The theory of the inflationary Universe, or the theory of the Multiverse (Multiverse). The birth of the universe

Immediately after its birth, the universe expanded incredibly rapidly.

Since the 30s of the XX century, astrophysicists have already known that, according to Hubble's law, the Universe is expanding, which means that it had its beginning at a certain moment in the past. The task of astrophysicists, therefore, outwardly looked simple: to track all stages of the Hubble expansion in reverse chronology, applying at each stage the appropriate physical laws, and, having passed this path to the end - more precisely, to the very beginning - to understand exactly how everything happened.

In the late 1970s, however, several fundamental problems related to the early universe remained unsolved, namely:

• The problem of antimatter. According to the laws of physics, matter and antimatter have an equal right to exist in the Universe ( cm. Antiparticles), but the universe is almost entirely composed of matter. Why did it happen?
• Horizon problem. According to the background cosmic radiation ( cm. Big Bang), we can determine that the temperature of the Universe is approximately the same everywhere, but its individual parts (clusters of galaxies) could not be in contact (as they say, they were outside horizon each other). How did it happen that thermal equilibrium was established between them?
• The problem of straightening space. The universe seems to have exactly the mass and energy needed to slow down and stop the Hubble expansion. Why, of all possible masses, does the universe have this one?

The key to solving these problems was the idea that immediately after its birth, the universe was very dense and very hot. All matter in it was a red-hot mass of quarks and leptons ( cm. Standard Model), which had no way to combine into atoms. Various forces acting in the modern Universe (such as electromagnetic and gravitational forces) then corresponded to a single field of force interaction ( cm. universal theories). But when the Universe expanded and cooled, the hypothetical unified field broke up into several forces ( cm. early universe).

In 1981, the American physicist Alan Guth realized that the separation of strong interactions from a unified field, which happened about 10 -35 seconds after the birth of the Universe (just think - this is 34 zeros and one after the decimal point!), Was a turning point in its development. happened phase transition matter from one state to another on the scale of the universe - a phenomenon similar to the transformation of water into ice. And just as when water freezes, its randomly moving molecules suddenly “seize” and form a strict crystalline structure, so under the influence of the released strong interactions, an instantaneous restructuring took place, a kind of “crystallization” of matter in the Universe.

Who saw how they burst water pipes or car radiator tubes in severe frost, as soon as the water in them turns into ice, it own experience knows that water expands when it freezes. Alan Guth was able to show that when the strong and weak interactions were separated, something similar happened in the Universe - a jump-like expansion. This extension is called inflationary, many times faster than the usual Hubble expansion. In about 10 -32 seconds, the Universe expanded by 50 orders of magnitude - it was smaller than a proton, and became the size of a grapefruit (for comparison: when water freezes, it expands by only 10%). And this rapid inflationary expansion of the universe removes two of the three above problems, directly explaining them.

Solution space straightening problems The following example illustrates best: imagine coordinate grid, drawn on a thin elastic card, which was then crumpled at random. Now if you take and shake this elastic card crumpled into a ball, it will again accept flat view, and the coordinate lines on it will be restored, no matter how much we deformed it when we crumpled it. The same way, no matter how curved the space of the Universe was at the time of the beginning of its inflationary expansion, the main thing is that at the end of this expansion, the space turned out to be completely straightened. And since we know from the theory of relativity that the curvature of space depends on the amount of matter and energy in it, it becomes clear why there is only enough matter in the Universe to balance the Hubble expansion.

Explains the inflationary model and horizon problem, although not so directly. From the theory of black body radiation, we know that the radiation emitted by a body depends on its temperature. Thus, from the emission spectra of remote parts of the Universe, we can determine their temperature. Such measurements gave stunning results: it turned out that at any observable point in the Universe the temperature (with a measurement error of up to four decimal places) is the same. If we start from the model of the usual Hubble expansion, then the matter immediately after the Big Bang should have scattered too far for the temperatures to equalize. According to the inflationary model, the matter of the Universe until the moment t = 10 -35 seconds remained much more compact than during the Hubble expansion. This extremely short period was quite enough for the thermal equilibrium to be established, which was not disturbed at the stage of inflationary expansion and has been preserved to this day.

American physicist, specialist in the field elementary particles and cosmology. Born in New Brunswick, New Jersey. He received his doctorate from the Massachusetts Institute of Technology, where he returned in 1986, becoming a professor of physics. Guth developed his theory of the inflationary expansion of the Universe while still at Stanford University, while working on the theory of elementary particles. Known for his review of the universe as an "endless self-assembly tablecloth."

