Most Mysterious Question That is Not Solved: Black Holes

## Introduction

Today, we are gonna show all that we know of one of the most extreme, mysterious, unpredictable, most dense, invisible, and the one and only black holes. As we know, black holes are incredibly unpredictable, probably the most unpredictable in history. So, let us dive in.

## The "Real" Introduction

Black holes are very extreme and dense 3D objects, that has been on the universe, they have been scaled to be as small as a city weighing 3-4 suns minimum, to 2/3 of nebulas, that are ranging to 66 billion solar masses.

### What is solar masses?

Solar masses are meant to scale the mass of a sun, for example, the density of 1 sun is 1 solar mass. So, if something, like about 3 suns dense, that means that it is 3 solar masses. Let's have this with a better example, our Sun is about 99.98% of the density in our Solar System. Now, if something, about 5 times the mass of our sun, is there, well, that means it is 5 solar masses. The formula is: 99.98% x 5 for Solar System object and orbit. So, solar masses means, times as dense as the Sun (Sol).

## What are the 2 main types and all the categories of black holes.

Firstly, we have to talk about all of the categories. The first one is also the first main category of black holes, called, Stellar Mass Black Holes. These ones are particularly baby black holes, and gave birth when a massive star, 3 times the density of the Sun, explodes into a super or hypernova. Either way, they will form a black hole once they die. The size of them is about 15 kilometers, the size to an average city, to about 70 kilometers, which is the size of the largest cities. They have a mass of 3 solar masses, to about 40 solar masses or a bit more.

### Unusual Intermediate Black Holes

The next category is the most unknown one out of all of the categories, with also the main ones. The name is Intermediate Black Holes. These things are as the size of moons and planets, ranging from 1000-about 10000 solar masses, they also have the diameter from 2000 to 12000 kilometers and they are not that common.

### Supermassive with Hyper Massive Black Holes

The Supermassive is the next and final main category and the second last category of the black holes, apparently, they are the size of the Solar System, and is tens to hundreds of millions of solar masses, but the density did not get there, the Hyper Massive black holes, are billions of solar masses, and is tens of the size of the Solar System.

## The Weird Difference between of the Black Holes

Now, the weird thing about a black hole is that the bigger it is, the weaker the gravity. However, the stellar black holes is smaller, so they are stronger, and since the larger ones like the Hyper Massive Black Holes, are billions of times larger, maybe even trillions, are weaker than the stellar mass black holes, so that is the weird difference.

## How do they appear? (Stellar Mass and Intermediate Black Hole Version)

### The Beginning of a Star Death

Now, we now know basic things of a black hole, now, we are gonna talk how did they appear. When a very massive star begins to die, their hydrogen starts running out to be exhausted, and the star loses it's fuel, hydrogen then fuses to helium at their cores, making them more dense, and packed together. When helium has more fuel than hydrogen, for example, hydrogen fuel is about 37.5% while helium fuel is 62.5%, they began to swell.

At first, it starts of slow, then, it gets bigger, the average star needs to swell to 50 times the capacity of it's size, meaning it will be 50 times larger, however, if the star is very massive, it is likely to swell about 200-400 times its normal size. When this happens, the helium will be denser, and create carbon. Not just that, but the mass will go away and the brightness of the star became brighter and brighter.

When carbon is done, the star may shrink again, when the carbon turns to neon, the core will start to be crushed, and the mass will increase several times there, when it turns to oxygen, the brightness will be incredibly bright, the heat will be hotter than usual, and the star will be almost its natural size again. When the star turns to silicon, the gravity may increase tens of times, and the star will spin faster. When it reaches to iron, scary things happen, the core then will be crushed by its layers, giving the core such density, that it implodes with 25% the speed of light and a fraction of a second, it implodes.

### The Red Nova, Super Nova, and Hyper Nova.

When the star dies, it will burst and explode, with billions of nuclear bombs setting off all at once of the energy. Things near it will be hit by lethal doses of radiation and heat, with also destruction to the mix. Normally, it will be a red nova, a nova explosion larger than average nova explosions, but if the star is slightly more dense, it will be a super nova, the most common for massive stars, and if the star is even more dense, it will be a hyper nova explosion, the strongest nova out of all categories.

### The Choices.

After the star dies, the core may remain, and then 2 options will come. If the star at least 3 times the mass of our sun implodes, there is now a chance that the core will be a black hole, however, if the star is less than 3 solar masses, that means that it is likely to be a neutron star.

## How do they appear? ( Supermassive and Hyper Massive Black Hole Version)

### The Beginning

When the universe is born, The Big Bang theory is explained the most, and some say that the larger ones are too big to be real that it was created on the explosion, so some put the finger blame at the Big Bang theory. Why? You might ask?

### The Reason

The reason why they put the blame is because of 2 reasons, firstly, it was the beginning of everything, and secondly, the black holes are way too big by an explosion of a average star.

## The Circular Matter Around Black Holes

So, now we know the basics of a black hole, let's talk about the matter cycling around the black hole. As we have to know, black holes are incredibly strong and all near it is trapped inside forever, but matter could cycle around the black hole, and that matter cycle is called, "The Accretion Disk". It is a very large disk, of matter surrounding it. The black hole's rotation is very fast and effective, that the speed emits incredibly high amounts of heat, so passing the disk is very hard, as there are two main reasons, the first is the most obvious.

It is large and wide, and also hot, with lethal doses of radiation, the second is that it might pull you and brings you around. Now, the Accretion Disk also spins fast, up to 90.0% of the speed of light, while the average speed is 50.0% the speed of light.

## The Event Horizon

Now, this one will be familiar, but for those who don't know, I will explain. Each and every black hole has a point or zone of no return, that is simple called, The Event Horizon. The Event Horizon is the last layer before entering the inner parts of a black hole, as nothing, even light can escape. If something falls through the event horizon, they will be trapped, forever in the depths of the darkness. The Event Horizon is also where the gravity starts to bend so much, that science and physics can't do well and know what really is inside of a black hole, either way, you explore in and found out what it is, but only to realize you can't return back at all.

## The Center of This Monster ( The Singularity)

There is a center to every part of a black hole, where all the mass is concentrated. It is called, "The Singularity". The Singularity is a infinitely small dot, that is 0-dimensional (0D), where gravity and density became infinite, and space curvature became infinite. However, Like I said, the Singularity is an infinitely small dot, with no surface, length, width, height, and volume. It is just, nothing. The Singularity is the most mysterious part of a black hole, because there is only a small point of data that is only discovered, and this is just theories, so we don't know what is really going on.

## Hawking Radiation Process

Now, you might wonder, how do black holes evaporate one day and die? Well, quantum fluctuations in the space floor bounces and creates particles and anti-particles, and they lived in a short time, before they annihilate each other. If one of these fluctuations happens near a black hole, the particle facing it will drop down to it's black hole, and the other steals the mass from it. It is called to be, "Hawking Radiation".

### Death of Every Black Hole

When this happens, it is incredibly slow at first, but year by year, it speeds up a tiny bit, and eventually, the black hole is losing mass faster than it absorbs, and it will get smaller overtime, after about 10^67 years, the smallest black holes will evaporate away with billions of nuclear bombs, packed into one, and then, nothing. However, even the long time when all the things die there, not a single black hole would have evaporated. Some of the biggest black holes like TON 618, or J2157, will evaporate at like 10^100 years, which says as googol, at their mass. So yes, hawking radiation is the process of evaporating a black hole.