Researchers have been able to tailor semi-conductors one atom at a time.

I read Michael Crichton's "Swarm", should we get our anti-nano fly swatters out?

DOWN, DOWN, DOWN, BACK, BACK, BACK!!!

I read Michael Crichton's "Swarm". should we get out our anti-nano fly swatters?

DOWN, DOWN, DOWN, BACK, BACK, BACK!!!

(a tip of the hat to Daffy Duck)

Shouldn't that be Dodge Parry Spin Thrust?

OT: DID has an article up on DARPA funding research into vortex rocket chambers. Hey, it works for vacuum cleaners, does anybody have any estimates on what kind of impact it could have? Peanuts on engine savings or something significant?

Dodge Parry Spin Thrust?

You forgot the 'boing' when he whacks himself in the bill ....

Making things very, very small is only useful if you can make a bazillion of them quickly. Without the ability to make a million transistors in a few hours using photolithography, there's no way ICs would have displaced transistors on little spindly tripod legs.

So how long does it take to move a single atom using an STM (this article) or laser tweezers (others)? Let's be generous and say it takes less than a millisecond. How long does that imply it would take to build a nanodevice about the size of a virus (200 nm)? About a billion milliseconds, or twelve years.

Moving single atoms around with macroscopic tools is interesting from the point of view of basic research, but will have nothing to do with any future nanotech. That awaits new methods of self-assembly, i.e. methods to move atoms around with microscopic tools, on microscopic time scales (picoseconds).

Well Carl, if we can get them to self-replicate, geometric progression should enable large quantites to be produced in moderate timeframes.

Yup. Isn't that what I said? They have to build themselves, or at least be built by other microscopic widgets.

I'll make a prediction for the first useful nanotech device. It's going to be fabricated by lithographic techniques, and what it's going to be is a thickish sheet containing bazillions of tiny one-way gates that can be tuned to allow only one particular molecule to go from one side to the other (but not back again).

Imagine the convenience. You take your generic liquid glop from the drain, or from a mine, or from someone's bloodstream, and you put it in contact with one or more filters like this, and they quietly and completely extract every molecule of the stuff you want or don't want.

You get perfect pollution remediation -- begin with raw sewage and end up with water so pure you could inject it into your veins. Perfect chemical engineering efficiency: you put your reaction mixture on one side, and draw off the product as it's made until you run out of reactants -- no waste, and no purification needed. Utterly sterile and dust-free rooms. Live underwater without carrying bottled air. Perfect closed-cycle recycling for spacecraft. Pull pure oxygen, water or hydrogen out of the lunar regolith. Perfect dialysis for folks with kidney problems. Instant cure for any poison or blood-borne infection. And so on.

We spend a huge amount of energy trying to reverse the entropy of mixing with clumsy, macroscopic techniques. Imagine how much would come within our grasp if we could do it directly, at the microscopic level, sorting molecules as easily and directly as robots can sort automobile parts or machine screws now.

It's not conceptually hard. Our cell membranes have "gates" that do this kind of thing all the time. We just need to learn how to build them artificially.