Curiosity is welcome here!
Our universe is a beautiful place, it contains everything that we know about and everything that we aspire to know about. It gave us birth and one day, unfortunately, will bestow upon us death. There are an infinite number of secrets hidden inside the cosmos and this website is entirely dedicated to uncovering as many that are humanly possible.
This is one of the most fascinating topics I have written on and the only thing one needs to understand them is the want to learn something new! (Let’s utilise the free time we have inside the protection of our homes for being productive and learning something new!)
So grab some snacks and get ready to have some fun with science!
I would recommend reading a previous post called The Basics of Black Holes before reading this one to get a better understanding of what black holes really are, how they are born and how they will eventually perish, but don’t worry I will try and include brief explanations about previously explained concepts here to prevent new readers who haven’t read the previous post from feeling lost.
The black hole information paradox and the holographic principle
With his theory of General Relativity in 1916 Albert Einstein predicted the existence of certain astronomical anomalies that in 1967 were coined ‘Black Holes’ by American Astronomer John Wheeler. Since their theorization black holes have single handedly managed to change all our existing perceptions of the universe and have fascinated curious minds around the world.
Black Holes have not only caused destruction in our universe but also could render our current understanding of it useless. How?
This threat is in the form of the ‘Black Hole Information Paradox’. To understand this contradiction between various laws of physics we will have to understand the law of ‘conservation of quantum information’.
In our everyday lives information would mean the knowledge of the physical properties of something or someone. Quantum Information on the other hand in very technical terms is the information of the state of a quantum system.
Everything in our universe is made up of atoms which are made up of particles like electrons, protons and neutrons. Quantum information is nothing but the knowledge of the quantum properties of these particles, ‘quantum properties’ no matter how complicated the name sounds are just – the position, velocity, charge, spin, etc. of the particles.
In very simple words, quantum information is the knowledge of the arrangement of these main constituent particles. For example, The same pieces of lego can create a bridge as well as a house. The only thing that changed was the arrangement of the legos, ergo, the information is what changed between the two figures.
Hence, the knowledge of these properties of an object would theoretically allow us to recreate it no matter what we physically do to it. This information is never lost and always exists in our universe. For example, if we incinerate a piece of garbage the remains still contain the quantum information which could allow us to create that same piece of garbage given the right equipment. Just like breaking a lego model into its constituent pieces but building it again using a predetermined process.
The Conservation Of Quantum Information
Quantum Mechanics(Branch of Physics) requires the total amount of quantum information in the universe to be conserved.
Therefore, the law of conservation of information states,“Information can be created or transfered, but cannot be destroyed.”
Here is where black holes come into the picture, when any kind of matter enters a black hole the quantum information of that specific body also enters the black hole. This information then is assumed to be lost forever and irretrievable. That is not a problem as the information is not destroyed and goes to someplace which we are not exactly aware of.
The main conceptions are that the quantum information of the matter entering the black hole is plastered onto its two-dimensional event horizon(The region beyond which even light cannot escape the gravitational pull of the black hole, surrounds the black hole), which might be possible as to an external observer anything going inside the black hole would slowly be disintegrated and smeared around the horizon. The other conception is that the quantum information that enters the black hole is lost in there forever. These theories will be discussed further ahead.
The problem arises when Black Holes die out due to Black Hole evaporation by Hawking radiation, potentially destroying all the information within them.
This phenomenon was already discussed in detail in a previous post called The Basics of Black Holes which I would recommend you read before moving ahead but this is a similar and thourough explanation of it. If you guys are familiar with this concept you can either go over it again or skip to the next section.
Our universe is very chaotic at the sub-atomic level, pairs of virtual particles are continuously created and removed from existence through their action on one another.
These particle pairs usually consist of a particle and its anti-particle, when these both come together they self annihilate.
When virtual particle pairs form on the event horizon(Boundary around a black hole beyond which not even light can escape the gravitational pull of the black hole) of a black hole hawking radiation is created.
Hawking radiation is nothing but the term given to radiation the black hole emits, this energy cannot be created from the black hole as according to thermodynamics ‘Energy cannot be created nor be Destroyed’. Then where does this radiation come from?
On the event horizon pairs of virtual particles tend to lose one particle out of the pair into the black hole, this ejects the other one out into space. The particles ejected out get converted into real particles and form this radiation.
The particles ejected out need energy to turn into real particles, this energy is given up by the black hole and results in it losing some of its mass.
Slowly and steadily over a very long period of time Black Holes evaporate into nothing through this process.
Creation of a Paradox
When we consider the fact that Black Holes will eventually get destroyed at some point in time, this means that the quantum information they collected in their lifetime gets destroyed along with them.
Hence, creating a paradox. If information indeed gets destroyed along with the Black Hole, then the basis of our understanding of the universe would have to be formulated all over again.
The First proposed solution we will discuss supports the theory that states that the quantum information entering the black hole is plastered or engrained onto the 2-dimensional surface of the Black Hole’s event horizon. As, with increase in mass of the black hole, the surface area of its event horizon also increases, allowing more information to be stored.
The solution proposed says that the quantum information of everything that went inside the black hole somehow gets imprinted on the Hawking radiation produced by it allowing the black hole to evaporate and the information to still exist in our universe, not violating the law of conservation of information.
This theory leads to various possibilities such as the fact that our universe might be a hologram. More on that later…
The other proposed solution gives rise to the idea of other universes connected with ours through Black Holes and also the existence of White Holes which are the theoretical opposites of Black Holes.
This hypothesis says that the quantum information going inside a Black Hole is not plastered on its event horizon but travels through the black hole into possibly another universe, where it is lost forever but not destroyed. This would be permissible as the information is irretrievable by us but is not destroyed.
The Holographic Principle
If the Quantum information of a 3-dimensional object entering a black hole is stored on the black hole’s 2-dimensional event horizon then that would mean that whatever the object exists as inside the black hole is a projection of the quantum information stored on the outside. How?
Let’s assume you are falling through a black hole, when you cross the event horizon the quantum information of your body is plastered across its 2-dimensional surface and stored there. According to an external observer outside you are stationary in space but slowly disintegrating and being plastered on the event horizon, but for you, you are going through the black hole and inching closer towards the singularity.
This means even after your information has been stored you continue to have real life experiences. Your information is gone but you are still conscious as a projection of your quantum information stored somewhere else.
Similarly, the holographic principle states that, “The description of a volume of space can be thought of as encoded on a lower-dimensional boundary to the region.”
This basically means that if the boundary of our universe is of a lower dimension (2-Dimensions) then all the contents inside that boundary could just be a projection of the quantum information encoded on that surface. Making us and everything we know, a magnificent hologram.
This paradox has pushed intellectuals to create unique and new theories to describe our universe. This is one problem which is at the heart of theoretical physics whose solution might just lead us to the sought after ‘Theory of Everything’ which would be able to bring Quantum theory(Explains the behaviour of matter and energy on the sub-atomic level) and General Relativity(Current description of gravitation in modern physics) together into one beautiful and concise description of all physical phenomena in the universe.
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-Kulvir Chavda (Writer)
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