Probability of the existence of parallel worlds. Parallel universes linked to the emergence of quantum paradoxes

In a 2011 interview, Columbia University physicist Brian Greene, who wrote the book The Hidden Reality: Parallel Universes and the Deep Laws of the Cosmos, explained that we're not quite sure how big the universe is. It can be very, very large, but finite. Or, if you go from Earth in any direction, space can stretch forever. This is how most of us imagine it.

But if the cosmos is infinite, it must be a multiple universe with infinite parallel realities, according to Greene. Imagine that the universe and all matter in it is equivalent to a deck of cards. Just like there are 52 cards in a deck, there will be exactly the same number of different forms of matter. If you shuffle the deck long enough, eventually the order of the cards will repeat the original. Likewise, in an infinite universe, matter will eventually repeat itself and organize itself in a similar way. The multiverse, the so-called multiverse, with an infinite number of parallel realities, contains similar but slightly different versions of everything that exists, and thus provides a simple and convenient way to explain repetition.

How can you explain how the universe begins and ends

Humans have a special passion - and it is connected with the ability of the brain to form schemes - we want to know the beginning and end of each story. Including the history of the universe itself. But if the Big Bang was the beginning of the universe, what caused it and what existed before it? Will the universe end and what will happen after it? Each of us has asked these questions at least once.

The multiverse can explain all these things. Some physicists have suggested that the infinite regions of the multiverse could be called brane worlds. These branes exist in multiple dimensions, but we cannot detect them because we can only perceive three dimensions of space and one of time in our own braneworld.

Some physicists think that these branes are piled together like plates, like sliced bread in a bag. Most time they are separated. But sometimes they collide. Theoretically, these collisions are catastrophic enough to cause repeated "big bangs" - so that parallel universes start anew, again and again.

Observations suggest that multiple universes may exist

The European Space Agency's Planck Orbital Observatory collects data on the cosmic microwave background, or CMB, the background radiation that is still glowing from the early and hot phase of the universe.

Her research also led to possible evidence for the existence of a multiverse. In 2010, a team of scientists from the UK, Canada and the US discovered four unusual and unlikely circular patterns in the CMB. Scientists have suggested that these marks may be "bruises" that were left on the body of our universe after a collision with others.

In 2015, ESA researcher Rang-Ram Hari made a similar discovery. Hari took the CMB model from the observatory's sky image and then removed everything else we know about it - stars, gas, interstellar dust, and so on. At this point, the sky should have been mostly empty, apart from the background noise.

But it didn't. Instead, within a certain range of frequencies, Hari was able to detect scattered patches on a map of space, areas that were about 4,500 times brighter than they should have been. Scientists have come up with another possible explanation: these areas are the imprints of collisions between our universe and a parallel one.

Hari believes that unless we find another way to explain these markings, "we will have to conclude that Nature, after all, can play dice, and we are just one random universe among many others."

The universe is too big to exclude the possibility of the existence of parallel realities

There is a possibility that multiple universes exist, although we have not seen parallel realities, because we cannot disprove its existence.

This may seem like a clever rhetorical stunt at first, but consider this: even in our world, we have found many things we didn't know existed before, and these things have happened - the 2008 global crisis is a good example. Before him, no one thought it was even possible. David Hume called these kinds of events "black swans": people will assume that all swans are white until they see black swans.

The scale of the universe makes it possible to think about the possibility of the existence of multiple universes. We know that the universe is very, very large, perhaps infinite in size. This means that we will not be able to detect everything that exists in the universe. And since scientists have determined that the universe is about 13.8 billion years old, we can only detect the light that managed to reach us during this time. If a parallel reality is further than 13.8 light years from us, we may never know about its existence, even if it exists in the dimensions we distinguish.

Multiple universes make sense in terms of atheism

As Stanford University physicist Andrei Linde explained in a 2008 interview, if physical world obeyed slightly different rules, life could not exist. If protons were 0.2% more massive than they are now, for example, they would be so unstable that they would decay into simple particles instantly without forming an atom. And if gravity were a little more powerful, the result would be monstrous. Stars like our sun would collapse tightly enough that they would burn out their fuel in a few million years, preventing planets like Earth from forming. This is the so-called "fine-tuning problem".

Some see this precise balance of conditions as evidence of the involvement of an omnipotent force, a higher being who created everything, which makes atheists very angry. But the possibility of the existence of a multiverse, in which this force will simply be in a separate reality with all the factors necessary for life, suits them quite well.

As Linde said, “For me, the reality of multiple universes is logically possible. We can say: perhaps this is some kind of mystical coincidence. Perhaps God created the universe for our good. I don't know anything about God, but the universe itself could reproduce itself an infinite number of times in all possible manifestations."

Time travelers can't break history

The popularity of the Back to the Future trilogy has made many people fascinated with the idea of time travel. Since the movie was released, no one has yet developed a DeLorean that can travel back and forth in time, decades or centuries. But scientists believe that time travel may be at least theoretically possible.

And if it is possible, we could be in the same position as main character"Back to the Future" by Marty McFly - risking inadvertently changing something in the past, thereby changing the future and the course of history. McFly accidentally prevented his parents from meeting and falling in love, thus successfully removing himself from family photographs.

