Thursday, January 31, 2008

Small is Beautiful Nanotechnology

Nanotechnology is the science of construction on scales of a billionth of a metre. It involves making things using beams, girders, pumps and wheels just one millionth of a millimetre long. Microelectromechanical machines with parts a thousandth of a millimetre across are now made by the million, and sold for use as sensors in such things as airbags, computer joysticks and inkjet printers - being so small makes them extraordinarily sensitive to movement. But compared to what's coming, this is crude. The future could be 1,000 times smaller and 1,000 times more unpredictable.

In 1959 the Nobel prize winner Richard Feynman proposed, almost jokingly, that there was "plenty of room at the bottom"; that things could be made very small, an atom at a time. K Eric Drexler, in a 1986 classic called Engines of Creation, mapped out the possibilities of a nanotechnological world describing self-replicating machines the size of molecules that could do whatever you want.

Realists point out that some of these things already exist anyway: the manufactured ones are called drugs and the self-replicating ones are called immune cells. But the implications of nonotechnology go further: little nanosubmarines that would roam around your body repairing tissues and preventing heart disease, or computers in your ballpoint pen that will blink when the ink gets low. The possibilities, like the tools themselves, are endless

Colin Humphreys, professor of materials science at Cambridge University, argues that one of the most interesting things about small lumps of matter is that their properties change dramatically as the samples shrink. "Silicon is a good example. Bulk silicon doesn't emit light. But if you make silicon very small, it emits light. It's a fundamental change in its properties that occurs when you get to 2-3 nanometers," he says.

Explanations for such phenomena lie in the realm of quantum physics, where matter in bulk can have hard, toe-stubbing solidity while the same substance on the atomic scale can seem so much empty space and random possibilities. Now physicists are creating semiconductor wafers only molecules thick to build what they call "quantum wells" and "quantum dots" for ever smaller, faster computers. Other potential payoffs light-emitting diodes so efficient and so durable that they could one day cut electric lighting costs by 80%, while nonotechnology will also have huge benefits in the area of keyhole surgery.

Douglas Philp, of Birmingham university, believes in looking at what nature does, and learning from it. He argues that replicating the way molecules work in life could be used to make things perfectly - no polluted reactions, no untidy catalysts, no faulty molecules. "The ultimate nanotechnologist is, in fact, life itself. We could spend hours discussing why life is very good at doing certain things on the nanometer scale," he says. "What we are saying is: okay, let's try and learn how nature does it, and apply that."

"You can apply the same Darwinian principles in chemistry that you can apply in biology," Philp says. "You could imagine a coffee cup that got better at keeping the coffee warm, because you are challenging it when you put the coffee in. As long as you have some selection criteria, the system will actually evolve."

What it will evolve into nobody knows: computers that will assemble themselves from buckets of goo as soon as you download the software; superweapons; the end of world hunger; the colonisation of the asteroids; extended lifetimes - anything you want. But Philp sounds a note of caution. "My personal view is that we are not, in the next 20 years, going to be carrying computers the size of cigarette lighters. There are some market issues here as well. How is it an advantage to have a computer that small? I don't know. My computer is quite small enough as it is. How fast is a computer? I mostly use mine to type papers."

Source: The Guardian

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