August 10, 2008

Mechanosynthesis

Brian Wang has an excellent post up about new funding for diamondoid mechanosynthesis viability. If you've never heard of it, it's the centerpiece of Dr. Eric Drexler's classic book Engines of Creation (highly recommended, very fun read, and it's free for download here). His follow-up, far more technical tome Nanosystems is also recommended. The basic idea is simple: with the right tools at the molecular scale, you could build working machines at that scale, molecule-by-molecule. The deliberate fabrication of these machines through mechanical action is why it's called mechanosynthesis, and "diamondoid" refers to the fact that nearly all such products will be given structure by carbon atoms in diamond configuration.

The ramifications of just getting that far are world-shaking: machines could operate on cells, build processors and electronic components with molecule-wide feature sizes. The real hope of the method, though, is to create tiny, multipurpose machine shops (i.e. nanofactories), that are capable of building copies of themselves. This is where the "grey goo", hollywood-nightmare version of nanotechnology gets its inspiration (it's also stupidly easy to prevent by proper nanofactory design). Nanofactories capable of self-replication would constitute a physical instantiation of a kinematic self-replicating machine, which has so far just been a neat thought experiment.

The experiments Wang describes are to explore the viability of the essential reactions of diamondoid mechanosynthesis. These have been the source of a great controversy and intense debate, particularly between Drexler and the late Dr. Richard Smalley.  I admit a certain bias in this debate, mostly because I found Smalley's tone to be positively trollish (personal attacks, appeals to emotion, flatly-inappropriate metaphors).  Nonetheless, his principal argument wasn't without merit, namely that we've never seen these sorts of reactions done by anything but living cells using wet chemistry and aqueous enzymes.  That's part of what these experiments will be trying to put to rest.  We already have dry enzymes for certain reactions, and we've done single-atom manipulations with scanning probe microscopes (SPM), both of which Smalley argued were impossibilities in the course of his debate with Drexler.

Posted by: leoncaruthers at 08:27 PM | No Comments | Add Comment
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