Fans of CBS' The Big Bang Theory might recall the Season 2 season finale, "The Monopolar Expedition," in which everyone's favorite socially challenged physicist, Sheldon, accepts an invitation to spend three months at the North Pole searching for magnetic monopoles.
He figures finding a magnetic monopole would put him on the fast track for a Nobel Prize. And he would be right. But he shouldn't count on finding one right away; magnetic monopoles have eluded our best scientists for centuries. (Episode highlights can be viewed here.)
Perhaps it's ironic that the #1 sitcom in America also has some of the most accurate cutting-edge physics on television, but it's not surprising - not if you know that the show has a regular technical consultant, UCLA physicist David Saltzberg.
Saltzberg even maintains a blog, The Big Blog Theory, where he comments on each new episode. In the entry for "The Monopolar Expedition," he explains the basics of magnetic monopoles - magnets with only one magnetic pole - and why they're so weird and significant to particle physics and cosmology:
As Saltzberg says, scientists have been tantalized by the prospect of magnetic monopoles since James Clerk Maxwell first formulated his famous four equations describing electromagnetism. Maxwell's equations are "asymmetrical": electricity has an electron monopole and a proton monopole, each with opposite charge, but magnetism does not.
Pierre Curie hypothesized that magnetic monopoles might exist in 1894, but the real mathematical heft for the idea came from Paul Dirac in 1931: he showed that if one quantized electric charges, then the existence of monopoles was consistent with Maxwell's equations. Specifically, monopoles could exit at the ends of long tubes carrying magnetic fields called "Dirac strings."
And the search was on! As it happens, the best places to look for these exotic particles is the North and South Poles, since scientists can use the Earth's magnetic field as "a funnel for magnetic monopoles." That, says Saltzberg, is why Sheldon is sent to the Arctic for his expedition.