Nanotechnology

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*Information technology - computers can become increasingly small yet still retain their ability to process.
 
*Information technology - computers can become increasingly small yet still retain their ability to process.
 
*Fuel technology - nano-scaled features can improve fuel efficiency or clean up emissions. Catalytic converters already use micro- and nano-scaled features to increase their efficiency.
 
*Fuel technology - nano-scaled features can improve fuel efficiency or clean up emissions. Catalytic converters already use micro- and nano-scaled features to increase their efficiency.
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*Sports and recreation - "respirocytes," nano-scaled SCUBA tanks the size of red blood cells, will let you hold your breath for hours without turning blue.
  
 
== In science woo ==
 
== In science woo ==

Revision as of 07:58, 16 March 2011

Drexler’s thesis is merely the source of the disease. What I’m really sick of are ding dongs trying to tell me toothpaste or golf balls is nanotech.
—Scott Locklin[1]

Nanotechnology (often referred to as "nanotech") is the art of working on materials at the nanometer (one billionth of a meter) scale, hence the name. It's materials science with "nano-" on the front because that gets funding from people who've heard of K. Eric Drexler.

There are two sorts of nanotechnology: reality, and science woo.

Contents

History

The idea was first postulated by Richard Feynman and popularised by the work of science fiction that Eric Drexler used as a Ph.D. thesis. Nanotechnology fanboys — as opposed to the people who actually work with the stuff — have a habit of downplaying Feynman's origination of the idea and playing up Drexler, possibly because the latter is far more indulgent of their fantasies.

Possible uses

There is no single unified thing that can be called "nanotechnology." Rather, many different technologies and industries are reaching the point where nanoscale operations are of interest. The areas that nanotechnology could be applied to include:

  • Fabrication - that material of unprecedented microscopic complexity can be constructed better than by conventional means. Nanotechnology building other pieces of nanotechnology is also one of the dreams.
  • Materials technology - materials with particular nano-scale features can often have specially designed properties, such as strength, durability or electrical conductance.
  • Medical technology - In the woo world (i.e., science fiction), nanomachines will be able to repair a body from almost complete mush into a fully functioning human. In reality, self assembling macromolecules can "puncture" bacterial cells to fight infection and deliver drugs more effectively and specifically.
  • Information technology - computers can become increasingly small yet still retain their ability to process.
  • Fuel technology - nano-scaled features can improve fuel efficiency or clean up emissions. Catalytic converters already use micro- and nano-scaled features to increase their efficiency.
  • Sports and recreation - "respirocytes," nano-scaled SCUBA tanks the size of red blood cells, will let you hold your breath for hours without turning blue.

In science woo

No, you don’t get it. You are still in a pretend world where atoms go where you want because your computer program directs them to go there.
—Richard Smalley to Drexler

The popular conception of nanotechnology is Drexler's concept of nanobots, like industrial robots scaled down a billion times. This is entirely made of bollocks and would violate physics, chemistry, and thermodynamics.[2][1]

The rules of mechanics don't scale as evenly with size (consider surface to volume ratios, for instance) which is why the energy consumed by small rodents per unit of mass is different than that for elephants and why the aerodynamics of a Boeing 747 are different to a similarly shaped toy only a few feet across. At the molecular level, the world looks and feels considerably different to macro scale. A solvent like water would feel more like treacle, and anything floating in it would be at the mercy of brownian motion that would make even the strongest rip currents look quite weak.

As an analogy of what would happen if molecular machines with moving arms were attempted: imagine a car production line with its hi-tech robotic arms that work fine at our macroscopic scale. To get a glimpse of what it would be like to operate a production line on the microscopic scale, imagine filling the factory completely with gravel and trying to watch the mechanical arms move through it - and then imagine if the gravel was also sticky. This is why enzymes don't use mechanical arms and rely on diffusion (indeed, the rate of diffusion is an ultimate barrier for chemical kinetics) to bring their substrates to their active sites.

That Drexler has pushed an idea which is actually impossible has not deterred nanotech fans, who get as upset as they usually do when an expert in a field they're talking about points out they're simply wrong, apparently from an emotional sunk cost fallacy.

Transhumanists routinely casually throw biology out the window, but with nanobot advocacy they manage the same contempt for chemistry and physics. (Michael Anissimov of SIAI advocates Digital Rights Management as the way to control dangerous science woo nanotechnology[3], thus also casually throwing mathematics out the window.) In cryonics, "but, nanobots!" is the standard answer to any objection. Some cryonics advocates are finally pointing out that this is not quite rational.[4]

Since real scientists have entered the field of nanotechnology and started using the term for things that do not defy physics, Dr. Drexler has taken to using his new favored term, "zettatechnology."[5]

In fiction

Drexler's vision of nanobots is a standard science fiction trope for magic. Applications include superhuman healing and body repair, superhuman powers, shapeshifting machines, constructing large structures at a miraculous pace,[6] self-repairing materials, instantly taking over and reprogramming any computer system[7] or even a person.[8] Alternatively, a swarm of nanomachines can be a weapon eating anything in its path like locusts.[9]

One common version is self-replicating nanomachines, which convert any available matter into more nanomachines to replenish and bolster their numbers. If left unchecked, these machines convert everything — the so called "grey goo" doomsday scenario.[10] The idea of creating self-replicating machines, which was an early goal of nanotechnology, has given way to the safer and simpler approach of building larger (relatively speaking) factories that can mass-produce nanomachines, making this scenario less likely to occur in reality.[11][12]

Writers like these little things because they don't have to show and explain how they work — all you see are the results.

