In science fiction wormholes, or wormholes, are a method often used to travel very long distances in space. Could these magical bridges really exist?
As enthusiastic as I am about humanity's future in space, there is one glaring problem. We are soft meat sacs, consisting mainly of water, and those others are so far from us. Even with the most optimistic spaceflight technologies, we can imagine that we will never reach another star in a time equal to the duration of a human life.
Reality tells us that even the stars closest to us are incomprehensibly distant, and it would take an enormous amount of energy or time to make the journey. Reality tells us that we need a spaceship that can somehow fly for hundreds or thousands of years while astronauts are born on it, generation after generation, live their lives and die on the flight to another star.
Science fiction, on the other hand, leads us to methods for building improved engines. Fire up the warp drive and watch the stars flash past, making the journey to Alpha Centauri as fast and enjoyable as cruising on a ship somewhere at sea.
Still from the movie "Interstellar".
Do you know what's even simpler? Worm-hole; a magical tunnel connecting two points of space and time. Just set your destination, wait for the stargate to stabilize and just fly... fly halfway across the galaxy to your destination.
Yes, it's really cool! Someone should have invented these wormholes, ushering in a brave new future of intergalactic travel. What are wormholes, and how soon can I use them? You ask...
A wormhole, also known as an Einstein-Rosen bridge, is a theoretical method of folding space and time so that you can connect two points in space together. Then you could instantly move from one place to another.
We'll use the classic demo from , where you draw a line between two points on a piece of paper, and then fold the paper and insert a pencil into those two points to shorten the path. This works great on paper, but is it real physics?
Albert Einstein, captured in a 1953 photograph. Photographer: Ruth Orkin.
As Einstein taught us, gravity is not a force that attracts matter like magnetism, it is actually the curvature of space-time. The Moon thinks it is simply following a straight line through space, but in reality it is following a curved path created by the Earth's gravity.
And so, according to physicists Einstein and Nathan Rosen, you could spin a ball of spacetime so dense that two points would be in the same physical location. If you could keep the wormhole stable, you could safely separate the two regions of spacetime so that they were still in the same location, but separated by the distance you liked.
We go down the gravity well on one side of the wormhole, and then appear with lightning speed in another place at a distance of millions and billions of light years. While creating wormholes is theoretically possible, they are practically impossible from what we currently understand.
The first big problem is that wormholes are impassable, according to the General Theory of Relativity. So keep this in mind, the physics that predicts these things prohibits their use as a method of transportation. Which is a pretty serious blow to them.
Artistic illustration of a spaceship moving through a wormhole into a distant galaxy. Credit: NASA
Secondly, even if a wormhole could be created, it would most likely be unstable, closing instantly after creation. If you tried to go to one end of it, you might just fall through.
Third, if they are traversable and it is possible to keep them stable, once any matter tries to pass through them - even photons of light - it would collapse the wormhole.
There is a glimmer of hope, as physicists still haven't figured out how to combine the theories of gravity and quantum mechanics. This means that the Universe itself may know something about wormholes that we do not yet understand. It is possible that they were created naturally as part of when the spacetime of the entire universe was pulled into a singularity.
Astronomers have proposed looking for wormholes in space by looking at how their gravity distorts the light of the stars behind them. None have shown up yet. One possibility is that wormholes look naturally like the virtual particles we know exist. Only they would be incomprehensibly small, on a Planck scale. You will need a smaller spaceship.
One of the most interesting implications of wormholes is that they could also allow you to travel through time. Here's how it works. First, create a wormhole in the laboratory. Then take one end of it, put a spaceship in it and fly at a significant fraction of the speed of light, so that the effect of time dilation takes effect.
For the people on the spaceship, only a few years will pass, while hundreds or even thousands of generations of people will pass on Earth. Assuming you could keep the wormhole stable, open, and traversable, then traveling through it would be very interesting.