After learning about the Big Bang theory, I asked myself the question, where did it come from that exploded?
The question of the origin of the Universe with all its known and yet unknown properties has been of concern to man since time immemorial. But only in the twentieth century, after the discovery of cosmological expansion, the question of the evolution of the universe began to gradually become clearer. Recent scientific data have led to the conclusion that our universe was born 15 million years ago as a result of the Big Bang. But what exactly exploded at that moment and what, in fact, existed before the Big Bang, still remained a mystery. The inflationary theory of the emergence of our world, created in the twentieth century, made it possible to make significant progress in resolving these issues, overall picture the first moments of the Universe today is already well drawn, although many problems are still waiting in the wings.
Until the beginning of the last century, there were only two views on the origin of our universe. Scientists believed that it is eternal and unchanging, and theologians said that the world was created and it will have an end. The twentieth century, having destroyed a lot of what had been created in previous millennia, managed to give its own answers to most of the questions that occupied the minds of scientists of the past. And perhaps one of greatest achievements of the past century is the clarification of the question of how the Universe in which we live arose, and what hypotheses exist about its future. A simple astronomical fact - the expansion of our Universe - has led to a complete revision of all cosmogonic concepts and the development of a new physics - the physics of emerging and disappearing worlds. Just 70 years ago, Edwin Hubble discovered that light from more distant galaxies is "redder" than light from closer ones. Moreover, the recession speed turned out to be proportional to the distance from the Earth (Hubble's expansion law). This was discovered thanks to the Doppler effect (the dependence of the wavelength of light on the speed of the light source). Since more distant galaxies appear more "red", it was assumed that they are moving away at a faster rate. By the way, it is not stars and even individual galaxies that scatter, but clusters of galaxies. The nearest stars and galaxies are connected with each other by gravitational forces and form stable structures. Moreover, in whatever direction you look, clusters of galaxies scatter from the Earth at the same speed, and it may seem that our Galaxy is the center of the Universe, but this is not so. Wherever the observer is, he will everywhere see the same picture - all the galaxies are running away from him. But such expansion of matter must have a beginning. This means that all galaxies must have been born at the same point. Calculations show that this happened about 15 billion years ago. At the moment of such an explosion, the temperature was very high, and a lot of light quanta should have appeared. Of course, everything cools down over time, and the quanta scatter over the emerging space, but the echoes of the Big Bang should have survived to this day. The first confirmation of the fact of the explosion came in 1964, when American radio astronomers R. Wilson and A. Penzias discovered relic electromagnetic radiation with a temperature of about 3° Kelvin (–270°C). It was this discovery, unexpected for scientists, that convinced them that the Big Bang really took place and that the Universe was very hot at first. The Big Bang theory has helped explain many of the problems facing cosmology. But, unfortunately, or perhaps fortunately, it also raised a number of new questions. In particular: What happened before the Big Bang? Why does our space have zero curvature and why is Euclid's geometry, which is studied at school, correct? If the Big Bang theory is correct, then why is the current size of our universe so much larger than the 1 centimeter predicted by the theory? Why is the Universe surprisingly homogeneous, while in any explosion the matter scatters in different directions extremely unevenly? What led to the initial heating of the Universe to an unimaginable temperature of more than 10 13 K?
All this indicated that the Big Bang theory was incomplete. For a long time it seemed that going further was impossible. Only a quarter of a century ago, thanks to the work of Russian physicists E. Gliner and A. Starobinsky, as well as the American A. Gus, a new phenomenon was described - the superfast inflationary expansion of the Universe. The description of this phenomenon is based on well-studied sections of theoretical physics - Einstein's general theory of relativity and quantum theory fields. Today it is generally accepted that this period, called "inflation", preceded the Big Bang.
When trying to give an idea of ​​the essence initial period The life of the Universe has to operate with such ultra-small and super-large numbers that our imagination hardly perceives them. Let's try to use some analogy to understand the essence of the process of inflation.
Imagine a snow-covered mountain slope interspersed with heterogeneous small objects - pebbles, branches and pieces of ice. Someone on top of this slope made a small snowball and let it roll down the mountain. Moving down, the snowball increases in size, as new layers of snow with all the inclusions stick to it. And than larger size snowball, the faster it will increase. Very soon, from a small snowball, it will turn into a huge lump. If the slope ends in an abyss, then he will fly into it with ever-increasing speed. Having reached the bottom, the lump will hit the bottom of the abyss and its components will scatter in all directions (by the way, part of the lump's kinetic energy will go to heat the environment and flying snow).
Let us now describe the main provisions of the theory using the above analogy. First of all, physicists had to introduce a hypothetical field, which was called "inflaton" (from the word "inflation"). This field filled the entire space (in our case, snow on the slope). Due to random fluctuations, it took on different values ​​in arbitrary spatial regions and at different points in time. Nothing significant happened until a homogeneous configuration of this field with a size of more than 10 -33 cm was accidentally formed. As for the Universe we observe, it apparently had a size of 10 -27 cm in the first moments of its life. It is assumed that on such scales the basic laws of physics known to us today are already valid, so it is possible to predict the further behavior of the system. It turns out that immediately after this, the spatial region occupied by the fluctuation (from the Latin fluctuatio - “fluctuation”, random deviations of the observed physical quantities from their average values) begins to increase very quickly in size, and the inflaton field tends to take a position in which its energy minimal (snowball rolled). Such an expansion lasts only 10 -35 seconds, but this time is enough for the diameter of the Universe to increase at least 1027 times and by the end of the inflationary period our Universe has acquired a size of about 1 cm. Inflation ends when the inflaton field reaches a minimum of energy - there is nowhere else to fall. In this case, the accumulated kinetic energy is converted into the energy of particles born and expanding, in other words, the heating of the Universe occurs. It is this moment that is called today the Big Bang.
The mountain mentioned above can have a very complex relief - several different lows, valleys below and all sorts of hills and bumps. Snowballs(future universes) are continuously born at the top of the mountain due to field fluctuations. Each lump can slide into any of the minima, thus giving rise to its own universe with specific parameters. Moreover, the universes can differ significantly from each other. The properties of our universe are amazingly adapted to the fact that intelligent life. Other universes may not have been as fortunate.
Once again, I would like to emphasize that the described process of the birth of the Universe "practically from nothing" is based on strictly scientific calculations. Nevertheless, any person who first gets acquainted with the inflationary mechanism described above has many questions.
Today our universe is made up of a large number stars, not to mention the hidden mass. And it might seem that the total energy and mass of the universe is enormous. And it is completely incomprehensible how all this could fit in the initial volume of 10-99 cm3. However, in the Universe there is not only matter, but also a gravitational field. It is known that the energy of the latter is negative and, as it turned out, in our Universe, the energy of gravity exactly compensates for the energy contained in particles, planets, stars and other massive objects. Thus, the law of conservation of energy is perfectly fulfilled, and the total energy and mass of our Universe are practically equal to zero. It is this circumstance that partly explains why the nascent Universe did not turn into a huge black hole immediately after its appearance. Its total mass was completely microscopic, and at first there was simply nothing to collapse. And only at later stages of development did local clumps of matter appear, capable of creating such gravitational fields near themselves, from which even light cannot escape. Accordingly, the particles from which the stars are "made" on initial stage development simply did not exist. Elementary particles began to be born at that period of the development of the Universe, when the inflaton field reached a minimum of potential energy and the Big Bang began.
