The Hunt for the Magnetic Monopole
If you have ever played with fridge magnets, you know the golden rule of magnetism: every magnet has a north pole and a south pole. Push two north poles together and they resist you. Flip one around and they snap together. It is a simple, familiar fact: magnetic poles always come in pairs. That leads to a natural question. If I cut a bar magnet in half, do I get one piece that is purely north and another that is purely south? In the workshop, the answer is no. Nature never hands you an isolated pole. Instead, you get two smaller magnets, each complete with its own north and south pole. Cut again, and you get four. Keep slicing down to the atomic level, and you still end up with a two-poled dipole, never a single pole. Magnetic Dipoles So imagine my surprise when I first heard about magnetic monopoles: hypothetical particles carrying only a single magnetic pole. How could something like that even exist? Yet for nearly a century, some of the greatest minds in physics have been hu...