CIRCUS acts and movie special effects may never be the same again, if an idea for an invisible cable made of carbon nanotubes works out.
Being narrower than the wavelength of light, nanotubes are normally invisible - as long as they are separated by more than one wavelength. Now Nicola Pugno of the Polytechnic of Turin in Italy has calculated how many nanotubes would be needed to support a person, taking into account small defects that develop in the tubes during manufacture. When held 5 micrometres apart, to keep them invisible, they would form a cable only 1 centimetre in diameter weighing a mere 10 milligrams per kilometre (Microsystem Technologies, DOI: 10.1007/s00542-008-0653-9). A plate with more closely spaced holes could slide along the cable, bringing the nanotubes closer, and so into view.
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By Dirk Bruere
Wed Jul 16 19:03:21 BST 2008
There was a SF story entitled "The Thin Edge" where such cables were used as criminal/terrorist weapons - just string them across a doorway etc and they become an invisible knife blade. More recently, anchor one end in a hand grip and the other in a ceramic ball and you have an instant decapitator.By Eric Kvaalen
Thu Jul 17 11:45:10 BST 2008
I don't see what would hold the nanotubes apart to keep the cable or blade invisible.By Armanian
Sun Jul 20 12:55:11 BST 2008
Well when multiple threads of cotton are put together they form a large visible string, now if you were to put those at either end of the door and let the strings hang they become far less visible to people. When the strings hang and someone walks into it, the strings then harden and might or might not join back together to form a large string. This same technique could be used as a method for trip wire, since when nanotubes are together they are visible but when they aren't like when they're dangling apart they aren't as visible.By Barasawa
Sun Jul 20 11:54:38 BST 2008
Why bother using a disk to make a small segment of it temporarily visible.By Captain Obvious
Sun Jul 20 12:53:54 BST 2008
The *concept* is old, and was part of science-fiction, for years.By Dave
Mon Jul 21 01:59:51 BST 2008
You're thinking shadow square wire, from Ringworld. I read that when I was a kid, great book if you're into SF.By Paul
Mon Jul 21 11:06:35 BST 2008
Yes, and here are the shadow squares too:All comments should respect the New Scientist House Rules. If you think a particular comment breaks these rules then please use the "Report" link in that comment to report it to us.
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