Build Small, Think Big

Nanotech is the ability to build complicated shapes and/or machines with every atom in its specified place. Chemists and biologists create molecules with every atom precisely placed--but the molecules we can build today are a tiny fraction of those that are possible. Engineers build incredibly complicated and useful machines--but even the most intricate is chock-full of wasted space. We have had several "revolutions" in technology--industrial, agricultural, medical, and computer--within the last two centuries. But each of these has only given us a small fraction of the capabilities we could have. Nanotech will let us finish the job, by being much more precise in our design and fabrication of machines and by using better materials.

Let's take a look at tiny gizmos. Start by taking apart a mechanical clock--clocks are full of small parts. Set a small metal gear on the floor, and start shrinking yourself. Shrink until you're the same size as the gear, about 200 times smaller than life-size. Hold up your hand and compare it to a tooth of the gear. They're about the same size--but the gear tooth is mostly featureless, while your hand has fingers, fingernails, muscles, blood vessels, and other working parts.

You shrink again, to a tenth of your already small size. Now you are one millimeter high. You can easily see microscopic roughness on the surface of the gear, but it is random and pointless; the clock would work better if its pieces were smooth. You spot something that looks like a grain of sand: a bacterium crawling across the gear's surface. Only 1/10,000 the size of the gear it's crawling on, it is a fully functional and highly intricate machine: it contains chemical factories, a navigation system, a self-repair mechanism, and a data storage and retrieval system. Bored with the gear, you shrink again, to get a better look at the bacterium; after shrinking another thousand times, you're the same size as the single-celled wonder.

You are now about 100 times shorter than the width of a human hair. At this scale, you can see blobs inside the bacterium. Some of them are ribosomes, which manufacture protein. Some are holding tanks for chemicals. There's one blob anchoring a thrashing tail as thick as your wrist and longer than you are tall. This is the flagellum, which the bacterium uses to swim, and the blob is the motor that turns it. It's about as wide as your hand--and remember, you're shrunk by a factor of two million. You glance at the random metal crystals of the gear, and then shrink again to get a closer look at the motor. After shrinking another twenty times, the motor is as big as you are--and the atoms in the motor are still only the size of your fingernail. The whole thing is wiggling like a nest of water balloons because of thermal noise, but it still manages to process 300,000 hydrogen ions every second as an energy source. The gear, meanwhile, has become merely a featureless smear of metal atoms extending as far as you can see--from an engineering point of view, almost all of the volume of the gear is wasted space.

What if we could build machines as small and precise as the flagellar motor, with every atom carefully placed? Such machines would be about a million times as small as they are today. Take a moment to imagine that. Picture a six-story building, with each room filled floor to ceiling with machinery. A chemistry lab; a computer center; lathes and drill presses; storage bins and holding tanks; vats and furnaces; anything else you can fit in. Now imagine more buildings next to the first. Fill them up with machinery too. Put them all the way out to the horizon, from sea to shining sea. Cover an area the size of the United States with machinery six stories high! Now shrink it one million times. You'd be able to hold the whole thing in your hand--all that complexity can fit into something about the size of a plastic dropcloth. A thousand engineers working a thousand years couldn't begin to fill the available space. There are limits to the amount of complexity we'll be able to cram in, but for most applications we won't need to worry about it.

Size isn't the only advantage of nanotech. The structure of biological organisms is mostly made up of long linear molecules, wadded into tiny lumps and stuck together with static cling. Just as diamond is stronger than wood, the machines we build can use materials that biology has never been able to work with. In fact, many researchers think that 3D forms of carbon, such as diamond or "buckytubes", will make ideal building materials for nanomachines. These materials are about fifty times as strong as the best steel. When things are stronger, they can be more efficient; as marvelous as the flagellar motor is, an electrostatic motor made of diamond should be able to produce ten million times the power in the same volume!