A guide to the impossible, the incredible and the miraculous.

In an abandoned attic near the British Museum:

Cornelius grabbed a blank sheet of paper, passed it through the roller, and began to type. The starting point of his tale was the Big Bang itself, as space set off on its ever-expanding journey into the future. After a brief burst of inflation, the universe was thrown into a series of phase transitions and formed an excess of matter over antimatter. During this primordial epoch, the Universe did not contain any cosmic structures at all.

After a million years and many reams of paper, Cornelius has reached the era of the stars - a time when stars are actively born, live their life cycles and generate energy through nuclear reactions. This bright chapter closes when galaxies run out of hydrogen gas, cease forming stars, and slowly fade away the longest-lived red dwarfs.

By typing nonstop, Cornelius brings his story into decay, with brown dwarfs, white dwarfs, neutron stars and black holes. In the midst of this frozen desert, dark matter slowly collects inside dead stars and annihilates into radiation that fuels space. The decay of the proton enters the scene at the end of this chapter as the mass-energy of degenerate stellar remnants slowly escapes and carbon-based life dies out completely.

When the tired author continues his work, the only heroes of his narrative are black holes. But black holes also cannot live forever. Emitting light as faint as ever, these dark objects evaporate in a slow quantum mechanical process. In the absence of another source of energy, the universe is forced to be content with this meager amount of light. After the evaporation of the largest black holes, the transitional twilight of the era of black holes surrenders under the onslaught of even deeper blackness.

At the beginning of the final chapter, Cornelius runs out of paper, but not time. There are no more stellar objects in the Universe, but only useless products left over from previous cosmic catastrophes. In this cold, dark and very distant era of eternal darkness, cosmic activity is noticeably slowing down. Extremely low energy levels are consistent with tremendous time spans. After its fiery youth and full of energy of middle age, the present universe is slowly creeping into darkness.

As the universe ages, its character is constantly changing. At every stage of its future evolution, the Universe maintains an amazing variety of complex physical processes and other interesting behavior. Our biography of the Universe, from its birth in an explosion to a long and gradual slide into eternal darkness, is based on the modern understanding of the laws of physics and the wonders of astrophysics. Thanks to the vastness and thoroughness of modern science, this narrative represents the most likely vision of the future that we can compose.

Insanely large numbers

When we discuss the vast range of exotic behavior of the universe that is possible in the future, the reader might think that anything can happen. But this is not the case. Despite the abundance of physical possibilities, only a tiny fraction of theoretically possible events will actually occur.

First of all, the laws of physics impose strict restrictions on any permitted behavior. The law of conservation of total energy must be observed. The law of conservation of electric charge must not be violated. The main guiding concept is the second law of thermodynamics, which formally states that the total entropy of a physical system should increase. Roughly speaking, this law suggests that systems should evolve into states of increasing disorder. In practice, the second law of thermodynamics forces heat to move from hot objects to cold objects, and not vice versa.

But even within the framework of the processes allowed by the laws of physics, many events that could happen in principle never actually happen. One common reason is that they simply take too long and other processes take place first, which are ahead of them. The cold fusion process is a good example of this trend. As we have already noted in connection with nuclear reactions in the interiors of stars, the most stable of all possible nuclei is the iron nucleus. Many smaller nuclei such as hydrogen or helium would give up their energy if they could combine to form an iron core. At the other end of the periodic table, larger nuclei such as uranium would also give up their energy if they could be divided into parts, and from these parts to make up an iron nucleus. Iron is the lowest energy state available to nuclei. The nuclei tend to stay in the form of iron, but energy barriers prevent this transformation from happening easily under most conditions. Overcoming these energy barriers typically requires either high temperatures or extended periods of time.

Consider a large lump of solid, such as a rock or perhaps a planet. The structure of this solid does not change due to ordinary electromagnetic forces, such as those involved in chemical bonding. Instead of preserving its original nuclear composition, matter, in principle, could regroup so that all of its atomic nuclei turned into iron. For such a restructuring of matter to occur, the nuclei must overcome the electrical forces that hold this matter in the form in which it exists, and the electrical repulsive forces with which the nuclei act on each other. These electrical forces create a strong energy barrier, much like the one shown in Fig. 23. Because of this barrier, the nuclei must regroup through quantum mechanical tunneling (as soon as the nuclei penetrate the barrier, a strong attraction initiates fusion). Thus, our piece of matter would show nuclear activity. Given enough time, the entire rock, or the entire planet, would be turned into pure iron.

How long would such a nuclear restructuring take? Nuclear activity of this type would convert rock cores to iron in about fifteen hundred cosmological decades. If this nuclear process took place, excess energy would be emitted into space, because iron nuclei correspond to a lower energy state. However, this cold fusion process will never be completed. It will never even really start. All the protons that make up the nuclei will decay into smaller particles much earlier than the nuclei are converted to iron. Even the longest possible lifetime of a proton is less than two hundred cosmological decades - much shorter than the huge amount of time required for cold fusion. In other words, the nuclei will disintegrate before they have a chance to turn into iron.

Another physical process that takes too long to be considered important for cosmology is the tunneling of degenerate stars into black holes. Because black holes are the lowest energy states available to stars, a degenerate white dwarf-like object has more energy than a black hole of the same mass. Thus, if a white dwarf could spontaneously transform into a black hole, it would release excess energy. Usually, however, such a transformation does not occur due to the energy barrier created by the pressure of the degenerate gas that supports the existence of the white dwarf.

Despite the energy barrier, a white dwarf could transform into a black hole through quantum mechanical tunneling. Because of the uncertainty principle, all the particles (10 57 or so) that make up a white dwarf could be within such a small space that they would form a black hole. However, this random event takes an extremely long time - on the order of 1076 cosmological decades. It is impossible to exaggerate the truly enormous size of 10 76 cosmological decades. If you write this immensely long period of time in years, you get one with 10 76 zeros. We might not even start writing this number in the book: it would have on the order of one zero for every proton in the visible modern Universe, plus or minus a couple of orders of magnitude. Needless to say, protons will decay and white dwarfs will disappear long before the universe reaches 1076th cosmological decade.

What actually happens in the long-term expansion process?

While many events are virtually impossible, a wide range of theoretical possibilities remains. The broadest categories of future behavior of the cosmos are based on whether the universe is open, flat, or closed. An open or flat universe will expand forever, while a closed universe will undergo re-contraction after a certain time, which depends on the initial state of the universe. Looking at more speculative possibilities, however, we find that the future evolution of the universe may be much more complex than this simple classification scheme suggests.

