September 18, 2003
From the desk of Jane Galt:Interesting story on the beanstalk convention, not least because the folks at Space.com who wrote it seem to have run out of apostrophes -- or perhaps they are omitting them in order to save weight and room.
Posted by Jane Galt at September 18, 2003 12:50 PM | TrackBack | Technorati inbound linksIt seems to me that there are a lot of questions to be addressed here which are bypassed in this item. I'm not an engineer, but the simple fact that carbon nanotubes are strong doesn't address their resistance to weathering, to severe flexing, to material fatigue, to fire, as well as to bombardment by cosmic radiation, and probably other considerations which a competent civil engineer could address. It seems to me that there is a lot of hand-waving here; that some people want to work on the second step because it's easier than the first.
well actually, a competent civil engineer couldn't address those at all wrt nanotubes
civils understand concrete... structural steel, macadam, asphalt, glass...
nanotubes you talk to a chem or mech who specialises in materials science, specifically in nano molecular tribology (don't ask)
now being acquainted with the discilpine, nanotubes are generally very resistant to all of the above concerns. a nanotube is an arbitrarily large molecule, with all of the atoms being bonded to other carbon atoms... molecular bonds are very strong, not something that you can easily take apart physically... carbon carbon bonds are also very hard to break in any fashion, as there isn't much you can do to move them to lower energy states (if anyone will let you, go and try to burn a diamond... nanotubes are like diamonds, but stronger, more tightly bound together).
due to the nature of carbon carbon structures (read diamond), their regular crystalline form, they are very capable conductors of electricity and heat (electron and heat flow can be thought of as vibration transmission, shaking one end of a pool cue transmits the input very quickly to the other end, shaking one end of a slack rope less so) which makes them very difficult to heat (much less chance of heat softening)
every structure and material we use today is composed of massively large (billions of trillions) numbers of molecules.. stress can overwhelm the adhesion of these molecules to each other (like really strong static cling) which gives you deterioration due to weathering, age, fatigue... so the reason why people who are massively better acquainted with the subject than ye olde henry are so incredibly excited and exuberant is because nanomaterials and the techniques that let us build arbitrarily large molecules let us do impossible things that violate all of the rules of materials as previously understood
the main issue with beanstalks is that we currently are just beginning to play with the materials, and making a 33000 mile long nanotube isn't exactly feasible... questions of how to make the material, not of whether it can perform
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