It’s a longstanding pain point for physicists: Their theory of gravity, general relativity, predicts that a black hole must contain a singularity, a point where space and time are infinitely warped and the laws of physics break down. Many researchers hope that a theory combining gravity and quantum mechanics—if it can ever be discovered—will someday remove the thorn. However, a full-fledged theory of quantum gravity may not be necessary, two theorists argue independently. A pinch of quantum mechanics—in the form of an effect called Hawking radiation—may suffice, enabling a black hole to form, age, and evaporate without creating a singularity. “If you had asked me beforehand whether such a result is possible, I would have said no,” says Astrid Eichhorn, a theoretical physicist at Heidelberg University who was not part of the studies.…