Astrophysicist, Doctor of Physical and Mathematical Sciences, Chief Researcher at the Institute of Astronomy of the Russian Academy of Sciences (INASAN) Nikolai Chugai answers:
— In astrophysics, the Big Bang is understood as the explosive process in which our Universe was born. This idea is based on the observed fact of galaxy recession, discovered in the late twenties of the last century. American astrophysicist Hubble. The recession of galaxies means that the universe was dense in the past.
In the forties of the 20th century it became clear that this was the first thing that came to mind Russian astrophysicist Georgy Gamow, who worked in the USA - that the Universe in the distant past was not only dense, but also very hot, so much so that things could happen in it thermonuclear reactions synthesis of chemical elements from a mixture of protons, neutrons and electrons. The hydrogen nucleus consists of one proton, so we can say that, according to Gamow's thought, in the beginning there was only hydrogen. This is also the most common in the modern Universe. chemical element. Everything else, including helium, the next most abundant element, arose from nuclear reactions. Gamow calculated the conditions under which the modern amount of helium was formed in the first few minutes after the explosion, and came to the conclusion that during the life of the Universe, the primary hot radiation should have cooled to 5 degrees on the Kelvin scale (zero of this scale corresponds to a temperature of -273 degrees Celsius ). In 1964, this guess was brilliantly confirmed: American radio astronomers Penzias And Wilson discovered this radiation in the centimeter range as a uniform background of the sky. Later measurements from satellites showed that the temperature of this background (relict radiation) is 2.7 degrees Kelvin.
CMB radiation is a decisive argument in favor of the Big Bang theory. The glow of the cosmic microwave background radiation allows us to understand many things, including the birth of galaxies and clusters of galaxies. The fact is that at first the Universe was absolutely homogeneous. But during the expansion process, small initial density disturbances began to intensify due to gravitational self-attraction, just as a planet is attracted to the Sun, a stone falls to the ground. The force of gravity causes these irregularities to become even denser. This is how galaxies and clusters of galaxies, stars and planets were formed.
The Big Bang theory has a strong competitor in the current decade - the cyclic theory.
The Big Bang theory is trusted by the vast majority of scientists who study early history of our Universe. It actually explains a lot and does not contradict experimental data in any way. However, it recently has a competitor in the form of a new, cyclic theory, the foundations of which were developed by two top-notch physicists - the director of the Institute for Theoretical Science at Princeton University, Paul Steinhardt, and the winner of the Maxwell Medal and the prestigious international TED Prize, Neil Turok, director of the Canadian Institute for Advanced Study in Theoretical Sciences. physics (Perimeter Institute for Theoretical Physics). With the help of Professor Steinhardt, Popular Mechanics tried to talk about the cyclic theory and the reasons for its appearance.
The title of this article may not seem like a very clever joke. According to the generally accepted cosmological concept, the Big Bang theory, our Universe arose from an extreme state of physical vacuum generated by a quantum fluctuation. In this state, neither time nor space existed (or they were entangled in a space-time foam), and all fundamental physical interactions were fused together. Later they separated and acquired independent existence - first gravity, then strong interaction, and only then weak and electromagnetic.
The moment preceding these changes is usually denoted as zero time, t=0, but this is pure convention, a tribute to mathematical formalism. According to the standard theory, the continuous passage of time began only after the force of gravity became independent. This moment is usually attributed to the value t = 10 -43 s (more precisely, 5.4x10 -44 s), which is called the Planck time. Modern physical theories are simply not able to meaningfully work with shorter periods of time (it is believed that this requires a quantum theory of gravity, which has not yet been created). In the context of traditional cosmology, there is no point in talking about what happened before the initial moment of time, since time in our understanding simply did not exist then.
The Big Bang theory is trusted by the vast majority of scientists studying the early history of our Universe. It actually explains a lot and does not contradict experimental data in any way. However, it recently has a competitor in the form of a new, cyclic theory, the foundations of which were developed by two top-class physicists - the director of the Institute for Theoretical Science at Princeton University, Paul Steinhardt, and the winner of the Maxwell Medal and the prestigious international TED Prize, Neil Turok, director of the Canadian Institute for Advanced Study in Theoretical Sciences. physics (Perimeter Institute for Theoretical Physics). With the help of Professor Steinhardt, Popular Mechanics tried to talk about the cyclic theory and the reasons for its appearance.
