en.wikipedia.org
Black hole
Compact astronomical body
- A black hole is an astronomical body so compact that its gravity prevents anything, including light, from escaping.
- Albert Einstein's theory of general relativity, which describes gravitation as the curvature of spacetime, predicts that any sufficiently compact mass will form a black hole.
- The boundary of no escape is called the event horizon.
- In general relativity, crossing a black hole's event horizon traps an object inside but produces no locally detectable change.
- General relativity also predicts that every black hole should have a central singularity, where the curvature of spacetime is infinite.