The science

The black hole acts like a sink, the matter in the accretion flow swirls around the hole, and speeds up when it gets closer and closer to eventually either disappear inside the hole or escapes via a magnetized outflow that we call a jet. Since no light or matter can escape from inside the hole, we see a hole in the accretion flow, this is called the shadow of the black hole, the darkest region in the universe.