A black hole is one of the most mysterious entities in the universe. Finding them is difficult because they do not emit any light, so they are virtually invisible.
Black holes have extremely strong gravity due to it’s unbelievable mass. The are formed when a large, very massive stars die and collapse inward after it’s burnt it’s hydrogen fuel. Due to the strong gravity no particles or not even a light can escape from a black hole.
Quantum theory show that every black hole emits radiation as well. This seems to contradict the statement that nothing can escape the black hole. However, the process can be interpreted as the production of particle / antiparticle pairs close to the event horizon, where one of the particles falls into the center of the black hole while the other escapes from it. In this way, a black hole can release particles without anything exceeding the event horizon from the inside out. The energy for this process called Hawking radiation comes from the gravitational potential of the black hole. So that it loses mass due to the radiation.