杏吧原创

Tiny terrors

Nano-robots have been striking fear into royalty and governments. Robert L. Park wonders what all the fuss is about

IS NANO-PHOBIA infectious? It certainly seems to be spreading. In Britain, Prince Charles gave it a helping hand by speaking out about his fears over nanotechnology earlier this year. Last month, green campaigners and others met in Brussels for the world鈥檚 first summit on the dangers of nanotechnology. The British government is so worried about nano-phobia it has asked the Royal Society to look into the issue. How seriously should we be taking it?

The laboratory techniques that gave birth to the nanotechnology revolution were hardly terrifying. Twenty years ago, at an IBM laboratory in Zurich, two scientists built the first scanning tunnelling microscope (STM), which made it possible to 鈥渟ee鈥 individual atoms by scanning a tiny probe over the surface of a silicon crystal. It was hard to believe that such a simple concept could produce an image in atomic detail. Labs all over the world were soon building their own STMs, and the inventors were awarded a Nobel prize.

Then, in 1990, another team of IBM scientists, this time in California, found they could use an STM to drag individual atoms of xenon over the surface of a crystal of nickel. Tediously, they spelled 鈥淚BM鈥 in block letters using 35 atoms of xenon. At that scale, it would be possible to write the entire Encyclopaedia Britannica on the head of a pin.

There you have it. The two essentials of nanotechnology: the ability to 鈥渟ee鈥 on the scale of individual atoms, and the ability to manipulate individual atoms or molecules. This is exciting stuff, but every good story has to have a dark side.

The dark side of nanotechnology is 鈥済rey goo鈥 鈥 the nightmare possibility that 鈥渘ano-robots鈥 could be programmed to gobble up their surroundings and turn everything on Earth into more nano-robots. There are other fears such as nanoscale particles creating unforeseen toxic hazards, but it鈥檚 the nano-machine scenario that gets most people going. Prince Charles worries a lot about grey goo, when he can spare the time from worrying about genetically modified food.

One problem for some critics is that these nano-bots, because they would be self-replicating, would qualify as a new form of life. The thought of creating life 鈥渋n a test tube鈥 is blasphemy to many religious believers, who insist that life is more than just chemistry and that to be alive inanimate matter must be imbued with a vital life force. It is also never an easy idea to sell to the public.

A certain K. Eric Drexler says he also worries about grey goo, but he doesn鈥檛 want the technology banned. He thinks the benefits outweigh the risks. Drexler is chairman of the Foresight Institute, a non-profit organisation dedicated to preparing the world for the coming nanotechnology revolution. Part engineer, part cult figure, Drexler is a futurist. He preaches the 鈥渢here are no limits, get ready for utopia鈥 gospel. In Drexler鈥檚 utopia nano-robots, or 鈥渁ssemblers鈥 as he calls them, will do all the work: making television sets or beefsteak by stacking molecules together like bricks. Other assemblers will be swept along in our bloodstream, destroying pathogens and repairing damage. Antibodies and enzymes already do these kinds of things, but I guess assemblers would do them better. We would become almost immortal. Now there鈥檚 an idea that will sell.

Drexler says he invented the word 鈥渘anotechnology鈥, and perhaps he did, but he doesn鈥檛 seem to have invented much of anything else. He is more of a 鈥渃oncept鈥 guy, drumming up support in Congress and getting quoted in the press.

Are self-replicating assemblers feasible? Richard Smalley, a chemist at Rice University in Houston, Texas, who was awarded a Nobel prize for his work in nanotechnology, doesn鈥檛 think so. Smalley co-discovered the three-dimensional nanoscale carbon cages called fullerenes, which have a whole host of potential uses. He dismisses the idea of nanometre-scale robots as 鈥渁 futurist鈥檚 daydream鈥. Not for want of a divine spark, but because the chemistry doesn鈥檛 add up. 鈥淪elf-replicating, mechanical nano-robots,鈥 Smalley says, 鈥渁re simply not possible in our world.鈥 In the US, nanotechnology is the highest priority in the science and technology budget, and is the subject of major nanotechnology programmes in five government agencies. But none of them has anything to do with nano-robots or assemblers.

Of course, we are already surrounded by legions of self-replicating assemblers. We call them bacteria, and they are enormously successful. As Stephen J. Gould liked to say, 鈥淭his is not the age of man. It is, as it has always been, the age of bacteria.鈥 Yet the simplest bacteria are already enormously complex, with DNA carrying instructions for reproduction and metabolism. Evolutionists aren鈥檛 sure how nature did it, and we can鈥檛 repeat the experiment. Nature had the luxury of time 鈥 billions of years of it. We mortals must show progress before our research grant runs out. Sleep well Charles.

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