However, a 2015 paper suggested that the existence of a multiverse does not make such a hassle necessary. “The existence of alternative worlds means that there is no single chronology that can be broken,” wrote Georg Dvorsky. On the contrary, if a person goes into the past and changes something, he will simply create a new set of parallel universes.

We could be a simulation for an advanced civilization

All these topics about parallel universes that we have discussed so far have been extremely interesting. But there is something else interesting.

In 2003, philosopher Nick Bostrom, director of the Future of Humanity Institute at Oxford University, wondered if everything we perceive to be reality - in particular, our separate parallel universe - could just be a digital simulation of another universe. According to Bostrom, it would take 1036 calculations to create a detailed model of the entire human history.

A well-developed alien civilization - creatures whose technological level would make us look like Paleolithic cave dwellers - could well have enough computing power for all this. Moreover, the simulation of each individual living person does not require some absolutely dizzying electronic resources, so there can be much more creatures simulated on a computer than real ones.

All this may mean that we live in a digital world, like from the movie The Matrix.

But what happens if this advanced civilization is itself a simulation?

People have been thinking about multiple universes since time immemorial.

Proving this will be extremely difficult. But here it is impossible not to recall the old sayings that are attributed either to Picasso or to Susan Sontag: if you can imagine something, it must exist.

And there is something in this. After all, long before Hugh Everett sipped his cognac, many people throughout human history imagined different versions of the multiverse.

Ancient Indian religious texts, for example, are filled with descriptions of many parallel universes. And the ancient Greeks had a philosophy of atomism, which stated that there are an infinite number of worlds scattered in the same infinite void.

The idea of multiple worlds was also raised in the Middle Ages. A Parisian bishop in 1277 argued that the Greek philosopher Aristotle was wrong when he said that there is only one possible world, because this calls into question the almighty power of God to create parallel worlds. The same idea was revived in the 1600s by Gottfried Wilhelm Leibniz, one of the pillars of the scientific revolution. He argued that there are many possible worlds, each endowed with a separate physics.

All of this fits into our schema of knowledge about the universe.

As strange as the concept of the multiverse may seem, in some way it fits into progress. modern history and how people see themselves and the universe.

In 2011, physicists Alexander Vilenkin and Max Tegmark noted that the people of Western civilization gradually calmed down as they discovered the nature of reality. They started with a mindset that the earth was the center of everything. It turned out that this is not so, and that ours is only a tiny part of the Milky Way.

The multiverse must take this idea to its logical conclusion. If the multiverse exists, it means that we are not the chosen ones and that there are infinite versions of ourselves.

But some believe that we are only at the very beginning of the path to the expansion of consciousness. As Stanford University theoretical physicist Leonard Susskind wrote, maybe in a couple of centuries philosophers and scientists will look back to our time as “a golden age in which the narrow provincial concept of the universe of the 20th century was replaced by a larger and better multiverse of staggering proportions.”

There is a theory according to which there are many universes where we live a completely different life: each of our actions is associated with a certain choice and, making this choice in our Universe, in a parallel one, the “other me” makes the opposite decision. How justified is this theory? scientific point vision? Why did scientists resort to it? Let's try to understand our article.

Multi-world concept of the universe
For the first time, the theory of a probable set of worlds was mentioned by the American physicist Hugh Everett. He offered his solution to one of the main quantum mysteries of physics. Before proceeding directly to the theory of Hugh Everett, it is necessary to understand what this mystery of quantum particles is, which has been haunting physicists around the world for more than a dozen years.

Imagine an ordinary electron. It turns out that as a quantum object, it can be in two places at the same time. This property is called the superposition of two states. But the magic doesn't end there. As soon as we want to somehow specify the location of the electron, for example, we try to knock it down with another electron, then from quantum it will become ordinary. How is this possible: the electron was both at point A and at point B, and suddenly jumped to B at a certain moment?

Hugh Everett offered his interpretation of this quantum riddle. According to his many-world theory, the electron continues to exist in two states at the same time. It's all about the observer himself: now he turns into a quantum object and is divided into two states. In one of them, he sees an electron at point A, in the other - at B. There are two parallel realities, and it is not known which of them the observer will find himself in. The division into reality is not limited to two: their branching depends only on the variation of events. However, all these realities exist independently of each other. We, as observers, fall into one, it is impossible to get out of which, as well as move to a parallel one.

From the point of view of this concept, the experiment with the most scientific cat in the history of physics, Schrödinger's cat, is also easily explained. According to the many-worlds interpretation of quantum mechanics, the unfortunate cat in the steel chamber is both alive and dead at the same time. When we open this chamber, we seem to merge with the cat and form two states - alive and dead, which do not intersect. Two different universes are formed: in one, an observer with a dead cat, in the other, with a live one.
It should be noted right away that the multi-world concept does not imply the existence of many universes: it is one, just multi-layered, and each object in it can be in different states. Such a concept cannot be considered an experimentally confirmed theory. So far, this is just a mathematical description of the quantum puzzle.

Hugh Everett's theory is supported by Howard Wiseman, a physicist at Griffith University in Australia, Dr. Michael Hall of the Griffith University Center for Quantum Dynamics, and Dr. Dirk-Andre Deckert of the University of California. In their opinion, there really are parallel worlds and are endowed with different characteristics. Any quantum riddles and patterns are a consequence of the “repulsion” of neighboring worlds from each other. These quantum phenomena arise so that each world is not like the other.

