Illustration showing tidal disruption event (TDE) based on ASASSN-14li event observed by NASA's SWIFT satellite. TDEs occur when a star passes close to a supermassive black hole and gets torn apart by the gravity of the latter. The debris forms a fan-shaped pattern around the black hole before eventually falling in. Here, the debris from the tidally disrupted star collided with itself causing shockwaves. These shockwaves emitted ultraviolet and visible light (purple, top right).