How long does the black hole stage of a massive star last?
1 Answer
The black hole stage of a massive star lasts indefinitely.
Explanation:
A black hole forms when the core of a large star collapses under gravity to a volume smaller than its Schwarzschild radius
Where
The black hole has an event horizon which is a surface through which material can pass but can never return.
Once created a black hole lasts indefinitely. It can get bigger if additional material falls into it. Black holes can also merge to form a bigger black hole.
The only known mechanism for a black hole to end is through Hawking radiation. Even in empty space, particle-anti particle pairs can form borrowing energy to do so. The particle and anti particle normally annihilate each other returning the borrowed energy. If such a pair forms near to a black hole, one particle can fall into the black hole and the other escapes. The energy of the escaping particle has to come from the black hole. Hawking radiation can cause a black hole to slowly evaporate.
We actually know very little about black holes. There are even theories that they don't exist. In any case our physics is unable to describe a black hole. We need new physics to understand them better.