The main problem is that we can make measurements that have a physical meaning and, therefore, make certain conclusions only in relation to the local region of the Universe - the part limited by the modern cosmological horizon. We can measure the total density of the universe within this local area, which is about twenty billion light years across. But density measurements within this local volume, alas, do not determine the long-term fate of the Universe as a whole, since our Universe can be much larger.

Suppose, for example, that we were able to measure that the cosmological density exceeds the value required to close the universe. We would come to the experimental conclusion that in the future our universe should undergo re-contraction. The universe would clearly be sent through an accelerating sequence of natural disasters leading to the Great Compression, described in the next section. But that's not all. Our local region of the Universe - the part that we observe is enclosed in this imaginary Armageddon scenario - could be nested in a much larger region of much lower density. In this case, only a certain part of the entire Universe would experience compression. The remaining part, covering, perhaps, most of the Universe, could continue to expand infinitely.

The reader may disagree with us and say that this complication is of little use: our own part of the universe is still destined to survive re-contraction. Our world will still not escape destruction and destruction. Yet this glimpse of the big picture dramatically changes our perspective. If the larger universe survives as a whole, the demise of our local area is not such a tragedy. We will not deny that the destruction of one city on Earth, say, due to an earthquake, is a terrible event, but still it is far from being as terrible as the complete destruction of the entire planet. Likewise, the loss of one small part of the entire universe is not as ruinous as the loss of the entire universe. Complex physical, chemical and biological processes can still unfold in the distant future, somewhere in the Universe. The destruction of our local Universe could be just another catastrophe from a whole series of astrophysical disasters, which, perhaps, will bring the future: the death of our Sun, the end of life on Earth, the evaporation and scattering of our Galaxy, the decay of protons, and, consequently, the destruction of all ordinary matter. evaporation of black holes, etc.

The survival of the larger Universe provides an opportunity for salvation: either real travel over long distances, or a substitute deliverance through the transmission of information through light signals. This life-saving path can turn out to be difficult or even forbidden: it all depends on how the closed region of our local space-time is combined with a larger region of the Universe. However, the fact that life can continue elsewhere keeps hope alive.

If our local area is re-compressed, there may not be enough time for all the astronomical events described in this book to occur in our part of the Universe. However, in the end, these processes will still occur in some other place in the Universe - far from us. How long we have before the local part of the Universe is re-compressed depends on the density of the local part. Although modern astronomical measurements indicate that its density is so low that our local part of the universe will not collapse at all, additional invisible matter may be lurking in the dark. The maximum possible permitted local density is about twice the value required for the local part of the Universe to be closed. But even with this maximum density, the universe cannot begin to contract until at least twenty billion years have elapsed. This time constraint would give us a delay of the local version of the Great Compression for at least another fifty billion years.

An opposite set of circumstances may also arise. Our local part of the universe can demonstrate a relatively low density and, therefore, qualify for eternal life. However, this local chunk of space-time can be nested in a much larger region of much higher density. In this case, when our local cosmological horizon becomes large enough to include a larger region of higher density, our local universe will become part of a larger universe destined to undergo re-contraction.

This destruction scenario requires our local universe to have an almost flat cosmological geometry, because only then does the expansion rate continue to fall steadily. Nearly flat geometry allows more and more regions of the metamscale universe (the big picture of the universe) to influence local events. This large surrounding area just needs to be dense enough to eventually survive re-contraction. It must live long enough (that is, not collapse too early) for our cosmological horizon to expand to the required large scale.

If these ideas are realized in space, then our local universe is not at all "the same" as the much larger area of ​​the Universe that engulfs it. Thus, at sufficiently large distances, the cosmological principle would be clearly violated: the Universe would not be the same at every point in space (homogeneous) and not necessarily the same in all directions (isotropic). Such a potential does not at all negate our use of the cosmological principle to study the history of the past (as in the Big Bang theory), since the Universe is clearly homogeneous and isotropic within our local region of space-time, the radius of which is currently about ten billion light years. Any potential deviations from homogeneity and isotropy are large, which means they can only appear in the future.

Ironically, we can impose restrictions on the nature of that larger region of the Universe that is currently outside our cosmological horizon. The cosmic background radiation is measured to be extremely uniform. However, large differences in the density of the Universe, even if they were outside the cosmological horizon, would certainly cause pulsations in this uniform background radiation. So the absence of significant pulsations suggests that any anticipated significant density perturbations must be very far away from us. But if large density perturbations are far away, then our local region of the Universe can live long enough before it encounters them. The earliest possible moment when large differences in density will have an impact on our part of the universe will come in about seventeen cosmological decades. But, most likely, this universe-changing event will occur much later. According to most versions of the theory of an inflationary Universe, our Universe will remain homogeneous and almost flat for hundreds and even thousands of cosmological decades.

Big compression

If the Universe (or part of it) is closed, then gravity will triumph over expansion and the inevitable contraction will begin. Such a Universe, experiencing a second collapse, would end its life path in the fiery denouement known as Big compression... The many vicissitudes that mark the time sequence of a shrinking universe were first examined by Sir Martin Rees, now Astronomer Royal of England. When the universe is thrown into this grand finale, there will be no shortage of disasters.

And although the universe is likely to expand forever, we are more or less confident that the density of the universe does not exceed twice the critical density. Knowing this upper bound, we can argue that minimally the possible time remaining before the collapse of the Universe in the Great Compression is about fifty billion years. Doomsday is still a long way off by any human standard of time, so rent should probably continue to be paid regularly.

Suppose that twenty billion years later, having reached its maximum size, the Universe is indeed undergoing re-contraction. At that time, the universe will be about twice as large as it is today. The background radiation temperature will be about 1.4 degrees Kelvin, half the temperature today. After the universe has cooled down to this minimum temperature, the subsequent collapse will heat it up as it rushes toward the Great Compression. Along the way, in the process of this compression, all structures created by the Universe will be destroyed: clusters, galaxies, stars, planets and even the chemical elements themselves.

