Because sometimes even scientists need an excuse for their messy desks.

By Dr Alastair Gunn

Published: Friday, 14 April 2023 at 12:00 am


Chaos theory is a branch of physics that describes the evolution of processes that are dependent on initial conditions. Some processes, which at first glance appear to be random, can in fact be based on underlying patterns and interdependencies.

The classic example of a chaotic system is termed the ‘butterfly effect’, first highlighted by mathematician and meteorologist Edward Lorenz. Lorenz envisaged the apparent chaos of a tornado being dependent on a butterfly flapping its wings several weeks prior to the storm. Almost negligible changes in initial conditions can have dramatic and unpredictable effects on the evolution of a chaotic system.

There are several areas of astronomy that benefit from an understanding of chaos theory. The obvious one is the gravitational interaction of celestial bodies. Such a system is chaotic, and a tiny error in the positions or velocities of the celestial bodies, or the introduction of small perturbations, means the system is unpredictable in the long term.

Weather and climate here on Earth are good examples of chaotic systems. Similarly, features such as the Great Red Spot on Jupiter are also chaotic. Although scientists have a good grasp of fluid dynamics and the forces that result in this massive storm system, its formation and evolution cannot be predicted from these principles.

Most of the processes going on in the Universe are essentially chaotic. The acceleration of charged particles, the creation of cosmic rays, the structure of magnetic fields, nuclear reactions within stars, chemical reactions in interstellar space, and many more phenomena, are all critically dependent on initial conditions. Ultimately, it would be fair to say the Universe itself is chaotic and therefore unpredictable.

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Asked by: Paul McPherson, Glasgow

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