The science

The recently released visually immersive movie "Interstellar" is based on real scientific concepts such as spinning black holes, wormholes and the expansion of time.

But if you are not familiar with these concepts, then you may get a little confused while watching.

In the film, a team of space explorers goes to extragalactic travel through a wormhole. On the other side, they enter a different solar system with a spinning black hole instead of a star.

They are in a race with space and time to complete their mission. Such space travel may seem a little confusing, but it is based on the basic principles of physics.

Here are the main 5 concepts of physics what you need to know to understand "Interstellar":

artificial gravity

most big problem that we humans encounter during long-term space travel is weightlessness. We were born on Earth and our body has adapted to certain gravitational conditions, but when we are in space long time, our muscles begin to weaken.

The characters in the film "Interstellar" also face this problem.

To deal with this, scientists create artificial gravity in spaceships. One way to do this is to spin spaceship, like in a movie. Rotation creates centrifugal force, which pushes objects towards the outer walls of the ship. This repulsion is similar to gravity, only in reverse direction.

This form of artificial gravity is what you experience when you are driving around a small radius curve and you feel like you are being pushed outward, away from the center point of the curve. In a spinning spaceship, the walls become the floor for you.

A spinning black hole in space

Astronomers, albeit indirectly, have observed in our universe spinning black holes. No one knows what is at the center of a black hole, but scientists have a name for it -singularity .

Rotating black holes warp the space around them differently than stationary black holes.

This distortion process is called "inertial frame drag" or the Lense-Thirring effect, and it affects what a black hole will look like by distorting space, and more importantly the spacetime around it. The black hole you see in the movie is enoughvery close to the scientific concept.

• Spaceship Endurance heading for Gargantua - fictional supermassive black hole 100 million times the mass of the sun.
• It lies 10 billion light-years from Earth and has several planets orbiting it. Gargantua spins at an astonishing 99.8 percent of the speed of light.
• Garagantua's accretion disk contains gas and dust at the temperature of the Sun's surface. The disk supplies the Gargantua planets with light and heat.

The complex appearance of the black hole in the film is due to the fact that the image of the accretion disk is warped by gravitational lensing. Two arcs appear in the image: one is formed above the black hole, and the other below it.

Mole Hole

The wormhole or wormhole used by the crew in Interstellar is one of the phenomena in the film whose existence has not been proven. It is hypothetical, but very convenient in the plots of science fiction stories, where you need to overcome a large space distance.

Wormholes are just a kind of shortest path through space. Any object with mass creates a hole in space, which means that space can be stretched, deformed, and even folded.

A wormhole is like a fold in the fabric of space (and time) that connects two very distant regions, which helps space travelers. travel a long distance in a short period of time.

The official name for a wormhole is "Einstein-Rosen Bridge" because it was first proposed by Albert Einstein and his colleague Nathan Rosen in 1935.

• In 2D diagrams, the mouth of a wormhole is shown as a circle. However, if we could see a wormhole, it would look like a sphere.
• On the surface of the sphere, a gravitationally distorted view of space from the other side of the "burrow" would be visible.
• The dimensions of the wormhole in the film are 2 km in diameter and the transfer distance is 10 billion light years.

Gravitational time dilation

Gravitational time dilation is real phenomenon observed on earth. It arises because time concerning. This means that it flows differently for various systems coordinates.

When you are in a strong gravitational environment, time passes more slowly for you compared to people in a weak gravitational environment.

Mole Hole. What is a "Wormhole"?

The hypothetical "Wormhole", which is also called the "molehole" or "wormhole" ( literal translation Wormhole) is a kind of space-time tunnel that allows an object to move from point a to point b in the universe not in a straight line, but around space. In the event that it is easier, then take any piece of paper, fold it in half and pierce it, the resulting hole will be the same wormhole
. So there is a theory that the space in the universe can be conditionally the same sheet of paper, attention, only adjusted for the third dimension. Various scientists deduce hypotheses that thanks to wormholes travel in space - time is possible. But at the same time, no one knows exactly what dangers wormholes can pose and what can actually be on the other side of them.

Theory wormholes.
In 1935, physicists Albert Einstein and Nathan Rosen, using the general theory of relativity, suggested that there are special "bridges" across space-time in the universe. These paths, called Einstein-Rosen bridges (or wormholes), connect two completely different points in space-time by theoretically creating a curvature in space that shortens travel from one point to another.

Again, hypothetically, any wormhole consists of two entrances and a neck (that is, the same tunnel. In this case, most likely, the entrances at the wormhole are spheroidal in shape, and the neck can represent both a straight segment of space and a spiral one.

Traveling through a wormhole.

The first problem that will stand in the way of the possibility of such travel is the size of wormholes. It is believed that the very first wormholes were very small size, about 10-33 centimeters, but due to the expansion of the universe, it became possible that the wormholes themselves expanded and increased along with it. Another problem with wormholes is their stability. Or rather, instability.

Explained by the Einstein-Rosen theory, wormholes will be useless for space-time travel because they collapse (close) very quickly. But more recent research on these issues implies the presence of "Exotic Matter", which allows holes to maintain their structure for a longer period of time.

But still theoretical science believes that if wormholes contain a sufficient amount of this exotic energy, which either appeared naturally or will appear artificially, then it will be possible to transmit information or even objects through space-time.

The same hypotheses suggest that wormholes can connect not only two points within one universe, but also be the entrance to others. Some scientists believe that if one wormhole entrance is moved in a certain way, then time travel will be possible. But, for example, the famous British cosmologist Stephen Hawking believes that such use of wormholes is impossible.

However, some scientific minds insist that if the stabilization of wormholes by exotic matter is indeed possible, then it will be possible for people to safely travel through such wormholes. And due to the "Ordinary" matter, if desired and necessary, such portals can be destabilized back.

According to the theory of relativity, nothing can move faster than light. So nothing can get out of this gravitational field, hitting it. The region of space from which there is no way out is called a black hole. Its boundary is determined by the trajectory of light rays, which were the first to lose the opportunity to break out. It is called the event horizon of a black hole. Example: looking out of the window, we do not see what is beyond the horizon, and the conditional observer cannot understand what is happening inside the boundaries of an invisible dead star.

