How we see Starry Nights: The Physics of Atmospheric Turbulence

Synopsis

Turbulence, introduced as a textbook example of chaos, displays remarkably predictable structure when viewed across length and time scales. Understanding this structure is important for modelling atmospheric motion and its effects, from aircraft turbulence to the distortion of light in astronomical observations. In this talk, I introduce atmospheric turbulence and Kolmogorov’s theory using Vincent van Gogh’s The Starry Night as a visual case study. The central question is how statistical laws emerge from complex, nonlinear fluid dynamics, and what they allow us to predict.

The energy cascade, which hands energy from large swirling motions to smaller ones, provides physical intuition for understanding Kolmogorov’s -5/3 law, and its prediction for how kinetic energy is distributed across spatial scales. I compare measurements in water and the atmosphere with analyses of The Starry Night, examining the appearance of similar scaling patterns and how to interpret them. These examples illustrate the character and limits of universal scaling in turbulence, and bring us back to The Starry Night: did van Gogh’s brushstrokes capture more than the appearance of a turbulent sky?