2. Stars about the size of our Sun burn out, become red giants, and then evolve into a white dwarf. More massive stars become luminous giant starts. When their nuclear energy is exhausted gravity is the only force left. The star collapse inward, and exploding mantles hurl outward, and the star becomes a brief blazing supernova. The star collapses so suddenly and so violently that nothing can stop it.
Gravity overwhelms all other forces, and all matter falls deep into the star.
The star becomes smaller and smaller, denser and denser. As it collapse, the escape velocity increases until it is equal to or grater then the escape velocity of light. Not even light is fast enough to escape from the pull of gravity. We cannot see black holes, because they emit no light energy. Black holes have tremendous gravitational forces.