THE FORMATION OF
BLACK HOLES
Table of Contents
As I have mentioned before, black holes form from dying stars that are at least 2.8 times the suns mass. But how do these colossal objects die and what makes them form into a black hole?
Inside a star
Why do stars shine? I am sure that at one point in time you looked up into the sky and wondered this very same question. Well the answer lies in Fusion. Fusion, very different from fission ( which is when you remove electrons from and atom releasing energy ), is when you merge atoms together also releasing energy. This happens constantly within a star and it is the source of all the energy and heat coming from the star. Fusion depends on temperature and density is stars, and stars go through many different fusion cycles throughout their lifetime. Normally the first cycle is the fusion of 2 hydrogen atoms into helium, at higher temperatures, carbon is formed from helium, then at even higher temperatures, heavier elements like iron are formed.
Fusion is also vital to the life of the star. Since stars are so big there is a long of gravity, pushing on the star.
The fusion pushes back against the gravity so that the 2 forces are at an equilibrium. But when the star runs out of fuel to burn, they collapse under their own gravity to stars the size of Earth, called white dwarfs. It stops at the white dwarf because of Electron Degeneracy Pressure, which is a force that puts the quantum law, no 2 particles and occupies the same quantum space, into use. The electrons stop the collapse. But if the star is between 1.44 times the suns mass ( or 1.44 solar masses ) and 2-3 solar masses then gravity can overcome electron degeneracy pressure before stopping due to neutron degeneracy pressure and become a neutron star. If the star it anything above 2-3 solar masses then it will over come both electron and neutron degeneracy pressure and become a black hole.
Watch this video about Fusion and the power it holds.
Schwarzschild Radius
We know that you need to shrink a Star to make a black hole but how small does one need to make it? Well that depends on an objects Schwarzschild radius.
The Schwarzschild radius ( SR ) of an object is how small the radius needs to become in order to make it a black hole. The equation to calculate the SR of an object is ...
For example, If we wanted to find the Schwarzschild radius of the Earth, our equation would look like this.
We would get value of about 8.7 millimeters. If we did the same for the sun, we would get a value of around 3km. This means that you would need to shrink the sun down to 3km in radius and 6km in diameter if you wanted to turn it into a black hole. But there is another way to make a black hole. If you increase the mass of an object, its radius will increase but its Schwarzschild Radius would increase 2x as fast. If you plotted this relation ship on a graph, it would look this.
The blue line is the original radius and the orange line is Schwazschield Radius. As you can see by increasing the mass, there will be a point where the radius meets the SR, and at that point the object becomes a black hole. This could happen when 2 neutron stars collide.
Here are some videos to watch on the formation of black holes