Inflationary cosmology
An integral part of standard cosmological theory is the concept of inflation (see sidebar). After the end of inflation, gravity came into its own, and the Universe continued to expand, but at a decreasing speed. This evolution lasted for 9 billion years, after which another anti-gravity field of an as yet unknown nature came into play, which is called dark energy. It again brought the Universe into a regime of exponential expansion, which seems to be preserved in future times. It should be noted that these conclusions are based on astrophysical discoveries made at the end of the last century, almost 20 years after the advent of inflationary cosmology.
The inflationary interpretation of the Big Bang was first proposed about 30 years ago and has been refined many times since then. This theory allowed us to solve several fundamental problems that previous cosmology could not cope with. For example, she explained why we live in a Universe with flat Euclidean geometry - according to the classical Friedmann equations, this is exactly what it should become with exponential expansion. The inflation theory explained why cosmic matter is granular on scales not exceeding hundreds of millions of light years, but is evenly distributed over large distances. She also provided an interpretation of the failure of any attempts to detect magnetic monopoles, the very massive particles with a single magnetic pole that are thought to have been produced in abundance before the onset of inflation (inflation stretched outer space so much that the originally high density of monopoles was reduced to almost zero, and so our devices cannot detect them).
Soon after the inflationary model appeared, several theorists realized that its internal logic did not contradict the idea of the permanent multiple birth of more and more new universes. In fact, quantum fluctuations, such as those to which we owe the existence of our world, can arise in any quantity if suitable conditions are present. It is possible that our universe emerged from the fluctuation zone that formed in the predecessor world. In the same way, we can assume that someday and somewhere in our own Universe a fluctuation will form that will “blow out” a young universe of a completely different kind, also capable of cosmological “childbirth.” There are models in which such daughter universes arise continuously, budding off from their parents and finding their own place. Moreover, it is not at all necessary that the same physical laws are established in such worlds. All these worlds are “embedded” in a single space-time continuum, but they are so separated in it that they do not sense each other’s presence. In general, the concept of inflation allows—indeed, forces!—to believe that in the gigantic megacosmos there are many universes isolated from each other with different structures.
Alternative
Theoretical physicists love to come up with alternatives to even the most generally accepted theories. Competitors have also appeared for the Big Bang inflation model. They did not receive widespread support, but they had and still have their followers. The theory of Steinhardt and Turok is not the first among them and certainly not the last. However, today it has been developed in more detail than others and better explains the observed properties of our world. It has several versions, some of which are based on the theory of quantum strings and multidimensional spaces, while others rely on traditional quantum field theory. The first approach gives more visual pictures of cosmological processes, so we’ll focus on it.
The most advanced version of string theory is known as M-theory. She claims that the physical world has 11 dimensions - ten spatial and one time. Floating in it are spaces of lower dimensions, the so-called branes. Our Universe is simply one of these branes, with three spatial dimensions. It is filled with various quantum particles (electrons, quarks, photons, etc.), which are actually open vibrating strings with a single spatial dimension - length. The ends of each string are tightly fixed inside the three-dimensional brane, and the string cannot leave the brane. But there are also closed strings that can migrate beyond the boundaries of branes - these are gravitons, quanta of the gravitational field.
How does the cyclic theory explain the past and future of the universe? Let's start with the current era. The first place now belongs to dark energy, which causes our Universe to expand exponentially, periodically doubling its size. As a result, the density of matter and radiation is constantly falling, the gravitational curvature of space is weakening, and its geometry is becoming more and more flat. Over the next trillion years, the size of the Universe will double about a hundred times and it will turn into an almost empty world, completely devoid of material structures. There is another three-dimensional brane nearby, separated from us by a tiny distance in the fourth dimension, and it too is undergoing a similar exponential stretching and flattening. All this time, the distance between the branes remains virtually unchanged.
And then these parallel branes begin to come closer together. They are pushed towards each other by a force field, the energy of which depends on the distance between the branes. Now the energy density of such a field is positive, so the space of both branes expands exponentially - therefore, it is this field that provides the effect that is explained by the presence of dark energy! However, this parameter gradually decreases after a trillion years will fall to zero. Both branes will still continue to expand, but not exponentially, but at a very slow pace. Consequently, in our world the density of particles and radiation will remain almost zero, and the geometry will remain flat.
