A tuning fork rings dully when it strikes a crack. That principle scales up in this experiment: physicists turned molecules into an ultrasensitive tuning fork to eavesdrop on the electron's asymmetry. Ytterbium fluoride molecules are cooled to near absolute zero, and then laser spectroscopy sets the electron vibrating in two states simultaneously. If its internal charge is lopsided, a phase shift pops up — a sour note strictly forbidden by the Standard Model (the reigning theory of particles). Catching it would mean rewriting physics.
The asymmetry being chased is so small that if the electron were the size of Earth, its effect on the radius would be thinner than a spider's web.