Copper wire's relatively cheap, pliable and can conduct electricity, but it's hardly ideal. Powering cities requires cables meters wide and the metal loses a lot of energy as heat. Fortunately, a team from Tel Aviv University thinks it's solved the problem. Borrowing a fiber of sapphire from the Oakridge National Lab in Tennessee, it developed a superconducting wire barely thicker than a human hair that conducts 40 times the electricity of its copper brethren. Cooled with liquid nitrogen, the sapphire superconductors carry current without heating up, which is key to their efficiency. The team is now working on practical applications of the technology -- because it's so small and pliable (unlike previous superconductors) it could replace copper in domestic settings and its cold efficiency makes it perfect to transmit power long distances from green energy stations. The wire's going on a world tour as we speak and will touch down at the ATSC conference in Baltimore in October. Anyone who makes jokes about wires and Baltimore will be asked to leave, politely.