“The last star will slowly cool down and disappear. “After that, the world will turn into a big emptiness, without light, life and meaning.”
This is what physicist Brian Cox warns us in the new BBC series “World”. The disappearance of the last star will only be the beginning of an infinitely long, dark era. All matter is eventually absorbed by Weberian black holes, which in turn gradually evaporate.
Space is constantly expanding outward until even this faint light is so scattered that it can no longer interact. The activity will stop.
Will that really happen? Strange, but some cosmologists believe that the cold, dark, empty world, just as it will be in the distant future – could be the source of a huge explosion.
The first matter
However, let us first consider how physical matter originally originated. If we want to explain the origin of stable matter composed of atoms and molecules, we will tell you that such a thing did not exist at the time of the Big Bang, it is for the next hundreds of thousands of years.
In fact, it is very detailed how the first atoms were formed from simple particles after the environment had cooled enough for the complex matter to be stable; We also know how these atoms were later synthesized into heavy elements in the stellar cavity. However, all this does not answer the question of how something came into being out of nothing.
So let’s move on to the past. The first particles of any kind of long-lived matter were protons and neutrons, which together form the nucleus of an atom. They appeared about a thousandth of a second after the Big Bang.
Up to this point there really was no matter what kind of matter we are familiar with. However, physics allows us to go back in chronology, to the physical processes that preceded any kind of stable matter.
This leads to e. წ. With the era of the Great Union. At the moment, we are in the world of speculative physics because we cannot produce enough energy in experiments to investigate the processes going on at that time.
However, the plausible hypothesis is that the physical universe was made up of short-lived “sauce” particles – including quarks, protons, and neutron building blocks.
There was approximately equal amounts of matter and “antimatter”: each type of matter, such as a quark, has an antimatter “mirror image” companion that is almost identical and differs in only one aspect.
Nevertheless, when they meet, matter and antimatter destroy each other with a flash of energy, which means that these particles are constantly being created and destroyed.
But how did these particles originate? Quantum field theory tells us that even a vacuum that is supposed to correspond to empty space-time is full of physical activity in the form of energy fluctuations. These oscillations can inspire particles, but they still disappear suddenly.
This may sound more like a mathematical trick than real physics, but such particles have been observed in countless experiments.
In the space-time vacuum, particles that are constantly being created and destroyed are apparently “out of nothing.” But all of this actually probably tells us that a quantum vacuum is something (despite the name) rather than nothing.
The well-known philosopher David Albert has publicly criticized the Big Bang, which in this way allows something to be taken from nothing.
Suppose and ask: Where did space-time itself come from? Then go back in time, really to the ancient “Planck era” – so early in the history of the universe, in the face of which even the best theories of physics are powerless.
This era stood after the Big Bang for only a trillionth of a trillionth of a trillionth of a trillionth of a second. At that point, space and time themselves became the subject of quantum fluctuations.
Typically, physicists work separately with quantum mechanics, which governs the microcosm of particles, and with general relativity, which fits on a larger, cosmic scale. However, to truly understand the Planck era, we need to complete the theory of quantum gravity, merging the two.
The best theory of quantum gravity does not yet exist, but there are attempts – for example, string theory and the quantum gravity of a loop. In these attempts, ordinary space and time are usually seen as emerging as waves on the surface of a deep ocean.
What we perceive as space and time is the result of quantum processes that take place on a deep, microscopic level – processes that do not make much sense to us as beings rooted in the macroscopic world.
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In the Planck era our ordinary understanding of space and time is violated, hence we can no longer rely on our ordinary understanding of cause and effect.
Yet every candidate theory of quantum gravity theory describes something physical that took place in the Planck era – a certain quantum precursor to ordinary space and time. But where did he come from?
Even if causation is no longer used in the usual way, it may still be possible to explain one component of the Planck-era universe in terms of another. Unfortunately, for the time being, even our best physicists are completely powerless to respond. Until we have the next progress in “Theory of Everything”, we will not get an answer with any kind of solution.
Most of what we can say with certainty at this point is that physics has not yet found proven instances of the emergence of something out of nothing.
Cycles from almost nothing
In order to really answer the question of how something can arise from nothing, we need to explain the quantum state of the whole universe at the beginning of the Planck era.
Every attempt to do so remains highly speculative. Some attempts are directed at supernatural forces, such as the Creator. Other candidates for explanations remain in the field of physics – for example, the multiverse containing an infinite number of parallel universes, or the cyclic model of the universe, birth and then rebirth.
Nobel Laureate in Physics 2020 Roger Penrose offers an intriguing but controversial model of the cyclic universe called “conformal cyclic cosmology.”
Penrose’s source of inspiration was an interesting mathematical connection between a very hot, dense, small state (as it was during the Big Bang) and an extremely cold, empty, expanded state (as it will be in the future).