About twenty billion years after the start of re-contraction, the universe will return to the size and density of the modern universe. And in the intermediate forty billion years, the Universe is moving forward, having approximately the same kind of large-scale structure. Stars continue to be born, evolve and die. Small stars that conserve fuel, like our close neighbor Proxima Centauri, don't have enough time to undergo any significant evolution. Some galaxies collide and merge within their parent clusters, but most of them remain largely unchanged. An individual galaxy takes more than forty billion years to change its dynamic structure. By inverting the Hubble law of expansion, some galaxies will move closer to our galaxy instead of moving away from it. It is only this curious blue-shifting trend that will allow astronomers to catch a glimpse of the impending catastrophe.

Individual clusters of galaxies, scattered in immense space and loosely bound in lumps and filaments, will remain intact until the Universe shrinks to a size five times smaller than it is today. At this hypothetical future conjunction, galaxy clusters merge. In today's universe, clusters of galaxies occupy only about one percent of the volume. However, once the universe shrinks to a fifth of its current size, clusters fill virtually all of space. Thus, the Universe will become one giant cluster of galaxies, but the galaxies themselves in this era, nevertheless, will retain their individuality.

As the contraction continues, the universe will very soon become a hundred times smaller than it is today. At this stage, the average density of the Universe will be equal to the average density of the galaxy. Galaxies will overlap each other, and individual stars will no longer belong to any particular galaxy. Then the entire Universe will turn into one giant galaxy filled with stars. The background temperature of the universe, created by cosmic background radiation, rises to 274 degrees Kelvin, approaching the point of ice melting. Due to the increasing compression of events after this era, it is much more convenient to continue the story from the position of the opposite end of the timeline: the time remaining until the Great Compression. When the temperature of the universe reaches the melting point of ice, our universe has ten million years of future history.

Until this moment, life on the terrestrial planets continues quite independently of the evolution of the cosmos around it. In fact, the warmth of the sky will eventually melt the frozen Pluto-like objects that drift around the periphery of each solar system and provide one last fleeting chance for life in the universe to flourish. This relatively short last spring will end as background temperature rises further. With the disappearance of liquid water throughout the Universe, more or less simultaneously there is a mass extinction of all living things. The oceans are boiling away, and the night sky is brighter than the daytime sky we see from Earth today. With only six million years left before the final contraction, any surviving life forms must either remain deep in the bowels of the planets, or develop sophisticated and efficient cooling mechanisms.

After the final destruction of first the clusters, and then the galaxies themselves, the next in the line of fire are the stars. If nothing else had happened, the stars would sooner or later collide and destroy each other in the face of ongoing and all-destructive compression. However, such a cruel fate will bypass them, because the stars will collapse in a more gradual manner long before the universe becomes dense enough for stellar collisions to occur. When the temperature of the continuously contracting background radiation exceeds the surface temperature of a star, which is between four and six thousand Kelvin, the radiation field can significantly change the structure of stars. And although nuclear reactions continue in the interiors of stars, their surfaces evaporate under the influence of a very strong external radiation field. Thus, background radiation is the main cause of the destruction of stars.

When stars begin to evaporate, the universe is about two thousand times smaller than it is today. In this turbulent era, the night sky looks as bright as the surface of the sun. The brevity of the remaining time is difficult to neglect: the strongest radiation burns away any doubts that less than a million years remain until the end. Any astronomers who have enough technological ingenuity to live up to this era may recall with humble amazement that the seething cauldron of the Universe they observe - stars frozen in a sky as bright as the Sun - is nothing more than the return of Olbers's paradox of an infinitely old and static universe.

Any cores of stars, or brown dwarfs, that survived to this era of evaporation will be torn to pieces in the most unceremonious manner. When the temperature of the background radiation reaches ten million degrees Kelvin, which is comparable to the current state of the central regions of stars, any remaining nuclear fuel can ignite and lead to a powerful and spectacular explosion. Thus, stellar objects that manage to survive evaporation will contribute to the general atmosphere of the end of the world, turning into fantastic hydrogen bombs.

Planets in a shrinking universe will share the fate of the stars. Giant balls of gas, like Jupiter and Saturn, evaporate much easier than stars and leave behind only central cores, indistinguishable from terrestrial planets. Any liquid water has long since evaporated from the surfaces of planets, and very soon their atmospheres will also follow its example. Only bare and barren wastelands remain. Rocky surfaces melt and layers of liquid rock gradually thicken, eventually engulfing the entire planet. Gravity keeps the dying molten remnants from flying apart, and they create heavy silicate atmospheres, which, in turn, escape into space. Evaporating planets, plunging into blinding flames, disappear without a trace.

When the planets leave the stage, the atoms of interstellar space begin to disintegrate into their constituent nuclei and electrons. The background radiation becomes so strong that photons (light particles) receive enough energy to release electrons. As a result, in the last several hundred thousand years, atoms have ceased to exist and matter disintegrates into charged particles. Background radiation interacts strongly with these charged particles, whereby matter and radiation are closely intertwined. Cosmic background photons, which have traveled unhindered for nearly sixty billion years since recombination, land on the surface of their "next" scattering.

The Rubicon is crossed when the universe shrinks to one ten-thousandth of its true size. At this stage, the radiation density exceeds the density of matter - this was the case only immediately after the Big Bang. In the Universe, radiation begins to dominate again. Because matter and radiation behave differently because they have undergone compression, further compression changes slightly as the universe undergoes this transition. There are only ten thousand years left.

When only three minutes are left before the final compression, atomic nuclei begin to decay. This decay continues until the last second, by which all free nuclei are destroyed. This epoch of antinucleosynthesis differs very significantly from the violent nucleosynthesis that occurred in the first few minutes of the primordial epoch. In the first few minutes of the history of space, only the lightest elements were formed, mainly hydrogen, helium and a little bit of lithium. In the last few minutes, a wide variety of heavy nuclei have been present in space. Iron nuclei hold the strongest bonds, so their decay requires the most energy per particle. However, the shrinking Universe creates ever higher temperatures and energies: sooner or later, even iron nuclei will die in this insanely destructive environment. At the last second of the life of the Universe, not a single chemical element remains in it. Protons and neutrons become free again - as in the first second of the history of space.

If at this epoch there is at least some life in the Universe, the moment of destruction of the nuclei becomes the line due to which they do not return. After this event, there will be nothing left in the universe that even remotely resembles carbon-based life on Earth. There will be no carbon left in the universe. Any organism that manages to survive the decay of nuclei must belong to a truly exotic species. Perhaps creatures based on strong interaction could see the last second of the life of the Universe.

