The previous two blog posts introduced the general idea of Vacuum Field Theory - A hypothetical concept used to explain the situation that existed before the big bang. It explains the creation of the primordial patch of spacetime (the initial singularity) and the events leading to the bang. The concept is summarized as follows:- “Before the origin of the universe by big bang or in other words the pre-big bang universe contained only vacuum consisting of a finite amount of energy (of very large magnitude) in the form of vacuum fields which is the total energy of the observable and the unobservable universes together. All the matter and radiations now seen in the universe were created from this energy – in fact from a part of it and the rest remains as unobservable or in the form of dark energy. The singularity – the primordial patch of spacetime was created by the action of gravity on vacuum fields which existed in the pre-big bang universe”.
However the definition of vacuum brings about confusion in the statement of the concept of Vacuum Field Theory. Vacuum is defined as a volume of space that is essentially empty of matter. Vacuum is empty space. It is conceived as a property of space. Space is indispensable for the existence of vacuum or in other words vacuum cannot exist without space. Big Bang is assumed to be the beginning of space and time. As there was no space prior to big bang the concept of vacuum prior to big bang appears to be invalid. So it is necessary to go into the properties of this no-space which existed prior to big bang.
No-space is equivalent to space. Because the spatial dimensions do exist even in a situation of no-space. Only difference is that it is in the absence of time. We cannot imagine a situation of no-space that is without spatial dimensions. Space is supposed to have begun with the big bang, that is with the beginning of time. The same space or spatial dimensions that exist after big bang was present before big bang also. But the situation before big bang was devoid of time, also it was devoid of matter. So the concept of space is not applied there and space is supposed to begin with time. But the actual scenario is different. Space was present in the universe before the big bang itself. Actually time began only later which will be explained in the succeeding blog posts. The space that existed prior to big bang was vacuum, a state which is devoid of matter. But it is not the conventional vacuum which is defined as empty space. As will be explained in later blogposts, this vacuum or space is further classified into two types - 1)Space with energy and 2)Space without energy. Since energy is assumed to exist in a situation prior to big bang and space (vacuum) was present in such a situation, it becomes necessary to assume existence of energy in the form of vacuum fields. So the same vacuum energy that is applicable to the post-big bang scenario is applicable to the pre-big bang scenario also.
So the statement of Vacuum Field Theory is refined as: - “Before the origin of the universe by big bang or in other words the pre-big bang universe contained only vacuum in a state of presence of space and absence of time, consisting of a finite amount of energy (of very large magnitude) in the form of vacuum fields which is the total energy of the observable and the unobservable universes together. All the matter and radiations now seen in the universe were created from this energy – in fact from a part of it and the rest remains as unobservable. The singularity – the primordial patch of spacetime was created by the action of gravity on vacuum fields containing energy which existed in the pre-big bang universe”.
Vacuum Field Theory is devised to give an approximation to the state before big bang and a solution to the problem of the enormous amount of energy that builds up giving an impression of 'creation out of nothing' during the instant of the big bang. Energy is assumed to be present in a state of presence of space and absence of time. To imagine, it is analogous to a state of eternal vacuum where no changes are occurring. Vacuum Field Theory assumes a hypothetical situation where none of the ordinary laws are applicable as there was no time but space and energy were present. Gravity was the only form of interaction assumed to be present in such a situation. This energy was present for a very long period when no observable changes were occurring and gravity acted on this energy (which was in the form of vacuum fields) to condense it to form the initial singularity or the primordial patch of spacetime. And then the events leading to the big bang as explained in the previous blog posts which are given below.
The primordial patch of spacetime contained vacuum dominated by energetic vacuum fields. As these vacuum fields fluctuated, their potential energy increased and decreased. During these fluctuations of the energetic scalar fields, they got temporarily stuck at a high value. These stuck scalar fields caused a bubble of false vacuum to nucleate from it, the peculiarity of the bubble being that it contained a large amount of anti gravitational energy which caused the bubble to expand. Eventually the false vacuum decayed and the energy of the vacuum fields contained within it was suddenly released, creating the expanding fireball of radiations and hot particles which then banged to create the universe....
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