Dynamic black holes may obey Hawking-style thermodynamics with an alternative entropy measure

Of the known things in the universe, black holes are among the most extreme. They pack huge amounts of mass densely into a small area, producing gravity that is so strong that even light cannot escape. To describe their properties, physicists have relied on complex equations from Einstein's theory of general relativity and quantum mechanics. But in the early 1970s, Stephen Hawking and other physicists found parallels between the laws of thermodynamics describing ordinary things—like how a stovetop boils a pot of water—and black hole mechanics.