If you walked in one direction, you would not only travel the distance between the wormholes, but you would also move forward in time, and on the way back: back in time.
Some physicists such as Leonard Susskind believe that this would not work because it would violate two fundamental principles of physics: the law of conservation of energy and the Heisenberg energy-time uncertainty principle.
Unfortunately, it seems that wormholes will have to remain in the realm of science fiction for the foreseeable future, perhaps forever. Even if it were possible to create a wormhole, you would need to keep it stable, open, and then figure out how to allow matter to pass into it without collapsing. Still, if you could figure this out, you would make space travel very convenient.
Title of the article you read "What are wormholes or wormholes?".
WORMHOLE - 1) astrophysics. The most important concept of modern astrophysics and practical cosmology. A “wormhole” or “wormhole” is a transdimensional passage connecting a black hole and its corresponding white hole.
An astrophysical wormhole pierces the folded space in extra dimensions and allows one to travel along a truly short path between star systems.
Research using the Hubble Space Telescope has shown 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 was shown theoretically (1993) that it was from this central hole that the Solar System arose.
According to modern concepts, the observable part of the Universe is literally all riddled with “wormholes” going “back and forth.” Many prominent astrophysicists believe that travel through “wormholes” is the future of interstellar astronautics. "
We are all accustomed to the fact that we cannot return the past, although sometimes we really want to. For more than a century, science fiction writers have been depicting various kinds of 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 pressing that at the end of the last century, even physicists far from fairy tales began to seriously search for solutions to the equations describing our world that would make it possible to create time machines and overcome any space and time in the blink of an eye.
Science fiction novels describe entire transport networks connecting star systems and historical eras. He stepped into a booth stylized, say, as a telephone booth, and found himself somewhere in the Andromeda nebula or on Earth, but visiting the long-extinct tyrannosaurs.
Characters in such works constantly use time machine null-transportation, portals and similar convenient devices.
However, science fiction fans perceive such travels without much trepidation - you never know what one can imagine, attributing the implementation of an idea to an uncertain future or to the insights of an unknown genius. What is much more surprising is that time machines and tunnels in space are quite seriously, as hypothetically possible, actively discussed 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 (GTR), the four-dimensional space-time in which we live is curved, and the familiar gravity is a manifestation of such curvature.
Matter “bends”, bends the space around itself, and the denser it is, the stronger the curvature.
Numerous alternative theories of gravity, numbering in the hundreds, differ from GTR in detail, but retain the main thing - the idea of the curvature of space-time. And if space is curved, then why shouldn’t it take, for example, the shape of a pipe, short-circuiting regions separated by hundreds of thousands of light years, or, say, eras distant from each other - after all, we are talking not just about space, but about space- time?
Remember, from the Strugatskys (who, by the way, also resorted to zero-transportation): “I don’t see at all why the noble don doesn’t...” - well, let’s say, not fly to the 32nd century?...
Wormholes or black holes?
Thoughts about such a strong curvature of our space-time arose immediately after the appearance 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 mathematician N. Rosen drew attention to the fact that the simplest solutions of the general relativity equations, which describe isolated, neutral or electrically charged sources of the gravitational field, have a spatial structure of a “bridge”, almost smoothly connecting two universes - two identical, almost flat, space-time.
This kind of spatial structures later received the name “wormholes” (a fairly loose translation of the English word “wormhole”).
Einstein and Rosen even considered the possibility of using such “bridges” to describe elementary particles. In fact, the particle in this case is a purely spatial formation, so there is no need to specially model the source of mass or charge, and with the microscopic dimensions of the wormhole, an external, remote observer located in one of the spaces sees only a point source with a certain mass and charge.
Electrical lines of force enter the hole from one side and exit from the other, without starting or ending anywhere.
In the words of the American physicist J. Wheeler, the result is “mass without mass, charge without charge.” And in this case, it is not at all necessary to assume that the bridge connects two different universes - no worse is the assumption that both “mouths” of the wormhole go out into the same universe, but at different points and at different times - something like a hollow “handle” sewn to the familiar, almost flat world.