New cycle
But the ending old story- just a prelude to the next cycle. The branes move towards each other and eventually collide. At this stage, the energy density of the interbrane field drops below zero, and it begins to act like gravity (let me remind you that gravity potential energy negative!). When the branes are very close, the interbrane field begins to amplify quantum fluctuations at every point in our world and converts them into macroscopic deformations of spatial geometry (for example, a millionth of a second before the collision, the estimated size of such deformations reaches several meters). After a collision, it is in these zones that the lion's share of the kinetic energy released during impact is released. As a result, it is there that the most hot plasma appears with a temperature of about 1023 degrees. It is these regions that become local gravitational nodes and turn into embryos of future galaxies.
Such a collision replaces the Big Bang of inflationary cosmology. It is very important that all newly emerged matter with positive energy appears due to the accumulated negative energy of the interbrane field, therefore the law of conservation of energy is not violated.
Inflationary theory allows for the formation of multiple daughter universes, which are continuously budding off from existing ones.
How does such a field behave at this decisive moment? Before the collision, its energy density reaches a minimum (and negative), then begins to increase, and during the collision it becomes zero. The branes then repel each other and begin to move apart. The interbrane energy density undergoes a reverse evolution - again it becomes negative, zero, positive. Enriched with matter and radiation, the brane first expands with a decreasing speed under the braking influence of its own gravity, and then again switches to exponential expansion. The new cycle ends like the previous one - and so on ad infinitum. Cycles that preceded ours also occurred in the past - in this model, time is continuous, so the past exists beyond the 13.7 billion years that have passed since the last enrichment of our brane with matter and radiation! Whether they had any beginning at all, the theory is silent.
The cyclic theory explains the properties of our world in a new way. It has a flat geometry because it stretches enormously at the end of each cycle and only slightly deforms before the start of a new cycle. Quantum fluctuations, which become the precursors of galaxies, arise chaotically, but on average evenly - therefore, outer space is filled with clumps of matter, but at very large distances it is quite homogeneous. We cannot detect magnetic monopoles simply because the maximum temperature of the newborn plasma did not exceed 10 23 K, and the formation of such particles requires much higher energies - on the order of 10 27 K.
The moment of the Big Bang is a collision of branes. A huge amount of energy is released, branes fly apart, slowing expansion occurs, matter and radiation cool, and galaxies are formed. The expansion is accelerated again due to the positive interbrane energy density, and then slows down, the geometry becomes flat. The branes are attracted to each other, and before the collision, quantum fluctuations are amplified and transformed into deformations of spatial geometry, which in the future will become the embryos of galaxies. A collision occurs and the cycle begins all over again.
A world without beginning and end
The cyclical theory exists in several versions, as does the inflation theory. However, according to Paul Steinhardt, the differences between them are purely technical and are of interest only to specialists, but the general concept remains unchanged: “Firstly, in our theory there is no moment of the beginning of the world, no singularity. There are periodic phases of intense production of matter and radiation, each of which can, if desired, be called the Big Bang. But any of these phases does not mark the emergence of a new universe, but only a transition from one cycle to another. Both space and time exist both before and after any of these cataclysms. Therefore, it is quite natural to ask what the state of affairs was 10 billion years before the last Big Bang, from which the history of the universe is measured.
The second key difference is the nature and role of dark energy. Inflationary cosmology did not predict the transition of the slowing expansion of the Universe into an accelerated one. And when astrophysicists discovered this phenomenon by observing distant supernova explosions, standard cosmology didn’t even know what to do with it. The dark energy hypothesis was put forward simply to somehow tie the paradoxical results of these observations into the theory. And our approach is much better secured by internal logic, since dark energy is present in us from the very beginning and it is this energy that ensures the alternation of cosmological cycles.” However, as Paul Steinhardt notes, the cyclic theory also has weak spots: “We have not yet been able to convincingly describe the process of collision and rebound of parallel branes that takes place at the beginning of each cycle. Other aspects of the cyclic theory are much better developed, but here there are still many ambiguities to be eliminated.”
Testing by practice
But even the most beautiful theoretical models need experimental verification. Can cyclic cosmology be confirmed or refuted by observation? “Both theories, inflationary and cyclical, predict the existence of relict gravitational waves, explains Paul Steinhardt. - In the first case, they arise from primary quantum fluctuations, which, during inflation, are spread throughout space and give rise to periodic fluctuations in its geometry - and this, according to the general theory of relativity, is gravitational waves. In our scenario, the root cause of such waves is also quantum fluctuations - the same ones that are amplified when branes collide. Calculations have shown that each mechanism generates waves with a specific spectrum and specific polarization. These waves were bound to leave imprints on cosmic microwave radiation, which serves as an invaluable source of information about early space. So far, such traces have not been found, but most likely this will be done within the next decade. In addition, physicists are already thinking about direct registration of relict gravitational waves using spacecraft, which will appear in two to three decades.”
