Discovering the Weak Force

Our universe is quite organized, with physics that follows well-defined rules. For example, the only way bits of mass are pulled together or pushed apart is through a specific force. So far, physicists have discovered four fundamental forces: electromagnetism, gravity, the strong nuclear force that holds protons and neutrons together inside an atom, and the weak force that governs radioactive decay of the atomic nucleus. For years, I never quite understood that last one, the weak force, and when