As with the many-worlds concept, string theory is difficult to prove experimentally. Moreover, mathematical apparatus theory is so difficult that for each new idea, a mathematical explanation must be sought literally from scratch.

Hypothesis mathematical universe
Cosmologist, professor at the Massachusetts Institute of Technology Max Tegmark in 1998 put forward his "theory of everything" and called it the hypothesis of the mathematical universe. He solved the problem of the existence of a large number of physical laws in his own way. In his opinion, each set of these laws, which are consistent from the point of view of mathematics, corresponds to an independent universe. The universality of the theory is that it can be used to explain the whole variety of physical laws and the values of physical constants.

Tegmark proposed to divide all the worlds according to his concept into four groups. The first includes worlds that are outside our cosmic horizon, the so-called extra-metagalactic objects. The second group includes worlds with other physical constants, different from the constants of our Universe. In the third - the worlds that appear as a result of the interpretation of the laws of quantum mechanics. The fourth group is a certain set of all universes in which certain mathematical structures are manifested.

As the researcher notes, our Universe is not the only one, since space is limitless. Our world, where we live, is limited by space, the light from which reached us 13.8 billion years after the Big Bang. We will be able to know for sure about other universes in at least another billion years, until the light from them reaches us.

Stephen Hawking: Black holes are the way to another universe
Stephen Hawking is also a proponent of the multiple universe theory. One of the most famous scientists of our time in 1988 for the first time presented his essay "Black Holes and Young Universes". The researcher suggests that black holes are the road to alternative worlds.
Thanks to Stephen Hawking, we know that black holes tend to lose energy and evaporate, releasing Hawking radiation, which received the name of the researcher. Before the great scientist made this discovery, the scientific community believed that everything that somehow fell into a black hole disappeared. Hawking's theory refutes this assumption. According to the physicist, hypothetically, any thing, object, object that falls into a black hole flies out of it and enters another universe. However, such a journey is a one-way movement: there is no way to return back.

From all this it follows that the passage through a black hole is unlikely to be a popular and reliable way. space travel. First, you will have to get there by moving in imaginary time and not caring that your real-time story ends sadly. Second, you wouldn't actually be able to choose a destination. It's like flying on some airline that's in your head,
– writes the researcher.

Parallel universes and Occam's razor
As we can see, it is still impossible to prove the theory of multiple universes with complete certainty. Opponents of the theory believe that we have no right to talk about an infinite number of universes, if only because we cannot explain the postulates of quantum mechanics. This approach runs counter to the philosophical principle of William of Ockham: "One should not multiply things unnecessarily." Proponents of the same theory say: it is much easier to assume the existence of many universes than the existence of one ideal.

Whose argumentation (supporters or opponents of the theory of the multiverse) is more convincing - you decide. Who knows, maybe it is you who will be able to guess the quantum riddle of physics and propose a new universal “theory of everything”.

And if you are concerned about the structure of our Universe and are attracted by the secrets of physics, we advise you to read our article about the computer simulation hypothesis.

Physicist and astronomer Stephan Feeney from University College London, one of the leading British universities, is convinced that traces of such collisions can be seen on maps of the cosmic microwave background radiation, which is believed to have been preserved from the initial stages of the existence of the Universe and evenly fills it. It is regarded as one of the main confirmations of the Big Bang theory.

Such maps show the results of measurements of the CMB spectrum - hotter regions are marked in red, colder ones in blue. Having carefully studied the round formations in the panorama, Feeney and his colleagues came to the conclusion that these are some kind of "cosmic potholes" left after the collision of parallel universes.

The center of such a circle is the hottest region, while closer to the periphery the colors of the spectrum become colder.

According to the assumptions of scientists, in the distant past in space there were real "battles" between parallel worlds, in which ours also participated. The "bubble universe" we live in, they say, has experienced at least four such collisions.

Many cosmologists, however, have already come out with criticism, stating that many other hasty conclusions can easily be drawn in this way. The authors of the study agree that there is still much to be cross-checked. However, if the theory of "bubbles" is confirmed by future research, then humanity will be able to "look" into parallel worlds for the first time, not limited only to its own universe, they optimistically say.

This "discovery" on the traces of relic radiation was made a month after another group of scientists, based on similar data, questioned the theory according to which the universe was created by the Big Bang. They believe that the universe was before him, and "big bangs" happen periodically - by cosmic standards.

Oxford University professor Roger Penrose and Yerevan University professor state university Vahe Gurzadyan found 12 concentric circles on the CMB maps, some of them have up to five rings. The division of the circle into five rings means that during the existence of the object that displays this circle, five large-scale events were noted.

Cosmologists believe that the circles are imprints of the most powerful gravitational radiation waves formed as a result of the collision of black holes during the "previous eternity" - the space epoch that was before the Big Bang.

Ultimately, black holes will consume all the matter in the universe, Professor Penrose believes. With the destruction of matter, only energy remains. And it, in turn, will cause a new Big Bang and a new "eternity". Meanwhile, according to the current Big Bang theory, the universe is constantly expanding, and this process will continue indefinitely. Some astronomers believe that as a result it will turn into a cold, dead wasteland.