The area occupied by the inflaton field grew at a speed much greater than the speed of light, but this does not in the least contradict Einstein's theory of relativity. Faster than light can not move only material bodies, and in this case the imaginary, non-material boundary of the region where the Universe was born moved (an example of superluminal motion is the movement of a light spot on the surface of the Moon during the rapid rotation of the laser illuminating it).
And environment did not resist at all the expansion of the area of ​​space covered by the ever more rapidly growing inflaton field, since it seemed to not exist for the emerging World. The general theory of relativity states that the physical picture that an observer sees depends on where he is and how he moves. So, the picture described above is valid for the "observer" located inside this area. Moreover, this observer will never know what is happening outside the region of space where he is. Another "observer", looking at this area from the outside, will not find any expansion at all. At best, he will see only a small spark, which, according to his watch, will disappear almost instantly. Even the most sophisticated imagination refuses to perceive such a picture. And yet it appears to be true. At least, this is what modern scientists think, drawing confidence in the already discovered laws of Nature, the correctness of which has been repeatedly verified.
It must be said that this inflaton field still continues to exist and fluctuate. But only we, internal observers, are not able to see this - after all, for us, a small area has turned into a colossal Universe, the boundaries of which even light cannot reach.
So, immediately after the end of inflation, a hypothetical internal observer would see the Universe filled with energy in the form material particles and photons. If all the energy that could be measured by an internal observer is converted into a mass of particles, then we will get approximately 10 80 kg. The distances between particles increase rapidly due to the general expansion. The gravitational forces of attraction between particles reduce their speed, so the expansion of the universe after the end of the inflationary period gradually slows down.
Immediately after birth, the universe continued to grow and cool. At the same time, cooling occurred, among other things, due to the banal expansion of space. Electromagnetic radiation is characterized by a wavelength that can be associated with temperature - the longer the average wavelength of the radiation, the lower the temperature. But if space expands, then the distance between the two "humps" of the wave will increase, and, consequently, its length. This means that in expanding space, the radiation temperature must also decrease. This is confirmed by the extremely low temperature of modern relic radiation.
As it expands, the composition of the matter that fills our world also changes. Quarks unite into protons and neutrons, and the Universe turns out to be filled with elementary particles already familiar to us - protons, neutrons, electrons, neutrinos and photons. There are also antiparticles. The properties of particles and antiparticles are almost identical. It would seem that their number should be the same immediately after inflation. But then all particles and antiparticles would mutually annihilate and building material for galaxies and we ourselves would not be left. And here again we are lucky. Nature made sure that there were a little more particles than antiparticles. It is thanks to this small difference that our world exists. And relic radiation is just a consequence of the annihilation (that is, mutual annihilation) of particles and antiparticles. Of course, on initial stage the energy of the radiation was very high, but due to the expansion of space and, as a consequence, the cooling of the radiation, this energy rapidly decreased. Now the energy of the CMB is about ten thousand times (104 times) less energy, enclosed in massive elementary particles.
Gradually, the temperature of the universe dropped to 1010 K. By this time, the age of the universe was about 1 minute. Only now have protons and neutrons been able to combine into nuclei of deuterium, tritium and helium. This was due to nuclear reactions, which people have already studied well, detonating thermonuclear bombs and operating atomic reactors on Earth. Therefore, one can confidently predict how many and what elements can appear in such a nuclear pile. It turned out that the currently observed abundance of light elements is in good agreement with the calculations. This means that the physical laws known to us are the same in the entire observable part of the Universe and were such already in the first seconds after the appearance of our world. Moreover, about 98% of the helium existing in nature was formed precisely in the first seconds after the Big Bang.
Immediately after birth, the Universe went through an inflationary period of development - all distances rapidly increased (from the point of view of an internal observer). However, the energy density at different points in space cannot be exactly the same - some inhomogeneities are always present. Suppose that in some area the energy is slightly greater than in neighboring ones. But since all sizes are growing rapidly, then the size of this area should also grow. After the end of the inflationary period, this expanded area will have slightly more particles than the space around it, and its temperature will be slightly higher.
Realizing the inevitability of the emergence of such areas, supporters of the inflationary theory turned to the experimenters: "it is necessary to detect temperature fluctuations ..." - they stated. And in 1992 this wish was fulfilled. Almost simultaneously, the Russian satellite "Relikt-1" and the American "COBE" detected the required fluctuations in the temperature of the cosmic microwave background radiation. As already mentioned, modern universe has a temperature of 2.7 K, and the temperature deviations found by scientists from the average were approximately 0.00003 K. It is not surprising that such deviations were difficult to detect before. So the inflationary theory received another confirmation.
With the discovery of temperature fluctuations, another exciting opportunity has emerged - to explain the principle of galaxy formation. Indeed, in order for gravitational forces to compress matter, an initial germ is needed - an area with increased density. If matter is uniformly distributed in space, then gravity, like Buridan's donkey, does not know in which direction to act. But it is precisely the areas with an excess of energy that generate inflation. Now the gravitational forces know what to act on, namely the denser areas created during the inflationary period. Under the influence of gravity, these initially slightly denser regions will shrink and it is from them that stars and galaxies will form in the future.
The current moment of the evolution of the Universe is extremely well adapted for life, and it will last for many more billions of years. Stars will be born and die, galaxies will rotate and collide, and clusters of galaxies will fly farther and farther apart. Therefore, humanity has plenty of time for self-improvement. True, the very concept of “now” for such a huge universe as ours is poorly defined. So, for example, the life of quasars observed by astronomers, remote from the Earth by 10-14 billion light years, is separated from our "now" just by those same 10-14 billion years. And the farther into the depths of the Universe we look with the help of various telescopes, the earlier period of its development we observe.
Today, scientists are able to explain most of the properties of our universe, from 10 -42 seconds to the present and beyond. They can also trace the formation of galaxies and predict the future of the universe with some confidence. Nevertheless, a number of "small" incomprehensibility still remains. First of all, this is the essence of the hidden mass ( dark matter) and dark energy. In addition, there are many models that explain why our Universe contains many more particles than antiparticles, and we would like to decide in the end on the choice of one correct model.
As the history of science teaches us, it is usually “minor imperfections” that open up further development paths, so that future generations of scientists will certainly have something to do. In addition, more deep questions are already on the agenda of physicists and mathematicians. Why is our space three-dimensional? Why are all the constants in nature as if “fitted” so that intelligent life arises? And what is gravity? Scientists are already trying to answer these questions.
And of course, leave room for surprises. It should not be forgotten that such fundamental discoveries as the expansion of the Universe, the presence of relic photons and vacuum energy were made, one might say, by chance and were not expected by the scientific community.

