The Galaxy NGC 4151 called the, "Eye of Sauron" due to its similarity to the eye in the film Lord of the Rings. The image shows the supermassive black hole, which is still active, that is to say that it engulfs gas and dust clouds from its surroundings. In this process, it emits ultraviolet radiation, which heats the ring-shaped dust cloud that orbits around the black hole at a distance and this causes the dust cloud to emit infrared radiation.