Observational evidence suggests that supermassive black holes are located at the centers of many galaxies is rapid & sudden changes in the orbits of stars & other objects in the galactic center.
A black hole is an area of spacetime with such intense gravitational pull that nothing can escape from it, not even light or other electromagnetic waves. According to general relativity theory, a compact enough mass can bend spacetime into a black hole. The event horizon is the line beyond which there is no escape. Despite having a significant impact on the outcome and circumstances of an object traversing it, general relativity states that it lacks any locally observable characteristics. A black hole behaves in many ways like a perfect black body since it does not reflect light.
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