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Blackhole - Beginning to end

Updated: Apr 16, 2023

BLACKHOLES - Introduction

Blackhole is region in space time where gravity is very high that it bend space time infinite such that nothing can escape it, not even electro magnetic radiation.


BLACKHOLES - Structure

Event Horizon :- It is boundary which separates Black part and glowing part. Here escape velocity is equal to speed of light. So nothing can escape a Black hole.

Singularity :- It is a point inside black hole where mass tends to infinity but volume is zero. Ya so here Gravity breaks and it indicates failure of Theory of relativity .


The Schwarzschild radius :- It is radius which define size of event horizon or Black hole.


BLACKHOLES - Birth

A super massive star (at least 3 times mass of our sun) when die forms Neutron star or Blackhole. If mass is lass than required mass than it will form white dwarf. If star is massive enough to trap light it form Black hole or it become Dense Neutron star. This limit was given by Indian scientist Subrahmanyam Chandrasekhar and thus it is known as Chandrasekhar limit.


BLACKHOLES - Death of Star

We know that star is made up of hydrogen gas. This hydrogen atom fuses together to form helium atom and release large amount of radiation When force of radiation balances force due to gravity star remains star. This force of radiation balance gravity till star start fusing iron. Fusion of iron do not provide sufficient force to balance force due to gravity as a result start get collapse into it’s own gravity. Now according to Chandrasekhar limit One of three :- White dwarf, Neutron star or Black hole will be form.


BLACKHOLES - Death of Blackhole

According to Quantum field theory, our universe is made up of different fields. Vibration in these fields produces what we called particles. For eg :- Vibration in Higgs field create Higgs boson (ie, God particles), Vibration in electro magnetic field create Photons. Same way vibration in quantum field produces particle and anti particle for infinitely small amount of time lets say it dt. When these phenomena occur near event horizon anti particle take mass of particle and starts it journey traveling away from event horizon. Thus mass and energy of Black hole reduced. This is very slow process. This process is known as Hawking radiation.


BLACKHOLES - Why they are Amazing ?


Time dilation

In theory of Relativity gravity is wrap/bend in space-time and if universe is one play/drama Space time is stage on which it occur. “ Mass bends space time and bend space time tells mass how to move”. So Black hole bend space time infinitely due to which time gets stuck. How ? Let’s see. Time is relative term. To define time we need reference. So lets take two points in space and named it A and B. Now lets take one particle. Now particle start it’s journey from A to B and comes back. Whatever happen now lets term it as 1 second. So time is nothing but it is measurement of repetitive moment of any object for an instant what we call 24 hours ? When earth completes one rotation on it’s axis and it is also repetitive moment. Lets come back. Now what if path through which these particle travelled get distorted ? Points are at same place in space but time get slow ? Why because particle has to travel extra distance but we didn’t change definition of time according to wrap in space time. So now imagine this event occur near black hole. Time gets stops.


Black hole Information paradox

To understand these let me give you an example, we all are sitting next to any device lets say any laptop. Now I tell you to give me information on laptop, what will you give me ? It’s processer name, color, memory, graphic card and all that right ? But is it important? For most of us it is but for scientist it is not. They care for Quantum information or Quantum numbers like principle quantum number, azimuthal quantum number, spin quantum number and magnetic quantum number. When your laptop is destroyed it’s quantum information remains same even if your mom throw your laptop away. But information such as detail of processer get destroyed. If you have quantum information of your laptop, with special type of holograms you can create same laptop. These is law of conservation of Quantum information. But now if your laptop is thrown into a black hole we don’t know where that quantum information has gone. Is it supplied to another universe or It is present in 2D event horizon or may be it got converted into hawking radiation – Answer of these no one knows. May be whole world is just a 3D hologram of these 2D information who knows


Black hole electron

So lets find out how Black hole which is astronomical entity can be related to electron which is elementary entity. What happens when we relate them ? So we use Theory of relativity to govern laws of physics which are applicable to Astronomical sized objects such as stars, planet, blackhole etc. We use Quantum mechanics to govern law of physics which are applicable for elementary particles which are extremely small. Like electron, quarks, neutrino etc. We don’t have any model which unify both of these. So Lets come to the point. What the hell is Black hole electron hypothesis. In short Black hole of size same as that of electron is blackhole electron hypothesis. If black hole with same mass, charge as that of electron would share all the properties of Electron. Black hole of such a small Schwarzschild radius will represent Singularity which is present inside a blackhole. So can we treat electron as singularity as all properties are same. Which theory we will apply as we apply theory of relativity on black hole and on other hand quantum field theory is applicable for electron. In calculation we will ignore quantum effects, electric charge and angular momentum of black hole. So this was crime – to relate general relativity and quantum mechanics.


Ergo sphere

Next thing come in our list is Ergo sphere. When Black hole spin too fast, it twist whole space time. Speed of spacetime depends on radius and it is inversely proportional. Means greater the radius from black hole lesser the speed of twisted space time. Here to remain stationary with respect to observer , observing from distant place where ergo sphere is not there (or inertial observer) he need speed more than that of speed of light. Speed of these different point decreases when we move away from blackhole. Locus of these point on space time forms shape like pumpkin. Set of all such points is called as Ergosurface.

So here we come to an end of article, hope you like it.


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