One mouth, into which the field lines enter, can be seen as a negative charge (for example, an electron), the other, from which they exit, as a positive charge (positron), and 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 “bridges,” and without them there is nothing to do in the microworld.
For known values of the 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 curved, loses its meaning at such points, since it is impossible to solve equations with infinite terms. General relativity itself quite clearly states where exactly it stops working. Let us remember the words said above: “connecting in an almost smooth way...”. This “almost” refers to the main flaw of the Einstein-Rosen “bridges” - a violation of smoothness in the narrowest place of the “bridge”, at the neck.
And this violation, it must be said, is very non-trivial: at such a neck, from the point of view of a remote observer, time stops...
According to modern concepts, what Einstein and Rosen considered to be the neck (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, from different sides of the “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 crossing which it is impossible to pass through the hole.
For a remote observer, a spaceship approaching the horizon of a sufficiently large (compared to the ship) black hole seems to freeze forever, and signals from it arrive less and less often. On the contrary, according to the ship's clock, the horizon is reached in a finite time.
Having passed the horizon, the ship (particle or ray of light) soon inevitably runs into a singularity - where the curvature becomes infinite and where (still on the way) any extended body will inevitably be crushed and torn apart.
This is the harsh reality of the inner workings of a black hole. The solutions of Schwarzschild and Reisner-Nordström, 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 the black holes themselves, and are just as eternal. But for a traveler who dares to penetrate beyond the horizon, the hole collapses so quickly that neither a ship, nor a massive particle, nor even a ray of light can fly through it.
In order to bypass the singularity and 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, a Schwarzschild black hole can be thought of as an impenetrable wormhole. The Reisner-Nordström black hole is more complex, but also impassable.
However, it is not so difficult to invent and describe traversable four-dimensional wormholes by selecting the desired type of metric (a metric, or metric tensor, is a set of quantities with the help of which four-dimensional distances-intervals between point-events are calculated, which fully characterizes the geometry of space-time, and gravitational field). Passable wormholes, in general, are 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, move at different rates - but it should not endlessly speed up or stop.
It must be said that various black holes and wormholes are very interesting micro-objects that arise by themselves, like quantum fluctuations of the gravitational field (at lengths of the order of 10-33 cm), where, according to existing estimates, the concept of classical, smooth space-time is no longer applicable.
At such a scale, 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 intertwined configurations appearing and disappearing at a frantic pace. Their sizes are unimaginably small - they are as many times smaller than the atomic nucleus as this nucleus is smaller than the planet Earth. There is no strict description of space-time foam yet, since a consistent quantum theory of gravity has not yet been created, but in general terms the picture described 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” for a reasonable-sized spaceship or at least a tank to pass through the neck without damage (without it, it would be uncomfortable among the tyrannosaurs, wouldn’t it?).
Therefore, first we need to obtain solutions to the gravity equations in the form of traversable wormholes of macroscopic dimensions. And if we assume that such a hole has already appeared, and the rest of space-time remains almost flat, then, consider, everything is there - the hole can be a time machine, and an intergalactic tunnel, and even an accelerator.
Regardless of where and when one of the mouths of a wormhole is located, the second can appear anywhere in space and at any time - in the past or in the future.
In addition, the mouth can move at any speed (within light speed) in relation to the surrounding bodies - this will not interfere with the exit from the hole into the (almost) 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 what speeds they move.
But, on the other hand, having assumed the existence of a time machine, we are immediately faced with a 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 dictates that this, most likely, simply cannot happen. 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 make their formation extremely difficult.
GTR, without a doubt, claims to describe reality. It found many solutions that describe spaces with closed time loops, but they, as a rule, for one reason or another are considered either unrealistic or, so to speak, “harmless.”