His radical theory to explain this correspondence is that these states become mathematically identical when they reach their own limits. Paradoxically, the complete absence of matter can produce all the matter we see in the universe.
In this sense, the big bang happened out of almost nothing. This is what remains after black holes absorb the matter of the entire universe, which in turn then erupts in the form of photons and is lost in emptiness.
Thus, the whole universe is created from something that is so close from another physical point of view that it is produced from nothing. However, this is nothing but a kind of something. It is an empty but still physical world.
How can the same situation be a cold, empty world from one perspective and a hot, dense world from another? The answer lies in a complex mathematical procedure called “conformal resizing” – a geometric transformation that actually changes the size of an object but leaves it unchanged.
Penrose showed how such re-scaling could be related to cold, dense, and hot, dense so that they matched in terms of their space-time, but not in size.
It is really hard to understand how two objects can be identical in this way when they have different dimensions, but Penrose argues that size, as a concept, loses meaning in such an extreme physical environment.
In conformal cyclic cosmology, the direction of explanation goes from the old and the cold to the young and the hot: the hot, dense state exists because of the cold, the empty state. But this “cause” is not what we think it is – a cause that will have its own effect over time. In this extreme situation, size alone does not lose relevance: so does time.
Cold, dense conditions and hot, dense conditions are actually located on different timelines. The cold, empty state must last forever from the point of view of one observer in its own temporal geometry, but the hot, dense state it produces is effectively “housed” in a new, own timeline.
This can help us to understand the emergence of a hot, dense state from a cold, empty state in an unreasonable way. But perhaps we should say that a hot, dense state arises, solidifies, or is realized by a cold, empty state.
Such are the distinctive metaphysical ideas that philosophers of science have extensively explored, especially in the context of quantum gravity, where ordinary cause and effect seem to be disturbed. Within our knowledge, it is difficult to distinguish between physics and philosophy.
Conformal cyclic cosmology offers somewhat detailed but speculative answers about the origin of the Big Bang. But if Penrose’s vision agrees with the future progress of cosmology, we may think that we still do not have the answer to a deep philosophical question – where does physical reality itself come from.
Where did the whole system of cycles come from? Then we come to the pure question of why there is something more than nothing – one of the greatest questions of metaphysics.
However, here our focus is on explanations that do not go beyond the realm of physics. There are three broad options for the in-depth question about the beginning of cycles.
They may not have a physical explanation at all. Or it may be infinitely repetitive cycles, each universe in its own order, the initial quantum state of each universe being explained by some characteristic of the previous universe. There can be one cycle and one repetitive world, and the beginning of this cycle can be explained by certain characteristics of its end.
The last two approaches avoid any unreasonable events, which makes them distinctly attractive. Nothing unexplained by physics should remain.
Penrose envisages a sequence of endless new cycles for a reason that is partly related to his own, preferred interpretation of quantum theory. In quantum mechanics, the physical system exists in superpositions of many different states at once, and only “chooses one” at random when we measure it.
For Penrose, each cycle involves random quantum events that unfold differently – meaning that each cycle will be different from the previous and the next. This is quite good news for experimental physicists, as it may give us little clue about the ancient world that formed us, and it must be a faint trace or anomaly in the residual radiation of the Big Bang observed by Planck.
Penrose and his colleagues believe that these traces may have already been noticed, linking Planck’s data characteristics to radiation from supermassive black holes in the previous world. However, such a view is challenged by other physicists.
A key part of Penrose’s vision is the endless new cycles. However, there is a natural way to transform conformal cyclic cosmology from a multi-cycle to a single-cycle form. Then, physical reality consists of one cycle around the Big Bang, with the state as empty as possible in the distant future, and then again with exactly the same Big Bang that gives rise to exactly the same universe.
This possibility is consistent with another interpretation of quantum mechanics called multiverse interpretation. The multivariate interpretation tells us that with each measurement of a superposed system, that measurement does not randomly select a state. Instead, the measurement result we see is just one possibility – something that is happening in our world.
The results of other measurements in other worlds of the multiverse are disconnected from us. Consequently, no matter how small the chance of something happening, if it has a chance of more than zero, it happens in a certain quantum, parallel world.
In other worlds there are people just like you who win the lottery, or suffer from terrible typhoons, or are constantly irritated, or experience all three at the same time.
Some believe that such parallel universes can also be observed in cosmic data by tracing other worlds colliding with us.
Quantum theory of the multiverse gives conformal cyclic cosmology a new twist, but not one that Penrose agrees with. Our Big Bang could be a rebirth of a single quantum multiverse containing infinitely many, many different universes and all at once. Everything that is possible happens – then it happens again and again.
Prepared according to The Conversation.