Turbulence, the splintering of smooth streams of fluid into chaotic vortices, doesn’t just make for bumpy plane rides. It also throws a wrench into the very mathematics used to describe atmospheres, oceans and plumbing. Turbulence is the reason why the Navier-Stokes equations—the laws that govern fluid flow—are so famously hard that whoever proves whether or not they always work will win a million dollars from the Clay Mathematics Institute.