Editor's note: The original online version of this story was previously posted.

Magnets are remarkable exemplars of fairness--every north pole is invariably accompanied by a counterbalancing south pole. Split a magnet in two, and the result is a pair of magnets, each with its own north and south. For decades researchers have sought the exception--namely, the monopole, magnetism’s answer to the electron, which carries electric charge. It would be a free-floating carrier of either magnetic north or magnetic south--a yin unbound from its yang.