Radical alternative
In the 1980s, Professor Steinhardt made significant contributions to the development of the standard Big Bang theory. However, this did not stop him from looking for a radical alternative to the theory into which so much work had been invested. As Paul Steinhardt himself told Popular Mechanics, the inflation hypothesis does indeed reveal many cosmological mysteries, but this does not mean that there is no point in looking for other explanations: “At first I was just interested in trying to understand the basic properties of our world without resorting to inflation. Later, when I delved deeper into this issue, I became convinced that the inflation theory is not at all as perfect as its supporters claim. When inflationary cosmology was first created, we hoped that it would explain the transition from the initial chaotic state of matter to the current ordered Universe. She did this - but went much further. The internal logic of the theory required the recognition that inflation constantly creates an infinite number of worlds. There would be nothing wrong with this if their physical structure copied our own, but this is precisely what does not happen. For example, with the help of the inflation hypothesis it was possible to explain why we live in a flat Euclidean world, but most other universes certainly will not have the same geometry. In short, we built a theory to explain our own world, and it got out of control and gave rise to an endless variety of exotic worlds. This state of affairs no longer suits me. Moreover, the standard theory is unable to explain the nature of the earlier state that preceded the exponential expansion. In this sense, it is as incomplete as pre-inflationary cosmology. Finally, it is unable to say anything about the nature of dark energy, which has been driving the expansion of our Universe for 5 billion years.”
Another difference, according to Professor Steinhardt, is the temperature distribution of background microwave radiation: “This radiation, coming from different parts of the sky, is not completely uniform in temperature, it has more and less heated zones. At the level of measurement accuracy provided by modern equipment, the number of hot and cold zones is approximately the same, which coincides with the conclusions of both theories - inflationary and cyclical. However, these theories predict more subtle differences between zones. In principle, they can be detected by the European Planck space observatory launched last year and other new spacecraft. I hope that the results of these experiments will help make a choice between inflationary and cyclical theories. But it may also happen that the situation remains uncertain and none of the theories receives unambiguous experimental support. Well, then we’ll have to come up with something new.”
The Big Bang theory has become almost as widely accepted a cosmological model as the Earth's rotation around the Sun. According to the theory, about 14 billion years ago, spontaneous vibrations in absolute emptiness led to the emergence of the Universe. Something comparable in size to a subatomic particle expanded to unimaginable sizes in a fraction of a second. But there are many problems in this theory that physicists are struggling with, putting forward more and more new hypotheses.
What's wrong with the Big Bang Theory
From the theory it follows that all planets and stars were formed from dust scattered throughout space as a result of an explosion. But what preceded it is unclear: here is our mathematical model space-time stops working. The Universe arose from an initial singular state, to which modern physics cannot be applied. The theory also does not consider the causes of the singularity or the matter and energy for its occurrence. It is believed that the answer to the question of the existence and origin of the initial singularity will be provided by the theory of quantum gravity.
Most cosmological models predict that the complete Universe is much larger than the observable part - a spherical region with a diameter of approximately 90 billion light years. We see only that part of the Universe, the light from which managed to reach the Earth in 13.8 billion years. But telescopes are getting better, we are discovering more and more distant objects, and so far there is no reason to believe that this process will stop.
Since the Big Bang, the Universe has been expanding at an accelerating rate. The most difficult riddle modern physics is the question of what causes acceleration. According to working hypothesis, the Universe contains an invisible component called “ dark energy" The Big Bang theory does not explain whether the Universe will expand indefinitely, and if so, what will this lead to - its disappearance or something else.
Although Newtonian mechanics was supplanted by relativistic physics, it cannot be called erroneous. However, the perception of the world and the models for describing the Universe have completely changed. The Big Bang theory predicted a number of things that were not known before. Thus, if another theory comes to replace it, it should be similar and expand the understanding of the world.
We will focus on the most interesting theories describing alternative models of the Big Bang.
