The universe will end with Big Rip, Big Freeze or Big Crunch
Now it is almost certain that the universe began with Big Bang. Whether the Big Bang was made by a supernatural/scientific force or by itself, but it is bound by its own rule that what is made is to be destroyed. It can be any mode of its destruction but scientifically three types of theories are given. Big Rip, Heat Death / Big Freeze or Big Crunch.
First, if we fossick the theory of heat death or Big Freeze, it is derived from a law of thermodynamics which says that in billions or trillions of years, the matter will end by turning itself into radiation gradually. All-stars will lose their energy. One day the universe cool completely and sink into darkness. Every energy that speeds it will be exhausted and everything will become stable/ still after being cold.
Apart from this, another possibility is that of Big Rip. Understand it in the way that everything in the universe is revolving in its place tied to gravity but in the universe, dark energy is one such force that is dominating gravity and the universe is expanding because of this. Galaxies are moving away from each other and Big Rip theory says that one day it will spread so much that the gravitational force will remain nominal. All the objects of the universe will break and due to the absence of gravity, they will go away from each other.
Even atoms will break apart and their subatomic particles i.e. protons, neutrons and electrons will be separated from each other. No particle will be able to affix each other. You can compare this situation with a balloon placed in a cardboard box, inside which you fill so much air that it explodes.
The third theory is of the Big Crunch. According to which one day it will stop expanding and gravity will re-dominate as the dark energy weakens and all the galaxies will be pulled towards each other and start hitting each other and its size will shrink continuously.
One lakh years before it ends, the temperature will rise as much as many stars have on their surface. In this condition, atoms will also be scattered and will be engulfed by black holes, dotted everywhere, swallowing all the matter around them.
One day all the matter will merge into the black hole
Then all will become a super black hole, weighing equally to the entire universe and which will eventually engulf the entire universe and all the matter of the universe will be crushed and compressed and gathered at a point of singularity. After this, the black hole will finish itself and the same point/ dot will be left which will contain the whole universe inside, waiting for the next big bang. That is, it reached there from where it had started.
Now some points are often raised here. For example, according to a law of thermodynamics, a new object can only be created from something already existing. That is, even though the process of creation and destruction of the universe might have been repeated previously but where did the material for the first universe come from? Where was God when there was nothing? When the universe was confined into a dot and there was no space, then where was the place for it to expand?
Understand this by the example of a balloon in the cardboard box. Your imagination actually makes you think according to the situation inside the balloon only. When you think of God or any question related to him, then you stay inside this balloon and your answers crash. But what if we try to find out the answers coming out of it?
To get the answers to these three questions above, you have to think beyond this cosmic balloon. Space was always there around this universe in the form of a box. Whether this balloon shrinks to just an inch or inflates and spreads throughout the box. Of course, the box is the limit of this balloon. It will expand and explode as soon as it reaches its end that is, will be terminated as Big Rip.
Is the universe a floating bubble in hyperspace
The String theory also states that our universe is floating in hyperspace in a bubble along with other bubbles. You can consider this bubble as a balloon and this part of hyperspace as a cardboard box. According to the knowledge gained so far, this universe seems so big that we cannot think anything outside it. But if we measure the size of ourselves and our world according to the world of bacteria, it will be understood that this universe might not be as big for the creatures living outside it as it seems to us.
Space, time, matter, everything, existing according to us might exist between the Big Crunch and the Big Bang but if anyone who inflates the balloon exists outside the box, will be considered eternal according to us.
Whoever is inside this bubble or the universe cannot escape the effects of space, time and matter. But who is outside this bubble will certainly be exempted from this effect. Now if we acknowledge this external power then the answer to this third question also comes that where did this ‘material’ initially come from.
While recognizing these possibilities a series of questions arise that the material might have come from outside to keep it in this box, but where did such materials come outside from? If the person who put this material in this box already existed then who created him and who made his creator? Our universe has a boundary, box-like so he will also have a limit, and what will be outside of the box which is his world?
In this way, it will be impossible to find the answers to the questions. So it is better that we keep it limited to the answer one step ahead of us. The people of that world might also be grappling with similar questions ahead of these.
Now if we start thinking in this way and try to find the answers to these questions, then as a ‘suppose’, let’s assume that this is all God’s creation and everything is created by an almighty God then some more questions would arise. In which, even if we keep away from ‘where did he, himself come from or who made him?’ then we still have to think one thing that why did he make all this?