Physicists have been attracted to studying cities of late because of two major reasons. Some branches of physics like statistical mechanics, which deals with aggregate behaviour rather than individual properties, are very useful in the study of social phenomena. Cities had received little attention from a quantitative point of view, which led academicians to study the aggregate properties of cities and look for natural laws in their behaviour.

Soon enough, some of them noticed similarities — as well as differences — in the behaviour of cities and living organisms. Living organisms slow down as they grow, while cities speed up as they expand. Both consist of networks: the nervous, circulatory and metabolic networks in animals and the transport, communication and other infrastructure networks in cities. Read More