The Universe is like a mirage of a black hole
The Universe arose due to the collapse of a star in a four-dimensional Universe, according to scientists from the Perimeter Institute of Theoretical Physics. The results of their study were published by Scientific American. Niayesh Afshordi, Robert Mann and Razi Pourhasan say that our three-dimensional Universe became a kind of “holographic mirage” when a four-dimensional star collapsed. Unlike the Big Bang theory, which posits that the universe arose from an extremely hot and dense space-time where the standard laws of physics do not apply, the new hypothesis of a four-dimensional universe explains both the origins and its rapid expansion.
According to the scenario formulated by Afshordi and his colleagues, our three-dimensional Universe is a kind of membrane that floats through an even larger universe that already exists in four dimensions. If this four-dimensional space had its own four-dimensional stars, they would also explode, just like the three-dimensional ones in our Universe. The inner layer would become black hole, and the external one would be thrown into space.
In our Universe, black holes are surrounded by a sphere called the event horizon. And if in three-dimensional space this boundary is two-dimensional (like a membrane), then in a four-dimensional universe the event horizon will be limited to a sphere that exists in three dimensions. Computer simulations of the collapse of a four-dimensional star have shown that its three-dimensional event horizon will gradually expand. This is exactly what we observe, calling the growth of the 3D membrane the expansion of the Universe, astrophysicists believe.
Big Freeze
An alternative to the Big Bang is the Big Freeze. A team of physicists from the University of Melbourne, led by James Kvatch, presented a model of the birth of the Universe, which is more reminiscent of the gradual process of freezing amorphous energy than its release and expansion in three directions of space.
Formless energy, according to scientists, like water, cooled to crystallization, creating the usual three spatial and one temporal dimensions.
The Big Freeze theory challenges Albert Einstein's currently accepted assertion of the continuity and fluidity of space and time. It is possible that space has components - indivisible building blocks like tiny atoms or pixels in computer graphics. These blocks are so small that they cannot be observed, however, following new theory, it is possible to detect defects that should refract the flow of other particles. Scientists have calculated such effects using mathematics, and now they will try to detect them experimentally.
Universe without beginning and end
Ahmed Farag Ali from Benha University in Egypt and Saurya Das from the University of Lethbridge in Canada have proposed a new solution to the singularity problem by abandoning the Big Bang. They introduced the ideas of the famous physicist David Bohm into the Friedmann equation describing the expansion of the Universe and the Big Bang. “It's amazing that small adjustments can potentially solve so many issues,” says Das.
The resulting model combined general relativity and quantum theory. It not only denies the singularity that preceded the Big Bang, but also does not admit that the Universe will eventually contract back to its original state. According to the data obtained, the Universe has a finite size and an infinite lifetime. In physical terms, the model describes a Universe filled with a hypothetical quantum fluid, which consists of gravitons - particles that provide gravitational interaction.
The scientists also claim that their findings are consistent with recent measurements of the density of the Universe.
Endless chaotic inflation
The term “inflation” refers to the rapid expansion of the Universe, which occurred exponentially in the first moments after the Big Bang. The inflation theory itself does not disprove the Big Bang theory, but only interprets it differently. This theory solves several fundamental problems in physics.
According to the inflationary model, shortly after its birth, the Universe expanded exponentially for a very short time: its size doubled many times over. Scientists believe that in 10 to -36 seconds, the Universe increased in size by at least 10 to 30 to 50 times, and possibly more. At the end of the inflationary phase, the Universe was filled with superhot plasma of free quarks, gluons, leptons and high-energy quanta.
The concept implies what exists in the world many universes isolated from each other with different device
Physicists have come to the conclusion that the logic of the inflationary model does not contradict the idea of the constant multiple birth of new universes. Quantum fluctuations - the same as those that created our world - can arise in any quantity if the conditions are right for them. It is quite possible that our universe has emerged from the fluctuation zone that formed in the predecessor world. It can also be assumed that someday and somewhere in our Universe a fluctuation will form that will “blow out” a young Universe of a completely different kind. According to this model, daughter universes can bud off continuously. Moreover, it is not at all necessary that the same physical laws are established in new worlds. The concept implies that in the world there are many universes isolated from each other with different structures.
Cyclic theory
Paul Steinhardt, one of the physicists who laid the foundations of inflationary cosmology, decided to develop this theory further. The scientist, who heads the Center for Theoretical Physics at Princeton, together with Neil Turok from the Perimeter Institute for Theoretical Physics, outlined an alternative theory in the book Endless Universe: Beyond the Big Bang ("The Infinite Universe: Beyond the Big Bang"). Their model is based on a generalization of quantum superstring theory known as M-theory. According to it, the physical world has 11 dimensions - ten spatial and one temporal. Spaces of lower dimensions, the so-called branes, “float” in it. (short for "membrane"). Our Universe is simply one of these branes.