Thus, a very interesting solution to Einstein’s equations was indicated by the Austrian mathematician K. Gödel: 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, calculations show that the minimum time extent of such a loop is much greater than the existence of the Universe.
Passable wormholes, considered as "bridges" between different universes, are temporary (as we have already said) to assume that both mouths open into the same universe, as loops arise immediately. What then, from the point of view of general relativity, prevents their formation - at least on a macroscopic and cosmic scale?
The answer is simple: the structure of Einstein's equations. On their left side there are quantities that characterize space-time geometry, and on the right side there is 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 movement.
One can "read" Einstein's equations from right to left, saying that with their help matter "tells" space how to bend. But it is also possible - from left to right, then the interpretation will be different: geometry dictates the properties of matter that could provide it, geometry, with existence.
So, if we need the geometry of a wormhole, let’s substitute it into Einstein’s equations, analyze it and find out what kind of matter is required. It turns out that it is very strange and unprecedented; it is called “exotic matter”. Thus, to create the simplest wormhole (spherically symmetrical), it is necessary that the energy density and pressure in the radial direction add up to a negative value. Need I say that for ordinary types of matter (as well as many known physical fields) both of these quantities are positive?..
Nature, as we see, has indeed put a serious barrier to the emergence of wormholes. But that’s just how humans are, and scientists are no exception: if a barrier exists, there will always be people who want to overcome it...
The work of theorists interested in wormholes can be divided into two complementary directions. The first, presupposing the existence of wormholes, considers the resulting consequences, 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 we 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?
American physicist Kip Thorne and his colleagues 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), accelerate to speed comparable to the speed of light, and then return back and slow down next to “A”. Then, due to the STR effect (time slowdown on a moving body compared to a stationary body), less time will pass for the mouth “B” than for the mouth “A”. Moreover, the greater the speed and duration of travel of the mouth of “B”, the greater the time difference between them.
This is, in fact, the same “twin paradox”, well known to scientists: a twin who returns from a flight to the stars turns out to be younger than his stay-at-home brother... Let the time difference between the mouths be, for example, six months.
Then, sitting near the mouth of “A” in the middle of winter, we will see through the wormhole a bright picture of the past summer and - in reality, we will return to this summer, passing right through the hole. Then we will again approach funnel “A” (it, as we agreed, is somewhere nearby), dive into the hole again and jump straight into last year’s snow. And so on as many times as you like. Moving in the opposite direction - diving into funnel “B” - let’s jump six months into the future...
Thus, having made 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
The exotic properties of matter that the building material for wormholes must have, as it turns out, can be realized through the so-called vacuum polarization of quantum fields.
This conclusion was recently reached by Russian physicists Arkady Popov and Sergei Sushkov from Kazan (together with David Hochberg from Spain) and Sergei Krasnikov from the Pulkovo Observatory. And in this case, the vacuum is not emptiness at all, but a quantum state with the lowest energy - a field without real particles. Pairs of “virtual” particles constantly appear in it, which again disappear before they could be detected by instruments, 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 they generate (under certain conditions) can reach very decent sizes. By the way, one of S. Krasnikov’s articles has a “frightening” title - “The Threat of Wormholes.” The most interesting thing in this purely theoretical discussion is that real astronomical observations in recent years seem to greatly undermine the position 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, have concluded that our Universe is not just expanding, but is scattering at an ever-increasing speed, that is, with acceleration. Moreover, over time this acceleration even increases. This is evidenced quite confidently by the latest observations carried out on the latest space telescopes. Well, now is the time to remember the connection between matter and geometry in General Relativity: the nature of the expansion of the Universe is tightly 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 acceleration to increase over 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 such 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 increasing). But (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.
It’s tempting to fantasize: sooner or later dark energy will be discovered, scientists and technologists will learn to condense it and build wormholes, and then it won’t be long before “dreams come true” - about time machines and tunnels leading to the stars...