The last second is a lot like the Big Bang movie shown backwards. After the decay of nuclei, when only one microsecond separates the Universe from death, the protons and neutrons themselves decay, and the Universe turns into a sea of ​​free quarks. As the compression continues, the universe becomes hotter and denser, and the laws of physics appear to be changing in it. When the universe reaches a temperature of about 10-15 degrees Kelvin, the weak nuclear force and the electromagnetic force combine to form the electroweak force. This event is a kind of cosmological phase transition, vaguely reminiscent of the transformation of ice into water. As we approach higher energies, near the end of time, we move away from direct experimental evidence, whereby the narrative, whether we like it or not, becomes more speculative. And yet we continue. After all, the universe still has 10-11 seconds of history.

The next important transition occurs when the strong force is combined with the electroweak. This event called great unification, combines three of the four fundamental forces of nature: strong nuclear force, weak nuclear force, and electromagnetic force. This unification takes place at an incredibly high temperature of 10 28 degrees Kelvin, when the universe has only 10 -37 seconds to live.

The last important event that we can celebrate on our calendar is the unification of gravity with the other three forces. This pivotal event occurs when the contracting universe reaches a temperature of about 1032 degrees Kelvin and only 10 -43 seconds remain before the Great Compression. This temperature or energy is commonly referred to as the Planck value... Unfortunately, scientists do not have a self-consistent physical theory for such a scale of energies, where all four fundamental forces of nature are combined into one whole. When this unification of the four forces occurs in the course of re-contraction, our current understanding of the laws of physics loses its relevance. What will happen next - we do not know.

Fine tuning our universe

Having looked at the impossible and incredible events, let us dwell on the most extraordinary event that happened - the birth of life. Our Universe is a pretty comfortable place to live, as we know it. In fact, all four astrophysical windows play an important role in its development. Planets, the smallest window in astronomy, are home to life. They provide "Petri dishes" in which life can arise and evolve. The importance of stars is also clear: they are the source of the energy needed for biological evolution. The second fundamental role of stars is that, like alchemists, they form elements heavier than helium: carbon, oxygen, calcium and other nuclei that make up the life forms we know.

Galaxies are also extremely important, although this is not so obvious. Without the cohesive influence of galaxies, the heavy elements produced by stars would be scattered throughout the entire universe. These heavy elements are the essential building blocks that make up both planets and all life forms. Galaxies, with their large masses and strong gravitational attraction, keep the chemically enriched gas left over after the death of stars from scattering. Subsequently, this previously processed gas is incorporated into future generations of stars, planets and people. Thus, the gravitational pull of galaxies ensures that heavy elements are easily accessible for subsequent generations of stars and for the formation of rocky planets like our Earth.

If we talk about the largest distances, then the Universe itself must have the necessary properties to allow the emergence and development of life. And while we have nothing remotely resembling a complete understanding of life and its evolution, one basic requirement is relatively certain: it takes a long time. The emergence of man took about four billion years on our planet, and we are ready to bet that, in any case, for the emergence of intelligent life, at least a billion years must pass. Thus, the universe as a whole must live for billions of years to allow the development of life, at least in the case of a biology that even vaguely resembles ours.

The properties of our universe as a whole also make it possible to provide a chemical environment conducive to the development of life. Although heavier elements like carbon and oxygen are synthesized in stars, hydrogen is also a vital component. It is part of two of the three water atoms, H 2 O, an important component of life on our planet. Looking at the huge ensemble of possible universes and their possible properties, we notice that as a result of primordial nucleosynthesis, all hydrogen could be converted into helium and even heavier elements. Or the universe could have expanded so rapidly that protons and electrons would never have met to form hydrogen atoms. Be that as it may, the Universe could have ended without creating the hydrogen atoms that make up the water molecules, without which there would be no ordinary life.

Taking these considerations into account, it becomes clear that our Universe really has the necessary features to allow our existence. Under the given laws of physics, determined by the values ​​of physical constants, the values ​​of fundamental forces and the masses of elementary particles, our Universe naturally creates galaxies, stars, planets and life. If physical laws had a slightly different form, our universe could be completely uninhabitable and extremely poor astronomically.

Let's illustrate the required fine-tuning of our Universe in a little more detail. Galaxies, one of the astrophysical objects necessary for life, form when gravity gains the upper hand over the expansion of the universe and provokes the collapse of local regions. If the force of gravity were much weaker or the rate of cosmological expansion was much faster, then by now there would not be a single galaxy in space. The universe would continue to scatter, but it would not contain a single gravitationally bound structure, at least for this moment in the history of the cosmos. On the other hand, if the force of gravity had a much greater magnitude or the expansion rate of the cosmos were much lower, then the entire Universe would again collapse in the Great Compression long before the formation of galaxies. In any case, there would be no life in our modern Universe. This means that the interesting case of a Universe filled with galaxies and other large-scale structures requires a rather delicate compromise between the force of gravity and the rate of expansion. And our universe has implemented just such a compromise.

As for the stars, here the required fine-tuning of the physical theory is associated with even more stringent conditions. The fusion reactions in stars play two key roles for the evolution of life: the production of energy and the production of heavy elements such as carbon and oxygen. For stars to play their intended role, they must live for a long time, reach high enough central temperatures, and be abundant enough. For all these pieces of the puzzle to fall into place, the universe must be endowed with a wide range of special properties.

Nuclear physics is probably the clearest example. Fusion reactions and nuclear structure depend on the magnitude of the strong interaction. Atomic nuclei exist as bound structures because strong interactions are capable of holding protons close to each other, even though the force of electrical repulsion of positively charged protons tends to tear the nucleus apart. If the strong interaction were slightly weaker, then there simply would be no heavy nuclei. Then there would be no carbon in the universe, and therefore no carbon-based life forms. On the other hand, if the strong nuclear force were even stronger, then two protons could combine into pairs called diprotons. In this case, the strong interaction would be so strong that all the protons in the Universe would combine into diprotons or even even larger nuclear structures, and there would be no ordinary hydrogen left. In the absence of hydrogen, there would be no water in the Universe, and therefore no life forms known to us. Luckily for us, our universe has just the right amount of strong interaction to allow hydrogen, water, carbon, and other essential constituents of life.