According to the theory space inflation, the early universe began to expand exponentially, just after the Big Bang. Cosmologists put forward this theory in 1981 to explain several important issues in cosmology.

One such problem is the horizon problem. Assume for a moment that the universe is not expanding. Now imagine that in the very early universe, a free-flying photon was fired until it collided with the Earth's N Pole. Now imagine that a photon was fired at the same time, this time in the opposite direction to the first. It should have hit the South Pole of the Earth.

Can two given photons exchange any information that happened at the time of their creation? Obviously not. Because the time required to transfer data from one photon to another, in this case, will be two ages of the Universe. Photons are isolated. They are beyond each other's horizon.

However, observations show that photons coming from opposite directions interacted in some way. Since the background microwave cosmic radiation has an almost identical temperature at all points in our sky.

This problem can be solved by assuming that some time after the Big Bang, the universe expanded exponentially. Up to this point, the universe could have had causal contact and a balanced overall temperature. Regions that are far apart today were very close in the early universe. This explains why photons coming from different directions almost always have the same temperature.

A simple model for understanding the expansion of the universe is like blowing up a balloon. To an observer on either side of the ball, it may appear that he is in the center of the expansion, as all neighboring points become further away.
When the balloon is inflated, the distances between objects on the surface of the balloon are about e60 = 1026. This is a number followed by twenty-six zeros. It transcends normal politico-economic debates about inflation.

quantum fluctuations

Let's imagine that before the balloon was inflated, there was an inscription written on it. So small that it could not be read. Inflating the balloon made the message readable. This means that inflation acts as a microscope that shows what was written on the original balloon.

Similarly, we can consider quantum fluctuations that were formed at the beginning of inflation. The expansion of the cosmos during the era of inflation acts as a huge microscope that shows quantum fluctuations. This leaves imprints in the background microwave cosmic radiation (hotter and colder regions) and in the expansion of galaxies.

When using classical physics, the evolution of the inflationary Universe is homogeneous - each point in space develops identically. However, the quantum physics introduces some uncertainty into the initial conditions for different points in space.

These variations act like seeds in the formation of the structure. After a period of inflation, when the fluctuations intensify, the distribution of matter will be slightly different from place to place in the universe. The force of gravity forms denser regions, which leads to the formation of galaxies.

Epigraph:
And the whole world is not enough!

I can bet that among those reading these lines there is not a single person who has never heard of the Big Bang theory in his life. I admit that similar characters come across on Earth - a peasant from an abandoned village in the mountains of Tibet, a native of the Tonga-Tonga tribe, a Mormon from Utah, they are probably found somewhere. However, if you can read, have access to the Internet and were able, albeit by chance, to go to this blog - I can guarantee that you must have heard something at least out of the corner of your ear, but heard about the Big Bang theory.

In this post I will talk about the current scientific understanding of this theory, the text turned out to be rather big, but I promise that today you will learn something new, something that you did not know before and did not even think about.

First of all, it's funny, but few people thought about what, in fact, is the Big Bang theory? Try right now to twist in your head the facts that you know about her, and then I will describe how she sounds in fact.

Have you tried? Well, 20 more seconds to think...

So. The Big Bang Theory claims that our universe used to be small and hot, but since then it has been expanding and cooling. Dot. There is nothing else in this theory, do not invent too much.

Surprisingly, in classical theory The Big Bang is not the most important - there is no actual Big Bang. Nowhere is it mentioned what kind of "explosion" it was, what exploded there, where it exploded, how and why.

Following the main thesis that "At first our universe was small and hot", you can mentally stretch it even further (although I draw your attention, this is NOT THE Big Bang theory anymore, these are precisely attempts to stretch the boundaries of applicability into the realm of conjectures and fantasies) and come to the assumption that even earlier the whole universe was gathered into one point, called point of singularity, which later exploded for some internal reason.