Physicists have found signs of the existence of another universe

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There are five types of black holes, but it is the stellar-mass black hole that interests us. Such objects are formed at the final stage of the life of a celestial body. In general, the death of a star can result in the following things:

1. It will turn into a very dense extinct star, consisting of a number of chemical elements - this is a white dwarf;

2. Into a neutron star - has an approximate mass of the Sun and a radius of about 10-20 kilometers, inside it consists of neutrons and other particles, and outside it is enclosed in a thin but solid shell;

3. Into a black hole, gravitational attraction which is so large that it can suck in objects flying at the speed of light.

When a supernova occurs, that is, the "rebirth" of a star, a black hole is formed, which can only be detected due to the emitted radiation. It is she who is able to generate a wormhole.

If we imagine a black hole as a funnel, then the object, having fallen into it, loses the event horizon and falls inward. So where is the wormhole? It is located in exactly the same funnel, attached to the tunnel of a black hole, where the exits face outward. Scientists believe that the other end of the wormhole is connected to a white hole (the antipode of a black one, into which nothing can fall).

Mole Hole. Schwarzschild and Reisner-Nordström black holes

The Schwarzschild black hole can be considered an impenetrable wormhole. As for the Reisner-Nordström black hole, it is somewhat more complicated, but also impassable. Still, it's not that hard to come up with and describe four-dimensional wormholes in space that could be traversed. You just need to choose the type of metric you need. The metric tensor, or metric, is a set of values ​​that can be used to calculate the four-dimensional intervals that exist between event points. This set of quantities fully characterizes both the gravitational field and the space-time geometry. Geometrically traversable wormholes in space are even simpler than black holes. They do not have horizons that lead to cataclysms with the passage of time. AT various points time can go by different pace, but it must not stop or accelerate indefinitely.

Pulsars: The Beacon Factor

In essence, a pulsar is a rapidly rotating neutron star. A neutron star is the highly compacted core of a dead star left over from a supernova explosion. This neutron star has a powerful magnetic field. This magnetic field is about one trillion times stronger. magnetic field Earth. The magnetic field causes a neutron star to emit strong radio waves and radioactive particles from its north and south poles. These particles can include various radiations, including visible light.

Pulsars that emit powerful gamma rays are known as gamma ray pulsars. If a neutron star is located with its pole towards the Earth, then we can see radio waves every time as soon as one of the poles falls into our foreshortening. This effect is very similar to the lighthouse effect. To a stationary observer, it seems that the light of a rotating beacon is constantly blinking, then disappearing, then appearing again. In the same way, a pulsar appears to blink as it rotates its poles relative to the Earth. Different pulsars emit pulses at different speeds, depending on their size and mass. neutron star. Sometimes a pulsar can have a companion. In some cases, he can attract his companion, which makes him rotate even faster. The fastest pulsars can emit more than a hundred pulses per second.

A hypothetical "wormhole", which is also called a "wormhole" or "wormhole" (literal translation of wormhole) is a kind of space-time tunnel that allows an object to move from point A to point B in the Universe not in a straight line, but around space. If it's easier, then take any piece of paper, fold it in half and pierce it, the resulting hole will be the same wormhole. So there is a theory that the space in the Universe can be conditionally the same sheet of paper, only adjusted for the third dimension. Various scientists deduce hypotheses that thanks to wormholes travel in space-time is possible. But at the same time, no one knows exactly what dangers wormholes can pose and what can actually be on the other side of them.

Wormhole theory

In 1935, physicists Albert Einstein and Nathan Rosen, using the theory of general relativity, suggested that there are special "bridges" across space-time in the universe. These paths, called Einstein-Rosen bridges (or wormholes), connect two completely different points in spacetime by theoretically creating a warp in space that shortens travel from one point to another.

Again, hypothetically, any wormhole consists of two entrances and a neck (that is, the same tunnel). In this case, most likely, the entrances at the wormhole are spheroidal in shape, and the neck can represent both a straight segment of space and a spiral one.

The general theory of relativity mathematically proves the probability of the existence of wormholes, but so far none of them have been discovered by man. The difficulty in detecting it lies in the fact that the alleged huge mass of wormholes and gravitational effects simply absorb light and prevent it from being reflected.

Several hypotheses based on general relativity suggest the existence of wormholes, where black holes play the roles of entry and exit. But it is worth considering that the appearance of the black holes themselves, formed from the explosion of dying stars, in no way creates a wormhole.

Journey through a wormhole

In science fiction, it's not uncommon for protagonists to travel through wormholes. But in reality, such a journey is far from being as simple as it is shown in films and told in fantasy literature.

The first problem that will stand in the way of the possibility of such travel is the size of wormholes. It is believed that the very first wormholes were very small in size, on the order of 10-33 centimeters, but due to the expansion of the Universe, it became possible that the wormholes themselves expanded and increased along with it. Another problem with wormholes is their stability. Or rather, instability.

Wormholes explained by the Einstein-Rosen theory will be useless for space-time travel because they collapse (close) very quickly. But more recent studies of these issues imply the presence of "exotic matter" that allows burrows to maintain their structure for a longer period of time.

Not to be confused with black matter and antimatter, this exotic matter is composed of negative density energy and colossal negative pressure. The mention of such matter is present only in some theories of vacuum within the framework of quantum field theory.

Yet theoretical science believes that if wormholes contain enough of this exotic energy, either naturally occurring or artificially generated, then it will be possible to transmit information or even objects through space-time.

The same hypotheses suggest that wormholes can connect not only two points within one universe, but also be the entrance to others. Some scientists believe that if one wormhole entrance is moved in a certain way, then time travel will be possible. But, for example, the famous British cosmologist Stephen Hawking believes that such use of wormholes is impossible.

Nevertheless, some scientific minds insist that if stabilization of wormholes with exotic matter is indeed possible, then it will be possible for people to safely travel through such wormholes. And due to the "ordinary" matter, if desired and necessary, such portals can be destabilized back.

Unfortunately, today's technologies of mankind are not enough for wormholes to be artificially enlarged and stabilized, in case they are nevertheless discovered. But scientists continue to explore concepts and methods for fast space travel and maybe one day science will come up with the right solution.

Video Wormhole: door through the looking glass

Sci-fi fans hope that humanity will one day be able to travel to the far reaches of the universe through a wormhole.

A wormhole is a theoretical tunnel through space-time that will potentially allow faster travel between distant points in space - from one galaxy to another, for example, as was shown in Christopher Nolan's film "Interstellar", which was released in theaters around the world at the beginning of this month.

