My old PhD supervisor, Mike Evans, is an occasional writer for the Sky At Night magazine and also blogs for physicsfocus. A quick look at his writing in either of these settings demonstrates that as well as being an expert in his field (which, broadly, is mine), he’s something of a philosopher with a very wide range of scientific interests.

However, this post finds Mike writing on the subject closest to his professional heart: statistical physics. This branch of physics is fundamental to our understanding of the world because it deals with situations where we have more than “just a few” of a particular entity. Considering that something as simple as a glass of water comprises billions and billions of mutually interacting and constantly moving water molecules, its clearly important to have an approach that is practical in these cases.

Further, statistical physics unifies things: a vast cloud of cosmic dust is quite different to a small tube of a colloidal suspension. But they’re similar in some ways. One of these ways is that on the tiniest length scales, they’re both made of protons, neutrons, and electrons. But, as Mike nicely points out, this misses the (thermodynamically) large picture: the two systems are also similar in that they both contain a very large number of their constituent particles, so that statistics governs their large-scale behaviour. In fact, this is arguably their most important similarity. Read the post to learn more about universality in statistical physics.

For anyone who wants some exceedingly clear and enjoyable insights into the life of a professional scientist, I can’t recommend Mike’s writing enough. Check out his personal blog too!