Penn State physicists use entropy law to predict black hole merger outcomes

Somewhere in the vast architecture of the cosmos, two black holes collide — and physicists at Penn State have found that even this most violent of events obeys a principle as old as the steam engine. By applying the laws of thermodynamic entropy to black hole mergers, the researchers have discovered that the second law — entropy never decreases — acts as a natural constraint on what can emerge from such collisions. This insight bridges the long-standing divide between general relativity and quantum mechanics, suggesting that nature's deepest rules govern the extreme and the everyday alike.