While the existence of wormholes is possible according to Einstein's theory of general relativity, such exotic travel is likely to remain in the region. science fiction, said the famous astrophysicist Kip Thorne from the California Institute of Technology in Pasadena, who served as an advisor and executive producer on Interstellar.

"The point is, we just don't know anything about them," said Thorne, who is one of the world's leading experts on relativity, black holes and wormholes. "But there are very strong signs that a person, according to the laws of physics, will not be able to travel through them.

"The main reason has to do with the instability of wormholes," he added. "The walls of the wormholes are collapsing so fast that nothing can get through them."

Keeping the wormholes open will require the use of something anti-gravity, namely negative energy. negative energy was created in the lab using quantum effects: one area of ​​space receives the energy of another area in which a deficit is formed.

"So it's theoretically possible," he said. "But we can never get enough negative energy, which will be able to keep the walls of the wormhole open."

Also, wormholes (if they exist at all) almost certainly cannot form naturally. That is, they must be created with the help of an advanced civilization.

This is exactly what happened in "Interstellar": Mysterious Creatures built a wormhole near Saturn, allowing a small group of pioneers, led by former farmer Cooper (played by Matthew McConaughey), to set out in search of a new home for humanity, whose existence on Earth is threatened by a global crop failure.

Persons interested in receiving additional information about science in the film "Interstellar", which deals with questions about gravitational slowdown and depicts several alien planets orbiting a closely spaced one, you can read new book Thorn, which is unequivocally called "Science from Interstellar".

Where is the wormhole. Wormholes in general relativity

(GR) allows the existence of such tunnels, although for the existence of a traversable wormhole it is necessary that it be filled with a negative one, which creates a strong gravitational repulsion and prevents the hole from collapsing. Wormhole-type solutions arise in various options, although up to full study question is still very far away.

The area near the narrowest section of the molehill is called the "throat". Wormholes are divided into "intra-universe" and "inter-universe", depending on whether it is possible to connect its inputs with a curve that does not cross the neck.

There are also passable (traversable) and impassable molehills. The latter include those tunnels that are too fast for an observer or a signal (having a speed of no more than light speed) to get from one entrance to another. Classic example impassable molehill - in, and passable -.

A traversable intraworld wormhole provides a hypothetical possibility if, for example, one of its entrances is moving relative to the other, or if it is in a strong one where the passage of time slows down. Also, wormholes can hypothetically create an opportunity for interstellar travel, and in this capacity, molehills are often found in.

Space wormholes. Through the "molehills" - to the stars?

Unfortunately, the practical use of "wormholes" to reach remote space objects there is no talk yet. Their properties, varieties, places of possible location are still known only theoretically - although, you see, this is already quite a lot. After all, we have many examples of how the theoretical constructions that seemed purely speculative led to the emergence of new technologies that radically changed the life of mankind. Nuclear energy, computers, mobile communications, genetic engineering ... but you never know what else?
In the meantime, the following is known about "wormholes", or "wormholes". In 1935, Albert Einstein and the American-Israeli physicist Nathan Rosen suggested the existence of a kind of tunnels connecting various remote regions of space. At that time, they were not yet called "wormholes", or "mole holes", but simply - "Einstein-Rosen bridges". Since such bridges required a very strong curvature of space to form, their lifetime was very short. No one and nothing would have time to "run" over such a bridge - under the influence of gravity, it almost immediately "collapsed".
And therefore, it remained completely useless in a practical sense, although an amusing consequence of the general theory of relativity.
However, later there were ideas that some interdimensional tunnels could exist enough long time- provided that they are filled with some exotic matter with a negative energy density. Such matter will create gravitational repulsion instead of attraction and thus prevent the channel from “collapsing”. Then the name "wormhole" appeared. By the way, our scientists prefer the name "molehill" or "wormhole": the meaning is the same, but it sounds much nicer ...
American physicist John Archibald Wheeler (1911-2008), developing the theory of "wormholes", suggested that they are penetrated electric field; Moreover, the electric charges themselves are, in fact, the necks of microscopic "wormholes". Russian astrophysicist Academician Nikolai Semyonovich Kardashev believes that "wormholes" can reach gigantic sizes and that in the center of our Galaxy there are not massive black holes at all, but the mouths of such "holes".
Of practical interest to future space travelers will be "wormholes", which are kept in a stable state for quite a long time and, moreover, are suitable for spacecraft to pass through them.
Americans Kip Thorne and Michael Morris created a theoretical model of such channels. However, their stability is ensured by “exotic matter”, about which nothing is really known and which, perhaps, it is better for earthly technology not to even meddle.
But the Russian theorists Sergei Krasnikov from Pulkovo observatory and Sergey Sushkov from Kazan Federal University put forward the idea that the stability of a wormhole can be achieved without any negative energy density, but simply due to the polarization of the vacuum in the “hole” (the so-called Sushkov mechanism).
In general, now there is a whole set of theories of "wormholes" (or, if you like, "wormholes"). A very general and speculative classification divides them into "passable" - stable, Morris - Thorn wormholes, and impassable - Einstein - Rosen bridges. In addition, wormholes vary in scale - from microscopic to gigantic, comparable in size to galactic "black holes". And, finally, according to their purpose: “intra-universe”, connecting different places of the same curved Universe, and “inter-world” (inter-universe), allowing you to get into another space-time continuum.

Gravity [From crystal spheres to wormholes] Petrov Alexander Nikolaevich

Wormholes

Wormholes

The mole had recently dug a new long gallery underground from his dwelling to the doors of the field mouse, and allowed the mouse and the girl to walk in this gallery as long as they liked.

Hans Christian Andersen "Thumbelina"

The idea of ​​wormholes belongs to Albert Einstein and Nathan Rosen (1909–1995). In 1935 they showed that general relativity allows so-called "bridges" - passages in space through which one can, it would seem, much faster than in the usual way to get from one part of space to another, or from one universe to another. But the "bridge" of Einstein - Rosen is a dynamic object, after the observer penetrates into it, the outputs are compressed.