I note that the theory of the Big Bang ("before the Universe was small and hot, and then it became large and cold") is not today theory, as such. We can assume that this is quite a scientifically established fact, confirmed huge amount observations, today there is not a single standing scientist who would doubt him. But as for the point of singularity (which, I repeat, lies outside the limits of applicability of the Big Bang theory), scientists not only do not have a common opinion, they do not have any opinion at all.

Nobody has the slightest idea what it is "singularity". Singularity is generally a placeholder (substitute word) for the phrase "I don't know". That is, to the question "Are the classes P and NP equal?", Or "Is Schrödinger's cat alive?", Or even "What does the clap of one palm sound like?" you can safely answer "Singularity!".
You won't be mistaken.

The Big Bang theory was formulated in the 20s of the last century, and since then, for a century, scientists have been only trying to understand what is the essence of the singularity, and is it possible to somehow get rid of it?

The main problem of the singularity is that natural division to zero, in the most literal sense. All formulas turn into nonsense, 3 becomes equal to 5, and one infinity starts to creep into another. And this is the end of physics, the end of science, only dragons-YGGOGs live on, and somewhere from the folds of space the Almighty himself winks maliciously.

A lot of different ways, approaches and tricks were proposed to replace the singularity, the best so far succeeded by the American physicist Alan Guth in 1981. As always, I remind you once again that science is a collective matter, Gut, like all his predecessors, climbed onto the shoulders of giants, but in this short text on fingers™ I will not list all the predecessors, colleagues and opponents, I will mention only one surname that deserves it - Alexey Starobinsky, who expressed similar ideas earlier, but the fame of the discoverer was assigned to Alan Gut.

Gut suggested making a tricky feint with his ears. Watch your hands and ears carefully, now I will show you a trick. let's mentally(!) we extract the word "singularity" from all the texts and put the phrase "scalar field" instead. I draw your attention, at this stage nothing has changed, the term "scalar field" continues to be a complete analogue () of "singularity", which, in turn, as we remember, is only a substitute for the phrase "I don't know".

What is this "scalar field", what are its characteristics, where did it come from, what the hell is going on - still no answers. As long as the "scalar field", or as it is also called in the English tradition the "field of inflatons" (because "inflation" is the same), this is only the result of a thought experiment in an attempt to get away from the singularity and come to something else. So far, this is nothing more than a replacement for sewing with soap. But we will be real scientists, we will bring our thought experiment to the end, and see what happens in the end.

So, according to Gut, the original proto-Universe was formless and empty, there was nothing in it and nothing happened, it was infinite, or at least very, very, very large, much larger than the modern one. observable universe, and all of it was filled with this very scalar field, about which we do not know anything, except that it is some kind of field, and that, as the name implies, it is scalar.

I will not burden the reader with the definition of "scalar", this is not particularly necessary within the framework of this post, it is quite simple and on fingers™ we can assume that this field contains some "tension". The field carries a certain energy in itself, like a thundercloud carries water ready to rain.

How is this situation better than the previous one with the singularity from the point of view of physics? Yes to everyone! Even if we do not know any characteristics of this field, even if we have no idea what kind of tension was there and where it came from, but this is not division by zero! Now we have a problem to be solved, we can start writing some formulas (you know, don’t feed a real scientist with honey, just give me some three-story formulas) into which it is possible to substitute initial conditions and coefficients, divide and multiply, calculate what be obtained in the end, and then compared with the results of direct observations and experiments.

Yes, it sounds funny and even somehow silly, a natural “thread on the soap”, but it turned out to be a real breakthrough. This is a step forward from the total "I don't know" inscribed on concrete wall, this is already a serious bid for success, for a detour, for a dig, or at least for a ladder.

However, the funny thing is that Alan Guth's trick with a scalar field was a success, but the formulas just didn't work out. Alan brought to science the idea of ​​a scalar field and its inflation (about the mechanism of inflation a little later), but he failed to correctly describe his thoughts in the dry language of mathematics. The rows diverged, everything again began to divide by zero, in short, a complete failure.

And only a year later, the subdued torch of the inflationary model was raised high by Andrei Linde, a Soviet scientist temporarily residing in the United States and head of the Department of Physics at Stanford University.

He corrected the mistakes of Alan Guth's theory, made the formulas converge and give a predictable and verifiable result, but along the way he opened a real Pandora's box, which I will mention at the very end of the post, I'll leave it for dessert.

The essence of the inflationary model of the Universe (briefly, figuratively and vaguely) is as follows:

We remember that the proto-Universe, the predecessor of our Universe, was filled with a certain scalar field, about which we know nothing, except for the presence of the field itself and its "scalar" nature. Scalar, not scalar, but nobody canceled the principles of quantum mechanics! For a hundred years now, no one, including Albert Einstein himself, has ever succeeded in the principles of quantum mechanics. Which means that even if this field was initially homogeneous (and, in principle, it does not have to be initially homogeneous), all the same, over time, under the influence of quantum fluctuations, small inhomogeneities will appear in it, which, according to the instructions of His Majesty the Quantum Chance, can overlap each other, forming large heterogeneities.

Well, large by quantum standards. Anyway, it's still milli-milli-milli-... (and another 10 times milli-) Joules, meters and kilograms, we are not talking about any of our Universe, with trillions of stars and galaxies.

And here suddenly it turns out that our field is not just any, but rather tricky! In an ordinary field, in which there is no friction, inhomogeneities simply sooner or later " close and short"on themselves. For example, let's take a well-known and understandable electromagnetic field. If somewhere there is a potential difference that continues to increase, then sooner or later, but it will definitely short-circuit. A discharge will run, a mini-spark (or mega-lightning, if the potential difference was large as in a thunderstorm) and the heterogeneity is leveled.

