1. THE BEGINNING – A COSMOLOGICAL MODEL

                            Singularity- that extremely hot and unimaginably dense primordial patch of spacetime- exactly where we reach after traveling back in time at least 13.7 billion years when we are asked about the beginning of the universe. That very tiny region from which the universe is said to have emerged. Our present knowledge about the universe starts from it.

The most successful model on the origin of the universe is the big bang theory which explains that universe started from the expansion of a tiny, hot and extremely dense fireball of hot particles and radiations. Of course, the primordial patch contained all the energy of the universe and precisely it was the expansion along with energy-matter conversion which created all the matter and radiations including all the planets, stars, galaxies, galactic clusters contained within the unimaginably vast universe. The rate of the expansion was unbelievable in the sense that in the first 10^-35th second, the universe had grown to the size of 10^(10^12) cm (trillionth power of ten) in diameter. The energy which propelled the expansion was very high that the actual size of the universe may be many times compared to what we observe today since the universe had been expanding for at least 13.7 billion years which is supposed to be the age of the universe.

Big bang model is successful in that it precisely predicted the relative amounts of hydrogen and helium- two of the most abundant elements in the universe. Also the microwave energy- the cosmic microwave background radiation was detected which is a relic of the expansion. The most important proof which confirmed the big bang model was the discovery that universe is expanding by Edwin Hubble in 1929. But the drawback of big bang model was that it did not explain the singularity, how it came into being and what caused it to bang. However the situation was resolved to a great extent by the inflation theory which explains the events leading to the bang and what caused it to bang.

Inflation theory explains that the singularity or the primordial patch contained within it vacuum fields which when fluctuated created a bubble of false vacuum containing enormous anti gravitational energy and it later decayed producing the expanding fireball. But inflation theory also starts from the singularity and gives us no details of what was there before it and what created it.

Two other models on the origin of the universe are- the instanton theory by Stephen Hawking and Neil Turok, multiverse theory by Andrei Linde. Of these instanton theory is a pure mathematical model and it explains that initially the universe sprouted from a region where space and time blended into one called the pea instanton such that all the physical laws are satisfied within it. But it does not explain how the universe originated. Linde's multiverse theory explains that the universe that we see today is nothing but a part of a multi-branching universe which was inflated from a pre-existing region and that region in turn inflated out of another pre-existing region. Thus he travels progressively backwards in time so that we cannot explain actually what happened in the beginning.

Both these theories and some other cosmological models provide an uncertainty about the origin of the universe. They indicate that the universe was created from nothing, but actually it is not.

What exactly do we mean when we refer to the word origin? - Creation of the primordial patch of spacetime? Nucleation of the bubble of false vacuum? Decay of the bubble releasing the enormous amount of energy contained in it creating the expanding fireball of particles and radiations? or Was it the very instant of the bang? We assume it to be the instant of the bang. Both instanton theory and the multiverse theory do not explain the creation of the singularity (the primordial patch of spacetime). Inflation theory successfully explains the bang and the events leading to it. So it is a theory of the bang, a formalism used to explain the big bang.

It also starts from the singularity and explains in detail the events leading to the bang. But it gives us no idea about the creation of the singularity or what was there before it. But it certainly provides us hints to what happened before the creation of the singularity and what might have led to the creation of it. Let's go to the details of inflation theory proposed by Alan Guth- Inflation theory explains that the primordial patch of spacetime contain 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.

Guth explains that as the bubble expanded, the energy density within the bubble would have remained constant and so the energy content increases as the bubble expands. This gives the impression that energy is being created out of nothing and so he calls it positive energy and in turn calls inflation “the ultimate free lunch”. To explain this he suggests that an equal amount of negative gravitational energy of the ordinary attractive kind was created simultaneously during the expansion and the net effect is zero. Basically this was an assumption to satisfy the law of conservation of energy and he admits that the total energy of the system is conserved.

But how can we explain the creation of such a huge amount of anti gravitational energy and the positive energy that builds up from within the primordial patch of spacetime which contain nothing but vacuum fields confined within a very small region (patch)?

Well, the situation can be explained with some other concepts as follows- Before the origin of universe by big bang or before the beginning of time (which was the instant of the 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 was created from this energy (a part of it) and the rest probably remains as the unobservable or in the form of dark energy.

Now the case of Guth's positive anti gravitational energy and the creation of the primordial patch of spacetime- According to Einstein's theory of relativity, mass and energy are equivalent and if matter is able to exert gravitational pull, then so must energy. The pre-big bang universe which contained energy in the form of vacuum fields exerted gravitational pull on the surrounding region which eventually increased the energy density of that region. Consequently all the surrounding regions containing the vacuum fields were pulled into that region so that they collapsed into it causing the region to become progressively smaller, denser and denser. Thus the primordial patch (the singularity) was created which contained all the vacuum field energy within it. These vacuum fields then fluctuated to produce the bubble of false vacuum which was actually not created from nothing, but from the region containing vacuum fields and vacuum field energy. 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.


