human
I'd like to learn more about astronomy. What are the most important facts about black holes?
assistant
The most important fact about black holes is that they are incredibly dense objects with gravity so strong that not even light can escape from them. They have such immense mass and gravity that nothing, including light, can escape their powerful pull. Black holes also emit radiation known as Hawking radiation, which is caused by quantum effects near the event horizon of a black hole. This radiation has been observed in several astrophysical sources.