Parallel worlds have attracted thousands of researchers, it has already been proven that this is a reality that exists in parallel. The physics of space can be both similar and different, there is witchcraft and magic, time flows differently. People who managed to accidentally find a portal to a parallel world were absent for a long time, and only hours passed in another reflection.

Parallel worlds - what is it?

The idea that there are many worlds was put forward by the ancient philosophers Democritus, Metrodorus of Chios and Epicurus. Later, scientists deduced the same theory, based on the principle of isonomy - equal being. The laws of physics argue that all dimensions are connected by photon tunnels, this allows you to move through them without distorting the law of conservation of energy. There is a version about such portals:

The door to another world opens in "black holes", as these are funnels that suck in matter.
It is possible to open a portal to a parallel world with correctly designed models of different mirrors. Such stone surfaces were found near the Tibetan pyramids, when members of the expeditions began to see themselves in a different reality.

Parallel worlds - evidence of existence

For many years, scientists have been breaking spears in disputes: do parallel worlds exist? Serious studies of the problem were carried out in the middle of the last century, when the scientist Hugh Everett published the materials of his scientific work, which give the formulation of photon mechanics by means of conditionality of states. The physicist was the first to notice the discrepancies between the wave and matrix formulas, which formed the basis of the theory of the Multiverse:

During the selection process, all its possibilities are realized.
Each choice is different because it is embedded in a different reflection.
It does not matter who makes the choice: an electron or a person.

The theory deduced by physicists about the presence of many worlds is called the theory of superstrings or the theory of the Multiverse. Parapsychologists, for their part, argue that there are supposedly more than 40 portals to other dimensions in the world, 4 of them are located in Australia, 7 more in the USA, and 1 in Russia, in the Gelendzhik region, in an old mine. There is evidence that a young guy who decided to go down there disappeared for a week, and went upstairs already very old, and did not remember anything about what had happened.

How many parallel worlds are there?

Physicists suggest that the existence of parallel worlds confirms the theory of superstrings. It testifies that all the elements of the world are made of vibrating threads and membranes of energy. According to this theory, there can be from 10 to the 100th power to 10 to the 500th power of other dimensions. Mathematicians give their proofs. If parallel lines can coexist in two-dimensional space, and parallel planes can coexist in three-dimensional space, then parallel three-dimensional spaces can also coexist in four-dimensional space.

What does a parallel world look like?

Scientists find it difficult to describe parallel worlds, because parallels cannot intersect, and it is difficult to visit that reflection for the sake of experience. In this matter, one can rely only on the words of eyewitnesses. In their vision, parallel worlds are:

nature of amazing beauty, inhabited by elves, gnomes and dragons;
an area that looks like a crater of a volcano, bathed in crimson light;
rooms and streets reminiscent of childhood places filled with light.

The only thing in which the descriptions are similar is in a strong stream of light that manifests itself from the void. Similar phenomena were seen by scientists in the pyramids of the pharaohs, the researchers deduced the version that the chambers are covered with unique alloys that glow in the dark. When trying to take out a chip on sunlight, these alloys decay, it is impossible to study them, therefore there is no exact data.

How to get into a parallel world?

Traveling is one of the popular themes of science fiction and the dream of many inhabitants of the Earth. According to theorists, the easiest way is a dream, in which information is received and transmitted many times faster than in reality. If we talk about conscious movement, then the situation is somewhat different. According to esotericists, it is possible to get into another world, but it is very dangerous, since the other nature of the emitted waves can negatively affect the structure human brain. But through trial and error, several ways have been developed to help make such a journey:

lucid dream, providing for turning off consciousness and immersion in another reality.
Meditation. The methods are similar.
With a mirror. Since ancient times, magicians have made special rites for this.
Through the elevator. The transition is best done at night, alone, press the numbers of the floors in a certain sequence.

Creatures from parallel worlds

It is difficult to say what parallel worlds are, what is found there. But beings from another reflection of reality have been observed by people at all times in great numbers. It's not just about humanoids. The most famous cases of such meetings:

93 year. In Rome, people saw a glowing, golden ball that floated across the sky.
235 year. In China, the warring parties saw a large scarlet ball that threw out rays in the form of daggers, moving from north to south.
848 year. The French noticed objects in the sky, shaped like luminous cigars.

fairies;
poltergeists;
critters.

Movies about parallel worlds

There are many films about parallel worlds, directors and writers called this fantasy genre. There, our world is depicted as part of the multiverse. All categories of viewers love to watch about parallel worlds. Most Popular Movies:

"Parallel Worlds" (2011, Canada)- adventure, fantasy.
The Chronicles of Narnia (2005, USA)- pure fantasy.
"Sliders" (1995 - 2000, USA)- series, closer to science fiction.
"Fierce Planet" (2011, USA)- adventure, fantasy, thriller.
"Verbo" (2011, Spain)- fantasy.

Books about parallel worlds

Are there parallel worlds on earth? Writers have been looking for an answer to this question for a long time. The very first tales about the Gardens of Eden, Hell, Olympus and Valhalla quite fall under the category of a story about parallel worlds. The specific concept of the existence of other dimensions appeared already in the 19th century, with the light hand of HG Wells. In modern literature, there are hundreds of novels about time travel, but the following classics are called the pioneers:

HG Wells, Door in the Wall.
Herbert Dent, Emperor of the If Country.
Veniamin Hirshgorn, "The Unceremonious Romance".
Jorge Borges, The Garden of Forking Paths.
"Tiered World" is a series of fantasy stories.
The Chronicles of Amber is the most vivid reflection of other dimensions in literature.

