A galaxy’s central supermassive black hole has seen more than a lifetime of growth. Sustained primarily by frequent small meals rather than rare and dramatic galactic mergers, as previously believed, the black holes selectively choose when and how much to consume. They can grow rapidly in merger-free spirals simply by attracting gas and other matter.
A supermassive black hole grew over time to become the giant that we observe. Before it was a black hole, it was a star that went supernova. Before it was a star, it came from clouds of gas, just like the matter it feeds on today. Each star has a life cycle, sometimes ending abruptly, other times becoming a black hole. Stars are born and resurrected as black holes. The supermassive black hole in the center of the galaxy is simply the eldest. Its ability to choose when and what to swallow is effectively a type of decision. Could the black hole be able to make complex decisions like a computer or even a brain? Does its massive gravity cause ripples throughout the galaxy that help stellar bodies form? In fact, the central black hole’s gravity must balance the amounts of gas, stars, planets, dark matter and power the spinning of the galaxy. It must be a pretty darn good decision-maker.