True, the estimate of the density of dark energy in the Universe, which ensures its accelerated expansion, is somewhat discouraging: if dark energy is distributed evenly, the result is a completely insignificant value - 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 creating a time machine can become real, it will not be very, very soon.
Need a donut hole
So far we have been talking about tunnel-shaped wormholes with smooth necks. But GTR also predicts another type of wormhole - 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 four-dimensional space-time, flat far from the field source, exists as if in two copies (or sheets), and the only things common to both of them are a certain thin ring (field source) 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 if you go through it, you will find yourself in a completely different world, although similar to “yours.” And in order to return back, you need to go through the ring again (and from any side, not necessarily from the one from which you just left).
The ring itself is singular - the curvature of space-time on it goes to infinity, but all the points inside it are completely normal, and a body moving there does not experience any catastrophic effects.
It is interesting that there are a great many such solutions - both neutral, and with an electric charge, and with rotation, and without it. This, 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 during compression the rotation only accelerates, especially during collapse into a black hole.
So, it turns out that it is rotating black holes that are “direct” candidates for “time machines”? However, black holes that form in star 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 related to the difficulties of moving out from under the event horizon onto a new space-time “sheet”. But this is not worth dwelling on 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: the wormholes could be smooth and composed of exotic matter, or they could arise due to a singularity while remaining traversable.
Space and strings
Thin singular rings resemble other unusual objects predicted by modern physics - cosmic strings, which were formed (according to some theories) in the early Universe when superdense matter cooled and changed its states.
They really resemble strings, only unusually 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 at high speeds, it is possible to create structures containing temporary loops. That is, by moving in a certain way in the gravitational field of these strings, you can return to the starting point before you left it.
Astronomers have been looking for this kind of space objects for a long time, and today there is already one “good” candidate - the object CSL-1. These are two surprisingly similar galaxies, which in reality are probably one, only bifurcated due to the effect of gravitational lensing. Moreover, in this case, the gravitational lens is 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 a “brane world” has gained popularity. 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 except the gravitational field. The gravitational field on the brane itself (and this is the only one we observe) obeys the modified Einstein equations, and they contain a contribution from the geometry of the surrounding volume.
So, this contribution can play the role of exotic matter that generates wormholes. Burrows can be of any size and at the same time do not have their own gravity.
This, of course, does not exhaust all the variety of “designs” of wormholes, and the general conclusion is that despite all the unusualness of their properties and despite all the difficulties of a fundamental, including philosophical, nature to which they can lead, their possible existence is worth be treated with complete seriousness and due attention.
For example, it cannot be ruled out that large holes exist in interstellar or intergalactic space, if only because of the concentration of that very dark energy that accelerates the expansion of the Universe.
There is no clear answer to the questions - what they might look like to an earthly observer and whether there is a way to detect them. Unlike black holes, wormholes may not even have any noticeable attractive field (repulsion is also possible), and therefore, one should not expect noticeable concentrations of stars or interstellar gas and dust in their vicinity.
But assuming that they can “short-circuit” regions or epochs far from each other, passing the radiation of 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 further away the galaxy is, the greater the spectrum shift (towards the red) its radiation comes to us. But when looking through a wormhole, there may not be a redshift. Or it will be, but something else. Some such objects can be observed simultaneously in two ways - through the hole or in the “usual” way, “past the hole”.
Thus, a sign of a cosmic wormhole could be the following: the observation of two objects with very similar properties, but at different apparent distances and at different redshifts.
If wormholes are nevertheless discovered (or built), the area of philosophy that deals with the interpretation of science will face new and, it must be said, very difficult tasks. And for all the seeming absurdity of time loops and the complexity of the problems associated with causality, this field of science, in all likelihood, will somehow sort it all out sooner or later. Just as I once “coped” with the conceptual problems of quantum mechanics and Einstein’s theory of relativity...
