People say that a black hole is created when the stars die. But, it’s not enough that they die, it takes a lot more! The stars collapse in on themselves so much that they basically make a bathtub drain in the universe. This thing sucks in and drains to who knows where everything that dares come near them. This is that simple!
While there can be different forms of black holes, a common type of black hole is produced by certain dying stars. But all starts don’t have that ability. Only those stars that have a mass greater than about 20 times the mass of our Sun may produce a black hole at the end of its life.
How Black holes are created
In the normal life of a star, it has to experience a constant conflict between gravity pulling in and pressure pushing out. In the process, nuclear reactions in the core of the star produce enough energy and pressure to push outward. But the situation is not the same all time. Generally, in most of the time of a star’s life, gravity and pressure balance each other exactly. That’s how the star remains stable. However, when a star runs out of nuclear fuel, gravity gets the upper hand and the material in the core is compressed even further. The more massive the core of the star, the greater the force of gravity that compresses the material, collapsing it under its own weight.
What happens when a small star dies?
For small stars, this goes other way round. When the nuclear fuel is exhausted and there are no more nuclear reactions to fight gravity, the repulsive forces among electrons within the star eventually create enough pressure to halt further gravitational collapse. The star then cools and dies peacefully. This type of star is called a “white dwarf.” This type of stars doesn’t create a black hole.
When a very massive star exhausts its nuclear fuel it explodes as a supernova. The outer parts of the star are expelled violently into space, while the core completely collapses under its own weight. If the core remaining after the supernova is very massive (more than 2.5 times the mass of the Sun), no known repulsive force inside a star can push back hard enough to prevent gravity from completely collapsing the core into a black hole.
From the perspective of the collapsing star, the core compacts into a mathematical point with virtually zero volume, where it is said to have infinite density. This is called a singularity.
Where singularity happens, it would require a velocity greater than the speed of light to escape the object’s gravity. Since no object can reach a speed faster than light, no matter or radiation can escape. Anything, including light, that passes within the boundary of the black hole — called the “event horizon”. Here, everything is trapped forever.