Likewise, if the weak nuclear force had a completely different force, it would significantly affect stellar evolution. If the weak interaction were much stronger, for example, in comparison with the strong interaction, then nuclear reactions in the interiors of stars would proceed at much higher rates, due to which the lifespan of stars would be significantly reduced. The name of the weak interaction would also have to be changed. In this matter, the universe has some delay due to the range of stellar masses - small stars live longer and can be used to control biological evolution instead of our sun. However, the pressure of the degenerate gas (from quantum mechanics) prevents stars from burning hydrogen once their mass becomes too small. Thus, even the lifespan of the longest-living stars would be seriously reduced. As soon as the maximum lifetime of a star falls below the billion-year mark, the development of life is immediately threatened. The actual value of the weak interaction is millions of times less than the strong one, due to which the Sun burns its hydrogen slowly and naturally, which is required for the evolution of life on Earth.

Next, we should consider the planets - the smallest astrophysical objects necessary for life. The formation of planets requires from the Universe the production of heavy elements, and, consequently, the same nuclear restrictions that have already been described above. In addition, the existence of planets requires that the background temperature of the universe be low enough for condensation of solids. If our Universe were only six times smaller than it is now, and, therefore, a thousand times hotter, then particles of interstellar dust would evaporate and there would simply be no raw materials for the formation of rocky planets. In this hot, hypothetical universe, even the formation of giant planets would be extremely depressed. Fortunately, our universe is cool enough to allow for the formation of planets.

Another consideration is the long-term stability of the solar system since its inception. In our modern Galaxy, both interactions and convergence of stars are both rare and weak due to the very low density of stars. If our Galaxy contained the same number of stars, but was a hundred times smaller, the increased density of stars would lead to a sufficiently high probability of some other star entering our solar system, which would destroy the orbits of the planets. Such a cosmic collision could change the orbit of the Earth and make our planet uninhabitable or even throw the Earth out of the solar system. In any case, such a cataclysm would mean the end of life. Fortunately, in our Galaxy, the estimated time after which our solar system will experience a collision that alters its course is much longer than the time it takes for life to develop.

We see that the long-lived Universe, which contains galaxies, stars and planets, requires a rather special set of values ​​of the fundamental constants that determine the values ​​of the main forces. So this required tweak raises a basic question: why does our universe have these specific properties that ultimately give rise to life? After all, the fact that the laws of physics are just such as to allow our existence is truly a remarkable coincidence. It seems as if the Universe somehow knew about our coming appearance. Of course, if conditions had developed somehow differently, we simply would not be here and there would be no one to ponder this issue. However, the question "Why?" from this does not disappear anywhere.

Understanding that why physical laws are exactly what they are, brings us to the border of the development of modern science. Preliminary explanations have already been put forward, but the question is still open. Since twentieth century science has provided a good working understanding of what there are our laws of physics, we can hope that the science of the twenty-first century will give us an understanding of why physical laws have just such a form. Some hints in this direction are already beginning to emerge, as we shall now see.

Eternal complexity

This seeming coincidence (that the Universe has exactly those special properties that allow the origin and evolution of life) seems much less wonderful if we accept that our Universe - the region of space-time with which we are connected - is just one of countless other universes. In other words, our universe is only a small part multiverse- a huge ensemble of universes, each of which has its own versions of the laws of physics. In this case, the entire set of universes would implement all the many possible variants of the laws of physics. Life, however, will only develop in those private universes that have the right version of physical laws. Then the fact that we happened to live in the Universe with the properties necessary for life becomes obvious.

Let's clarify the difference between "other universes" and "other parts" of our universe. The large-scale geometry of spacetime can be very complex. We currently live in a homogeneous piece of the universe, the diametral size of which is about twenty billion light years. This area is a part of space that can have a causal effect on us at a given time. As the universe moves into the future, the region of space-time that can affect us will increase. In this sense, as we age, our Universe will contain more space-time. However, there may be other regions of space-time that never will not be in a causal relationship with our part of the Universe, no matter how long we wait and no matter how old our Universe becomes. These other areas grow and evolve completely independently of the physical events that occur in our universe. Such areas belong to other universes.

As soon as we admit the possibility of other universes, the set of coincidences that exists in our universe looks much more pleasant. But does this concept of other universes really make that sense? Is it possible to naturally place multiple universes within the Big Bang theory, for example, or at least its reasonable extensions? Ironically, the answer is an emphatic yes.

Andrei Linde, an eminent Russian cosmologist currently at Stanford, introduced the concept eternal inflation... Roughly speaking, this theoretical idea means that at all times some region of space-time, located somewhere in the multiverse, is going through an inflationary expansion phase. According to this scenario, space-time foam, through the mechanism of inflation, continuously spawns new universes (as discussed in the first chapter). Some of these inflationary expanding regions are evolving into interesting universes like our own local patch of space-time. They have physical laws governing the formation of galaxies, stars and planets. In some of these areas, intelligent life may even develop.

This idea has both physical meaning and significant intrinsic appeal. Even if our universe, our own local region of space-time, is destined to die a slow and painful death, there will always be other universes around. There will always be something else. If the multiverse is viewed from a greater perspective, covering the entire ensemble of universes, then it can be considered truly eternal.

This picture of cosmic evolution gracefully bypasses one of the most vexing questions in twentieth-century cosmology: if the universe began in a Big Bang that happened just ten billion years ago, what was before that Big Bang? This difficult question of "what was when there was nothing yet" serves as the border between science and philosophy, between physics and metaphysics. We can extrapolate the physical law back in time to the moment when the universe was only 10 -43 seconds, although as we approach this moment, the uncertainty of our knowledge will grow, and earlier eras are generally inaccessible to modern scientific methods. However, science is not standing still, and some progress is already beginning to appear in this area. Within the broader context that the concept of multiverse and eternal inflation provides, we can indeed formulate the answer: before the Big Bang, there was (and still is!) A foamy region of high-energy space-time. From this cosmic foam some ten billion years ago our own Universe was born, which continues to evolve today. Similarly, other universes continue to be born all the time, and this process can go on indefinitely. True, this answer remains a little unclear and perhaps somewhat unsatisfactory. Nevertheless, physics has already reached the point where we can at least begin to address this long standing question.

With the concept of the multiverse, we get the next level of the Copernican revolution. Just as our planet does not have a special place in our solar system, and our solar system has a special status in the universe, so our universe does not have a special place in the gigantic cosmic mixture of universes that make up the multiverse.