By the way, first, attentive star reader(*) , here I must declare that the electromagnetic field is not a scalar field, but quite the opposite - a vector field, and a very confused one at that. But in this specific example it plays no role at all. And in that and in that field the short is almost the same, according to one scenario. Well, and secondly, it cannot be said that it will definitely short out immediately, charges can accumulate for years and even millions of years. It all depends on a thousand different conditions, but if you wait long enough (e.g. eternity), then short circuit inhomogeneities will surely happen. Naturally, this is all nothing more than an analogy, and at this point it’s not very direct, I’m just trying on fingers™ to explain the behavior of an incomprehensible scalar field using the example of an understandable electromagnetic one.

So, in an electromagnetic field practically no friction, so to speak. Electrons have a finite speed of movement and they experience the direct resistance of the medium, which we call resistance electric current , but field changes are transmitted at the rate of the electromagnetic field, i.e. at the speed of light. If we go too far off topic, then reader with two asterisks (**) must know that even a complete and absolute vacuum has some analogue of "resistance" electromagnetic waves, but this is already a very deep wilds of the Casimir force and other effects of vacuum fluctuations, we should not go deep there yet, even though such posts from the series on fingers™ are planned for the unknown but foreseeable future.

In short, we can say that the electromagnetic field has no internal friction, or it is negligible. Well, short and short in the blink of an eye. If we impose an analogy on an analogy, we can say that the closure of the electromagnetic field is like a mountain located in a high potential area on which the ball lies, and the low potential area is a hole under the mountain where this ball will eventually fall. Since there is almost no friction, the ball rushes down at full speed, in fact, at the speed of light. Bang, and fell.

When falling, some kind of energy is sure to be released, which will go to heat the surrounding space, the earth and the ball. In the case of an electromagnetic field, a natural discharge of the field occurs, i.e. lightning. If it happened under water (and electric discharges can also short out under water), then a tiny air bubble forms in this place when the water breaks down into its constituent oxygen and hydrogen. The discharge is literally lightning fast, the potential difference drops quickly, the air bubble is very small.

Now back to our hypothetical scalar field. Since it is still hypothetical, you can fantasize about it and its properties as you like. Let us assume that there is internal friction in this field and it is very large. Very, very big. Shifting to the analogy with the ball, it will fall from the mountain not in a vacuum or air there, but in a very viscous and viscous liquid, for example, in sunflower oil or honey.

Therefore, the force of gravity pulls the ball down, and the force of friction prevents it from falling quickly and pulls it back up. And instead of rapidly rushing to the foot (and we remember that this is just an analogy of how quickly discharges uneven field strength), the ball smoothly, almost with constant speed, i.e. descends almost uniformly. The rarefaction of the scalar field is responsible for the creation of a vacuum, i.e. of our dear space-time, the fall of its potential seems to inflate a balloon, only instead of air there is a vacuum, and instead of a balloon - our Universe. If everything happened without friction, the intensity of the scalar field would drop very quickly and we would have a small bubble of vacuum in the vast vast ocean of the proto-Universe. But friction (and in fact the scalar field itself) does not allow tension to fall quickly, interferes with pulls itself back. Because of this, while the tension is slowly decreasing, in fact, it stands still, the "force of inflation", i.e. the force that bursts the resulting vacuum in all directions remains constant, and continues to pump with the same effort, despite the fact that the dimensions of the newborn Universe are increasing and increasing.

Scientists know, and you can take my word for it, or you can check and google that in this case we get an equation whose solution is the exponent. Those. it turns out natural exponential expansion of the universe. Billions billion billion times. For not a very large, very short period of time. It all depends on what coefficients we have included in the exponent, i.e. what was the initial intensity of the scalar field, what was the friction force, etc.

Calculations show that if the "expansion force" does not decrease with time, in some 10 -36 fractions of a second the new Universe (that is, this original bubble of vacuum) can expand 10 26 times. Yes, this exceeds the speed of light by many orders of magnitude, but there is no paradox here. The Theory of Relativity forbids any matter to move in space faster than the speed of light, but does not forbid the space itself (i.e. emptiness) to expand to the sides at any speed.

It turns out that there was no Big Bang as an "explosion" at all. There was a fast, very fast, explosively or exponentially fast "inflation and expansion" of the bubble of our Universe, exactly what inflation, from English word inflation- "inflate", "inflate".

But here's a tricky one! The vacuum is expanding, i.e. absolute emptiness, where did all the energy and matter that now make up all our stars, galaxies and other content of modern space come from? And why was the Universe hot before, why should there be a hot, empty vacuum or what?

Here again is a complicated thing with furious formulas, I will try to explain it with the help of what would you think? Analogies on fingers™, Well, of course!

You know that if something expands very quickly in our country, then this something just as rapidly loses energy, in the sense that it spreads it just as quickly over the entire expanding volume, and at each individual point or cubic meter of space, energy becomes less and less. This is not khukhr-mukhr for you, by the way, this is the first law of thermodynamics!

We do the opposite. If the bubble of the Universe is stretched very quickly, it will start instantly accumulate energy. After all, gravitational energy always goes with a minus sign. If we spread two bodies in space, or, say, lift a heavy load above the Earth's surface, the potential, and hence the total energy of the system will increase! And since everything happens quickly (let me remind you, very-very-very-... and 26 more times very quickly), then in the case of some gas, for example air, it cools sharply, forms fog and water vapor in it precipitates, forming natural snow or ice. Everyone saw that if you open the valve of a liquefied gas cylinder, the cylinder is immediately covered with frost.

