Carbon nanotubes are pretty cool. The microscopic, cylindrical structures are physically strong and highly conductive, making them a potentially attractive alternative to copper wiring. Actually building a usable cable out of the things has stumped scientists since the 80s, but researchers at Rice University in Houston, Texas, have made one that equals the electrical conductivity of copper wire with just one sixth the weight.
The cable uses lengths of double-walled nanotubes that are flexible enough to be knotted together. Attaching multiple lengths in this manner doesn't affect the cable's conductivity, according to the researchers, who were able to power a standard light bulb for days using power from a wall socket. The nanotubes are said to have a higher current density than copper, and they produce very little heat. That particular combination is what makes nanotube technology an intriguing proposition for integrated circuits like microprocessors.
Despite their ability to carry high current densities, carbon nanotubes generate little heat because the electron flow doesn't disturb the surrounding atoms. In traditional metal conductors, electron flow "causes a scattering of electrons within the lattice of the material," which jostles the surrounding atoms. The resulting friction produces heat.
Although carbon nanotubes aren't yet ready for commercial applications, it's nice to see progress being made in the field. I suspect we'll be hearing quite a lot more about them in the future.