A slightly more believable description of nanotechnology can be found in Neal Stephenson's book The Diamond Age. In this, not only is there a detailed description of how the machines would be built, there is even a discussion of associated problems, such as heat dissipation.

In reality

Needless to say, reality is much duller than fiction - unless you like the actual science, of course. Instead of creating the tiny magic robots popularized by science fiction, current nanotechnology focuses on creating much simpler structures, such as nanoparticles that can deliver drugs to specific cells, and materials with advantageous properties.Better understanding of materials at the nanoscale is explaining many apparently odd things. Colloidal nano-particles of gold are red, rather than yellow as the bulk metal is, and this effect is responsible for the colours of medieval stained glass. Some of the odd properties of soot are because it contains buckyballs and nanotubes. Scientists working on these nano-scaled advances tend to refer to it as either "chemistry" or "materials science", as "nanotechnology" is not a functioning research field in its own right and is just an umbrella term for a variety of research ventures that span multiple disciplines.

Molecular nanotechnology, which aims to engineer mechanical systems at the molecular level, is barely in its infancy. Molecular recognition - the ability for catalysts to actively recognise and orientate their substrates - is an emerging area of research and could become the norm for chemical synthesis in a few decades. However, this still relies on normal chemical synthetic routes with one catalyst tuned to one reaction (or group of reactions), and so the dream of assembling molecules "atom by atom" may not even be possible in the sense claimed by those writing about nanobots. So far, scientists are pretty good at arranging atoms in patterns with a scanning tunneling microscope (STM), as was famously done by IBM to demonstrate STM technology and in the case of "quantum corals" that demonstrate the wave-like properties of electrons. If nanomachines are built, they will work much more like the currently-known nanomachines - antibodies and proteins and so forth, restricted to catalysing only one family of reactions, and more complicated nanomachines will be closer the size of biological cells.

Mechanical nanocomputers are theoretically possible, and research is steadily getting there. So far there's a 300nm electromechanical reed relay gate[13][14] and an inverter that runs at 500kHz[15]. The application is environments that would trash electronics, e.g. high temperatures. For comparison, current computers' electronic transistors are on the order of 30nm (as of 2010) and computer chips run at up to 3GHz.

That's not to say that this stuff isn't insanely cool. For instance, sending in a specially-designed killer molecule to cure cancer.[16] Holy crap!

It should be noted that there are examples of self replicating machines that "eat" the ground and then sense the available resources of the surrounding territory and assemble useful products, even erecting mini solar panels to assist the process as well as producing the next generation of their initial seeding mechanism, all fully automated and largely unattended. They are called things like "tomato plants". Advocates of nanotech woo often tag life "soft nanotech", as if that makes "hard nanotech" (woo) merely unrealised rather than impossible. This is in reference to the fact that such "hard" nano-tech seems to imply solid, robot-like structures (made of diamond, for example) while "soft" is closer to more malleable molecular structures.

Problems

Nanotechnology as an idea doesn't have any problems per se, particularly as nanotechnology that does have problems doesn't exist. However, there are problems with some of the public depictions or expectations of nanotechnology, especially if portrayed as "just around the corner" instead of part of the abstract sci-fi realm along with things like anti-gravity.

The main practical problem with nanotechnology is the phrase being overused as funding hype for what anyone else would call material science or synthetic biology.

External links

Footnotes

  1. 1.0 1.1 Nano-nonsense: 25 years of charlatanry (Scott Locklin, Locklin on science blog, August 25th 2010)
  2. Rupturing The Nanotech Rapture: Biological nanobots could repair and improve the human body, but they'll be more bio than bot Richard A.L. Jones, IEEE Spectrum, June 2008
  3. http://www.imminst.org/forum/index.php?s=&act=ST&f=41&t=10070&st=0&
  4. Cryonicists' sunk costs reasoning about Drexler's "nanotech." (Mark Plus, The Life of Man Qua Man on Earth blog, 2010-08-31)
  5. What is Zettatechnology? (A to Z of Nanotechnology)
  6. Total Annihilation: "It would have been too complex and time consuming to have little guys with hammers and scaffolds every time something was built in the game. It also wasn't futuristic enough. We needed something like magic, but with a thin veneer of science around it. Nanotechnology to the rescue!"
  7. wp:T-X
  8. http://memory-alpha.org/en/wiki/Assimilation
  9. wp:The Day the Earth Stood Still (2008 film), wp:G.I. Joe: The Rise of Cobra, etc.
  10. For example, the Replicators in Stargate
  11. http://nanotechweb.org/cws/article/indepth/19648
  12. http://www.crnano.org/BD-Goo.htm
  13. Babbage nanomachine promises low-energy computing (New Scientist #2573, 25 March 2010)
  14. Diego N. Guerra, Adi R. Bulsara, William L. Ditto, Sudeshna Sinha, K. Murali and P. Mohanty, A Noise-Assisted Reprogrammable Nanomechanical Logic Gate. Nano Letters, 10 March 2010, DOI: 10.1021/nl9034175
  15. http://www.newscientist.com/article/dn19440-steampunk-chip-takes-the-heat.html
  16. This Is the Future of the Fight Against Cancer (Janet Fang, Nature, 21 March 2010 doi:10.1038/news.2010.138)
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