Technology is all about making things smaller, and to that end, right now they're working on making the smallest things possible. Nanotechnology is the science of making robots that aren't much bigger than a molecule, and there are lots of reasons for doing it, the biggest being because we fucking can.
Imagine sending a million microscopic machines into a person's bloodstream programmed to attack a tumor, or shoot the AIDS virus with tiny little phasers. Imagine swarms of little cleaning droids mopping up the pollution in our rivers, or tiny manufacturing droids that can build anything we want, in seconds, molecule-by-molecule.
The big problem is, of course, how you actually build trillions of these little bastards. Simple: you teach them to replicate like cells, using materials from the environment.
Just think about, like, a million of these little fuckers!
What Could Possibly Go Wrong?
K. Eric Drexler, one of the founding fathers of the whole nanotechnology concept, came up with a number of spine-chillingly plausible doomsday scenarios. The problem is our nanobots would be like cellular terminators, much more advanced than any of the pansy-ass creations nature invented. They could out-compete organic life overnight, obliterating it in a frenzy of Darwinism.
A million of these little fuckers!!
Taken to its extreme, we have the scenario affectionately known as the gray goo problem, which speculates the machines would simply start replicating out of control until everything in existence is just a mass of tiny, scuttling robots, which scientists imagine would look like a pile of gray slop floating through the void.
So, Basically It's Like...
Imagine you meet a magical leprechaun. For a bargain price, he offers to fix up the your house and add an extra room. So you take him home, and he proceeds to eat your house and shit out a hundred and forty more leprechans, which promptly murder you.
How Long Have We Got?
Scientists excitedly assure us that we will have a fully operational murderous death-swarm within twenty years, maybe even as soon as 2010. Right now they're trying to build something called a fabricator, which from our reading is some kind of indestructible robot swarm-queen built out of diamond, who will give birth to trillions of nanomachines and command them to consume all in their path.