Is it possible to reverse the compression? It turns out you can. To do this, it is necessary to fill the “bridge” space with a special substance that prevents compression. Such "bridges" are called wormholes, in the English version - wormholes(wormholes).

special wormhole material and usual differ in that they “push through” space-time in different ways. In the case of ordinary matter, its curvature (positive) resembles part of the surface of a sphere, and in the case of special matter, the curvature (negative) corresponds to the shape of the surface of the saddle. On fig. 8.6 schematically represents 2-dimensional spaces of negative, zero (flat) and positive curvature. Therefore, for the deformation of space-time, which will not allow the wormhole to shrink, exotic matter is needed, which creates repulsion. The classical (not quantum) laws of physics exclude such states of matter, but quantum laws, more flexible, allow. Exotic matter prevents the formation of an event horizon. And the lack of a horizon means that you can not only fall into a wormhole, but also return. The absence of an event horizon also leads to the fact that the traveler, a fan of wormholes, is always available to telescopes of external observers, and radio contact can be maintained with him.

Rice. 8.6. Two-dimensional surfaces of different curvature

If we imagine how black holes are formed, then how "wormholes" are created in modern era and whether they are created at all is completely unclear. On the other hand, there is now an almost generally accepted opinion that at an early stage in the development of the Universe there were a lot of wormholes. It is assumed that before big bang(which we will discuss in the next chapter), before the expansion, the Universe was a space-time foam with very large curvature fluctuations, mixed with a scalar field. The foam cells were interconnected. And after the Big Bang, these cells could remain connected, which may be wormholes in our era. This type of model was discussed in Wheeler's publications in the mid-1950s.

Rice. 8.7, Wormhole in a closed universe

So, there is a fundamental possibility to enter a wormhole and go outside at another point in the universe or in another universe (Fig. 8.7). If using enough powerful telescope look through the neck inside the wormhole, you can see the light of the distant past and learn about the events that happened several billion years ago. Indeed, the signal from the place of observation could wander around the Universe for a long time in order to reverse side enter the wormhole and exit at the observation point. And if wormholes actually arose simultaneously with the birth of the Universe, then in such a tunnel you can see the most distant past.

It is from the position of time travel that two well-known scientists, recognized experts in the study of black holes, Kip Thorne from the California Institute of Technology and Igor Novikov from the Astrospace Center of the Lebedev Physical Institute, published a series of papers in the early 1980s defending the fundamental possibility of creating a time machine.

However, if one thinks of fantasy novels on this subject, each states that time travel is likely to be destructive. In a serious theory, it turns out that no destructive actions with the help of the time machine of Thorn and Novikov are impossible. Cause-and-effect relationships are not violated, all events occur in such a way that they cannot be changed - there will certainly be a hindrance that will prevent the time traveler from killing the "Bradbury Butterfly".

The entrance to a wormhole can be the most different sizes, there are no restrictions - from cosmic scales to the size, literally, of grains of sand. Since a wormhole is a kind of relative of a black hole, you should not look for additional dimensions in its structure. If this is a move somewhere, then in the language of geometry it is a complex topology. Let's ask a question. How to find a wormhole? Again, remember that this is a relative of a black hole, then near the space-time should be strongly curved. Manifestations (observable and unobservable) of such a curvature were discussed above. However, models of wormholes are possible for which there is no local curvature. Approaching such a "hole", the observer will not experience anything, but if he stumbles upon it, he will fall as if from a cliff. But such models are the least preferred, various contradictions and exaggerations arise.

Recently, a group of our scientists - Nikolai Kardashev, Igor Novikov and Alexander Shatsky - came to the conclusion that the properties of the exotic matter that supports the wormhole are very similar to the properties of magnetic or electric fields. As a result of research, it turned out that the entrance to the tunnel will be very similar to a magnetic monopole, that is, a magnet with one pole. In the case of wormholes, there is no real monopole: one neck of a wormhole has a magnetic field of one sign, and the other has a different sign, only the second neck can be in another universe. One way or another, but magnetic monopoles in space have not been discovered so far, although their search is ongoing. But they are actually looking for elementary particles with such a property. In the case of wormholes, it is necessary to look for large magnetic monopoles.

One of the tasks of the recently launched international observatory "RadioAstron" is precisely the search for such monopoles. Here is what the project manager Nikolai Kardashev says in one of his interviews:

“With these observatories, we will look inside black holes and see if they are wormholes. If it turns out that we see only clouds of gas passing by and observe various effects associated with the gravity of a black hole, for example, the curvature of the trajectory of light, then this will be a black hole. If we see radio waves coming from inside, it will be clear that this is not a black hole, but a wormhole. Let's build a picture of the magnetic field using the Faraday effect. So far, this lacked permission ground-based telescopes. And if it turns out that the magnetic field corresponds to a monopole, then this is almost certainly a "wormhole." But first you need to see.

…First, we propose to investigate supermassive black holes in the centers of our and nearby galaxies. For ours, this is a very compact object with a mass of 3 million solar masses. We think it's a black hole, but it could also be a wormhole. There are objects even more grandiose. In particular, in the center of the closest to us from massive galaxies M 87 in the constellation Virgo is a black hole with a mass of 3 billion suns. These objects are among the most important for RadioAstronom research. But not only them. There are, for example, some pulsars that may be two entrances to the same "wormhole". And the third type of objects - bursts of gamma radiation, in their place there is also a short-term optical and radio emission. We observe them from time to time even at very large distances - as for the most distant visible galaxies. They are very powerful, and we do not yet fully understand what they are. In general, a catalog of a thousand objects for observation has now been prepared.”

wormhole - 1) astrophysicist. The most important concept modern astrophysics and practical cosmology. "Wormhole", or "molehole", is a trans-spatial passage that connects a black hole and its corresponding white hole.

The astrophysical "wormhole" pierces the space folded in additional dimensions and allows you to move through the real world. shortcut between star systems.

Studies conducted using orbiting telescope Hubble showed that every black hole is the entrance to a "wormhole" (see Hubble's LAW). One of the largest holes is located in the center of our galaxy. It has been theoretically shown (1993) that it is from this central hole that the Solar System originated.

According to modern concepts, the observable part of the Universe is literally all riddled with "wormholes" going "back and forth." Many leading astrophysicists believe that travel through "wormholes" is the future of interstellar astronautics. "

We are all used to the fact that the past cannot be returned, although sometimes we really want to. Science fiction writers have been painting for over a century different kind incidents that arise due to the ability to travel through time and influence the course of history. Moreover, this topic turned out to be so burning that at the end of the last century, even physicists far from fairy tales began to seriously look for such solutions to the equations that describe our world, which would allow creating time machines and overcoming any space and time in the blink of an eye.

Fantasy novels describe entire transport networks connecting star systems and historical eras. I stepped into a booth stylized, say, as a telephone booth, and ended up somewhere in the Andromeda Nebula or on Earth, but - visiting long-extinct tyrannosaurs.

