The holy grail of nano technology, assemble structures from the atom up!!!

[Gardamorg]

Originally Posted by Moontanman

I guess old age and reality has hemmed in my ability to fantasize.

Let's let my argument become fantasy first.

[Gardamorg]

Let's further explore these energy nano bots, the smallest nano bots we could make using matter could shoot pulses that magnetically blow atoms and quarks apart, and more, smaller, pulse charges could be used to move these quarks and atoms into place after a long struggle that requires that percision that only machines could produce.

[freeztar]

**Moved from Engineering to the Watercooler**

[Moontanman]

Quote:
Originally Posted by Moontanman
I guess old age and reality has hemmed in my ability to fantasize.

Possibly I should said reality and old age has diminished my ability to delude myself into believing fantasy. I still like fantasy but I don't believe it any more.

[CraigD]

Originally Posted by kanuck

I'm curious about how this may affect the world. I think a replicator will still need particles to be of some use, but where will it take them from? Will it use the gases of our atmosphere? You can't create something from nothing, can you?

Correct.

Most descriptions of nano-fabricators or “replicators” like the “personal fabricator” described in the BBC documentary assume that part of the swarm of nanobots in it will be dedicated to taking apart any sort of feed stock atom-by-atom, so as long as you feed it something with the right atoms, it can reassemble them into whatever its programmed to make. Fiction writers commonly describe throwing sand “for silicon and oxygen”, water “for hydrogen”, twigs and sticks or just good (for carbon and nitrogen) into a hopper.

These “atom assemblers” wouldn’t be able to make carbon into iron, gold, platinum, or plutonium, but as common and rare metals are useful mostly because of the ease with which they can be fabricated using old-fashioned, macroscopic techniques, they wouldn’t need to. Building materials atom-by-atom, carbon, silicon, and other readily available elements can in principle do nearly anything we currently do with less available elements. Useful chemical properties of metals like silver and platinum can, in principle, be mimicked by nanometer scale structures made of other elements. Color pigments that in the present day use various metals could be made nanoscopically using diffraction and scattering effects – examples of this in nature are bird feathers, which can be bright green and blue, even though they’re made of the same drab-colored keratins as ordinary animal hair.

In addition to “you can’t create something from nothing”, you can’t do mechanical work – moving individual atoms around is at least as much work as moving the same atoms in their usual large collections – without energy. So in addition to needing feed stock – which should be pretty much free - personal fabricator will need to be “plugged in” to some power source, so among the first things you’d likely want to fabricate would be lots of photovoltaic panels to cover every available sunlit surface, and ultracapacitors to store the energy.

[Gardamorg]

Originally Posted by CraigD

Correct.

Most descriptions of nano-fabricators or “replicators” like the “personal fabricator” described in the BBC documentary assume that part of the swarm of nanobots in it will be dedicated to taking apart any sort of feed stock atom-by-atom, so as long as you feed it something with the right atoms, it can reassemble them into whatever its programmed to make. Fiction writers commonly describe throwing sand “for silicon and oxygen”, water “for hydrogen”, twigs and sticks or just good (for carbon and nitrogen) into a hopper.

These “atom assemblers” wouldn’t be able to make carbon into iron, gold, platinum, or plutonium, but as common and rare metals are useful mostly because of the ease with which they can be fabricated using old-fashioned, macroscopic techniques, they wouldn’t need to. Building materials atom-by-atom, carbon, silicon, and other readily available elements can in principle do nearly anything we currently do with less available elements. Useful chemical properties of metals like silver and platinum can, in principle, be mimicked by nanometer scale structures made of other elements. Color pigments that in the present day use various metals could be made nanoscopically using diffraction and scattering effects – examples of this in nature are bird feathers, which can be bright green and blue, even though they’re made of the same drab-colored keratins as ordinary animal hair.

In addition to “you can’t create something from nothing”, you can’t do mechanical work – moving individual atoms around is at least as much work as moving the same atoms in their usual large collections – without energy. So in addition to needing feed stock – which should be pretty much free - personal fabricator will need to be “plugged in” to some power source, so among the first things you’d likely want to fabricate would be lots of photovoltaic panels to cover every available sunlit surface, and ultracapacitors to store the energy.

So couldn't you make metals significantly lighter, so you could have 50,000-20,000 pound space shuttles that are the same size as Orion?

And couldn't you make new chemical rocket fuel that's more powerful than anything in nature?

[CraigD]

Originally Posted by Gardamorg

So couldn't you make metals significantly lighter, so you could have 50,000-20,000 pound space shuttles that are the same size as Orion?

I can’t see how you could use nanotech to make metal structural materials more than slightly less massive.

Because metals have regular crystal structures, their density (mass divided by volume) is the same whether they are forged the old fashioned way, or some more modern way, such as vapor deposition, or, someday, individual atom nano-assembly. Although nano-assembly could allow metal parts to be made that were so free of microscopic defect that a smaller part could be trusted to do what current engineering safety margins require a larger part to do, and/or make parts with optimal qualities, such improvements would, I think, be slight, and possibly unwise, as by eliminating safety margins, you’d be placing a lot of trust in nano-assembler software.

