My background is in astronomy, where power laws are ubiquitous. (There's a joke that when you get some data, you fit it to a power law. If that's not a good e

My background is in astronomy, where power laws are ubiquitous. (There's a joke that when you get some data, you fit it to a power law. If that's not a good enough fit, you fit it to a broken power law.) The reason they're so common is that a power law is generally the distribution you get anytime you have a scale-invariant process.