Imagine this kitchen scene, circa 2047: it’s time to make dinner. But the fridge and oven are now obsolete. Instead, you go to a device resembling a microwave oven–we’ll call it the Assembl-o-Tron. It has tubes running out the back that feed into a public plumbing system run by the DRM, the city’s Department of Raw Materials. There’s a keypad programmed with the family favorites. You hit F3 for sirloin, fries and a salad. The Assembl-o-Tron sucks at the DRM line for a dime’s worth of elemental gunk. Then, billions of microscopic robot assemblers pull and tug at the individual atoms the DRM has provided: carbon, nitrogen, hydrogen and oxygen, maybe a few metals. In seconds, the assemblers have rearranged the elements precisely to yield the proteins and carbohydrates and whatever else makes up a good sirloin 50 years from now. Captain Kirk, it’s chow time! After dinner, the garbage and fine china can be dumped back into the ‘Tron for “disassembly.” As long as the DRM isn’t offline, cooking and cleanup are forever consigned to antiquity. Now, that’s progress.
This is the future world of nanotechnology, the study of the really, really teeny-tiny–there are a billion nanometers in a meter. That infinitesimal scale is where the real action of the universe is. It’s where atoms dance with other atoms to form molecules of everything, from wood to Kevlar to Pop-Tarts. “When you start thinking what you can do if you could really position atoms wherever you dream of them, it looks like a wonderful future,” says Rick Smalley, a chemist and the director of Rice University’s Center for Nanoscale Science and Technology. It is today’s science fiction–almost all theory still, but just close enough to plausibility to beguile physicists and chemists, biologists and engineers.
Playing games in the nanoworld holds the Promethean promise of giving society any material it wants at virtually no cost–500-story skyscrapers made from diamond rather than steel, fabulously powerful microprocessors, spaceships that have the strength of titanium but the weight of plastic, paint that changes color, “smart” fog that hovers invisibly in our homes, materializing into furniture or a bathrobe when we say so. Armadas of medical robots will patrol the bloodstream, killing cancers and viruses or scraping out arterial blockages. In this future, we’ll all die only of boredom.
Even today, the nascent science of the itty-bitty is taking form. The technology of MEMS–micro-electro-mechanical systems–already exists and has practical applications. These Lilliputian sensors, motors, gears and other micromachines–from coffee cup to speck-of-sand in size–can recognize light and sound and motion. Working in concert with microchips, MEMS can “think” and then take action. That’s what a whisker-size sensor in an airbag does. Or a blood-pressure kit and carbon-monoxide detector for use at home. These very basic sensing devices are part of a $2 billion industry that some experts predict will be worth more than $100 billion by 2010. “Microprocessors defined the 1980s and cheap lasers allowed the telecommunications revolution of the ’90s,” says Paul Saffo, an analyst with the Institute for the Future in Menlo Park, Calif. “MEMS and sensors generally will shape the first decade of the next century.”
As spectacular as these kinds of gadgets may be, though, it is the far smaller realm of nanotechnology that may ultimately change the lives of our children. MEMS will tie together the digital and analog world, allowing computers to interact with inanimate objects–houses, say, could be programmed to adjust their energy requirements to the needs of their inhabitants and those of the neighbors. Nanotech lets us in on creation itself: if we have the constituent molecules, we can do anything.
The idea for nanotechnology started with Richard Feynman, the legendary physicist. In late 1959, Feynman gave a speech at Cal-tech called “There’s Plenty of Room at the Bottom.” Near the end of his talk, Feynman posed the ultimate challenge of matter. “I am not afraid to consider the final question. . .can (we) arrange atoms the way we want, all the way down.” What in the laws of physics said otherwise?
Feynman’s idea lay largely dormant until 1981, when a 26-year-old MIT grad student named K. Eric Drexler published a paper in the Proceedings of the National Academy of Sciences titled “Molecular Engineering: An Approach to the Development of General Capabilities for Molecular Manipulation.” In it, Drexler argued that DNA and nature’s own synthesis of protein provided a kind of “existence proof”–it must work because it does–that human beings should be able to assemble molecules. The trick, he realized, was devising the tiny machinery necessary to snap together the atomic Legos. These “nanobots” would be the workers in nanoscale construction zones. Build them so they can reproduce themselves, and when you make one you’ve got a trillion, thereby facilitating unimaginable feats of engineering–Genesis, by any other name.
DREXLER CONTINUES TO WRITE PAPERS. BUT the gospel of nanotechnology is now preached by his wife, Chris Peterson, who runs the Foresight Institute they set up as a nanotech clearinghouse. “If molecular machines already exist naturally, like the ones inside a cell,” Peterson says, “it’s not an unreasonable goal to set ourselves to build similar systems.” But how do you build a nanobot?
Nanoists like to cite work already done on atomic structures. In 1989, for example, scientists using a scanning probe microscope were able to arrange 35 xenon atoms on a nickel surface to form the letters of their employer, IBM. Scanning probe microscopy (SPM) involves dragging a tiny tip across the surface of an object; the point is sharp enough to “feel” individual atoms, its motion sensed by computer right down to the angstrom (one tenth of a nanometer). It’s a tricky business, since the tip breaks easily. With some finesse, SPM can be used for harder tasks. In 1996, another team of IBM physicists in Zurich built a nanoscale abacus, with each “bead” consisting of a carbon molecule.
Not just any carbon molecule, but a “buckyball”–60 carbon atoms arranged in the shape of a soccer ball, with the same structure as the geodesic dome popularized by Buckminster Fuller. Buckyballs were discovered in 1985 and now represent the most important component of nano design. Strung together, they become “buckytubes” or “carbon nanotubes.” They’re being called the “ultimate fiber”–hollow cylinders of carbon that weigh a fraction of steel but have 100 times the strength. Buckytubes are roughly 10 nanometers wide and have amazing traits: they’re virtually unbreakable, they’re good conductors of electricity and they’re almost inert chemically. All that suggests that someday buckytubes may be the “nanofingers” used to control teenyweeny devices; their conductivity also means they may become molecular wires, leading to a new generation of computers. “You can see how we’re beginning to dream bold dreams,” says Smalley, who won the Nobel Prize for codiscovering buckyballs.
Even so, buckytubes represent a far cry from the self-replicating assemblers necessary in Drexlerland. The fact remains that it’s all theoretical: nobody’s close to making one. “I am deeply concerned that a universal assembler is flat-out impossible,” says Smalley, who of all people appreciates the magnificence of scientific discovery. No one knew about buckyballs or buckytubes until he came along. No, nanotech may lie forever beyond the grasp of scientists who would usurp nature. But that wouldn’t be all bad. Do we really want a world where any Joe with a bale of hay and a bucket of water can make a great steak?