Disputes and hypotheses about the existence of twin planets unknown to us, parallel universes and even galaxies have been going on for many decades. All of them are based on the theory of probability without involving the ideas of modern physics. V last years to them was added the idea of the existence of a superuniverse, based on proven theories - quantum mechanics and the theory of relativity. Polit.ru publishes an article Max Tegmark"Parallel Universes", which puts forward a hypothesis about the structure of the alleged superuniverse, theoretically including four levels. However, in the next decade, scientists may have real opportunity obtain new data on the properties of outer space and, accordingly, confirm or refute this hypothesis. The article was published in the journal "In the world of science" (2003. No. 8).

Evolution has provided us with an intuition about everyday physics vital to our distant ancestors; therefore, as soon as we go beyond the everyday, we may well expect oddities.

The simplest and most popular cosmological model predicts that we have a twin in a galaxy about 10 to the power of 1028 meters away. The distance is so great that it is beyond the reach of astronomical observation, but this does not make our twin any less real. The assumption is based on the theory of probability without involving the ideas of modern physics. Only the assumption is accepted that space is infinite and filled with matter. There may be many habitable planets, including those where people live with the same appearance, the same names and memories, who have gone through the same life ups and downs as we do.

But we will never be able to see our other lives. The farthest distance we can see is that which light can travel in the 14 billion years since the Big Bang. The distance between the most distant visible objects from us is about 431026 m; it determines the region of the Universe available for observation, called the volume of the Hubble, or the volume of the cosmic horizon, or simply the Universe. The universes of our twins are spheres of the same size centered on their planets. This is the simplest example of parallel universes, each of which is only a small part of the superuniverse.

The very definition of "universe" suggests that it will forever remain in the field of metaphysics. However, the boundary between physics and metaphysics is determined by the possibility experimental verification theories, not the existence of unobservable objects. The boundaries of physics are constantly expanding, including more and more abstract (and previously metaphysical) ideas, for example, about a spherical Earth, invisible electromagnetic fields, time dilation at high speeds, superposition of quantum states, space curvature and black holes. In recent years, the idea of a superuniverse has been added to this list. It is based on proven theories—quantum mechanics and the theory of relativity—and it meets both of the main criteria of empirical science: it allows predictions and can be refuted. Scientists consider four types of parallel universes. The main question is not whether a superuniverse exists, but how many levels it can have.

Level I

Beyond our cosmic horizon

The parallel universes of our counterparts constitute the first level of the superuniverse. This is the least controversial type. We all recognize the existence of things that we cannot see, but could see by moving to another place or simply by waiting, as we wait for the appearance of a ship from the horizon. Objects beyond our cosmic horizon have a similar status. The size of the observable region of the universe increases by one light year each year as light reaches us from ever more distant regions, behind which lies an infinity that has yet to be seen. We will probably die long before our twins are within sight, but if the expansion of the universe helps, our descendants will be able to see them with sufficiently powerful telescopes.

Level I of the superuniverse seems trivially obvious. How can space not be infinite? Is there a sign somewhere that reads "Watch out! End of space? If there is an end to space, what is beyond it? However, Einstein's theory of gravity called this intuition into question. A space can be finite if it has positive curvature or an unusual topology. A spherical, toroidal, or "pretzel" universe can have a finite volume without boundaries. Background cosmic microwave radiation makes it possible to test the existence of such structures. However, the facts still speak against them. The model of the infinite universe corresponds to the data, and strict restrictions are imposed on all other options.

Another option is this: space is infinite, but matter is concentrated in a limited area around us. In one version of the once popular "island universe" model, it is assumed that on large scales matter is rarefied and has a fractal structure. In both cases, almost all universes in a level I superuniverse must be empty and lifeless. Recent studies of the three-dimensional distribution of galaxies and background (relic) radiation have shown that the distribution of matter tends to be uniform on large scales and does not form structures larger than 1024 m. If this trend continues, then the space outside the observable Universe should be replete with galaxies, stars and planets.

For observers in parallel universes of the first level, the same laws of physics apply as for us, but under different starting conditions. According to modern theories, the processes taking place on early stages The big bang, randomly scattered matter, so there was a possibility of any structures.

Cosmologists accept that our Universe with an almost uniform distribution of matter and initial density fluctuations of the order of 1/105 is quite typical (according to at least, among those in which there are observers). Estimates based on this assumption show that your closest replica is at a distance of 10 to the power of 1028 m. At a distance of 10 to the power of 1092 m there should be a sphere with a radius of 100 light years, identical to the one in the center of which we are located; so that everything that we see in the next century will be seen by our counterparts who are there. At a distance of about 10 to the power of 10118 m from us, there should be a Hubble volume identical to ours. These estimates are derived by counting the possible number of quantum states that a Hubble volume can have if its temperature does not exceed 108 K. The number of states can be estimated by asking: how many protons can a Hubble volume with such a temperature hold? The answer is 10118. However, each proton can either be present or absent, giving 2 to the power of 10118 possible configurations. A "box" containing so many Hubble volumes covers all possibilities. Its size is 10 to the power of 10118 m. Beyond it, the universes, including ours, must repeat themselves. Approximately the same figures can be obtained on the basis of thermodynamic or quantum gravitational estimates of the general information content of the Universe.

