Can Nanobots Actually Exist?

[BrianHG]

Can Nanobots Actually Exist?

[RoGeorge]

Of course they are 

[apis]

They already do exist, we call them things like "cells", "bacteria" and "virus". Of course those are all natural and more electro-chemical than electro-mechanical on the microscopic level (as far as we know) but I never understood why they wouldn't classify as nanobots, you would have to make up definitions to explicitly exclude those things in order to differentiate it from artificial "mechanical" nanobots.

Also: All caps in title? and why this trend with click-baity titles?

[RoGeorge]

They already do exist, we call them things like "cells", "bacteria" and "virus". Of course those are all natural

Recently not all natural 
https://www.ted.com/talks/craig_venter_is_on_the_verge_of_creating_synthetic_life/transcript?language=en
https://www.ted.com/talks/craig_venter_unveils_synthetic_life?language=en

[Cyberdragon]

Nanobots probably will be more artificial cell/virus like, chemically powered and controlled, possibly creating a small amount of electricity for certain functions (molecules that move based on electricity exist). If you wanted a ROM you could store data in a DNA like structure. Reprogrammable ones would be harder, as making microscopic electronics 3D like that is not like normal chip making.

[Rerouter]

Many electromechanical structures have been built using the bare minimum amount of atoms, there is even power sources etc,

The main issue is you need to reach a certain level of complexity to actually do anything we would consider useful with them,

E.g. you want to join polymers into a single strand without using any chemical initiator (essentially spider web spinning), this could likely be accomplished by a nanomachine, but it would be a right pain to build, / test

For health / medicine, re purposing viruses and bacteria seem to be the path they are heading down now. Enter a Cell, Hijack the internals to accomplish some change, then ideally discarded, as the second they can self replicate it could cause some grief, and you can't exactly sell a health perk to the public if it spreads like the common cold.

E.g. they make a virus that patched in something that extended the length of your telomeres on the next division cycle, you would only need it to apply to a small fraction of the cells in your body to have there intended result, but if it went rampant, and kept on re patching that for every cell division, It would cause issues.

[apis]

Even if you build a complete nano scale factory, the problem is that its output will also be nano scale, so in order to be able to use the technology to produce material in useful amounts you need it to be self replicating. If every factory could produce two new factories you would have exponential growth and eventually you would have enough of them that they could do something useful.

We don't even have any human scale machines that are capable of complete self replication (not counting biological lifeforms). It might be doable eventually, but it will be incredibly difficult to do on a nanometer scale. On the other hand, manipulating yeast/bacteria to produce complex chemicals we need is already being done commercially. Living cells have already solved the exponential replication rate problem.

[BrianHG]

Also: All caps in title? and why this trend with click-baity titles?

Sorry, it was a copy and paste from the Youtube video title which already was all in caps.
I still like to see the possibilities of man made mechanical microscopic structural devices.

[RoGeorge]

Don't worry, no need to say sorry.
Previous messages (including titles) can be edited at any time.

[GlennSprigg]

World's smallest electric motor made from a single molecule....

https://www.sciencedaily.com/releases/2011/09/110904140353.htm

[Psi]

A nanobot that can interact with something the size of a red blood cell is likely possible.

A nanobot that can take atoms apart and put them back together to make a different atom is likely not possible without some completely new physics.
Not because you can't take atoms apart but because any machine big enough to have a computer, control systems and all the moving parts needed would likely be way to large to interact with individual atoms.

[Brumby]

I sometimes wonder about the mechanics of nano construction.  At that scale, you could likely design structures that perform self assembly, due to the physics of their geometry and composition.

I believe this has been observed with the tobacco mosaic virus.  After separating the central helical structure from the sheath they then placing the two components in proximity and watched the helical structure wind itself back into the sheath.

Understanding such behaviour and being able to design custom behaviours could result in self assembling structures.  How complex or functional these structures might be is a matter of conjecture at this point.

[ScottBLAM]

They call it "Grey Death", one of many ways the universe could end.

 I forgot what sci-fi or futurist I heard it from but the concept was that nano-machines would consume, replicate, and continue until there was nothing left of a planet. And even then, after a cosmic catastrophe a planet could break up and send off "Grey Death" to other planets and with enough time possibly even other solar systems.

Be careful with replicating nano-machines.

[coppercone2]

A wmd type that the game deus ex invisible war was about. The opening introduction features a rather interesting grey goo weapon and the rest of the game ocassionally deals with nanite pollution issues.

[apis]

As i wrote before, self replicating nanobots already exist, and they are indeed eating up the resources of the earth. There are limits to what they can do since they need energy and has to follow the laws of nature like everything else, but even so, some of them are pretty dangerous.

[coppercone2]

They wont adapt to eat stainless steel for energy somehow though.

Yes very unlikely its possible

[CatalinaWOW]

The grey death visions of nanomachines ignore energy conservation and entropy rules among other things. 

While nanoscale machines are quite possible it will take even more imagination to find many real uses for them.  Genetic engineered/artificial life is much more likely and feasible, but for refining and materials production applications.  It seems very unlikely that meaningful fabrication will follow from this route.  I mean all sorts of animals are possible, but who really needs a fifteen inch tall giraffe and we already know easier ways to make existing creatures.

[rcarlton]

They turned people into nanobots in this old movie: https://en.wikipedia.org/wiki/Fantastic_Voyage

[Alex Eisenhut]

https://en.wikipedia.org/wiki/Ribosome