Kirill Bronnikov, Doctor of Physical and Mathematical Sciences
A group of physicists from Germany and Greece under the general leadership of Burkhard Clayhaus presented a fundamentally new look at the problem wormholes. That's what they're called hypothetical objects where the curvature of space and time occurs.
They are believed to be tunnels through which one can travel to other worlds in one moment.
Wormholes, or wormholes, as they are also called, are known to every science fiction fan, 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 in a very short time. As for real wormholes, the situation with them is much more complicated. It is still unclear whether they actually exist, or whether this is all the result of the wild imagination of theoretical physicists.
According to traditional views, 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 time certain tunnels can appear in our Universe through which you can get from one point in space to another almost instantly (that is, without losing time).
It would seem that you can teleport with their help to your heart's content! But here’s the problem: 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 what could be inside such a tunnel (although, alas, it is also only theoretical). It is believed that everything there is filled with 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, inside the tunnel everything is completely different from normal people. But it is precisely this irregular matter that provides that very miraculous transition through the wormhole.
As a matter of 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 prohibited is, as we know, permitted. Therefore, many astrophysicists, since the middle of the last century, have been actively trying to find traces of at least some more or less stable wormhole.
Strictly speaking, 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 a very simple matter (of course, provided that the wormhole is located not far from the solar system). However, the search for this object is complicated by the fact that scientists still, strictly speaking, do not quite understand what exactly to look for. In fact, it is impossible to directly see this hole, since it, like black holes, sucks everything into itself (including radiation), but does not release anything. We need some indirect signs of its existence, but the question is - what exactly?
And recently, a group of physicists from Germany and Greece, under the general leadership of Burkhard Clayhaus 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 really exist in the Universe and be quite stable. And, according to Clayhouse’s group, there is no exotic matter inside them.
Scientists believe that the emergence of wormholes was caused by quantum fluctuations that were characteristic of 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 is a kind of conditional concept that can be used as a qualitative description of subatomic space-time turbulence at very short distances (on the order of the Planck length, that is, a distance of 10 -33 cm).
Figuratively speaking, quantum foam can be imagined as follows: imagine that somewhere in very short periods of time, in very small regions of space, energy sufficient to transform this piece of space into a black hole can spontaneously appear. And this energy appears not just out of nowhere, but as a result of the collision of particles with antiparticles and their mutual annihilation. And then a kind of seething cauldron will appear before our eyes, in which black holes continuously appear and immediately disappear.
So, according to the authors of the study, Immediately after the Big Bang, our Universe consisted entirely of quantum foam.. And they arose in her at every moment of time not only black holes, but also wormholes. And then the inflation (that is, expansion) of the Universe should not only inflate it to enormous sizes, but also at the same time sharply increase the holes and make them stable. So much so that it became possible for even fairly large bodies to penetrate them.
However, there is one catch here. The fact is that although large bodies, according to this model, can enter a wormhole, the gravitational influence on them upon entry should be very small. Otherwise they will simply be torn into pieces. But if the curvature of space-time at the entrance is “smooth,” then the journey through it itself cannot be instantaneous. It, according to the researchers’ calculations, will take tens or even hundreds of light years, since the exit from the wormhole, accessible to a large body, will be very far from the entrance.
Researchers believe that detecting these objects in the Universe, although not easy, is still possible. Even though they may be similar to black holes, there are still differences. For example, in a black hole, gas that falls beyond the event horizon immediately stops emitting X-rays, while gas that falls into a wormhole (which does not have an event horizon) continues to do so. By the way, similar behavior of 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 may be a stable wormhole.
According to the Clayhouse group's concept, there may be other signs indicating the existence of wormholes. Theoretically, one can imagine a situation where astronomers will directly note the inadequacy of the picture behind the wormhole if the telescope accidentally turns 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 should actually be in this place. The star's gravity (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 purely theoretical, is very important for astronomers. For the first time, she systematizes all the possible signs of wormholes that can be observed. This means that, 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 Clayhouse group's model is true, the value of wormholes for humanity is sharply reduced. After all, they do not provide an immediate transition to other worlds. Although, of course, you should still study their properties in case they are useful for something else...
