Emily Sohn, reporting for Discovery News:
“At the center of a star, the core is so dense that nuclear interactions take place and as a result, light comes out. And basically, the light that comes out of a star is brighter and reactions are faster the larger the star is,” Bettencourt said. “That’s a little bit like what cities do, too. It’s mathematically different, but the larger the population is, the faster the rates of social interaction.”
“Stars are nuclear reactors and cities are a different kind of reactor,” he added. “They are social reactors.”