This concept suggests that the initial singularity was produced by the action of gravity on vacuum fields. Thus the universe was not created from nothing - but from a finite amount of energy present even before the beginning. The extremely high energy density of the initial singularity would require it to have undergone a period of contraction of the vacuum fields containing all the energy of the universe driven by gravity or some other mechanism to satisfy the law of conservation of energy.

2. A COSMOLOGICAL ANALYSIS – THE ORIGIN

 

           The past century has seen discoveries providing a deeper insight into the greatest mystery ever and the most important quest in the history of mankind – the origin and evolution of the universe. The latter has not remained a quest as it was explained effectively by concepts which flourished in the 20^th century. The prime candidate which stands upright amongst all the other theories is the big bang nucleosynthesis proposed by Gamow et al. The theory is backed up by concepts like expansion of the universe at an accelerated pace explained by the Hubble’s law, cosmological red shift of light from distant galaxies and the cosmic microwave background radiation. Backbone of big bang theory is the expansion itself which led to the prediction of the bang. Big bang nucleosynthesis effectively answers the questions related to the evolution of the universe i.e. events that took place right after the bang which include separation of fundamental interactions (electromagnetic, strong, weak and gravitational), formation of sub-atomic particles followed by atoms of various elements, formation of various galactic clusters including galaxies which in turn contain stars etc – in short it explains the formation of matter that we see today in the universe.

But big bang theory gives us no idea about the initial singularity which was a primordial patch of spacetime and from which the extremely hot and dense expanding fireball was created. Also big bang theory gives us no explanation of the cause of bang. Inflation theory gives us the solution here as it explains how the expanding fireball was created and what caused it to bang which were already explained in the previous blog post. 


Alan Guth in his inflation theory says that the initial singularity or the primordial patch of spacetime contained within it vacuum fields which fluctuated and temporarily got stuck at a value. These stuck scalar fields gave rise to a bubble of false vacuum which contained within it a huge amount of anti-gravitational energy. But here he does not explain the cause of anti-gravitational energy instead states that it was cancelled by the buildup of an equal amount of gravitational energy so that the net effect is zero. He assumes that as the bubble expanded the energy density within it remained constant. So, as the bubble expanded in size its energy content increased. Later the bubble decayed releasing the energy contained within in the form of an exploding fireball which then banged to create the universe. This is where we reach on answering the question – “how the universe originated and evolved?”

But still the answer remains incomplete because of the initial singularity – the primordial patch of spacetime. On answering the question, we start only from this singularity as we don’t know anything about what was there before or in other words none of the theories satisfactorily explain what created this singularity and what was present before it came into being. Along with this question of singularity arise some other important questions like the anti-gravitational energy within the bubble, the grand unified interaction and ultimately ‘creation out of nothing’. All these questions can be answered in a simple yet effective manner using some other concepts.

The previous blog post introduced this concept which states that – “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”. This concept will be called the Vacuum Field Theory (VFT) or Vacuum Field Hypothesis (VFH) on the origin of universe - which is a hypothetical concept.

As we all know, energy and matter are equivalent by the relation E=mc^2 and are interconvertible. We have already observed materialization of energy in phenomenon like pair production. This materialization of energy was the mechanism behind the origin of our universe. We assume an initial amount of energy in the form of vacuum fields which by the action of gravity condensed into the singularity from which was created the expanding fireball by inflation to undergo the big bang.

This assumption leads us to another important result – gravity was the primary interaction of our universe or it was the very first form of interaction to be present in the universe. But it was not the ordinary gravity that we observe today, a stronger and more dominant one which was the grand unified interaction. This is a direct consequence of matter-energy equivalence by Albert Einstein. As matter and energy are equivalent, if matter is able to exert gravity then so must energy. The universe which existed before the big bang or before the creation of the singularity contained vacuum fields with energy (analogous to vacuum energy). So like matter, this energy was also able to exert gravitational pull – what we don’t know here is the mechanism by which gravity operates or the composition of gravity even though presence of ‘gravitons’ was hypothesized but never observed (in fact gravitons cannot be observed/detected by any detector on earth - when I stated this I meant the case of a single graviton and not that of gravitational waves and I still believe that a single graviton might never be detected by human beings - the reason is explained here in the simplest way and in more detail here). These initial vacuum fields containing energy lead us to make the most important assumption – that gravity was the first form of interaction to be present in the universe and that it was the grand unified interaction.

