Black holes are thought to arise when very massive stars collapse, creating regions of space from which neither light nor any other form of matter can escape. The centers of many galaxies, including our own Milky Way, are believed to contain supermassive black holes, millions to billions of times more massive than our Sun. By definition, you can’t “see” a black hole, but you can infer its existence from its effect on the motion of nearby bodies.

Source: Wall Street Journal January 03, 2019 16:51 UTC