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That essay is 60 years old. A lot of these ideas have been developed further and thoroughly tested. We now have extremely ridiculously high resolution lithograp

by jpm_sd 6y ago

That essay is 60 years old. A lot of these ideas have been developed further and thoroughly tested. We now have extremely ridiculously high resolution lithography, using electron beams and ultraviolet light. We have atomic force microscopes, which we can use to shove around individual atoms to spell out IBM and other such nonsense. But atoms ain't Lego bricks, and you can't turn cute 3D animations [1] into real mechanisms by wishful thinking. [1] https://chem.beloit.edu/classes/nanotech/nanorex/index.html https://chem.beloit.edu/classes/nanotech/nanorex/index.html

petermcneeley 6y ago
Right but in this area the actual physics hasnt changed much if at all in 60 years. As for the reference animations I am not sure if they actually correspond to real physics even if you could arrange the molecules in such a fashion. Of course biology does such things but the scale here is a different. https://www.youtube.com/watch?v=dYt5135_0bs https://www.youtube.com/watch?v=dYt5135_0bs I think if you wanted to do what Feynman wanted you would need extremely accurate simulations that would include your mechanism for construction. I ran into these issues when doing electrochemical deposition for copper microstructures. The effect had an interaction with the double layer that drove the deposition. This basically meant that the mechanism for construction was very fickle.
- marcosdumay 6y ago
  > As for the reference animations I am not sure if they actually correspond to real physics even if you could arrange the molecules in such a fashion. Well, they are made with molecular mechanics simulations, so I imagine they are very accurate at every point, except where atoms moving in different directions interact. They are also not completely wrong at those points, but probably wrong enough for the work to be useless. Anyway, your complaint applies to Drexler's work, not to his goals. Yes, he didn't really try to make a working device (WTF is that obsession with gears? Notice only the last 3 designs have anything to do with molecular construction? Somewhere on his site he explains those 3 came from a student, while he was focusing on the gears.) and was much more prolific as a sci-fi author than a scientist. That doesn't mean that the idea can not be implemented.

by jpm_sd 6y ago

petermcneeley 6y ago

Right but in this area the actual physics hasnt changed much if at all in 60 years. As for the reference animations I am not sure if they actually correspond to real physics even if you could arrange the molecules in such a fashion. Of course biology does such things but the scale here is a different. https://www.youtube.com/watch?v=dYt5135_0bs https://www.youtube.com/watch?v=dYt5135_0bs I think if you wanted to do what Feynman wanted you would need extremely accurate simulations that would include your mechanism for construction. I ran into these issues when doing electrochemical deposition for copper microstructures. The effect had an interaction with the double layer that drove the deposition. This basically meant that the mechanism for construction was very fickle.

marcosdumay 6y ago
> As for the reference animations I am not sure if they actually correspond to real physics even if you could arrange the molecules in such a fashion. Well, they are made with molecular mechanics simulations, so I imagine they are very accurate at every point, except where atoms moving in different directions interact. They are also not completely wrong at those points, but probably wrong enough for the work to be useless. Anyway, your complaint applies to Drexler's work, not to his goals. Yes, he didn't really try to make a working device (WTF is that obsession with gears? Notice only the last 3 designs have anything to do with molecular construction? Somewhere on his site he explains those 3 came from a student, while he was focusing on the gears.) and was much more prolific as a sci-fi author than a scientist. That doesn't mean that the idea can not be implemented.