Darwinian view of the universes

The spacetime of our universe becomes more complex as it ages. At the very beginning, right after the Big Bang, our universe was very smooth and homogeneous. These initial conditions were necessary for the universe to evolve into its present form. However, as the Universe evolves as a result of galactic and stellar processes, black holes are formed, permeating space-time with their internal singularities. Thus, black holes create what might be thought of as holes in spacetime. In principle, these singularities can also provide communication with other universes. It may also happen that new universes will be born in the singularity of the black hole - the universes-children, which we talked about in the fifth chapter. In this case, our universe can give rise to a new universe connected with ours through a black hole.

If this chain of reasoning is followed to its logical end, an extremely interesting scenario arises for the evolution of universes in the multiverse. If universes can give birth to new universes, then concepts of heredity, mutation, and even natural selection can appear in physical theory. This concept of evolution was defended by Lee Smolin, a physicist, an expert in general relativity and quantum field theory.

Suppose that singularities inside black holes can give birth to other universes, as is the case with the birth of new universes, which we talked about in the previous chapter. As these other universes evolve, they usually lose causation with our own universe. However, these new universes remain connected to ours through a singularity located at the center of the black hole. - Now let's say that the laws of physics in these new universes are similar to the laws of physics in our universe, but not absolutely. In practice, this statement means that physical constants, values ​​of fundamental forces and masses of particles have similar, but not equivalent values. In other words, the new universe inherits a set of physical laws from the parent universe, but these laws may differ slightly, which is very similar to gene mutations during the reproduction of the flora and fauna of the Earth. In this cosmological setting, the growth and behavior of the new universe will resemble, but not exactly, the evolution of the original mother universe. Thus, this picture of heredity of universes is completely analogous to the picture of biological life forms.

With inheritance and mutation, this ecosystem of universes gains an exciting opportunity for Darwin's evolutionary scheme. From a comological-Darwinian point of view, universes that create large numbers of black holes are "successful". Since black holes are the result of the formation and death of stars and galaxies, these successful universes must contain large numbers of stars and galaxies. In addition, it takes a long time to form black holes. Galaxies in our Universe take a billion years to form; massive stars live and die in shorter times of millions of years. To allow the formation of a large number of stars and galaxies, any successful universe must not only have the necessary values ​​of the physical constants, but also be relatively long lived. With stars, galaxies, and long lifetimes, the universe may well allow life to evolve. In other words, successful universes automatically have nearly the requisite characteristics for biological life forms to emerge.

The evolution of a complex set of universes as a whole proceeds in a similar way to biological evolution on Earth. Successful universes create large numbers of black holes and give birth to large numbers of new universes. These astronomical "babies" inherit from the mother universes various kinds of physical laws, with minor modifications. Those mutations that lead to the formation of even more black holes lead to the production of more "children". As this ecosystem of universes evolves, the most common universes are those that form incredible numbers of black holes, stars and galaxies. These same universes have the highest chances of the origin of life. Our universe, for whatever reason, has exactly the characteristics that allow it to live long and form many stars and galaxies: according to this huge Darwinian scheme, our own universe is successful. When viewed from this enlarged perspective, our universe is neither unusual nor fine-tuned; it is, rather, an ordinary, and therefore expected, universe. While this picture of evolution remains speculative and controversial, it provides an elegant and compelling explanation of why our universe has the properties we observe.

Pushing the boundaries of time

In the biography of space lying in front of you, we have traced the development of the Universe from its sparkling, singular beginning, through the warm and familiar sky of our time, through the strange frozen deserts, to the possible final death in eternal darkness. When we try to look even deeper into the dark abyss, our predictive abilities are significantly impaired. Consequently, our hypothetical travels through space time must complete, or at least become terribly incomplete at some future age. In this book, we have constructed a timeline spanning hundreds of cosmological decades. Some readers will undoubtedly think that we have gone so far in our story too self-confidently, while others may wonder how we could stop at a point that, in comparison with eternity, is so close to the very beginning.

One thing we can be sure of. On its way into the darkness of the future, the Universe exhibits a wonderful combination of transience and immutability, closely intertwined with each other. And while the universe itself will stand the test of time, there will be virtually nothing left in the future that even remotely resembles the present. The most enduring characteristic of our ever-evolving universe is change. And this universal process of ongoing change requires an expanded cosmological perspective, in other words, a complete change in our view of the largest scales. Since the universe is constantly changing, we must try to understand the current cosmological era, the current year, and even today. Every moment of the unfolding history of space presents a unique opportunity, a chance to achieve greatness, an adventure to be lived. According to Copernicus's time principle, each future era is replete with new possibilities.

However, it is not enough to make a passive statement about the inevitability of events and “without grieving, let what should happen to happen”. A passage often attributed to Huxley states that "if six monkeys are put behind typewriters and allowed to type whatever they want for millions of years, then in time they will write all the books that are in the British Museum." These imaginary monkeys have long been cited as an example whenever it comes to an unclear or untenable thought, as a confirmation of incredible events, or even for an implicit understatement of the great achievements of human hands, with a hint that they are nothing more than a happy accident among the great. many failures. After all, if something can happen, it will certainly happen, right?

However, even our understanding of the future space, which is still in its infancy, reveals the obvious absurdity of this point of view. A simple calculation suggests that it would take almost half a million cosmological decades (many more years than the number of protons in the universe) for randomly chosen monkeys to create just one book by accident.

The universe is written to completely change its character, and more than once, before these same monkeys at least begin to complete the task assigned to them. In less than one hundred years, these monkeys will die of old age. In five billion years, the Sun, transformed into a red giant, will burn the Earth, and with it all the typewriters. After fourteen cosmological decades in the Universe, all the stars will burn out and the monkeys will no longer be able to see the keys of the typewriters. By the twentieth cosmological decade, the Galaxy will lose its integrity, and the monkeys will have a very real chance to be swallowed up by a black hole in the center of the Galaxy. And even the protons that make up the monkeys and their work are destined to disintegrate before the expiration of forty cosmological decades: again, long before their Herculean labor does not even go far enough. But even if the monkeys were able to survive this catastrophe and continue their work with the faint glow emitted by black holes, their efforts would still be in vain in the hundredth cosmological decade, when the last black holes left the Universe in an explosion. But even if the monkeys survived this catastrophe and survived, say, to the one hundred and fiftieth cosmological decade, they would only achieve the opportunity to face the ultimate danger of the cosmological phase transition.

