Minimum Viable Cosmology - 7
Time to rethink the λCDM model
Having covered some of the problems of communicating ideas and abstract concepts as per Ludwig Wittgenstein in the previous posting, we’ll attempt to consider entropy, complexity and chaos as it relates to the Minimum Viable Cosmology in this posting.
Entropy, often associated with disorder, is a measure of the randomness or uncertainty within a system. It was first introduced in thermodynamics to describe the tendency of energy to disperse and systems to move towards equilibrium. The Second Law of Thermodynamics states that the entropy of an isolated system tends to increase over time. This implies that systems naturally evolve towards a state of higher disorder or randomness. In cosmology, it has been used to explain the arrow of time - the one-way direction of time from the past to the future. This is often referred to as the "thermodynamic arrow of time."
Unlike entropy, complexity does not have a universally agreed-upon definition. However, it often involves the presence of multiple components, non-linear interactions, feedback loops, and the ability to adapt and self-organise. While entropy and complexity may appear to be opposing forces, they are deeply intertwined. In fact, complexity can emerge from the interplay between order and disorder, and entropy serves as a driving force. The emergence of life is thought to be a prime example of increasing complexity in the universe. Life, as we know it, is a complex, self-organising system that can process information, reproduce, and evolve. The existence of life in the universe represents a high degree of complexity, which was driven by the increasing entropy.
Chaos refers to a state of apparent randomness and unpredictability within a system. It is characterised by extreme sensitivity to initial conditions, where even the slightest change can lead to drastically different outcomes. Chaos theory, pioneered by mathematician Edward Lorenz, emphasises the idea that seemingly chaotic systems can possess underlying order and deterministic behavior. The famous "butterfly effect" is a prime example, illustrating how a small perturbation, like the flapping of a butterfly's wings, can have far-reaching consequences.
Chaotic dynamics have been identified in various cosmological contexts. For example, the three-body problem, a classic problem in celestial mechanics involving the motion of three bodies under mutual gravitational attraction, is known to exhibit chaotic behavior. This has implications for understanding the stability and evolution of planetary systems, star clusters, and galaxies.
For further exploration, let’s do a deep dive into the video by Professor Jim Al-Khalili, who asks: “What is self-organisation?”
In summary it can be said that complexity and self-organising systems depend on feedback loops where the output becomes the input for the next calculation as in: x = x2 + c .
On a more grandeur scale we can see the whole universe as a self-organising system moving towards the Great Attractor.
Is the universe so vast and complex that the human mind could never fully comprehend it? That is our next question for the Minimum Viable Cosmology 8.