Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: Stefanb on 22/07/2009 07:37:01
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Assuming that all matter can be described simply by the number/arrangement of elementary particles: is it possible to scan an object, record all the various placements etc. of elementary particles in that object, and then take different particles and arrange them- using the previous data- into effectively the same object?
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In theory yes if that was all there was to be done. however the elementary particles all have some energy of motion as well. this is because although they are bound in positions they jiggle about and you have to include all the motions of the particles and groups of particles in your reconstruction and quantum theory notably the uncertainty principle prevents you from finding out enough information to actually perform the reconstruction including all the positions and energies.
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Also, you are, effectively, talking nuclear fusion (building up elements from fundamental particles). This would produce embarrassingly large amounts of energy when making elements lighter than iron and require energy for heavier elements. Bearing in mind the difficulty in producing any fusion in a controllable way, I think it's probably definitely in the realms of Science Fiction on those grounds alone.
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You don't necessarily need to worry about fusion; if your hypothetical matter-copying device had in storage all the different isotopes you'd need, perhaps the problem may be solved.
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Stefanb
How big a scale are you envisaging this to work at?
How accurately do you want the copying process to be?
Exton:
You are imagining as sort of 'stores' with rows and rows of drawers. Each one would have a quantity of each isotope (what about the unstable ones?). To build your canary, you'd go to the stores and buy the appropriate ingredients and then you'd bolt them together.
This sort of thing is done, already, (on a very small scale) by chemical engineers, who bolt together atoms and make complex molecules.
Any fool can make good copies of CO2 molecules - just by breathing out!
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Small objects at first...
I was thinking maybe we could have the technology necessary in one hundred to two hundred years. Maybe the energy needed for the reconstructer could come from controlling the energy being released in the compounding of the elements and using it for the machine...
But I thought that maybe you could reassemble a living thing providing you got everything correct.
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Sorry, this may be the wrong forum :)
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This sort of thing is done, already, (on a very small scale) by chemical engineers, who bolt together atoms and make complex molecules.
Any fool can make good copies of CO2 molecules - just by breathing out!
I know. I was under the impression, though, that the original poster had something in mind that is more along the lines of the "replicators" from star trek.
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I think there is a problem with the original question. Synthesis is one thing - we could, in principle, build any organic molecule and even launch it into 'life' by initiating the chemical processes in an appropriate sequence. However, if you wanted to Replicate, then this would involve 'precise' analysis of the original then precise synthesis.
The replica would not be the original - it would be a copy with inaccuracies. Thermal noise and even Heisenberg would prevent that.
SO, boringly, I would have to ask how near the original would your copy need to be and how much of our resources would we want to spend on the exercise. What would be the point of the exercise (Apart from showing that it could be done), bearing in mind that we could envisage making 'near enough' copies. In fact we can do a lot of that sort of thing already.
Star Trek and The Fly are Science fiction. Interesting to think about but they are products of a fiction writer's (often deliberately) limited appreciation of real Science. Just extending the fictional timescale of such developments doesn't necessarily make them any more likely.
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I think we would need quantum computers for the vast quantities of data required - I suspect with modern hard drive technology the disk would need to be light years across!
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We just need to build some Heisenberg compensators:
http://www.time.com/time/magazine/article/0,9171,981892,00.html
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I reckon that Reproduction, by living things does a pretty good job of replicating 'just enough' to produce individuals which are identifiable as being of the same species as the parent. In the case of cloning, they are 'identical' but only to the degree necessary to keep the organism going.
Very smart indeed. The ultimate in "near enough for Jazz".
I think the "light years" diameter Hard drive could be spot on as an estimate of the requirement for storing a total replica so LIFE does quite a good job in one tiny nucleus.
Humans are funny beings, though. Such is their obsession with extending life and immortality that they even think that a reconstructed clone or a defrosted corpse would still be 'them'.
Edit - god someone was quick off the mark - I just added a bit of whimsey!
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Heisenberg compensators
That's got to be the oxymoron of the week [:D]
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I think we would need quantum computers for the vast quantities of data required - I suspect with modern hard drive technology the disk would need to be light years across!
...along with sensing devices capable of obtaining all the data, virtually instantly, in the first place.
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I don't think it's Star Trek-like, personally.
Because if you did manage to make a copy then you'd have two... And if you used this to "teleport" then you would have to destroy the original. Or maybe the copy after it has finished. And that would make a bit too much of an ethics debate to show up on national television.
And on the topic of the hard drives spanning light years-
We've come really far already! Giant machines to microchips is a huge step. So maybe in a few hundred to thousand years (providing we are still alive) we could accomplish the feat of minimizing the space necessary to contain such data.
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There's also something in quantum mechanics called the "no cloning theorem," thatbasically says that you can't copy a quantum state exactly. But like others have said, if all you want to do is make something with similar properties as the thing you're trying to copy, that isn't a problem. If you want an exact replicate, that would be impossible.
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Of course it's star trek-like! That television show features a device that matches your description exactly.
That's not to say that it's impossible.
The real problem, in my mind, is the actual act of rebuilding something on an atomic (or whatever) level. Problems like energy use and computational power exist, but they aren't literally impossible to overcome. Those things are just a matter of worrying about details.
The thing that i can't quite see is how you'd rebuild something even if you had all the data storage and energy that you'd ever need. As someone else said, chemical engineers have all sorts of ways of assembling molecules, but their methods often involve protracted sequences of events that are very dependent upon the material you're trying to make; the techniques used in chemistry don't lend themselves easily to a general purpose "matter reconstructor".
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There's also something in quantum mechanics called the "no cloning theorem," thatbasically says that you can't copy a quantum state exactly. But like others have said, if all you want to do is make something with similar properties as the thing you're trying to copy, that isn't a problem. If you want an exact replicate, that would be impossible.
I don't think that is a limitation. An 'identical' object one metre to the left of another object does not have the same totality of quantum numbers.
It's still codswallop, tho!