darius comments on FAI FAQ draft: What is nanotechnology? - Less Wrong

0 Post author: lukeprog 22 November 2011 10:13PM

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Comment author: darius 23 November 2011 05:06:18AM 3 points [-]

Isn't an H atom more like 0.1nm in diameter? Of course it's fuzzy.

I agree with steven0461's criticisms. Drexler outlines a computer design giving a lower bound of 10^16 instructions/second/watt.

Should there be a ref to http://e-drexler.com/d/07/00/1204TechnologyRoadmap.html ?

Quibbling about words: "atom by atom" seems to have caused some confusion with some people (taking it literally as defining how you build things when the important criterion is atomic precision). Also "nanobots" was coined in a ST:TNG episode, IIRC, and I'm not sure if people in the field use it.

Comment author: steven0461 23 November 2011 05:15:41AM 4 points [-]

You're thinking of "nanites", I'm pretty sure.

Comment author: darius 23 November 2011 05:21:22AM 0 points [-]

Oh, you're right, thanks.

Comment author: steven0461 23 November 2011 05:27:22AM 3 points [-]

Apparently .24nm is twice the Van der Waals radius and .1nm is twice the Bohr radius. I'm not sure which one has a better case for being called the "true radius".

Comment author: darius 23 November 2011 07:41:39AM 2 points [-]

Ah -- .1nm is also the C-H or C-C bond length, which comes to mind more naturally to me thinking about the scale of an organic molecule -- enough to make me wonder where the 0.24 was coming from. E.g. a (much bigger) sulfur atom can have bonds that long.

Comment author: lukeprog 23 November 2011 07:41:55PM 1 point [-]

Drexler outlines a computer design giving a lower bound of 10^16 instructions/second/watt.

I've seen this before but now I can't find it. Do you have a link?

Comment author: steven0461 23 November 2011 08:17:14PM *  1 point [-]

I think it's in Chapter 12 of Drexler's Nanosystems, which may be worth citing regardless. ETA: or to read about it online, Chapter 11 of his MIT dissertation linked at the top.

Comment author: darius 25 November 2011 09:09:24AM 1 point [-]

Yes, that's where I got the figure (the printed book). The opening chapter lists a bunch of other figures of merit for other applications (strength of materials, power density, etc.)