And in the case of the Universe, on the contrary, the temperature rises sharply, a phase transition occurs and the released energy "precipitates" in the form of energy itself (photons) and matter (electrons, protons and other elementary particles). That is why, at the end of inflation, which began not so hot, the Universe quickly warms up to unlimited energies and temperatures that were previously thought to have burst out right from the point of singularity. And then when the ball hit the bottom of the hole and the period of exponential expansion is over, everything continues according to the old scenario of the classical Big Bang, the Universe is expanding, but not exponentially, but slowly, by inertia. But now all this comes out without the Big Bang itself and its singularity.

It sounds unusual, it sounds like some kind of deception, but if you think about it, everything is logical - the increased potential energy, the gravitational energy with a minus sign is exactly compensated by the kinetic energy, the energy of motion (temperature) and the rest energy (mass) of "precipitated" particles of matter. The total energy of the universe continues to be zero, minus one hundred and plus one hundred results in zero. Like minus a billion and plus a billion.

To be completely accurate, it’s not quite exactly zero in the end, because the intensity of the original scalar field, from which it all started, in this place still fell almost to zero. But the absolute value of this fall, some fractions of a Joule ( Or what is the strength of the inflaton field measured there?), still remains within the limits, albeit large, but still quantum effects. This cannot be compared with trillions-billions (more precisely 10 50 and so on) kilograms of matter born and the same orders of stored gravitational energy. The mouse gave birth to a mountain, in the truest sense of the word. More precisely, a mountain and a pit nearby for balance.

Once again, for clarity, I will repeat the previous paragraph in slightly different words. When, as a result of a drop in the strength of the scalar field, a small bubble of our space-time appeared in it, i.e. ordinary vacuum, this space-time turns out to be "slightly bent". Why? Because that's how any energy affects space. Newton thought there was gravity strength attraction of two masses. Einstein said that gravity is only bending space. If the space is "bent", some gravitational energy is already stored in it, even if this space is absolutely empty and there is no mass in it. What's oppressing our space? It is oppressed by energy (it is more correct to say - the energy-momentum tensor). Mass is also energy, a lot of energy, but you can do without mass at all, in general, any energy oppresses space. When, under the influence of the falling energy of the scalar field, "a small bubble of vacuum inflated", it already contains the energy of the scalar field, the vacuum in it is already "bent". If this bubble is quickly stretched to the sides, the gravitational energy will increase sharply, which will cause "precipitation" of mass, which, on the one hand, adds energy to the Universe (because E = mc 2) with a plus sign, and on the other hand, adds to the Universe gravitation of this mass with a minus sign, which means that the race-competition of the mountain and the mouse will continue further.

Yes, I remind you, if anyone forgot that all this is happening as part of a thought experiment to get rid of the singularity! This is still just a gymnastics of the mind, there is still not much smell of science here, although the thought experiment itself is a mandatory attribute scientific method. To rise in the rank of at least a hypothesis, not to mention a theory, you need to go through a lot and explain a lot.

I repeat, we are still in the process of exchanging sewing for soap. We have not gone anywhere from the incomprehensible original singularity, we just called it a little differently and, as a result, stood upside down. However, the specific details of the theory of the inflationary expansion of the Universe, in contrast to the classical theory of the Big Bang, allow us to find explanations for many observed phenomena (the problem of initial conditions, the problem of homogeneity and isotropy of the observable Universe, the problem of the plane of the observable Universe, the problem with magnetic monopoles, and much more), before which the singularity of the Big Bang gave in. This makes the inflationary model very attractive, but does not prove it at all and does not declare it correct. The inflationary model has been in a state of "young and promising", but "unproven and slightly fantastic" theory since the 80s last century the last millennium (I so intricately said "30 years ago"), until the first, still timid, unconfirmed and very circumstantial evidence appeared in 2014, in the sense experimental results confirming it. And here it’s not just an application, it’s a real success!

What are these experiments, what are their results, what is " gravitational waves"how are they related to inflation and why is their discovery drawn to nobel prize, which, I think, Alan Gut and Andrey Linda will eventually be awarded, as well as all other technical details are gathered together and will be described separately, in the second part of this story, they pull on a full-fledged separate post. Here I just outlined the essence of the inflationary theory, stopping it at the stage of 2013 - interesting, tempting, but not confirmed by anything.

And now the promised sweet.

Yes, it is too early to speak with firm certainty. Yes, all this is still written with a pitchfork in the water, and it does not have to be at all. Yes, there is still a long, long road of calculations, mistakes and experiments ahead, but.

The most delicious thing is that the inflationary theory of Alan Gut, or rather, just the mathematical calculations of Andrey Linde, imply an absolutely wonderful and mind-blowing thing.

Linde's additions are officially called the "chaotic theory of inflation". Its central part, the very essence of the theory, says that these "discharges of the scalar field" are simply obliged chaotically, i.e. by chance, occur anywhere and everywhere in the original proto-Universe. And this means that our specific Big Bang (which, as we already know from the current post, was not an explosion at all), which led to the formation of our specific Universe, is only one discharge, a separate specific bubble of the resulting space, which we call our cosmos. And around not just “maybe”, but according to the formulas, billions and billions of other bubbles, other universes should be floating around. In each of these universes (already with a small letter), the scalar field fell / discharged a little differently, and therefore the laws of physics in these universes can differ significantly from ours. Stars and galaxies could not have formed there at all, or vice versa, something could have formed there that we never dreamed of in our wildest fantasies.

