Have scientists finally made sense of Hawking ’s famous formula for disorder in a black hole?

Fifty years ago, famed physicist Stephen Hawking wrote down an equation that predicts that a black hole has entropy, an attribute typically associated with the disordered jumbling of atoms and molecules in material. The arguments for black hole entropy were indirect, however, and no one had derived the famous equation from the fundamental definition of entropy—at least not for realistic black holes. Now, one team of theorists claims to have done so, although some experts are skeptical. Reported in a paper in press at Physical Review Letters , the work would solve a homework problem that some theorists have labored over for decades . “It’s good to have it done,” says Don Marolf, a gravitational theorist at the University of California, Santa Barbara who was not involved in the research. It “shows us how to how to move forward, that’s great.” Entropy is one of the most slippery concepts in thermodynamics. Why does salt melt ice on a sidewalk? The salt does not add energy to warm the ice. Rather, there are just far more ways to arrange the atoms and molecules that yield a puddle of salty water than there are arrangements that keep the two substances separated in their own crystals. That means the puddle has more entropy than the crystals, and the system evolves to the macroscopic state with the greatest entropy. However, a black hole is not a material object—it’s the gravitational field left behind when a massive star colla...
Source: Science of Aging Knowledge Environment - Category: Geriatrics Source Type: research