21:11 09/11/2018👁 1 719
This text represents the third version of my book about wormholes and. I tried to make it understandable for the widest possible range of readers. Understanding the material does not require special education from the reader; the most general ideas from a high school course and cognitive curiosity will be quite enough. The text does not contain formulas and does not contain complex concepts. To make things easier to understand, I have tried to use explanatory illustrations where possible. This version has been supplemented with new sections and illustrations. Corrections, clarifications and clarifications were also made to the text. If any section of the book seems boring or incomprehensible to the reader, then it can be skipped while reading without much damage to understanding.
What is commonly called a “Wormhole” in astrophysics
In recent years, many reports have appeared in the media about the discovery by scientists of certain hypothetical objects called “wormholes.” Moreover, there are even ridiculous reports of observational detection of such objects. I even read in the tabloids about the practical use of certain “wormholes”. Unfortunately, most of these reports are very far from the truth; moreover, even the concept of such “wormholes” often has nothing in common with what is commonly called “wormholes” in astrophysics.
All this prompted me to write a popular (and at the same time reliable) presentation of the theory of “wormholes” in astrophysics. But first things first.
First a little history:
The science-based theory of wormholes originated in astrophysics back in 1935 with the pioneering work of Einstein and Rosen. But in that pioneering work, the “wormhole” was called by the authors a “bridge” between different parts of the Universe (the English term is “bridge”). For a long time, this work did not arouse much interest among astrophysicists.
But in the 90s of the last century, interest in such objects began to return. First of all, the return of interest was associated with a discovery in cosmology, but I will tell you why and what the connection is a little later.
The English-language term that has taken root for “wormholes” since the 90s has become “wormhole,” but the first to propose this term back in 1957 were American astrophysicists Mizner and Wheeler (this is the same Wheeler who is considered the “father” of American hydrogen bombs). “wormhole” is translated into Russian as “worm hole.” Many Russian-speaking astrophysicists did not like this term, and in 2004 it was decided to hold a vote on various proposed terms for such objects. Among the suggested terms were: “wormhole”, “wormhole”, “wormhole”, “bridge”, “wormhole”, “tunnel”, etc. Russian-speaking astrophysicists who have scientific publications on this topic (including me) took part in the voting. As a result of this vote, the term “wormhole” won, and henceforth I will write this term without quotes.
1. So what is commonly called a wormhole?
In astrophysics, wormholes have a clear mathematical definition, but here (due to its complexity) I will not give it, and for the unprepared reader I will try to give the definition in simple words.
You can give different definitions to wormholes, but what is common to all definitions is the property that a wormhole must connect two non-curved regions of space. The junction is called a wormhole, and its central section is called the neck of the wormhole. The space near the neck of the wormhole is quite strongly curved. The concepts of “uncurved” or “curved” require detailed explanation here. But I will not explain this now, and I ask the reader to be patient until the next section, in which I will explain the essence of these concepts.
A wormhole can connect either two different universes, or the same universe in different parts. In the latter case, the distance through the wormhole (between its entrances) may be shorter than the distance between the entrances measured from the outside (although this is not at all necessary).
Further, I will use the word “universe” (with a small letter) to refer to the part of space-time that is limited by the entrances to wormholes and black holes, and the word “Universe” (with a capital letter) will mean all space-time, not anything limited.
Strictly speaking, the concepts of time and distance in curved space-time cease to be absolute values, i.e. as we subconsciously have always been accustomed to consider them. But I give these concepts a completely physical meaning: we are talking about proper time, measured by an observer who moves freely (without rocket or any other engines) almost at the speed of light (theorists usually call him an ultra-relativistic observer).