The Steinhardt and Turok model states that the Big Bang occurred as a result of the collision of our brane with another brane - an unknown universe. In this scenario, collisions occur endlessly. According to the hypothesis of Steinhardt and Turok, another three-dimensional brane “floats” next to our brane, separated by a tiny distance. It is also expanding, flattening and emptying, but after a trillion years the branes will begin to move closer together and eventually collide. This will release a huge amount of energy, particles and radiation. This cataclysm will trigger another cycle of expansion and cooling of the Universe. From the model of Steinhardt and Turok it follows that these cycles have existed in the past and will certainly repeat in the future. The theory is silent about how these cycles began.
Universe
like a computer
Another hypothesis about the structure of the universe says that our entire world is nothing more than a matrix or a computer program. The idea that the Universe is a digital computer was first put forward by German engineer and computer pioneer Konrad Zuse in his book Calculating Space (“Computational space”). Among those who also viewed the Universe as a giant computer are physicists Stephen Wolfram and Gerard 't Hooft.
Digital physics theorists propose that the universe is essentially information, and therefore computable. From these assumptions it follows that the Universe can be considered as the result of work computer program or digital computing device. This computer could be, for example, a giant cellular automaton or a universal Turing machine.
Indirect evidence virtual nature of the universe called the uncertainty principle in quantum mechanics
According to the theory, every object and event in the physical world comes from asking questions and recording “yes” or “no” answers. That is, behind everything that surrounds us, there is a certain code, similar to the binary code of a computer program. And we are a kind of interface through which access to the data of the “universal Internet” appears. An indirect proof of the virtual nature of the Universe is called the uncertainty principle in quantum mechanics: particles of matter can exist in an unstable form, and are “fixed” in a specific state only when they are observed.
Digital physicist John Archibald Wheeler wrote: “It would not be unreasonable to imagine that information resides in the core of physics as in the core of a computer. Everything is from the bit. In other words, everything that exists - every particle, every force field, even the space-time continuum itself - receives its function, its meaning and, ultimately, its very existence."
Nov 26, 2014
They say that time is the most mysterious matter. No matter how much a person tries to understand its laws and learn to control them, he always gets into trouble. Taking the last step towards solving the great mystery, and considering that it is practically already in our pocket, we are always convinced that it is still just as elusive. However, man is an inquisitive creature and the search for answers to eternal questions for many becomes the meaning of life.
One of these secrets was the creation of the world. Followers of the “Big Bang Theory,” which logically explains the origin of life on Earth, began to wonder what happened before the Big Bang, and whether there was anything at all. The topic for research is fertile, and the results may be of interest to the general public.
Everything in the world has a past - the Sun, the Earth, the Universe, but where did all this diversity come from and what came before it?
It is hardly possible to give a definite answer, but it is quite possible to put forward hypotheses and look for evidence for them. In search of the truth, researchers have received not one, but several answers to the question “what happened before the Big Bang?” The most popular of them sounds somewhat discouraging and quite bold - Nothing. Is it possible that everything that exists came from nothing? That Nothing gave birth to everything that exists?
Actually, this cannot be called absolute emptiness and are there still some processes going on there? Was everything born from nothing? Nothingness is the complete absence of not only matter, molecules and atoms, but even time and space. Rich soil for the activity of science fiction writers!
Scientists' opinions about the era before the Big Bang
However, Nothing cannot be touched, ordinary laws do not apply to it, which means you either speculate and build theories, or try to create conditions close to those that resulted in the Big Bang and make sure your assumptions are correct. In special chambers from which particles of matter were removed, the temperature was lowered, bringing it closer to space conditions. The observational results provided indirect confirmation of scientific theories: scientists studied the environment in which the Big Bang could theoretically arise, but calling this environment “Nothing” turned out to be not entirely correct. The mini-explosions that occur could lead to a larger explosion that gave birth to the Universe.
Theories of universes before the Big Bang
Adherents of another theory argue that before the Big Bang there were two other Universes that developed according to their own laws. What exactly they were is difficult to answer, but according to the theory put forward, the Big Bang occurred as a result of their collision and led to the complete destruction of the previous Universes and, at the same time, to the birth of ours, which exists today.