The characters of such works constantly use zero-transportation of the time machine, portals and similar convenient devices.

However, fans of science fiction perceive such trips without much trepidation - you never know what can be imagined, referring the realization of the invented to an uncertain future or to the insights of an unknown genius. Much more surprising is the fact that time machines and tunnels in space are quite seriously discussed as hypothetically possible in articles on theoretical physics, on the pages of the most reputable scientific publications.

The answer lies in the fact that, according to Einstein's theory of gravity - the general theory of relativity (GR), the four-dimensional space-time in which we live is curved, and gravity, familiar to everyone, is a manifestation of such curvature.

Matter "bends", warps the space around it, and the denser it is, the stronger the curvature.

Numerous alternative theories gravitation, the number of which goes to hundreds, differing from general relativity in details, retains the main thing - the idea of ​​space-time curvature. And if space is curved, then why not take, for example, the shape of a pipe, short-circuiting regions separated by hundreds of thousands of light years, or, let's say, eras far from each other - after all we are talking not just about space, but about space-time?

Remember, the Strugatskys (who also, by the way, resorted to zero-transportation): “I absolutely don’t see why the noble don shouldn’t ...” - well, let’s say, not fly to the XXXII century? ...

Wormholes or black holes?

Thoughts about such a strong curvature of our space-time arose immediately after the advent of general relativity - already in 1916, the Austrian physicist L. Flamm discussed the possibility of the existence of spatial geometry in the form of a kind of hole connecting two worlds. In 1935, A. Einstein and the mathematician N. Rosen drew attention to the fact that the simplest solutions of the GR equations, describing isolated, neutral or electrically charged sources of the gravitational field, have a spatial structure of a “bridge” that almost smoothly connects two universes - two identical, almost flat, space-time.

Of such kind spatial structures later they were called "wormholes" (a fairly free translation of the English word "wormhole" - "wormhole").

Einstein and Rosen even considered using such "bridges" to describe elementary particles. Indeed, the particle in this case is a purely spatial formation, so there is no need to specifically model the source of mass or charge, and with the microscopic dimensions of the wormhole, an external, distant observer located in one of the spaces sees only a point source with a certain mass and charge.

Electric lines of force enter the hole from one side and exit from the other, without beginning or ending anywhere.

By expression American physicist J. Wheeler, it turns out "mass without mass, charge without charge." And in this case, it is not at all necessary to believe that the bridge connects two different universes - the assumption that both "mouths" of the wormhole open into the same universe, but at different points and at different points, is no worse. different times- something like a hollow "handle", sewn to the usual almost flat world.

One mouth into which the lines of force enter can be seen as negative charge(for example, an electron), the other from which they come out - as positive (positron), the masses will be the same on both sides.

Despite the attractiveness of such a picture, it (for many reasons) did not take root in elementary particle physics. It is difficult to attribute quantum properties to Einstein-Rosen's "bridges", and without them there is nothing to do in the microcosm.

At known values masses and charges of particles (electrons or protons), the Einstein-Rosen bridge does not form at all, instead, the "electric" solution predicts the so-called "bare" singularity - the point at which the curvature of space and the electric field become infinite. The concept of space-time, even if it is curved, loses its meaning at such points, since it is impossible to solve equations with infinite terms. The general relativity itself quite clearly states where exactly it stops working. Let us recall the words said above: "almost smoothly connecting ...". This "almost" refers to the main flaw of the "bridges" of Einstein - Rosen - a violation of smoothness in the narrowest part of the "bridge", on the neck.

And this violation, it must be said, is very non-trivial: on such a neck, from the point of view of a distant observer, time stops...

In modern terms, what Einstein and Rosen saw as the throat (that is, the narrowest point of the "bridge") is in fact nothing more than the event horizon of a black hole (neutral or charged).

Moreover, with different sides"bridge" particles or rays fall on different "sections" of the horizon, and between, relatively speaking, the right and left parts of the horizon there is a special non-static area, without overcoming which it is impossible to go through the hole.

For a distant observer, a spaceship approaching the horizon of a sufficiently large (compared to the ship) black hole seems to freeze forever, and signals from it reach less and less often. On the contrary, by ship's clock the horizon is reached in a finite time.

Having passed the horizon, the ship (a particle or a ray of light) soon inevitably rests on a singularity - where the curvature becomes infinite and where (still on the way) any extended body will inevitably be crushed and torn apart.

Takova harsh reality internal structure of a black hole. The Schwarzschild and Reisner-Nordstrom solutions describing spherically symmetric neutral and electrically charged black holes were obtained in 1916-1917, but physicists fully understood the complex geometry of these spaces only at the turn of the 1950s-1960s. By the way, it was then that John Archibald Wheeler, known for his work in nuclear physics and the theory of gravity, proposed the terms "black hole" and "wormhole".

As it turned out, there really are wormholes in the Schwarzschild and Reisner-Nordström spaces. From the point of view of a distant observer, they are not completely visible, like black holes themselves, and are just as eternal. But for a traveler who dared to penetrate beyond the horizon, the hole collapses so quickly that neither a ship, nor a massive particle, nor even a ray of light will fly through it.

In order, bypassing the singularity, to break through "to the light of God" - to the other mouth of the hole, it is necessary to move faster than light. And physicists today believe that superluminal speeds of movement of matter and energy are impossible in principle.

Wormholes and time loops

So, the Schwarzschild black hole can be considered as an impenetrable wormhole. The Reisner-Nordstrom black hole is more complicated, but also impassable.

However, it is not so difficult to come up with and describe traversable four-dimensional wormholes, choosing the desired type of metric (a metric, or metric tensor, is a set of quantities that are used to calculate four-dimensional distances-intervals between event points, which fully characterizes the geometry of space-time, and gravitational field). Traversable wormholes are, in general, geometrically even simpler than black holes: there should not be any horizons leading to cataclysms with the passage of time.

Time at different points can, of course, go at a different pace - but it should not infinitely accelerate or stop.

It must be said that various black holes and wormholes are very interesting micro-objects that arise by themselves as quantum fluctuations of the gravitational field (at lengths of the order of 10-33 cm), where, according to existing estimates, the concept of a classical, smooth space-time is no longer applicable.

