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 Eric 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.[7][1] However, not many people realise why it’s bollocks, as it isn’t really due to us limiting what our technology might one day do, it’s purely down to the physics of how the world works.
The rules of mechanics don’t scale evenly with size — consider surface to volume ratios, which are why the energy consumed by small rodents per unit of mass is different from that for elephants, and why the aerodynamics of a Boeing 747 are different from a small 747-shaped toy. At the molecular level, the world is 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.
Imagine what manufacturing would look like if your machines’ gears rotated randomly, the size of the gears’ teeth fluctuated randomly, and everything (gears, grippers, working materials) is coated in glue.
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, then of SIAI, advocated Digital Rights Management as the way to control dangerous science woo nanotechnology,[8] 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.[9]
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. It’s a bit like calling speech “soft telepathy” to imply that “hard telepathy” is a difference of degree, rather than kind.
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In reality
Reality is rather duller than fiction — unless you like the actual science, of course.
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. Nanoparticles (colloids) 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 (and a handy buzzword to get funding from people who think they’re buying magical robots).
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).
Molecular nanotechnology, which aims to engineer mechanical systems at the molecular level, is barely in its infancy. 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 making “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 to 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[17][18] and an inverter that runs at 500kHz.[19] The application is environments that would trash electronics, e.g. high temperatures. For comparison, current computers’ electronic transistors are on the order of 22nm (as of 2012) and mainstream consumer computer chips run at between 1GHz and 4GHz or so.
That’s not to say that this stuff isn’t insanely cool. For instance, sending in a specially-designed killer molecule to cure cancer.[20] Holy crap!
It should be noted that there are examples of self replicating machines that dig into the ground and vacuum up the atmosphere. They 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”.