However, our closest twin is likely to be closer to us than these estimates give, since the process of planet formation and the evolution of life favor this. Astronomers believe that our Hubble volume contains at least 1020 habitable planets, some of which may be Earth-like.

In modern cosmology, the concept of a Level I superuniverse is widely used to test a theory. Consider how cosmologists use the CMB to reject the model of finite spherical geometry. Hot and cold "spots" on the CMB maps have a characteristic size that depends on the curvature of space. So, the size of the observed spots is too small to be consistent with the spherical geometry. Their average size varies randomly from one Hubble volume to another, so it is possible that our Universe is spherical, but has anomalously small spots. When cosmologists say that they rule out the spherical model at a 99.9% confidence level, they mean that if the model is correct, then less than one Hubble volume in a thousand will have spots as small as those observed. It follows that the superuniverse theory is verifiable and can be rejected, even though we cannot see other universes. The main thing is to predict what the ensemble of parallel universes is like and find the probability distribution, or what mathematicians call the measure of the ensemble. Our universe must be one of the most probable. If not, if our universe turns out to be unlikely within the framework of the superuniverse theory, then this theory will run into difficulties. As we shall see later, the problem of measure can become quite acute.

Level II

Level III

Quantum set of universes

The superuniverses of levels I and II contain parallel universes, extremely remote from us beyond the limits of astronomy. However, the next level of the superuniverse lies right around us. It arises from a famous and highly controversial interpretation of quantum mechanics, the idea that random quantum processes cause the universe to "multiply" into multiple copies of itself, one for each possible outcome of the process.

At the beginning of the twentieth century. quantum mechanics explained the nature nuclear world, which did not obey the laws of classical Newtonian mechanics. Despite the obvious successes, there was a heated debate among physicists about what the true meaning of the new theory was. It determines the state of the Universe not in such concepts of classical mechanics as the positions and velocities of all particles, but through a mathematical object called the wave function. According to the Schrödinger equation, this state changes over time in a way that mathematicians define by the term "unitary." It means that the wave function rotates in an abstract infinite-dimensional space called the Hilbert space. Although quantum mechanics is often defined as fundamentally random and indeterminate, the wave function evolves in a quite deterministic way. There is nothing random or uncertain about her.

The hardest part is relating the wave function to what we observe. Many valid wave functions correspond to unnatural situations like the one where the cat is both dead and alive in the so-called superposition. In the 20s. 20th century physicists get around this oddity by postulating that the wave function collapses to some particular classical outcome when one makes an observation. This addition made it possible to explain the results of observations, but turned an elegant unitary theory into a sloppy and not unitary one. Fundamental randomness, usually attributed to quantum mechanics, is a consequence of precisely this postulate.

Over time, physicists abandoned this view in favor of another, proposed in 1957 by Princeton University graduate Hugh Everett III. He showed that it is possible to do without the collapse postulate. Pure quantum theory does not impose any restrictions. Although it predicts that one classical reality will gradually split into a superposition of several such realities, the observer subjectively perceives this splitting as just a slight randomness with a probability distribution exactly the same as that given by the old postulate of collapse. This superposition of the classical universes is the level III superuniverse.

For more than forty years, this interpretation has confused scientists. However, the physical theory is easier to understand by comparing two points of view: external, from the position of a physicist studying mathematical equations (like a bird surveying the landscape from the height of its flight); and internal, from the position of an observer (let's call him a frog) living in a landscape overlooked by a bird.

From the point of view of a bird, the level III superuniverse is simple. There is only one wave function that smoothly evolves in time without splitting and parallelism. The abstract quantum world, described by an evolving wave function, contains a huge number of continuously splitting and merging lines of parallel classical histories, as well as a number of quantum phenomena that cannot be described within the framework of classical concepts. But from the point of view of a frog, one can see only a small part of this reality. She can see the level I universe, but a decoherence process similar to the collapse of the wave function, but with unitarity preserved, prevents her from seeing parallel copies of herself at level III.

When an observer is asked a question that he must quickly answer, a quantum effect in his brain leads to a superposition of decisions like "keep reading the article" and "stop reading the article." From the bird's point of view, the act of making a decision causes a person to multiply into copies, some of which continue to read, while others stop reading. However, from an internal point of view, neither of the doubles is aware of the existence of the others and perceives the split simply as a slight uncertainty, some possibility of continuing or stopping reading.

Strange as it may seem, the exact same situation occurs even in the Level I superuniverse. Obviously, you decided to continue reading, but one of your counterparts in a distant galaxy put the magazine down after the first paragraph. Levels I and III differ only in where your counterparts are located. At level I they live somewhere far away, in good old three-dimensional space, and at level III they live on another quantum branch of infinite-dimensional Hilbert space.

The existence of level III is possible only under the condition that the evolution of the wave function in time is unitary. So far, experiments have not revealed its deviations from unitarity. In recent decades, it has been confirmed for everyone more large systems, including C60 fullerene and kilometer-long optical fibers. Theoretically, the proposition about unitarity was reinforced by the discovery of coherence violation. Some theorists working in the field of quantum gravity question it. In particular, it is assumed that evaporating black holes can destroy information, and this is not a unitary process. However, recent advances in string theory suggest that even quantum gravity is unitary.

