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Black Holes- Part 1

Hi guys,

New guy here 😀 . I’m Jackson and you would have known me by now after being mentioned in some of the previous posts. However, if you are new to this blog, I am Clyde’s classmate and often discusses Science topics with Clyde. And yes, I am also the new admin here. As I am new here, I will start with an easy topic that requires not much concept          — just fun facts and no Math at all– unlike the mind-boggling Special Relativity that Clyde is doing. Without further ado, let’s jump into one of the most interesting topic, ‘Black Holes’.

Okay, so What is a Black Hole? 

Just from the name itself, most of you would have guessed a hole, a tear in a paper, a pit in the ground. In fact, it is a hole in space time itself, a hole where time slows down so much that you will eventually reach a point where it stops, a hole with an attraction so great that not even light, the fastest thing in the universe can escape. It is an area in the universe where if you drop into…… whoosh, you will disappear, cease to exist, voided from the rest of the world. Sounds dreadful eh? The idea of Black Holes started of as just an abstract concept that was not supported by any evidence and not many scientist believed it exist. Only in 1931, when an astronomer by the name of Chandrasekhar calculated and gave mathematical evidence of potential high mass stars that could form Black Holes, did scientist started paying attention to it.

Even until this day, no scientist has truely understood this mysterious entity, all the laws of physics break down at the singularity of a Black Hole and since no information can escape, there is no way to observe the events at the singularity.

Let’s look at the science of a Black Hole.

Formation of a Black Hole

Imagine an object that is constantly being compressed, its volume will decrease while its mass remains the same, this causes the object’s density to increase as, desity = mass/volume, the mass is a constant hence, a lower volume divided would cause a higher density. An increase in density would also cause the object’s surface gravity increase. As the object is compressed, the object will eventually reach a size where it would have a surface gravity so great that not even light can escape, this is known as the  Schwarzschild Radius. At this point, the object would no longer be able to hold against its own gravity and would collapse infinitely into a point in spacetime known as the singularity, forming a black hole.

However, compressing an object into its Schwarzchild Radius and making a self sustaining Black Hole with brute force is unrealistic and is immensely difficult (so don’t even think about squeezing your golfball into a star hungry galatic black hole of mass destruction to take over the human race). In fact, you will need the power of the stars.

Stars are fueled by nuclear fusion. The proccess of nuclear fusion is basically the combination of two atomic nuclei, releasing the binding energy within the atom. In this proccess, the total mass of the two nucleus decrases, as they are being converted into energy, hence proving the mass energy equivalence. You can find out how much energy is released by finding the change in mass of the atoms and multiplying it with the speed of light squared (3×10^8^2). As the speed of light is HUGE, the energy released, which uses the square of the speed of light, would be unimaginable.
Let’s get back to point, the stars in the universe all start out with one element, Hydrogen. These Hydrogen atoms undergo nuclear fusion and fuses together to form Helium. Helium would then continue fusing to form Carbon, Oxygen and so on. As fusion occurs in a star, energy would be given out as radiation. The radiation would be causing the outward force that prevents the star from collapsing into itself. Usually, an averaged sized star would not have enough energy to continue nuclear fusion after all the carbon has fused to form oxygen, they would cool down into a white dwarf. However, a star that is much more massive would continue the fusion proccess all the way until iron atoms are formed. As iron atoms can no longer fuse, the proccess stops. By then, so much pressure would have built up from the outward force the star is exerting against its own gravity to balance out. Once the fusion proccess stops and the star no longer emits radiation, the gravitational force would suddenly overwhelm the star’s outward force, and in a short period of time, all the matter rushes inwards to the center of the star.

This would be followed by an explosion known as supernova or sometimes even more powerful explosions known as hypernova. After that, the collapse would either stop, forming a neutron star (the densest and smallest stars known to exist in the universe, it is so compressed that all the electron have the energy state to combine with protons to form neutrons, in a proccess known as inverse Beta Decay) or have high enough mass to continue collapsing into a singularity, creating a black hole.

There is another way in which Black Holes can form from the collision of two neutron stars but I will not go into detail on that.

Thanks,
Tiong Jackson :p

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