The Compact Muon Solenoid searches for muons at the Large Hadron Collider in Cern. You're clear on protons, neutrons, and electrons, but how about muons? They have a charge similar to electrons, but are bigger. Muons are also unstable, lasting for a tiny fraction of a second, unlike electrons. And recent research shows that muons do not act in ways standard physics theory would predict. This is potentially a huge finding, one Clara Moskowitz follows as a senior editor at Scientific American. Moskowitz stops by for a quick lesson.