Black hole, artwork. Surrounding gas and dust are spiralling into the black hole, dragged by immense gravitational forces. This forms an accretion disc (purpleyellow). The extreme conditions cause the emission of highenergy jets. A black hole is formed when the core of a star collapses under its own weight, increasing its gravitational field to the point where, beyond a boundary known as the event horizon, nothing, not even light, can escape. This leads to its black appearance. Only stars of a sufficient mass will form a black hole. In the background is the bright band of the stars of the Milky Way galaxy.