And although by the one hundred and fiftieth cosmological decade of the monkey, typewriters and printed sheets will be destroyed more than once, time itself, of course, will not end. As we gaze into the gloom of the future, we are more limited by a lack of imagination and perhaps by an inadequacy of physical understanding than by a really small set of details. The lower energy levels and the seeming lack of activity that await the universe are more than offset by the increased amount of time it has. We can look to an uncertain future with optimism. And although our cozy world is destined to disappear, a huge set of interesting physical, astronomical, biological and, perhaps, even intellectual events are still waiting in the wings, as our Universe continues on its way into eternal darkness.

Space-time capsule

Several times throughout this biography of the universe, we have encountered the possibility of sending signals to other universes. If we could, for example, create a universe in a laboratory setting, an encrypted signal could be transmitted into it before it loses causality with our own universe. But if you could send such a message, what would you write in it?

Perhaps you would like to preserve the very essence of our civilization: art, literature and science. Every reader will have some idea of ​​what constituents of our culture should be preserved in this way. While each person would have their own opinion on this, we would have behaved very badly if we had not made at least some suggestion for archiving some part of our culture. As an example, we propose the encapsulated version of science, or rather physics and astronomy. Some of the most basic messages might include the following:

Matter is made up of atoms, which in turn are made up of smaller particles.

At small distances, the particles exhibit the properties of a wave.

Nature is governed by four fundamental forces.

The universe is made up of evolving space-time.

Our Universe contains planets, stars and galaxies.

Physical systems evolve into states of lower energy and increasing disorder.

These six points, the universal role of which should be clear at this time, can be considered the treasures of our achievements in the physical sciences. Perhaps these are the most important physical concepts that our civilization has discovered to date. But if these concepts are treasures, then the scientific method undoubtedly should be considered their crown. If there is a scientific method, then with enough time and effort, all these results are obtained automatically. If it were possible to transmit to another universe just one concept representing the intellectual achievements of our culture, then the most rewarding message would be the scientific method.

We are faced with compression in one form or another on a daily basis. When we squeeze water out of a sponge, we pack a suitcase before going on vacation, trying to fill all the empty space with the necessary things, we compress files before sending them by e-mail. The idea of ​​removing "empty" space is very familiar.

On both a cosmic and an atomic scale, scientists have repeatedly confirmed that emptiness occupies most of the space. Yet it is extremely surprising how true this statement is! When Dr. Caleb A. Scharf of Columbia University (USA) wrote his new book "Zoomable Universe", he admittedly planned to use it for some kind of dramatic effect.

What if we can somehow collect all the stars in the Milky Way and place them next to each other, like apples tightly packed in a large box? Of course, nature will never allow humans to subdue gravity, and the stars are likely to merge into one colossal black hole. But as a thought experiment, it's a great way to illustrate the volume of space in the galaxy.

The result is shocking. Assuming there may be about 200 billion stars in the Milky Way, and we generously assume that they are all the same diameter as the Sun (which is overstated, since the vast majority of stars are less massive and smaller in size), we could still collect them into a cube. the length of the faces of which corresponds to two distances from Neptune to the Sun.

“There is a huge amount of empty space in space. And that brings me to the next level of insanity, ”writes Dr. Scharf. According to the observable universe, defined by the cosmic horizon of the movement of light since the Big Bang, current estimates suggest that there are between 200 billion and 2 trillion galaxies. Although this large number includes all the small "protogalaxies" that will eventually merge into large galaxies.

Let's be bold and take as many of them as possible, and then pack all the stars in all of these galaxies. While impressively generous, let's say they're all the size of the Milky Way (although most are actually much smaller than our Galaxy). We get 2 trillion cubic meters, the edges of which will be 10 13 meters. Place these cubes in a larger cube and we are left with a mega cube with a side length of approximately 10-17 meters.

Pretty big, right? But not on a cosmic scale. The diameter of the Milky Way is about 10 21 meters, so a 10 17 meter cube is still only 1 / 10,000 the size of the Galaxy. In fact, 10 17 meters is about 10 light years!

Naturally, this is just a little gimmick. But it effectively indicates how small the volume of the Universe actually occupied by dense matter, compared to the emptiness of space, perfectly characterized by Douglas Adams: “The cosmos is large. Really great. You simply will not believe how vast, enormous, mind-bogglingly large the cosmos is. Here's what we mean: you might think it's a long way to the nearest diner, but that doesn't mean anything to space. " (The Hitchhiker's Guide to the Galaxy).

That joint gravitational attraction of all its matter will eventually stop the expansion of the Universe and cause it to contract. Due to the increase in entropy, the compression pattern will be very different from the time-reversed expansion. While the early universe was very homogeneous, the collapsing universe will split into separate isolated groups. Eventually, all matter collapses into black holes, which will then grow together, creating a single black hole - the Great Compression singularity.

The latest experimental evidence (namely: the observation of distant supernovae as objects of standard luminosity (for more details see Distance scale in astronomy), as well as a thorough study of the relic radiation) lead to the conclusion that the expansion of the Universe is not slowed down by gravity, but, on the contrary, is accelerating. However, due to the unknown nature of dark energy, it is still possible that one day the acceleration will change sign and cause compression.

see also

• Big bounce
• Oscillating Universe

Notes (edit)

Wikimedia Foundation. 2010.

• Big train robbery
• Big Island

See what "Big Compression" is in other dictionaries:

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EXPANSION OR CONTRACTION OF THE UNIVERSE ?!

The removal of galaxies from each other is currently explained by the expansion of the Universe, which began thanks to the so-called "Big Bang".

To analyze the distance of galaxies from each other, we use the following known physical properties and laws:

1. Galaxies revolve around the center of the metagalaxy, making one revolution around the center of the metagalaxy in 100 trillion years.

Consequently, the metagalaxy is a giant torsion in which the laws of vortex gravity and classical mechanics operate (Ch. 3.4).

2. Since the Earth increases its mass, it is permissible to assume that all other celestial bodies or their systems (galaxies), under the influence of their own gravity, also increase their mass, in accordance with the laws presented in Chapter 3.5. Then, based on the formulas from the same chapter, it is obvious that galaxies should move in a spiral, towards the center of the metagalaxy, with acceleration inversely proportional to the distance to the center of the metagalaxy or the increase in the mass of galaxies.

The radial acceleration of galaxies moving in the direction of the center of the metagalaxy causes them to move away from each other, which was recorded by Hubble and which, until now, is mistakenly classified as an expansion of the Universe.

