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 20th 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?”
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 4th 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....
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....
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