On such scales, there should be something similar to water or soap foam in a turbulent stream, constantly “breathing” due to the formation and collapse of small bubbles. Instead of calm empty space we have mini-black holes and wormholes of the most bizarre and intertwining configurations appearing and disappearing at a frantic pace. Their dimensions are unimaginably small - they are as many times smaller atomic nucleus what time is the core smaller planet Earth. There is no rigorous description of the space-time foam yet, since a consistent quantum theory of gravity has not yet been created, but in in general terms the described picture follows from the basic principles of physical theory and is unlikely to change.

However, from the point of view of interstellar and intertemporal travel, wormholes of completely different sizes are needed: “I would like” a spaceship of reasonable size or at least a tank to pass through the neck without damage (it would be uncomfortable among tyrannosaurs without it, right?).

Therefore, to begin with, it is necessary to obtain solutions to the equations of gravity in the form of traversable wormholes of macroscopic dimensions. And if we assume that such a hole has already appeared, and the rest of the space-time has remained almost flat, then consider that there is everything - a hole can be a time machine, an intergalactic tunnel, and even an accelerator.

Regardless of where and when one of the mouths of a wormhole is located, the second one can be anywhere in space and at any time - in the past or in the future.

In addition, the mouth can move at any speed (within the limits of light) with respect to the surrounding bodies - this will not prevent the exit from the hole into the (practically) flat Minkowski space.

It is known to be unusually symmetrical and looks the same at all its points, in all directions and in any inertial systems no matter how fast they move.

But, on the other hand, assuming the existence of a time machine, we are immediately faced with the whole "bouquet" of paradoxes such as - flew into the past and "killed grandfather with a shovel" before grandfather could become a father. Normal common sense suggests that this, most likely, simply cannot be. And if a physical theory claims to describe reality, it must contain a mechanism that prohibits the formation of such "time loops", or at least makes them extremely difficult to form.

GR, no doubt, claims to describe reality. Many solutions have been found in it that describe spaces with closed time loops, but as a rule, for one reason or another, they are recognized as either unrealistic or, let's say, “non-dangerous”.

Yes, very interesting solution Einstein's equations were pointed out by the Austrian mathematician K. Godel: this is a homogeneous stationary universe, rotating as a whole. It contains closed trajectories, traveling along which you can return not only to the starting point in space, but also to the starting point in time. However, the calculation shows that the minimum time length of such a loop is much longer than the lifetime of the Universe.

Traversable wormholes, considered as "bridges" between different universes, are temporary (as we said) to assume that both mouths open into the same universe, as loops appear immediately. What then, from the point of view of general relativity, hinders their formation - according to at least, on macroscopic and cosmic scales?

The answer is simple: the structure of Einstein's equations. On their left side there are quantities that characterize the space-time geometry, and on the right - the so-called energy-momentum tensor, which contains information about the energy density of matter and various fields, about their pressure in different directions, about their distribution in space and about state of motion.

One can "read" Einstein's equations from right to left, stating that they are used by matter to "tell" space how to curve. But it is also possible - from left to right, then the interpretation will be different: geometry dictates the properties of matter, which could ensure its existence, geometry.

So, if we need the geometry of a wormhole, let's substitute it into Einstein's equations, analyze and find out what kind of matter is required. It turns out that it is very strange and unprecedented, it is called “exotic matter”. So, to create the simplest wormhole (spherically symmetric), it is necessary that the energy density and pressure in the radial direction add up to a negative value. Is it necessary to say that for ordinary types of matter (as well as for many known physical fields) both of these quantities are positive?..

Nature, as we see, has indeed put up a serious barrier to the emergence of wormholes. But this is how a person works, and scientists are no exception: if the barrier exists, there will always be those who want to overcome it ...

The work of theorists interested in wormholes can be conditionally divided into two complementary directions. The first, assuming in advance the existence of wormholes, considers the consequences that arise, the second tries to determine how and from what wormholes can be built, under what conditions they appear or can appear.

In the works of the first direction, for example, such a question is discussed.

Suppose we have a wormhole at our disposal, through which one can pass in a matter of seconds, and let its two funnel-shaped mouths "A" and "B" be located close to each other in space. Is it possible to turn such a hole into a time machine?

The American physicist Kip Thorne and his collaborators showed how to do this: the idea is to leave one of the mouths, "A", in place, and the other, "B" (which should behave like an ordinary massive body), to disperse to speed comparable to the speed of light, and then return back and brake near "A". Then, due to the SRT effect (deceleration of time on a moving body compared to a stationary one), less time will pass for the mouth “B” than for the mouth “A”. Moreover, the greater was the speed and duration of travel of the mouth "B", the greater will be the time difference between them.

This, in fact, is the same “twin paradox” well-known to scientists: a twin who returned from a flight to the stars turns out to be younger than his homebody brother ... Let the time difference between the mouths be, for example, half a year.

Then, sitting near the mouth of "A" in the middle of winter, we will see through the wormhole a vivid picture of the past summer and - really this summer and return, having passed through the hole through. Then we will again approach the funnel "A" (it, as we agreed, is somewhere nearby), once again dive into the hole and jump straight into last year's snow. And so many times. Moving in the opposite direction - diving into funnel "B", - let's jump half a year into the future ...

Thus, having performed a single manipulation with one of the mouths, we get a time machine that can be "used" constantly (assuming, of course, that the hole is stable or that we are able to maintain its "operability").

The works of the second direction are more numerous and, perhaps, even more interesting. This direction includes the search for specific models of wormholes and the study of their specific properties, which, in general, determine what can be done with these holes and how to use them.

Exomatter and dark energy

Exotic properties of matter that must be possessed construction material for wormholes, as it turns out, can be realized due to the so-called vacuum polarization of quantum fields.

This conclusion has recently been reached Russian physicists Arkady Popov and Sergey Sushkov from Kazan (together with David Hochberg from Spain) and Sergey Krasnikov from the Pulkovo Observatory. And in this case, vacuum is not emptiness at all, but quantum state with the lowest energy - a field without real particles. Pairs of "virtual" particles constantly appear in it, which again disappear earlier than they could be detected by devices, but leave their very real trace in the form of some energy-momentum tensor with unusual properties.

And although the quantum properties of matter manifest themselves mainly in the microcosm, the wormholes generated by them (under certain conditions) can reach very decent sizes. By the way, one of the articles by S. Krasnikov has a "frightening" title - "The Threat of Wormholes." The most interesting thing about this purely theoretical discussion is that the real astronomical observations recent years seem to greatly undermine the positions of opponents of the possibility of the very existence of wormholes.

