(Note: This is the third part in the series on Complexity. Please read Part 1 and Part 2 first.)
At and soon after the moment of the Big Bang, there was little or no complexity. Then why is it that we see so much complexity around us? And why is the complexity increasing all the time? Answers to these questions require some groundwork, particularly if unexplained jargon must be avoided. I lay the groundwork in this and the next few articles in this series. In the context of our ecosphere, it is explained that the reason why its complexity has been increasing all the time is that the Sun has been bombarding it with low-entropy or high-grade energy.
We begin by describing how complexity may possibly be quantified. In the literature, most definitions of complexity are actually definitions of degree of complexity. The degree of complexity may be defined either in terms of information theory, or in terms of thermodynamics. The two are really one and the same thing, but they provide different insights into the evolution of complexity in the cosmos. In the language of information theory, the degree of complexity of a system may be defined roughly as the amount of ‘information’ needed for describing the structure and function of the system. In thermodynamic parlance, degree of complexity has been quantified by Eric Chaisson (2001) in terms of ‘rate of flow of free energy per unit mass.’ For explaining terms like ‘information’ and ‘free energy’, we have to introduce the basics of thermodynamics and information theory. We take up the thermodynamic aspect in this article. Read the full story