This is likely unimportant, however, since even present-day technology is already preferring non-metal elements – primarily carbon - for structures such as airframes. Much lighter and stronger than metals, such materials (eg: carbon fiber) already are used in most new high-performance airplanes (2004’s SpaceShipOne and the soon-to-be flown SpaceShipTwo – though arguably not really worthy of the name “spaceship” – are primarily carbon fiber), sports equipment, etc, leading many technologists to describe “the age of metal” as a bygone technological age.

Current carbon fiber technology is similar to weaving, producing essentially thread made of short graphene strands. Nanotech promises to greatly improve this, producing large tetrahedrally bonded crystals – in other words, diamond – or very long single graphenes While large diamond crystals are at present very expensive gemstones, in the future, via nanotech, diamond crystals massing hundreds or many thousands of kilograms promise to be an amazingly good engineering material, leading many futurists to describe this future (which some anticipate being less than a decade, others more than a century, away) as “the diamond age”. For example, Neal Stephenson’s 1995 novel “The Diamond Age”, describes a future dominated by nanotech, in which Eric Drexler is regarded a nearly mythological hero (rather than something of a charlatan and a con man, as many technologists presently consider him, or simply wishful and naïve, as technologists such as 1996 Chemistry Nobel laureate and discoverer of buckminsterfullerene Richard Smalley).

While, IMHO, there’s a general consensus among technologists that nanotech of some sort will result in much improved engineering materials, there’s not much of a consensus on what this technology will, in detail, be like. My personal opinion is that it won’t be much like the “free-swimming” nanobots Drexler describes, but will involve purely mechanical “dry nanotech”, as opposed to biological life-like “wet nanotech”. I think that it’s character will derive from present day devices like atomic force microscopes and laparoscopic surgical instruments. My opinion is mostly a guess – as, I think, is the opinion of most technologists, including the ones interviewed in the BBC program video linked in post #1.

Originally Posted by Gardamorg

And couldn't you make new chemical rocket fuel that's more powerful than anything in nature?

I don’t think so.

Chemical rocket fuels are typically liquids or amorphous, “gummy” solids. They have no crystal structure to be assembled into, so nano-assembly technology appears of little application to them.

However, this too is likely to be irrelevant. As Moontanman’s signature suggests, many people don’t think chemical-fuel rockets have a very promising future. Though I’m not confident that the design being pursued by the folk at nuclearspace.com will work, I agree that something radically different than how we’ve launched spacecraft for the past half century is needed.

[Moontanman]

I've given it some thought and I can see a way nano tech might be able to make metal objects with a lot less mass but even stronger than current metals are. Has any ever given any thought to how Styrofoam can be so light and yet so strong? Melt Styrofoam down and you get a thin sheet of very weak plastic. All you have to do is make metal foam! A ton of titanium could make an enormous amount of titanium foam, enough to make a complete space shuttle and maybe the rocket it launches on. Nano bots might be able to construct things out of metal foam or it's slowly constructed equivalent. Of course metal foams have to be made in a very low gee environment, orbit in other words so nano bots aren't really necessary to make metal foam. An ounce of something like aluminum or titanium could make a very large object if it was made into foam. As for rocket fuel, metallic hydrogen seems to have some real possibility as a mono propellant but even though it would be better than chemical it still wouldn't touch nuclear. Nano bots wouldn't make any difference to metallic hydrogen.

[modest]

Although I'm not at all familiar with nanotechnology futurism, I would tend to agree. Arranging atoms one by one would presumably allow for a "material" to be constructed with any chosen architecture. Materials with internal structure resembling something like the steel frame of a skyscraper with trusses and whatnot would greatly lighten something of equal strength - that, at least, sounds intuitively possible to me.

If, for example, we could manipulate carbon nanotubes to achieve junctions such as this,


-source

then I believe we could make some extremely light and extremely strong things much like we do on a macroscopic scale now (like suspension bridges).

~modest

[Gardamorg]

If we could manipulate the structures of atoms, and piece together neutrons and protons, and quarks, then we could change the density and all and all strength of materials themselves by literally building at the subatomic level, building from the particle up.

What I am talking about is an atom that looks like a nano tube, and a bunch of these atoms might make up a super duper strong nano tube, stronger than a nano tube made just from regular atoms. Which means you could make it lighter and stronger than you ever could with plain atomic manipulation. Structured atoms that are like supports that make up a nano support, and nano supports could be the nano tubes that make up a metal.

If nano bots could shoot small electromagnetic charges that are unstable and explode a after they've been created, and make them stable enough to last long enough to hit and explode in the perfect spot on a subatomic particle to actually move it in a certain direction, and then fire many more to actually propel sub atomic particles into a structure with the thrust from the specific impulse of these little nuclear pulses, then we could build atoms with specific structures in the way I'm proposing by propelling them toward each other.

It would be like positioning chunks of metal with kinetic explosions.

This process could make titanium a thousand times lighter.