Is the Black Hole Still There When We Look? --- Observing Quantum Gravity in Extremely Cold Horizons

Classically, black holes are perfect absorbers: any light that reaches the horizon is lost forever. But does this picture survive once the black hole is treated as a genuine quantum system? Addressing this requires confronting quantum fluctuations of spacetime geometry---normally the realm of inaccessible quantum gravity. Recent advances show that near-extremal, ultra-cold black holes provide a setting where such effects can be analyzed. Strikingly, when probed with light of decreasing frequency, the quantum black hole evolves from opaque to translucent and finally transparent, vanishing from view. I will review this and other new phenomena of extremely cold black holes, which offer unique glimpses into how quantum gravity can overturn even the most familiar features of classical black holes.