Astrophysicists, studying the statistics of supernova explosions in galaxies billions of light years away from us, concluded that our Universe is not just expanding, but is expanding at an ever-increasing speed, that is, with acceleration. Moreover, over time, this acceleration even increases. This is quite confidently indicated by the most recent observations carried out on the latest space telescopes. Well, now it's time to remember the connection between matter and geometry in general relativity: the nature of the expansion of the Universe is firmly connected with the equation of state of matter, in other words, with the relationship between its density and pressure. If the matter is ordinary (with positive density and pressure), then the density itself falls over time, and the expansion slows down.

If the pressure is negative and equal in magnitude, but opposite in sign to the energy density (then their sum = 0), then this density is constant in time and space - this is the so-called cosmological constant, which leads to expansion with constant acceleration.

But for the acceleration to grow with time, and this is not enough - the sum of pressure and energy density must be negative. No one has ever observed such matter, but the behavior of the visible part of the Universe seems to signal its presence. Calculations show that this kind of strange, invisible matter (called "dark energy") in the present era should be about 70%, and this proportion is constantly increasing (unlike ordinary matter, which loses density with increasing volume, dark energy behaves paradoxically - the Universe is expanding, and its density is growing). But after all (and we have already talked about this), it is precisely such exotic matter that is the most suitable “building material” for the formation of wormholes.

One is drawn to fantasize: sooner or later, dark energy will be discovered, scientists and technologists will learn how to thicken it and build wormholes, and there - not far from the "dream come true" - about time machines and about tunnels leading to the stars ...

True, the estimate of the density dark energy in the universe that provides it accelerated expansion: if the dark energy is evenly distributed, a completely negligible value is obtained - about 10-29 g/cm3. For an ordinary substance, this density corresponds to 10 hydrogen atoms per 1 m3. Even interstellar gas is several times denser. So if this path to the creation of a time machine can become real, then it will not be very, very soon.

Need a donut hole

Until now, we have been talking about tunnel-like wormholes with smooth necks. But GR also predicts another kind of wormholes - and in principle they do not require any distributed matter at all. There is a whole class of solutions to Einstein's equations, in which the four-dimensional space-time, flat far from the source of the field, exists, as it were, in duplicate (or sheets), and common to both of them are only a certain thin ring (the source of the field) and a disk, this ring limited.

This ring has a truly magical property: you can “wander” around it for as long as you like, remaining in “your” world, but once you pass through it, you will find yourself in a completely different world, although similar to “your own”. And in order to go back, you need to go through the ring again (and from any side, not necessarily from the one you just left).

The ring itself is singular - the curvature of space-time on it turns to infinity, but all points inside it are quite normal, and the body moving there does not experience any catastrophic effects.

Interestingly, there are a great many such solutions - both neutral and electric charge, both with and without rotation. Such, in particular, is the famous solution of the New Zealander R. Kerr for a rotating black hole. It most realistically describes black holes of stellar and galactic scales (the existence of which most astrophysicists no longer doubt), since almost all celestial bodies experience rotation, and when compressed, the rotation only accelerates, especially when collapsing into a black hole.

So, it turns out that rotating black holes are "direct" candidates for "time machines"? However, black holes that form in stellar systems are surrounded and filled with hot gas and harsh, deadly radiation. In addition to this purely practical objection, there is also a fundamental one, connected with the difficulties of getting out from under the event horizon to a new spatio-temporal “sheet”. But it is not worth dwelling on this in more detail, since, according to general relativity and many of its generalizations, wormholes with singular rings can exist without any horizons.

So there are at least two theoretical possibilities for the existence of wormholes connecting different worlds: burrows can be smooth and consist of exotic matter, or they can arise due to a singularity, while remaining passable.

Space and strings

Thin singular rings resemble other unusual objects predicted modern physics, - cosmic strings formed (according to some theories) in early universe when superdense matter cools down and its states change.

They really do resemble strings, only extraordinarily heavy - many billions of tons per centimeter of length with a thickness of a fraction of a micron. And, as was shown by the American Richard Gott and the Frenchman Gerard Clement, from several strings moving relative to each other with high speeds, it is possible to compose constructions containing temporary loops. That is, moving in a certain way in the gravitational field of these strings, you can return to the starting point before you flew out of it.

Astronomers have long been looking for this kind space objects, and today there is already one "good" candidate - the CSL-1 object. These are two surprisingly similar galaxies, which in reality are probably one, only bifurcated due to the effect of gravitational lensing. And in this case gravitational lens- not spherical, but cylindrical, resembling a long thin heavy thread.

Will the fifth dimension help?

In the event that space-time contains more than four dimensions, the architecture of wormholes acquires new, previously unknown possibilities.

Thus, in recent years, the concept of "brane world" has become popular. It assumes that all observable matter is located on some four-dimensional surface (denoted by the term "brane" - a truncated word for "membrane"), and in the surrounding five or six-dimensional volume there is nothing but a gravitational field. The gravitational field on the brane itself (and this is the only one we observe) obeys the modified Einstein equations, and they have a contribution from the geometry of the surrounding volume.

So, this contribution is capable of playing the role of exotic matter that generates wormholes. Burrows can be of any size and still not have their own gravity.

This, of course, does not exhaust the whole variety of "constructions" of wormholes, and the general conclusion is that, for all the unusual nature of their properties and for all the difficulties of a fundamental, including philosophical, nature, to which they can lead, their possible existence is worth treated with full seriousness and due attention.

It cannot be ruled out, for example, that large holes exist in interstellar or intergalactic space, if only because of the concentration of the very dark energy that accelerates the expansion of the Universe.

There is no unequivocal answer to the questions - how they can look for an earthly observer and whether there is a way to detect them - yet. Unlike black holes, wormholes may not even have any noticeable field attraction (repulsion is also possible), and therefore, in their vicinity one should not expect noticeable concentrations of stars or interstellar gas and dust.

But assuming that they can “short-circuit” regions or epochs that are far from each other, passing the radiation of the luminaries through themselves, it is quite possible to expect that some distant galaxy will seem unusually close.

Due to the expansion of the Universe, the farther away the galaxy, the greater the shift of the spectrum (toward the red side) its radiation comes to us. But when looking through a wormhole, there may not be any redshift. Or will be, but - another. Some of these objects can be observed simultaneously in two ways - through the hole or in the "usual" way, "past the hole."

