Experimental physicist Daniela Angulo poses with an apparatus in the physics lab at the University of Toronto. Scientists have long known that light can sometimes appear to exit a material before entering it—an effect dismissed as an illusion caused by how waves are distorted by matter. Now, researchers at the University of Toronto, through innovative quantum experiments, say they have demonstrated that "negative time" isn't just a theoretical idea—it exists in a tangible, physical sense, deserv...