The “compression” theory says that the Universe exists and has always existed; only the conditions of its development change, which lead to the disappearance of life in one region and the emergence in another. Life disappears as a result of the “collapse” and appears after the explosion. No matter how paradoxical it may sound. This hypothesis has a large number of supporters.
There is another assumption: as a result of the Big Bang, a new Universe arose from nothingness and inflated, like a soap bubble, to gigantic proportions. At this time, “bubbles” budded from it, which later became other Galaxies and Universes.
Theory " natural selection” suggests that we are talking about “natural cosmic selection”, like the one Darwin talked about, only on a larger scale. Our Universe had its own ancestor, and it, in turn, also had its own ancestor. According to this theory, our Universe was created by a Black Hole. and are of great interest to scientists. According to this theory, in order for a new Universe to appear, “reproduction” mechanisms are necessary. The Black Hole becomes such a mechanism.
Or maybe those who believe that as our Universe grows and develops is expanding, heading towards the Big Bang, which will be the beginning of a new Universe, are right. This means that once upon a time, an unknown and, alas, disappeared Universe became the progenitor of our new universe. The cyclical nature of this system looks logical and this theory has many adherents.
It is difficult to say to what extent the followers of this or that hypothesis came close to the truth. Everyone chooses what is closer in spirit and understanding. The religious world gives its own answers to all questions and puts the picture of the creation of the world into a divine framework. Atheists are looking for answers, trying to get to the bottom of things and touch this very essence with their own hands. One may wonder what caused such persistence in searching for an answer to the question of what happened before the Big Bang, because it is quite problematic to derive practical benefit from this knowledge: a person will not become the ruler of the Universe, according to his word and desire, new stars will not light up and existing ones will not go out . But what is so interesting is what has not been studied! Humanity is struggling to solve mysteries, and who knows, maybe sooner or later they will fall into man’s hands. But how will he use this secret knowledge?
Illustrations: KLAUS BACHMANN, GEO magazine
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The Big Bang belongs to the category of theories that attempt to fully trace the history of the birth of the Universe, to determine the initial, current and final processes in its life.
Was there something before the Universe came into being? This fundamental, almost metaphysical question is asked by scientists to this day. The emergence and evolution of the universe has always been and remains the subject of heated debate, incredible hypotheses and mutually exclusive theories. The main versions of the origin of everything that surrounds us, according to the church interpretation, assumed divine intervention, and scientific world supported Aristotle's hypothesis about the static nature of the universe. The latter model was adhered to by Newton, who defended the boundlessness and constancy of the Universe, and by Kant, who developed this theory in his works. In 1929, American astronomer and cosmologist Edwin Hubble radically changed scientists' views of the world.
He not only discovered the presence of numerous galaxies, but also the expansion of the Universe - a continuous isotropic increase in the size of outer space that began at the moment of the Big Bang.
To whom do we owe the discovery of the Big Bang?
Albert Einstein's work on the theory of relativity and his gravitational equations allowed de Sitter to create a cosmological model of the Universe. Further research was tied to this model. In 1923, Weyl suggested that matter placed in outer space should expand. The work of the outstanding mathematician and physicist A. A. Friedman is of great importance in the development of this theory. Back in 1922, he allowed the expansion of the Universe and made reasonable conclusions that the beginning of all matter was at one infinitely dense point, and the development of everything was given by the Big Bang. In 1929, Hubble published his papers explaining the subordination of radial velocity to distance; this work later became known as “Hubble’s law.”
G. A. Gamow, relying on Friedman’s theory of the Big Bang, developed the idea of high temperature original substance. He also suggested the presence of cosmic radiation, which did not disappear with the expansion and cooling of the world. The scientist performed preliminary calculations of the possible temperature of residual radiation. The value he assumed was in the range of 1-10 K. By 1950, Gamow made more accurate calculations and announced a result of 3 K. In 1964, radio astronomers from America, while improving the antenna, by eliminating all possible signals, determined the parameters of cosmic radiation. Its temperature turned out to be equal to 3 K. This information became the most important confirmation of Gamow’s work and the existence of cosmic microwave background radiation. Subsequent measurements of the cosmic background carried out in outer space, finally proved the accuracy of the scientist’s calculations. You can get acquainted with the map of cosmic microwave background radiation at.
Modern ideas about the Big Bang theory: how did it happen?