Thus, the sign of a cosmic wormhole can be as follows: the observation of two objects from very similar properties, but at different visible distances and with different redshifts.

If wormholes are nevertheless discovered (or built), the area of ​​philosophy that deals with the interpretation of science will face new and, I must say, very difficult tasks. And for all the seeming absurdity of time loops and the complexity of the problems associated with causality, this area of ​​\u200b\u200bscience, in all likelihood, sooner or later will figure it all out somehow. Just as at one time "handled" with conceptual problems quantum mechanics and Einstein's theory of relativity...

Kirill Bronnikov, Doctor of Physical and Mathematical Sciences

A group of physicists from Germany and Greece general guidance Burkhard Klayhaus presented in principle A New Look to the problem wormholes. So called hypothetical objects where there is a curvature of space and time.

It is believed that they are tunnels through which you can travel to other worlds at one moment.

Wormholes, or, as they are also called, wormholes, are known to every fan of science fiction, where these objects are described very vividly and impressively (although in books they are more often called zero-space). It is thanks to them that heroes can move from one galaxy to another for a very a short time. As for real wormholes, the situation with them is much more complicated. It is still not clear whether they actually exist, or whether this is all the result of the wild imagination of theoretical physicists.

According to traditional notions, wormholes are some hypothetical property of our universe, or rather, space and time. According to the concept of the Einstein-Rosen bridge, at every moment in our Universe, some tunnels can appear through which you can get from one point in space to another almost simultaneously (that is, without loss of time).

It would seem that teleport with their help for your own pleasure! But here's the trouble: firstly, these wormholes are extremely small (only elementary particles can easily roam through them), and secondly, they exist for an extremely short time, millionths of a second. That is why it is extremely difficult to study them - until now, all models of wormholes have not been experimentally confirmed.

Nevertheless, scientists still have some idea of ​​\u200b\u200bwhat could be inside such a tunnel (although, alas, also only theoretical). It is believed that everything there is crammed with the so-called exotic matter (not to be confused with dark matter, these are different matters). And this matter got its nickname from the fact that it consists of fundamentally different elementary particles. And because of this, most physical laws are not observed in it - in particular, energy can have a negative density, the force of gravity does not attract, but repels objects, etc. In general, everything inside the tunnel is completely different from normal people. But it is precisely this irregular matter that provides that miraculous transition through the wormhole.

In fact, Einstein's famous general theory of relativity is very loyal to the possibility of the existence of wormholes - it does not refute the existence of such tunnels (although it does not confirm). Well, what is not forbidden, as you know, is allowed. Therefore, many astrophysicists have been actively trying to find traces of at least some more or less stable wormhole since the middle of the last century.

As a matter of fact, their interest can be understood - if it turns out that such a tunnel is possible in principle, then traveling through it to distant worlds will become very a simple matter(of course, provided that the wormhole will be located close to solar system). However, the search for this object is hampered by the fact that scientists still, in fact, do not quite imagine what exactly to look for. In fact, it is impossible to see this hole directly, since, like black holes, it sucks everything into itself (including radiation), but does not release anything. Need some indirect signs its existence, but the question is - which ones?

And just recently, a group of physicists from Germany and Greece, under the general leadership of Burkhard Kleihaus from the University of Oldenburg (Germany), in order to alleviate the suffering of astrophysicists, presented a fundamentally new look at the problem of wormholes. From their point of view, these tunnels can indeed exist in the universe and be quite stable at the same time. And there is no exotic matter, according to the Klayhouse group, inside them.

Scientists believe that the emergence of wormholes was caused by quantum fluctuations inherent in the early universe almost immediately after the Big Bang and gave rise to the so-called quantum foam. Let me remind you that quantum foam- this is a kind of conditional concept that can be used as a qualitative description of subatomic space-time turbulence at very small distances (of the order of the Planck length, that is, a distance of 10 -33 cm).

Figuratively speaking, quantum foam can be represented as follows: imagine that somewhere in very short periods of time in very small regions of space, energy sufficient to turn this piece of space into a black hole can spontaneously appear. And this energy appears not just from nowhere, but as a result of the collision of particles with antiparticles and their mutual annihilation. And then before our eyes there will be a kind of seething cauldron, in which black holes continuously appear and immediately disappear.

So, according to the authors of the study, Right after the Big Bang, our universe was all quantum foam.. And arose in it at every moment of time not only black holes, but also wormholes. And then inflation (that is, expansion) of the Universe should not only inflate it to a huge size, but at the same time sharply increase the holes and make them stable. So much so that it became possible to penetrate even fairly large bodies into them.

True, there is one snag here. The fact is that although large bodies, according to this model, can enter a wormhole, gravitational influence on them at the entrance should be very small. Otherwise, they will simply be torn apart. But if the curvature of space-time at the entrance is "smooth", then the journey itself through it cannot be instantaneous. It, according to the calculations of the researchers, will take tens or even hundreds of light years, since the exit from the wormhole, accessible large body, will be located quite far from the entrance.

Researchers believe that finding these objects in the universe, although not easy, is still possible. While they may look like black holes, there are still differences. For example, in a black hole, gas that falls outside the event horizon immediately stops emitting x-rays, and the one that fell into the wormhole (which has no event horizon) continues to do so. By the way, this behavior of the gas was recently recorded by Hubble in the vicinity of the Sagittarius A* object, which is traditionally considered a massive black hole. But judging by the behavior of the gas, it could be a stable wormhole.

According to the concept of the Klayhouse group, there may be other signs that indicate the existence of wormholes. Theoretically, one can assume a situation where astronomers will directly note the inadequacy of the picture behind the wormhole if the telescope is accidentally turned into its sector of the starry sky. In this case, it will show a picture tens or hundreds of light years away, which astronomers can easily distinguish from what actually should be in this place. The gravity of the star (if it is on the other side of the wormhole) can also distort the light of distant stars passing near the wormhole.

It should be noted that the work of Greek and German physicists, although it is purely theoretical, is very important for astronomers. She systematizes everything for the first time possible signs wormholes that can be observed. So, guided by it, these tunnels can be detected. That is, now scientists know what exactly they need to look for.

Although, on the other hand, if the model of the Klayhouse group is true, the value of wormholes for humanity is sharply reduced. After all, they do not provide a one-time transition to other worlds. Although, of course, their properties should still be studied - all of a sudden they will come in handy for something else ...