If so, then black holes do not destroy information, but simply transmit it somewhere. If physics is unitary, the standard picture of the impact of quantum fluctuations in the initial stages of the Big Bang must be changed. These fluctuations do not randomly determine the superposition of all possible initial conditions that coexist simultaneously. In this case, the violation of coherence makes the initial conditions behave in a classical way on different quantum branches. The key point is that the distribution of outcomes in different quantum branches of one Hubble volume (Level III) is identical to the distribution of outcomes in different Hubble volumes of one quantum branch (Level I). This property of quantum fluctuations is known in statistical mechanics as ergodicity.

The same reasoning applies to level II. The process of breaking symmetry does not lead to a single outcome, but to a superposition of all outcomes that quickly diverge into their separate paths. Thus, if the physical constants, the dimension of space-time, etc. may differ in parallel quantum branches at level III, they will also differ in parallel universes at level II.

In other words, the level III superuniverse does not add anything new to what is available at levels I and II, only more copies of the same universes - the same historical lines develop over and over again on different quantum branches. The heated controversy surrounding Everett's theory appears to soon subside as a result of the discovery of equally grandiose but less contentious Levels I and II superuniverses.

The applications of these ideas are profound. For example, such a question: is there an exponential increase in the number of universes over time? The answer is unexpected: no. From the bird's point of view, there is only one quantum universe. What is the number of separate universes in this moment for a frog? This is the number of markedly different Hubble volumes. The differences may be small: imagine the planets moving in different directions, imagine yourself married to someone else, and so on. At the quantum level, there are 10 to the power of 10118 universes with temperatures no higher than 108 K. The number is gigantic, but finite.

For a frog, the evolution of the wave function corresponds to an infinite movement from one of these 10 states to the power of 10118 to another. You are now in universe A, where you are reading this sentence. And now you are already in universe B, where you are reading the following sentence. In other words, there is an observer in B that is identical to the observer in universe A, with the only difference being that he has extra memories. At every moment there are all possible states, so that the passage of time can occur before the eyes of the observer. This idea was expressed in his science fiction novel Permutation City (1994) by writer Greg Egan (Greg Egan) and developed by physicist David Deutsch (David Deutsch) from the University of Oxford, independent physicist Julian Barbour (Julian Barbour) and others. we see the idea of a superuniverse can play key role understanding the nature of time.

Level IV

Other mathematical structures

The initial conditions and physical constants in the superuniverse levels I, II, and III may differ, but the fundamental laws of physics are the same. Why did we stop there? Why can't physical laws themselves differ? How about a universe that obeys classical laws without any relativistic effects? How about time moving in discrete steps, like in a computer?

What about the universe as an empty dodecahedron? In the level IV superuniverse, all of these alternatives do exist.

That such a superuniverse is not absurd is evidenced by the correspondence of the world of abstract reasoning to ours. real world. Equations and other mathematical concepts and structures - numbers, vectors, geometric objects - describe reality with amazing plausibility. Conversely, we perceive mathematical structures as real. Yes, they meet the fundamental criterion of reality: they are the same for everyone who studies them. The theorem will be true regardless of who proved it - a person, a computer or an intelligent dolphin. Other inquisitive civilizations will find the same mathematical structures that we know. Therefore, mathematicians say that they do not create, but discover mathematical objects.

There are two logical, but diametrically opposed paradigms of correlation between mathematics and physics, which arose in ancient times. According to Aristotle's paradigm, physical reality is primary, and mathematical language is only a convenient approximation. Within the framework of Plato's paradigm, it is the mathematical structures that are truly real, and observers perceive them imperfectly. In other words, these paradigms differ in their understanding of what is primary - the frog point of view of the observer (Aristotle's paradigm) or the bird's view from the height of the laws of physics (Plato's point of view).

Aristotle's paradigm is how we perceived the world from early childhood, long before we first heard about mathematics. Plato's point of view is acquired knowledge. Modern theoretical physicists lean towards it, suggesting that mathematics describes the universe well precisely because the universe is mathematical in nature. Then all physics is reduced to the solution mathematical problem, and an infinitely smart mathematician can only calculate the picture of the world on the basis of fundamental laws at the level of a frog, i.e. figure out which observers exist in the universe, what they perceive, and what languages they have invented to convey their perception.

Mathematical structure is an abstraction, an unchanging entity outside of time and space. If the story were a movie, then the mathematical structure would correspond not to one frame, but to the film as a whole. Let's take for example a world consisting of zero-size particles distributed in three-dimensional space. From the bird's point of view, in four-dimensional space-time, particle trajectories are spaghetti. If the frog sees particles moving at constant speeds, then the bird sees a bunch of straight, uncooked spaghetti. If a frog sees two particles orbiting, then a bird sees two "spaghetti" twisted into a double helix. For a frog, the world is described by Newton's laws of motion and gravitation, for a bird - by the geometry of "spaghetti", i.e. mathematical structure. The frog itself for her is a thick ball of them, the complex interweaving of which corresponds to a group of particles that store and process information. Our world is more complicated than this example, and scientists do not know which of the mathematical structures it corresponds to.

