What was more surprising was that each individual’s data fit into the same mathematical model—a type of power law—that predicts the probability of finding a person in a certain location. That probability distribution is dependent on an individual’s average travel distance and decreases the further he or she roams. A power law distribution allows for real probabilities for very large values. (A distribution of human height, by contrast, is not a power law distribution because human heights fall within a relatively limited range.)

”Human mobility and how we travel is so amazingly complex,” says Max Planck’s Brockmann. ”What is very strange is that despite this complexity, all the traveling behavior can be accounted for by very simple mathematical laws.”