Turbulent mind, turbulent flow: post-impressionism and physics

Posted on by milliesc

By Prerna Roy, 12N

Millions of people have seen The Starry Night, yet the underlying physics and mathematics of the artwork are unknown to many. Painted by Vincent Van Gogh in June 1889, The Starry Night shows a phenomenon that many scientists and mathematicians are still baffled by: turbulent flow. The Starry Night is also an example of luminance.

 

Impressionist paintings such as ‘The Starry Night’ have shown to capture the motion of light – something that is not well documented in physics, nor is easy to calculate.

 

Turbulent flow and luminance are two different concepts that have worked together to make Van Gogh’s beautiful painting, The Starry Night. Turbulent flow occurs in fluids only – liquids and gases – and the motion of these fluids are irregular, unpredictable and often described as chaotic. In The Starry Night, turbulent flow is seen from the quick, hard strokes in the painting. Turbulent flow is difficult to describe, and in short is usually described using ‘eddies’. Big eddies will transfer their energy to smaller eddies, and the process continues.

 

On the other hand, luminance is the intensity of light emitted from a surface in a given direction – in terms of Van Gogh’s artwork, the intensity of light from the colours on the canvas. Luminance can briefly be explained how ‘strongly’ light is given off from another surface in a specific direction. The more intense the light given off is, the higher its luminance.

 

Our brains process the motion of turbulent flow and luminance in two different areas: the more primitive visual cortex that does not see colour, but sees contrast and light will merge the colours of two entirely different coloured areas if they have the same luminance. Conversely, in the primate subdivision of the brain, the contrasting, differently coloured areas will be viewed without blending them. When these two processes occur at once it creates the sensation of light moving and radiating – this is how Impressionist work such as The Starry Night looks as though it is glowing. This is especially seen in the upper portion of the painting, where similar luminance between the yellows, whites and blues makes the sky appear more vibrant, hence giving the phenomenon of stars twinkling in the painting.

 

Decades after the painting was made, a Russian mathematician named Andrey Kolmogorov, had proposed an attempted mathematical equation to explain energy in a turbulent fluid. Afterwards, many other mathematicians and scientists alike tested this equation and found that Kolmogorov was extremely close to finding out how turbulent flow works. Mexican physicist Jose Luis Aragon and his team were inspired by a comparison between a picture eddies of gas and dust around a star from NASA’s Hubble Space Telescope and The Starry Night. They investigated many of Van Gogh’s paintings to see whether mathematical turbulence, as proposed by Kolmogorov, was reminiscent in his work. They first digitised the paintings, and afterwards take measurements of the variation of brightness between any two pixels. It was found that They Starry Night had structure patterns of turbulent flow. The measurements taken from The Starry Night were impressively close to Kolmogorov’s equation.

 

Interestingly enough, many paintings from Van Gogh’s time in the Saint Paul asylum in Saint Rémy had measurements eerily close to Kolmogorov’s equation, although paintings from the calmer period of his life showed no such turbulence. Paintings such as Road with Cypress and Star and Wheat Field with Crows both showed structures of mathematically calculated turbulent flow. As well as this, impressionist works by other artists did not come close to the fluid turbulence Van Gogh had achieved – making him truly one of a kind.

 

What makes Van Gogh’s work so special is that most examples of naturally-occurring turbulent flow vanish within a few seconds or minutes – the movement of smoke particles leaving a cigarette, the air currents within our atmosphere and even the motion of boiling water inside a kettle. It is difficult to calculate turbulence because the nature of it requires it to constantly change its movement in both direction and speed – there is no easy way to measure the relationship between these ever-changing properties. Van Gogh’s work almost captures turbulent flow as a still, after all, it did match up to the approximation made by Kolmogorov.

 

Overall, Van Gogh’s ability to paint to such a high degree of accuracy to Kolmogorov’s equation shows a beauty in science that is often forgotten behind all the formulas, equations and laws. Furthermore, the fact he painted these works whilst being in a turbulent mind of his own certainly shows an unappreciated impressiveness, as he was almost unheard of during his lifetime. His works have not only had an impact on art everywhere, but also has intrigued the scientific community with his wonderful, science-filled and fascinating work.

 

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