Plato's paradigm contains the question: why is our world the way it is? For Aristotle, this is a meaningless question: the world exists, and so it is! But the followers of Plato are interested: could our world be different? If the universe is essentially mathematical, then why is it based on only one of the many mathematical structures? There seems to be a fundamental asymmetry at the very core of nature. To solve the puzzle, I suggested that mathematical symmetry exists: that all mathematical structures are physically realizable, and each of them corresponds to a parallel universe. The elements of this superuniverse are not in the same space, but exist outside of time and space. Most of them probably do not have observers. The hypothesis can be seen as extreme Platonism, stating that the mathematical structures of the Platonic world of ideas, or the "mental landscape" of San Jose University mathematician Rudy Rucker, exist in a physical sense. This is akin to what cosmologist John D. Barrow of the University of Cambridge called "p in the sky", philosopher Robert Nozick of Harvard University described as the "principle of fertility", and philosopher David K. Lewis ) of Princeton University called "modal reality". Level IV closes the hierarchy of superuniverses, since any self-consistent physical theory can be expressed in the form of some mathematical structure.

The Level IV superuniverse hypothesis allows for several verifiable predictions. As at level II, it includes the ensemble (in this case, the totality of all mathematical structures) and selection effects. In classifying mathematical structures, scientists should note that the structure that describes our world is the most general of those that are consistent with observations. Therefore, the results of our future observations should become the most general of those that agree with the data of previous studies, and the data of previous studies the most general of those that are generally compatible with our existence.

Assessing the degree of generality is not an easy task. One of the striking and encouraging features of mathematical structures is that the properties of symmetry and invariance that keep our universe simple and orderly tend to be common. Mathematical structures usually have these properties by default, and getting rid of them requires the introduction of complex axioms.

What did Occam say?

Thus, theories of parallel universes have a four-level hierarchy, where at each next level the universes are less and less reminiscent of ours. They can be characterized by different initial conditions (level I), physical constants and particles (level II) or physical laws (level IV). It's funny that level III has been the most criticized in recent decades as the only one that does not introduce qualitatively new types of universes. In the coming decade, detailed measurements of the CMB and the large-scale distribution of matter in the universe will allow us to more accurately determine the curvature and topology of space and confirm or disprove the existence of level I. The same data will allow us to obtain information about level II by testing the theory of chaotic perpetual inflation. Advances in astrophysics and high-energy particle physics will help refine the degree of fine-tuning of physical constants, strengthening or weakening Level II positions. If efforts to create a quantum computer are successful, there will be an additional argument in favor of the existence of level III, since the parallelism of this level will be used for parallel computing. Experimenters are also looking for evidence of unitarity violation, which will allow us to reject the hypothesis of the existence of level III. Finally, the success or failure of an attempt to solve the main problem of modern physics - to combine general theory relativity with quantum field theory - will answer the question about level IV. Either a mathematical structure will be found that accurately describes our universe, or we will hit the limit of the incredible efficiency of mathematics and be forced to abandon the Level IV hypothesis.

So, is it possible to believe in parallel universes? The main arguments against their existence boil down to the fact that it is too wasteful and incomprehensible. The first argument is that superuniverse theories are vulnerable to Occam's Razor because they postulate the existence of other universes that we will never see. Why should nature be so wasteful and "amuse" itself by creating an infinite number of different worlds? However, this argument can be reversed in favor of the existence of a superuniverse. What exactly is wasteful nature? Certainly not in space, mass or number of atoms: there are already an infinite number of them at level I, the existence of which is not in doubt, so there is no point in worrying that nature will spend some more of them. The real issue is the apparent reduction in simplicity. Skeptics worry about the extra information needed to describe the invisible worlds.

However, the whole ensemble is often simpler than each of its members. The information volume of the number algorithm is, roughly speaking, the length of the shortest number expressed in bits. computer program, which generates this number. Let's take the set of all integers as an example. Which is simpler - the whole set or a single number? At first glance - the second. However, the former can be built with a very simple program, and a single number can be extremely long. Therefore, the whole set turns out to be simpler.

Similarly, the set of all solutions to the Einstein equations for a field is simpler than any particular solution - the first consists of only a few equations, and the second requires a huge amount of initial data to be specified on some hypersurface. So, complexity increases when we focus on a single element of the ensemble, losing the symmetry and simplicity inherent in the totality of all elements.

In this sense, the superuniverses are more high levels simpler. The transition from our universe to a level I superuniverse eliminates the need to set initial conditions. Further transition to level II eliminates the need to specify physical constants, and at level IV nothing needs to be specified at all. Excessive complexity is only a subjective perception, the point of view of a frog. And from the perspective of a bird, this superuniverse could hardly be any simpler. Complaints about incomprehensibility are aesthetic, not scientific nature and are justified only with the Aristotelian worldview. When we ask a question about the nature of reality, shouldn't we expect an answer that may seem strange?

A common feature of all four levels of the superuniverse is that the simplest and perhaps the most elegant theory includes parallel universes by default. To reject their existence, it is necessary to complicate the theory by adding processes that are not confirmed by experiment and postulates invented for this - about the finiteness of space, the collapse of the wave function and ontological asymmetry. Our choice comes down to what is more wasteful and inelegant - a lot of words or a lot of universes. Perhaps, over time, we will get used to the quirks of our cosmos and find its strangeness charming.