Understanding the evolution of the universe
The universe is a huge and mysterious place, human beings are just a minuscule spec in the vastness of the universe, yet we somehow have the necessary competence and mind to have an understanding of the universe, or as we like to think we understand.
Imagine from the perspective of a cat, lying with you on the sofa and watching television, but what according to the cat is going on there; you know that you are watching a movie which has a great story, cinematography, and acting; but for the cat, it’s just flashy lights and sounds coming out from a part of the wall and no matter how much you try to explain the cat the story of the movie, but the cat will just say meow, there is an upper limit of intelligence of cats and dogs and other animals, and no matter how much they try they won’t understanding astrophysics.
Is it the same with another animal of the animal kingdom, called human beings?
Do humans have an upper limit of intelligence, and no matter how much we try we can never understand certain things, just because monkey brains….
Q. Is there a limit imposed on human beings by nature itself?
Yes and no
Yes because we perceive the universe through our 5 sense organs, which are sight, smell, touch, hearing and speaking; let’s look at them one by one
Sight: We look at the universe in a certain way, we need light for our sight apparatus to work, and light comes in various forms, there’s a whole spectrum of lights, called the electromagnetic spectrum

And we just use a very tiny part of this spectrum called visible light, and we call it visible light because it just happens that our sun emits light in this particular range of wavelength, so we developed eyes that are suitable for this particular range, if our sun would be emitting energy in X-rays instead of the visible spectrum, we would have developed eyes that are suitable for X-rays and we would be looking at the universe in X-rays, it would be a totally different universe for us.
Right now we can only see a particular range of this whole light spectrum, there’s a lot of universe hidden in plain sight right in front of us; there are radio waves and microwaves right in front of you right now, but you can not see it, there’s a limit imposed by the nature itself of what we can and can not see in the universe.
Smell: Almost the same with smell also, a dog can smell more and better than human beings, there is a range and limit to what we can and can not smell.
Touch: Our touch perception is very much dependent upon how well our cells are workings, and cells’ functioning is very much dependent upon the surroundings, for example, if you go to a very cold place your touch perception mostly goes numb, now think of the universe, how good your touch perception would be when the universe is concerned.
Have you ever experienced that something touched you but you were not able to see what, just a feel?
Hearing: Like all the animals humans too have a hearing range, there’s a limit to what we can and can not hear

The human range of hearing the universe is just from 20-20,000 Hz, a dolphin can hear much more than us, again nature has put a limit to what we can and can not perceive in the universe.
Speaking: What we speak totally depends upon the language we speak, and obviously, there’s no universal language(yet, or as far as we know), so even if someone comes and speaks to us, or if someone is speaking to us right now, we can not know, maybe that “thing” is outside our visible range, outside our hearing range, and outside our known ways of communicating, like that cat we can not know the story going on right in front of us.
No, because although nature has put our bodies under certain limitations, but has also provided us with tools to surpass those limitations, we just need to make ourselves competent enough to access those tools.
For example, we have limitations to our sight, but someone got access to the tools of intellect and made cameras which can see into other spectrums like X-rays, gamma rays, infrared, and the rest of them.
But again who knows, maybe there are more spectra outside this electromagnetic spectrum.
We were given a limitation of being stuck to the ground, we can not fly, well we build rockets.
We were given the limitation of not being able to communicate with the universe, well we discovered mathematics.
So we just need to tap into our intelligence and get access to the tools using which we can surpass the limitations that nature has put on other animals but we can go past them.
Q. How much have we understood about the universe?
Well quite less to be honest, and in that also we don’t if we know it correctly.
To begin with, we know that only 5% of the constituents of the universe is visible matter, every star, every galaxy, every planet everything that you can “see” in the universe constitutes just 5% of the universe, rest 95% of the universe, we have no clue what it is, well we have some theories, like Dark matter and dark energy, where dark matter constitutes for almost 25% of the universe, we can not see it, feel it, hear it or interact with it by any means, we just know there’s something out there because of how light is behaving and Dark energy constitutes for almost 70% of the universe and is said to be something that is responsible for the accelerated expansion of the universe.
Dark matter and dark energy are those empty cheques of the universe which we have no idea how to fill it up.
Dark matter is something that we know that we don’t know, Dark energy is something that we don’t even know what we don’t know.

Q. How did the universe begin?
This is a very profound question which may or may not have one or any correct answers.
One of the leading theories about the origin of the universe is called the “Big Bang Theory” which states that the universe was created almost 13.8 billion years ago from an infinitely small and dense point called a singularity. According to this theory, there was a huge explosion in that singularity(because, reasons) and everything that we know of today came out of that explosion.
We came to this conclusion because in 1929, Edwin Hubble, using the largest telescope of the time, discovered that the more distant a galaxy is from us, the faster it appears to be receding into space, i.e. the space or the universe is expanding, and if we trace back that expansion in time it should eventually come to a single point, the singularity.

So it solves some of the problems like why is the universe expanding, but it gave us some more questions like what caused that singularity to explode? What was there before that singularity? How did that singularity come into being?
So to answer these questions, we came up with more theories.
Another theory for the origin of the universe is called “Big Bounce”.
It says that the expansion of the universe will eventually stop and after that, it will start to collapse back into a single point, so because the whole universe will be concentrated into a single point, because of extreme pressure it will explode and expand, again the expansion will eventually stop and the whole universe will collapse back into a singularity.
So this theory answers some of the questions like, what was there before the singularity? What caused that singularity to explode? How that singularity came into being?

But this theory also was not able to answer some of the questions like why is the speed of expansion of the universe increasing. It has been experimentally verified that the speed of expansion is increasing, how’s that? And if the universe kept on ever-expanding what will happen after that?
The third leading theory in this context is “Eternal cyclic universe” or “Conformal Cyclic Cosmology”
This theory was given by Nobel prize winner Roger Penrose.
According to this theory, the universe began from “Nothing” and if the universe kept on expanding; all the particles will be so far away from each other that “Nothing” will be left in between them, which again imitates the circumstances of the beginning of the universe and then due a phenomenon called “Quantum fluctuations” a new universe will begin from that “Nothing”.

Well, again some people believe that the universe is flat(Scientifically proven, and no it doesn’t mean that the Earth is flat) and it has always existed and will always exist, with no beginning and no end.

Some people believe that the universe is inside a black hole because we don’t know what is inside a black hole, there might be a universe inside it, and if that’s the case even our universe might be inside a black hole, who knows?

Some people believe that there is no universe, to begin with, the whole universe is a part of a video game(Yes, this is actually a scientific theory, called a simulation hypothesis). According to this theory, as in a video game, the universe inside the game is immediately created as soon as the player goes to a certain place and the whole universe with all its constituents is just a bunch of binary codes and nothing is “real” that can be the case with our universe also.

Some people believe that the universe is just a “thought” inside a brain(Yes this is also a legit scientific theory, called “boltzmann brain”); according to this theory, only one thing exists in the universe and that is a brain, and that brain is simulating the universe inside it, kind of like how we dream, we create a new universe inside our brain.

According to quantum mechanics, a new universe is created every instant and every time a decision is made.