Thus, based on the above, the conclusion follows:

The universe is not expanding; on the contrary, it is spiraling or contracting.

It is likely that the metagalaxy Black Hole is located in the center of the metagalaxy, so it is impossible to observe it.

When galaxies revolve around the center of a metagalaxy in a lower orbit, the speed of the orbital motion of these galaxies should be greater than that of galaxies moving in a higher orbit. In this case, galaxies, at certain mega time intervals, should approach each other.

In addition, stars with inclinations of their own orbits to the galactic, gravitational torsion should move away from the center of the galaxy (see Ch. 3.5). These circumstances explain the approach of the galaxy M31 to us.

At the initial stage of the appearance of the cosmic torsion, it should be in the state of BH (see Ch. 3.1). During this period, the cosmic torsion increases its relative mass to the maximum extent. Consequently, the magnitude and the vector of the velocity of this torsion (BH) also have maximum changes. That is, Black Holes have a character of movement that does not significantly correspond to the movement of neighboring cosmic bodies.

At present, a BH has been discovered that is approaching us. The movement of this BH is explained by the above dependence.

It should be noted the contradictions of the "Big Bang" hypothesis, which for some unknown reason are not taken into account by modern science:

According to the 2nd law of thermodynamics, the system (Universe), left to itself (after the explosion) turns into chaos and disorder.

In fact, the harmony and order observed in the Universe is contrary to this law,

Any particle of an exploded substance with tremendous force must have only a rectilinear and radial direction of its own motion.

The universal rotation in outer space of all celestial bodies or their systems around their center or other bodies, including the metagalaxy, completely refutes the inertial nature of the motion of space objects obtained from the explosion. Consequently, an explosion cannot be the source of motion for all space objects.

• - How could huge intergalactic voids form in outer space after the "Big Bang" ?!
• - according to the generally accepted Friedman model, the cause of the "Big Bang" was the compression of the Universe to the size of the solar system. As a result of this super-giant compaction of cosmic matter, the "Big Bang" took place.

Followers of the idea of ​​the "Big Bang" are silent about the obvious absurdity in this hypothesis - how could the infinite Universe shrink and fit into a limited volume equal to the size of the solar system !?

The most notable theory is about how the Big Bang Universe began, where all matter first existed as a singularity, an infinitely dense point in tiny space. Then something caused her to explode. Matter expanded at an incredible rate and eventually formed the universe we see today.

The Big Squeeze is, as you might have guessed, the opposite of the Big Bang. Everything that scattered around the edges of the Universe will be compressed under the influence of gravity. According to this theory, gravity will slow down the expansion caused by the Big Bang and eventually everything will return to a point.

1. Inevitable heat death of the Universe.

Think of heat death as the exact opposite of the Big Squeeze. In this case, gravity is not strong enough to overcome the expansion, as the universe is simply heading for exponential expansion. The galaxies drift apart like unhappy lovers, and the all-encompassing night between them grows wider and wider.

The universe obeys the same rules as any thermodynamic system, which will ultimately lead us to the fact that heat is evenly distributed throughout the universe. Finally, the entire universe will be extinguished.

1. Thermal death from Black holes.

According to popular theory, most of the matter in the universe revolves around black holes. Just look at galaxies that contain supermassive black holes at their centers. Most of the black hole theory involves the swallowing up of stars or even entire galaxies as they enter the hole's event horizon.

Eventually, these black holes will consume most of the matter, and we will remain in the dark universe.

1. End of Time.

If something is eternal, then it is definitely time. Whether there is a universe or not, time goes by. Otherwise, there would be no way to distinguish one moment from the next. But what if time is wasted and just stood still? What if there are no more moments? Just the same moment in time. Forever and ever.

Suppose we live in a universe in which time never ends. With an infinite amount of time, anything that can happen is 100% likely to happen. The paradox will happen if you have eternal life. You live an infinite time, so anything that can happen is guaranteed to happen (and will happen an infinite number of times). Stopping time can happen too.

1. Great Collision.

The Big Collision is similar to the Big Squeeze, but much more optimistic. Imagine the same scenario: Gravity slows down the expansion of the universe and everything contracts back to one point. In this theory, the force of this rapid contraction is sufficient to start another Big Bang, and the universe begins again.

Physicists don't like this explanation, so some scientists argue that the universe may not go all the way back to the singularity. Instead, it will squeeze very hard and then push off with a force similar to the one that pushes the ball away when you hit it on the floor.

1. The Great Divide.

Regardless of how the world ends, scientists don't yet feel the need to use the (grossly understated) word "big" to describe it. In this theory, the invisible force is called "dark energy", it causes the acceleration of the expansion of the universe, which we observe. Eventually, the speeds will increase so much that matter begins to break into small particles. But there is also a bright side to this theory, at least the Big Rip will have to wait another 16 billion years.

1. Vacuum Metastability Effect.

This theory hinges on the idea that the existing universe is in an extremely unstable state. If you look at the values ​​of quantum particles in physics, then you can make the assumption that our universe is on the brink of stability.

Some scientists speculate that billions of years later, the universe will be on the brink of collapse. When this happens, at some point in the universe, a bubble will appear. Think of it as an alternate universe. This bubble will expand in all directions at the speed of light, and destroy everything it touches. Eventually, this bubble will destroy everything in the universe.

1. Temporary Barrier.

Because the laws of physics don't make sense in an infinite multiverse, the only way to understand this model is to assume that there is a real boundary, a physical boundary of the universe, and nothing can go beyond. And in accordance with the laws of physics, in the next 3.7 billion years, we will cross the time barrier, and the universe will end for us.

1. This will not happen (because we live in a multiverse).

According to the scenario of multiverse, with infinite universes, these universes can arise in or out of existing ones. They can arise from Big Bangs, destroyed by Big Compressions or Gaps, but this does not matter, since there will always be more new Universes than destroyed ones.

1. Eternal Universe.

Ah, the age-old idea that the universe has always been and always will be. This is one of the first concepts that humans have created about the nature of the universe, but there is a new round in this theory, which sounds a little more interesting, well, seriously.

Instead of the singularity and the Big Bang, which marked the beginning of time itself, time may have existed earlier. In this model, the universe is cyclical and will continue to expand and contract forever.

In the next 20 years, we will be more confident in saying which of these theories is most consistent with reality. And perhaps we will find the answer to the question of how our Universe began and how it will end.