This whole conglomerate of inflating bubbles-universes is commonly called multiverse, although Linde himself prefers to speak in Russian "Many Faces of the Universe". It turns out that the modern scientific understanding of the origin and structure of our world is now as follows:

There is an infinite or at least a very large multiverse filled with some kind of scalar field. How long it has existed, where it came from, what the conditions are in this multiverse - we have no idea. Even half a dozen. But scientists are pretty sure that in some places in this multiverse, the scalar field begins to fall, inflating the bubbles of ordinary universes and forming in them the space-time we are used to. Our particular bubble began to inflate about 13.8 billion years ago, and the scalar field in our Universe, by the way, has not gone anywhere, now it is almost at a minimum, but not equal to zero! That which pushes the galaxies of our universe apart, and what we call Dark Energy, this is the same "scalar field", more precisely, only a part of it. Here, by the way, there should be several paragraphs explaining that the long-sought Higgs field, formed by the seemingly recently found Higgs boson, is also a product of a scalar field, namely its grandson, because between the scalar and the Higgs there is, rather it should be, yet another super-Higgs field into which the scalar field degenerates and which, in turn, degenerates into the Higgs field. But this is not entirely proven, and already quite aside from our current conversation, so perhaps that's enough about it.

Around Bubbles of our universe are bubbles of other universes, which are formed from the fall of the scalar field in those specific places. Somewhere their own small-town big bang (also with a small letter) is just beginning, but somewhere everything has long ended, and "between" these universes there is just a scalar field in its high energy state. The multiverse becomes like Swiss cheese, where the cheese itself is a scalar field, and the holes in it are myriads and myriads of universes, one of which is ours.

Is it possible to drill tunnels through this scalar field to get to other "parallel" universes? Unknown.
How far is it from our bubble to the neighboring one, and is it possible to get there through higher dimensions? Unknown.
Do they really exist, these other universes around ours, or is it all just fantasy? It is not known, but now in science there is a very strong confidence in this.

Isn't it wonderful?

UPD: Read the continuation of the post in the article.

Inflationary model of the Universe(lat. inflatio "swelling") - a hypothesis about the physical state and law of the expansion of the Universe at the early stage of the Big Bang (at temperatures above 10 28 ), suggesting a period of accelerated expansion compared to the standard model of the hot Universe.

The first version of the theory was proposed in 1981 by Alan Gut, however, Soviet and ex-Soviet astrophysicists Aleksey Starobinsky, Andrey Linde, Vyacheslav Mukhanov and a number of others made a key contribution to its creation.

Disadvantages of the Hot Universe Model

where ρ (\displaystyle \rho ) is the average density of the universe.

The disadvantage of this model is the extremely high requirements for the homogeneity and isotropy of the initial state, the deviation from which leads to a number of problems.

The problem of large-scale homogeneity and isotropy of the Universe

The size of the observable region of the universe l 0 (\displaystyle l_(0)) coincides in order of magnitude with the Hubble distance r H = c / H 0 ≈ 10 28 (\displaystyle r_(H)=c/H_(0)\approx 10^(28)) see (where H- Hubble constant), that is, due to the finiteness of the speed of light and the finiteness of the age of the Universe, it is possible to observe only regions (and the objects and particles located in them) that are now at a distance from each other l ≤ l 0 (\displaystyle l\leq l_(0)). However, during the Planck era of the Big Bang, the distance between these particles was:

and the size of the causally connected area (horizon) was determined by the distance:

(Planck time ( t P l a n c k ≈ 10 − 43 (\displaystyle t_(\mathrm (Planck) )\approx 10^(-43)) sec), that is, in the volume l′ (\displaystyle l") contained ~10 90 such Planck regions, the causal relationship (interaction) between which was absent. The identity of the initial conditions in so many causally unrelated regions seems extremely unlikely. In addition, even in the later epochs of the Big Bang, the problem of the identity of the initial conditions in causally unrelated regions is not removed: for example, in the epoch of recombination, the now observed CMB photons coming to us from close directions (differing by arcseconds) should have interacted with regions of primary plasma, between which, according to the standard model of the hot Universe, a causal relationship did not have time to be established during the entire time of their existence from t P l a n c k . (\displaystyle t_(\mathrm (Planck) ).) Thus, one could expect a significant anisotropy of the cosmic microwave background radiation, but observations show that it is highly isotropic (deviations do not exceed ~10 −4).

The Flat Universe Problem

According to observational data, the average density of the universe ρ (\displaystyle \rho ) close to the so-called. critical density, at which the curvature of the space of the Universe is equal to zero. However, according to the calculated data, the density deviation ρ (\displaystyle \rho ) from critical density ρ c r i t (\displaystyle \rho _(\mathrm (crit) )) should increase with time, and in order to explain the observed spatial curvature of the Universe in the framework of the standard model of the hot Universe, one has to postulate the density deviation in the Planck epoch ρ P l a n c k (\displaystyle \rho _(\mathrm (Planck) )) from ρ c r i t (\displaystyle \rho _(\mathrm (crit) )) no more than 10 −60 .

The Problem of the Large-Scale Structure of the Universe

The inflationary model assumes the replacement of the power law of expansion R (t) ∼ t 1 / 2 (\displaystyle R(t)\sim t^(1/2)) to the exponential law:

where H (t) = (1 / R) d R / d t (\displaystyle H(t)=(1/R)dR/dt) is the Hubble constant of the inflationary stage, which generally depends on time.

The value of the Hubble constant at the stage of inflation is 10 42 s −1 > H> 10 36 sec −1 , that is, it is gigantically superior to it contemporary meaning. Such an expansion law can be provided by the states of physical fields (“inflaton field”) corresponding to the equation of state p = − ε (\displaystyle p=-\varepsilon ), i.e. negative pressure; This stage is called the inflationary stage.