A black hole’s event horizon marks the point at which not even light can escape.
A black hole is a mysterious and extremely dense object. A black hole cannot be seen directly,but it can be revealed by stars moving around it — or sometimes by a hot, bright disk of material orbiting it. Some black holes are stellar remnants, others are supermassive ones in the centers of most large galaxies. Scientists have theorized that in a Black Hole’s center, gravity is so strong due to infinite density that the spacetime curvature ( e.g. gravity) becomes infinite. This is called a singularity and is described by general relativity. A black hole’s event horizon marks the point where not even light can escape. Tidal forces will shred and “spagettify” any object close to the event horizon.
Image obtained with the Event Horizon Telescope of the shadow of a supermassive black hole at the center of the galaxy M87. It has a mass of 6.5 billion times the mass of the Sun. The bright ring is an emission arising from hot gas swirling around the black hole near the event horizon under the influence of strong gravity. Against a bright background, the black hole appears to cast a shadow. Credit: Event Horizon Telescope collaboration et al.
Anatomy of a supermassive black hole. Black holes are typically surrounded by an accretion disk swirling around it, feeding it with gas and stars. The accretion disk also emits huge amounts of radiation which makes it detectable over large distances. There is an event horizon that marks the point of no return for light — and anything else — and a singularity in its center that arises from infinite density. As a powerful jet, it spews out massive amounts of material which impacts not only the surrounding regions but the entire galaxy and its evolution.