Turbulent fluid flows appear random and disordered. Airplane contrails are an obvious example of this, while water flowing through a pipe provides another common example, although it is observable only in a laboratory. This randomness means that designing household plumbing uses tables of the pressure needed to enforce a desired flow rate. However, this fact points to a key property, namely that averages like pressure and flow rate are predictable, even if flow details are not.The scientific problem of deriving mathematical equations to describe the statistics of turbulent flows has a long...