A star with a mass greater than about 20 times the mass of our Sun may produce a black hole at the end of its life. This collapse establishes gravity victory over the star. In other words, it is the ultimate death if the star, including its core. Then the core compacts into a mathematical point with virtually zero volume, where it is said to have infinite density. This is referred to as a singularity. When this happens, escape would require a velocity greater than the speed of light. No object can reach the speed of light.
Last but not least, Scientists have expected a kind of supernova evolving explosions of much more massive stars that are incredibly powerful and leave nothing behind not even a black hole. But no one till now had seen any of this.
BLACK HOLES