Limitations & Ethical Issues

Every technology has its limits and Nano is no elixir -- it can't turn lead into gold.

Every technology has its limits and Nano is no elixir — it can't turn lead into gold. That would require changing the structure of atoms. Nanotech can only build objects using atoms. The real utility of nano might lie in the new things we could create. How about a machine that eats hazardous waste?

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Limits to Nanotechnology

Raw materials: Despite the fact that we still have a wealth of mineral resources on Earth, the scale of building with nanotechnology could outstrip that supply. Scarcity of materials could be a limit on nano designs.

Danger from random radiation: Natural radiation does not bother routine items very much. But it does affect objects at the atomic scale by disturbing the arrangement of atoms. For example, the rearrangement of atoms in human cells by radiation commonly results in cancer. If a nano machine is only 50 atoms across, radiation could significantly damage it. Therefore, even huge machines built by nanotechnology might be in danger.

Atomic magnets pose aterrible bind: Atoms behave somewhat like magnets. When they are brought too close together, overlap repulsion forces push them apart; at a distance, Van der Waals Forces pull them together. And chemical bonding only allows atoms to be arranged in particular ways. None of these forces are noticeable at the macroscopic level, but they will limit the way we can build with atoms.

Wayward atoms: The Heisenberg Uncertainty Principle says that you cannot know exactly where an electron is and how fast it is moving. Then how can we build objects with them?

Energy from where?
The source of energy for nanomachines with is yet to be known. While energy supply seems like a small hurdle given many other problems that must be overcome, smaller problems have kept artificial intelligence on the conception stage for decades.

Limits of human comprehension
What may stop nanotechnology is not physics but the limits of human comprehension. Nature is no doubt endlessly complex. And nano intends to outdo nature; to design everything about an object that takes nature thousands of years to create using chance experimentation (evolution).

Take for example, an apple. To build an apple with the help of nanotech, you would need an atomic map of an apple containing trillions of parts. You would then have to design proteins that could learn that map and place each atom perfectly. Understanding such a complex system may not be humanly possible.

Moral implications
Society also limits technology. And with a technology as revolutionary as nanotechnology, people may place far more restrictions on this.

How will they spend their time? With nano machines doing almost everything, only creative work will remain. And if one can't be creative enough, what will she/he do? If one acquires material possessions free of charge, does she/he have to work? If there's no work, no jobs, what will the government tax? Nanotechnology's impact on the political, economic, and social cover of society could be very real.

True, nanotechnology conjures up visions of utopian existence, but they could also give rise to a lot more risks to our lives. For instance, nanotech can enable unlimited supply of weapons. If let off into the environment, nano machines could reduce all matter to dust, the 'grey-goo' fear. Possible destruction of the biosphere will certainly lead to control of the technology or even a ban.

And most importantly, if you can make anything easily and cheaply, what do you choose to make? Society will place restrictions on what is done based on common social values.

The ultimate limit on nanotechnology may be that some things just cannot be done because they are too complex.