We mainly addressed 4 problems in answering the question “how the universe originated?” and those were – 1) creation of the singularity (primordial patch of spacetime) 2) anti-gravitational energy within the bubble 3) the grand unified interaction and ultimately 4) creation out of nothing. Now it’s time to give solutions to these problems one by one.

First is the creation of the singularity or the primordial patch of spacetime. Einstein in his theory of relativity, proposed spacetime continuum as the 4^th dimension in which all events of the universe are supposed to take place. The universe originated from the singularity which is also supposed to be a primordial patch of spacetime. Alan Guth in his inflation theory also suggests that the singularity was a primordial patch of spacetime containing vacuum fields from which the expanding fireball was created, but he failed to explain from where this primordial patch of spacetime came into being. Here comes the twist – in that it was not a patch of spacetime but a point or a region which contained vacuum fields where all the energy was concentrated. It was not spacetime but vacuum because there was space but no time and so no unified spacetime, but there was energy (it must be mentioned here that space was present even before the big bang as will be clarified in the following blog posts). In fact it was only later that time and together the spacetime continuum came into being and that was with the materialization of energy or in other words – with the creation of the expanding fireball which marked the beginning of time.

But the mathematical equations leading to the inflation theory are based on the concept that the singularity was a patch of spacetime. So if we consider singularity to be a patch of spacetime for the sake of equations then it becomes necessary to assume that a patch of spacetime was created from vacuum (actually not from vacuum but from "nothing" or "no-space" as explained in later blogposts) by the action of gravity on the pre–big bang vacuum fields which contained all the energy of the universe. Both are possible and will be clarified in the future. But the solution which is applicable to both is that – the singularity was created by the action of gravity on the pre–big bang vacuum fields containing energy.

Second problem is the enormous amount of anti-gravitational energy that builds up within the bubble of false vacuum. Guth explains inflation as the ‘ultimate free lunch’ as he assumes the energy density within the bubble to be constant giving the impression that as the bubble expanded energy was just created out of nothing. To balance this positive anti-gravitational energy build up, he states that an equal amount of gravitational energy of the ordinary attractive kind was simultaneously created so that the net effect is zero. In fact the situation is not like that but the amount of energy contained in the pre-big bang vacuum fields was unimaginably large and that energy under the action of gravity condensed into the singularity and the effect of this huge anti-gravitational energy that builds up within the bubble which caused big bang, was to balance that amount of energy which got condensed under the influence of gravity so that the net effect is zero (it is known now that energy can exert gravity - in the beginning I assumed that gravity acted on the pre-big bang vacuum fields to condense it to form the singularity which then went on to undergo the big bang the validity of which is not yet proved - there is a possibility of it becoming true as there seems to be no other way of explaining the creation of the singularity and the initial primordial patch of spacetime - but in M-theory the singularity is supposed to have got created by the collision of 2 branes which had size larger than our universe). Thus the total energy of the system is conserved and we get the solution to the second problem (validity of this is yet to be verified).

Third is that of the grand unified interaction. We know there are mainly 4 types of fundamental interactions and they are – electromagnetic, weak (together electro weak), strong and gravitational. Of these gravity is the weakest but surprisingly it is the candidate for the grand unified interaction. As we move back in time towards the instant of the big bang, all the interactions get unified and gravity assumes a stronger and dominant identity. As we have already seen that potential energy was present in the pre-big bang vacuum fields and gravity acted on these energy fields to create the singularity. Thus gravity was the primary interaction of the universe or the grand unified interaction. It was only after the bang, that the interactions separated and gravity got weaker. This is the solution to the third problem.

Fourth and the most confusing problem that scientists had in answering the question “how the universe originated?” is ‘creation out of nothing’. As already explained, the main theories of origin are – the big bang theory and inflation theory (now of course M-theory is also added - but the problem with it is that it is not observationally verified unlike the big bang theory, as the higher dimensions and supersymmetry which form the backbone of M-theory are not yet observed in nature). But big bang theory begins from the expanding fireball and inflation theory from the singularity and both assume that these were ‘created from nothing’. This problem is also solved here as – “the pre-big bang universe contained vacuum (actually not vacuum but "no-space" or "no-energy space" - i.e. to say it contained both space with energy in some regions and space without energy in the other regions) consisting of a finite amount of energy (of very large magnitude) in the form of vacuum fields. All the matter and radiations now seen in the universe were created from this energy and not from ‘nothing’. This gives us the solution to the final problem.

Thus we can complete the answer to the question “how the universe originated?” We can hope that this question is answered satisfactorily with sufficient experimental and observational evidence in the near future itself….


IMPORTANT NOTE (May, 2017):- My initial blogposts had errors, inaccuracies and redundancies which are getting corrected with the passage of time and with the expansion of my knowledge field....

3. VACUUM FIELD THEORY (REFINED)

 

                                   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....