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Reverse Arrow Of Time                 Hello friends, in this blog you will get to know about the reversible arrow of time. Are the arrows of time reversible? We have already published a blog in which we have discussed on the arrows of time. If you have not read that, we request you to read that before. Let’s start this-                 Have you ever thought that what would happen if and when the universe stopped expanding and began to contract again? Would the thermodynamic arrow reverse and disorder begin to decrease with time? Would we be able to remember our future then?                 You all can feel very boring in it because we this exists only on theories to find out what would happen if the universe collapse. And the universe will not start to collapse for at least another ten thousand million years. But we have an idea, if you want to know the existence of these results, you can jump in a black hole. Then you will be able to know your future and will be abl
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The Boundary Condition Of The Universe

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The Boundary Condition Of The Universe                       Welcome friends, we will describe here the boundary condition of the universe. In this theory, we can solve many our difficulties about the universe. We all know that the universe was completely in ordered state in its origin as we have described in arrow of time . But why should it be at complete ordered state? Why was it not in the state of complete disorder at all time? And why is the direction of time in which disorder increases the same as that in which the universe expands?                                It seems that the universe evolves according to well defined laws which we can be discovered and understood. Can’t we think that the similar rules will work at the beginning of the universe? We can’t predict the beginning of the universe because we know that all our laws break down at the point of singularity.                                 The universe could have started out in a very smoot
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The No Boundary Condition Of The Universe

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The No Boundary Condition Of The Universe                             Hello friends, in this blog we will discuss on the no boundary condition of the universe. At first, I would like to introduce you from the topic. No boundary condition means a limited space-time. Actually we have some theories that predict the starting of the universe. Let’s discuss on it-                           If we talk about the classical theory of gravity, we find that there are only two ways of starting of the universe, either with the starting of time or with infinite time. But if we talk about the quantum gravity , it shows another way of beginning of the universe, in which the time direction is on same footing as directions in space, it is possible for space-time to be finite in extent and yet to have no singularity that formed a boundary or edge. It is just like the surface of the earth which has only two dimensions and is finite in extent but it doesn’t have any boundary.       
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Quantum Gravity

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Quantum Gravity                                          You must have heard about gravity which works between large bodies. But here quantum gravity is different from general gravity. Quantum gravity works on quantum particles like electron and proton.                                    In order to predict how the universe should have started off. The singularity theorem predicted that the beginning of time would have been a point of infinite density and infinite curvature of space-time. All our rules of science would break down in such points because our rules work in nearly flat space-time. There should be another theory for such points that is very difficult to generate because we don’t have any guide from observational evidence. However, we know something important that singularity is the point of huge gravity. In this condition, gravity affects quantum particles. So we can make a new theory of gravity that is quantum theory. And this theory will work in eac
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The Inflationary Model

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The Inflationary Model                         The inflationary model of the universe was published by Alan Guth from MIT.                                When the hot big bang theory published, we found so many difficulties about the universe. If you want to read such difficulties click here . In order to avoid such difficulties with the very early stages of the hot big bang model, the inflationary model was published.                               According to this theory the early universe might have had the period of very rapid, or exponential, expansion. This expansion is said to be inflationary- an analogy with the inflation in prices that occurs to a great or lesser in every country.                                      Guth suggested that the universe started out from big bang very hot. One would expect that at such high temperatures, the strong and weak nuclear forces would all be unified in one force, as was described in grand unified theory . As
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Black Holes

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Black Holes                                         Hello friends, black holes are such dead stars which had mass at least 1.44 times greater than the sun. We should know about a star’s lifecycle, if we want to know about black hole. We have already published a blog on a star’s lifecycle. If you have not read, click here . In this blog we will discuss on advance properties of a black hole. So let’s start-                            Chandrashekhar, an Indian scientist, had shown that exclusion principle could not halt the collapse of a star more massive than the Chandrashekhar limit, but the problem of understanding what would happen to such a star, according to general relativity, was first solved by Robert Oppenheimer. His result suggested that there would be no observational consequences that could be detected by the telescopes of the day. Then the second world war started and Oppenheimer involved in atom bomb project. The picture that we know from Oppenheimer’s work
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The arrow of Time

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                                                   The arrow of Time                          Hello friend, have you ever thought why we are able to remember our past only. Why the time goes to end? We have some scientific theories to understand this system.               In the universe, there are at least three arrows of time- 1. Thermodynamic arrow of time. 2. Psychological arrow of time. 3. Cosmological arrow of time. Thermodynamic arrow of time: It is something related to the second law of thermodynamics which says that the entropy of a system always increases. And there present many disordered states than ordered once. Suppose you have a jigsaw in a box. There is only one certain ordered state of jigsaw but there are so many disordered states of that.                If a system starts out with an ordered state and it evolves with the passes of time. There are so many chances that the system will be disordered in future because there are many d
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