they announced that they had turned to nanopen into a nanoplotter. This device can draw multiple 15-nanometer-wide lines of molecules with only five nanometers separation. They liken it to four-color printing, but rather than producing arbitrary patterns of colors, they produce arbitrary materials. The underlying technology is the scanning tunneling microscope (STM), invented back in the 1980s. The STM reads electric current from the surfaces of conductors to construct images of atoms. A derivative tool, the atomic force microscope (AFM), responds to fluctuations in other forces, like mechanical or electrostatic forces, to map the atomic-scale topography of a surface.
What's intriguing about the nanoplotter is that the AFM, at its heart, is a relatively inexpensive device in common use in university and corporate laboratories, and it works under normal atmospheric conditions. And the nanoplotter is basically an AFM modified to write instead of read.
Up to this point, the news out of nanotech labs had been in the nature of technology demos. Writing "IBM" on the head of a pin. The nanoplotter is something else -- a practical tool that can be automated and used to crank out nanostructures in bulk. "This technology should become a real workhorse for the nanotechnologist," one of its inventors said. "It will soon be possible to pattern one master plate with thousands of different organic nanostructures, each structure designed to react with a certain disease agent, for example."
The same trick of turning an AFM into a writing instrument can place not just molecules but individual atoms, making it possible to build new molecules like laying bricks. IBM researchers have done just that, constructing a molecule consisting of 18 cesium and 18 iodine atoms. If the obvious next step is to bring bulk manufacturing methods like the nanoplotter down to this atomic level where IBM has begun the first crude hand-assembly work, that is the step that will turn science fiction into reality and will answer Feynman's 1959 challenge.
...he had paid to have a bunch of 'sites implanted in his muscles -- little critters, too small to see or feel, that twitched Bud's muscle fibers electrically according to a program that was supposed to maximize bulk. Combined with the testosterone pump embedded in his forearm, it was like working out in a gym night and day, except you didn't have to actually do anything and you never got sweaty.
-- Neal Stephenson, The Diamond Age.
Matter will become software...[w]e'll be able to use the Internet to download not just software but hardware, too.
-- James C. Ellenbogen, Mitre Corp.
A full report on the advances of the past year would have to talk about nanotubes -- stretched-out buckyballs that show great potential as materials for molecular manufacturing and that can probably be manufactured in bulk -- and the whole wet side of nanotechnology. But then I wouldn't have space to report on advances in nanoelectronics. Maybe next month.
...rapidly cascading advances in molecular-scale science may soon constitute what economists refer to as a disruptive technology -- one that changes basic industrial assumptions, just as the transistor did...
-- John Markoff, New York Times (http://www.nytimes.com/library/tech/99/11/biztech/articles/01nano.html).
Nanoelectronics, too, made important advances in 1999. In July, HP and UCLA researchers announced that they had fabricated rudimentary logic gates the size of a single molecule. Within months, Yale and Rice University researchers had improved on the rudimentary gates, and HP researchers figured out how to create conductive wires a few atoms wide. Other researchers, working in secrecy, are rumored to be closing in on the construction of a practical nanoscale memory device. Some in the field are predicting that, in two to five years, we will begin to see practical nanoelectronics that drop the minimum feature size to a level two orders of magnitude lower than the current theoretical limit of about 0.10 microns.
If that happens, it could lead to as large a technological and social disruption as the invention of the transistor or the integrated circuit. Nanocomputing will require entirely new approaches to computer architecture and software development, it will make possible applications that are today beyond the reach of the most powerful computers, and it will do interesting things to Intel's stock price. A $15 billion fab that produces components on the micron scale will have a hard time competing with nanoscale production that can be done as cheaply as producing photographic film.
But don't sell your Intel stock on my say-so; this is all just guesswork. There are still fundamental problems to be solved before nanotechnology becomes a practical reality. Nobody really knows yet how to produce nanoscale products in bulk. Nobody has broken ground on a nanotech factory. If the nanotech revolution is a mountain-climbing expedition, we're still hiking up through the foothills to the base camp.
But for the first time in the history of this outrageous trek, it seems clear that we are actually on the way.
DDJ