The small world of nanotechnology

Robert L. Park, Professor of Physics, University of Maryland, Project Syndicate

Imagine looking through a powerful microscope and discovering incredibly tiny machines taking apart the stuff around them, molecule by molecule, and reassembling the molecules to make exact replicas of themselves. The replicas, of course, will do the same thing. After 20 generations, each machine will have become more than a million. Can they be stopped, or will they take over the world?

This is not some futuristic science-fiction story about technology run amok. This is the world we live in today, where such machines are just about everywhere. Countless millions of them inhabit the gut of every human being. We call them bacteria, and they took over the world billions of years before we humans showed up. We treat them with respect, or they kill us.

Evolutionists aren't sure about the progenitors of bacteria, and we can't repeat nature's experiment. Nature, after all, had the luxury of time, billions of years of it, whereas we mortals must demonstrate progress before our research grants run out. In any case, the simplest bacteria are marvelously complex, with strands of DNA carrying complete instructions for metabolism and reproduction.

Nevertheless, some biologists believe that they are on the verge of creating a microbe in the laboratory. Long chains of DNA can now be manufactured to order, and scientists are identifying which genes are essential. If a new microbe is created in the lab, it will be because scientists have learned how to follow nature's recipe.

But what if, instead of trying to mimic nature, a new kind of life could be invented from scratch?

What if this life were closer to the sort of mechanical devices humans know how to build, but on a very small scale.

How small? At a 1959 meeting of the American Physical Society, Richard Feynman, perhaps the most admired physicist of our time, gave a talk entitled, There's Plenty of Room at the Bottom. On the scale of atomic dimensions, Feynman pointed out, all 24 volumes of the Encyclopedia Britannica could fit on the head of a pin. He challenged his colleagues to develop the capability to manipulate and control things on that scale.

Thirty years later, scientists at an IBM laboratory in California arranged 35 atoms of xenon on the surface of a nickel crystal, to spell "IBM" in block letters. This was accomplished with a Scanning Tunneling Microscope (STM), a device developed at an IBM laboratory in Zurich whose inventors were awarded the 1986 Nobel Prize in physics.

It was hailed as the start of the nano revolution -- the advent of technology on a scale a thousand times smaller than the world of microelectronics. At this point, however, "revolution" might seem to be an exaggeration. The IBM scientists had proven that it is possible to manipulate individual atoms, but doing so still had no practical use.

Then, in 1996, Richard Smalley of Rice University was awarded a Nobel Prize in chemistry for the discovery of fullerenes, beautiful nanometer-scale carbon structures with remarkable properties and many potential applications. There are still no nano-scale products on the market, but governments around the world are betting huge research budgets on the power of nanotechnology to transform the world as profoundly as the microelectronics revolution.

Indeed, a 1986 book by a futurist named K. Eric Drexler, Engines of Creation: The Coming Era of Nanotechnology, argues that the way to manipulate things with atomic precision is with nano-scale machines. Drexler is the Chairman of the Foresight Institute, which is dedicated to preparing the world for the nanotechnology revolution. He sees a world in which incredibly tiny self-replicating robots, which he calls "assemblers," will do all the work, guiding chemical reactions by positioning reactive molecules with atomic precision. Supplied with raw materials, assemblers could be programmed to build whatever we need, including more assemblers.

But is there a darker side to nano? As Richard Smalley asks, what's to stop self-replicating nano-robots from continuing to munch and replicate "until everything on earth becomes an undifferentiated mass of grey goo?" This worries enough people, including Prince Charles in the UK, that there have been calls for banning further research into nanotechnology. But to do so would be a serious mistake.

In the first place, grey goo is a purely imaginary danger. There are no assemblers, and nobody really knows how to build one. And if there were assemblers, they would face the same limitation as the bacteria with which we started our story: They can't travel long distances without hitching a ride, and would simply run out of raw material.

Moreover, assemblers aren't the only way to manipulate things on an atomic scale. None of the current government-funded research is going into assemblers. The scientists who invented the STM weren't trying to build assemblers, and they never heard of K. Eric Drexler. They were just trying to understand basic surface physics. Getting to the future, it seems, does not require the help of futurists.

The writer is director of the Washington Office of the American Physical Society.