One of the models that comprehensively explains the emergence and development processes of the Universe known to us is the Big Bang theory. According to the widely accepted version today, there was originally a cosmological singularity - a state of infinite density and temperature. Physicists have developed a theoretical justification for the birth of the Universe from a point that had an extreme degree of density and temperature. After the Big Bang occurred, the space and matter of the Cosmos began an ongoing process of expansion and stable cooling. According to recent studies, the beginning of the universe was laid at least 13.7 billion years ago.
Starting periods in the formation of the Universe
The first moment, the reconstruction of which is allowed by physical theories, is the Planck epoch, the formation of which became possible 10-43 seconds after the Big Bang. The temperature of the matter reached 10*32 K, and its density was 10*93 g/cm3. During this period, gravity gained independence, separating itself from the fundamental interactions. The continuous expansion and decrease in temperature caused a phase transition of elementary particles.
The next period, characterized by the exponential expansion of the Universe, came after another 10-35 seconds. It was called "Cosmic inflation". An abrupt expansion occurred, many times greater than usual. This period provided an answer to the question, why is the temperature at different points in the Universe the same? After the Big Bang, the matter did not immediately scatter throughout the Universe; for another 10-35 seconds it was quite compact and a thermal equilibrium was established in it, which was not disturbed by inflationary expansion. The period provided the base material - quark-gluon plasma, used to form protons and neutrons. This process took place after a further decrease in temperature and is called “baryogenesis.” The origin of matter was accompanied by the simultaneous emergence of antimatter. The two antagonistic substances annihilated, becoming radiation, but the number of ordinary particles prevailed, which allowed the creation of the Universe.
The next phase transition, which occurred after the temperature decreased, led to the emergence of the elementary particles known to us. The era of “nucleosynthesis” that came after this was marked by the combination of protons into light isotopes. The first nuclei formed had a short lifespan; they disintegrated during inevitable collisions with other particles. More stable elements arose within three minutes after the creation of the world.
The next significant milestone was the dominance of gravity over other available forces. 380 thousand years after the Big Bang, the hydrogen atom appeared. The increase in the influence of gravity marked the end of the initial period of the formation of the Universe and started the process of the emergence of the first stellar systems.
Even after almost 14 billion years, cosmic microwave background radiation still remains in space. Its existence in combination with the red shift is cited as an argument to confirm the validity of the Big Bang theory.
Cosmological singularity
If, using the general theory of relativity and the fact of the continuous expansion of the Universe, we return to the beginning of time, then the size of the universe will be equal to zero. The initial moment or science cannot describe it accurately enough using physical knowledge. The equations used are not suitable for such a small object. A symbiosis is needed that can combine quantum mechanics and the general theory of relativity, but, unfortunately, it has not yet been created.
The evolution of the Universe: what awaits it in the future?
Scientists are considering two possible scenarios: the expansion of the Universe will never end, or it will reach a critical point and the reverse process will begin - compression. This fundamental choice depends on the average density of the substance in its composition. If the calculated value is less than the critical value, the forecast is favorable; if it is more, then the world will return to a singular state. Scientists currently do not know the exact value of the described parameter, so the question of the future of the Universe is up in the air.
Religion's relationship to the Big Bang theory
The main religions of humanity: Catholicism, Orthodoxy, Islam, in their own way support this model of the creation of the world. Liberal representatives of these religious denominations agree with the theory of the origin of the universe as a result of some inexplicable intervention, defined as the Big Bang.
The name of the theory, familiar to the whole world - “Big Bang” - was unwittingly given by the opponent of the version of the expansion of the Universe by Hoyle. He considered such an idea "totally unsatisfactory." After the publication of his thematic lectures, the interesting term was immediately picked up by the public.
The reasons that caused the Big Bang are not known with certainty. According to one of the many versions, belonging to A. Yu. Glushko, the original substance compressed into a point was a black hyper-hole, and the cause of the explosion was the contact of two such objects consisting of particles and antiparticles. During annihilation, matter partially survived and gave rise to our Universe.
Engineers Penzias and Wilson, who discovered the cosmic microwave background radiation of the Universe, received Nobel Prizes in physics.
The temperature of the cosmic microwave background radiation was initially very high. After several million years, this parameter turned out to be within the limits that ensure the origin of life. But by this period only a small number of planets had formed.
Astronomical observations and research help to find answers to the most important questions for humanity: “How did everything appear, and what awaits us in the future?” Despite the fact that not all problems have been solved, and the root cause of the appearance of the Universe does not have a strict and harmonious explanation, the Big Bang theory has gained sufficient quantity confirmations that make it the main and acceptable model of the emergence of the universe.