Obviously, it is practically impossible to create such an observer technically, but acting in the spirit of Einstein, we can imagine a thought experiment in which the observer saddles a photon (or other ultra-relativistic particle) and moves on it along the shortest trajectory (like Baron Munchausen on a nucleus).
Here it is worth recalling that the photon moves along the shortest path by definition; such a path is called the zero geodesic line in the general theory of relativity. In ordinary uncurved space, two points can be connected by only one zero geodesic line. In the case of a wormhole connecting entrances in the same universe, there can be at least two such paths for a photon (and both are shortest, but unequal), and one of these paths passes through the wormhole, and the other does not.
Well, it seems like I gave a simplified definition for a wormhole in simple human words (without using mathematics). However, it is worth mentioning that wormholes through which light and other matter can pass in both directions are called traversable wormholes (from now on I will simply call them wormholes). Based on the word “passable,” the question arises: are there impassable wormholes? Yes, I have. These are objects that externally (at each of the inputs) are like a black hole, but inside such a black hole there is no singularity (in physics, a singularity is an infinite density of matter that tears apart and destroys any other matter falling into it). Moreover, the property of singularity is mandatory for ordinary black holes. And the black hole itself is determined by the presence of a surface (sphere), from under which even light cannot escape. This surface is called the black hole horizon (or event horizon).
Thus, matter can get inside an impenetrable wormhole, but cannot leave it (very similar to the property of a black hole). Moreover, there may also be semi-passable wormholes, in which matter or light can only pass through the wormhole in one direction, but cannot pass in the other.
2. Curvature tunnel? Curvature of what?
At first glance, creating a wormhole tunnel from a curved space seems quite attractive. But when you think about it, you begin to come to absurd conclusions.
If you are in this tunnel, what walls can prevent you from escaping from it in the transverse direction?
And what are these walls made of?
Can empty space really prevent us from passing through them?
Or is it not empty?
In order to understand this (I don’t even suggest imagining it), let’s consider space that is not curved by gravity. Let the reader consider that this is an ordinary space with which he is always accustomed to deal and in which he lives. In what follows I will call such a space flat.
Figure 1. (original drawing by the author)
Schematic representation of the curvature of two-dimensional space. The numbers indicate successive stages of transition: from the stage of uncurved space (1) to the stage of a two-dimensional wormhole (7).
Let's take as a beginning some point “O” in this space and draw a circle around it - see figure No. 1 in Figure 1. Let both this point and this circle lie on some plane in our flat space. As we all know very well from the school mathematics course, the ratio of the length of this circle to the radius is equal to 2π, where the number π = 3.1415926535.... Moreover: the ratio of the change in the circumference to the corresponding change in the radius will also be equal to 2π (hereinafter, for brevity, we will just say ATTITUDE).
Now let’s place some body with mass M at our point “O”. If we believe Einstein’s theory and experiments (which were repeatedly carried out both on Earth and in the solar system), then space-time around the body will be curved and the above-mentioned RATIO will be less than 2π. Moreover, the larger the mass M, the smaller it is – see figures No. 2 – 4 in Figure 1. This is the curvature of space! But not only space is curved, time is also curved, and it is more correct to say that all space-time is curved, because in the theory of relativity, one cannot exist without the other - there is no clear boundary between them.
In what direction is it bent? - you ask.
Down (under the plane) or vice versa - up?
The correct answer is that the curvature will be the same for any plane drawn through the point “O”, and the direction has nothing to do with it. The very geometric property of space changes so that the ratio of the circumference to the radius also changes! Some scientists believe that the curvature of space occurs in the direction of a new (fourth) dimension. But the theory of relativity itself does not need an additional dimension; three spatial and one time dimensions are enough for it. Usually the time dimension is assigned an index of zero, and space-time is designated as 3+1.
How severe will this curvature be?
For a circle that is our equator, the relative decrease in RATIO will be 10-9, i.e. for the Earth (length of the equator)/(radius of the Earth) ≈ 2π (1 – 10-9)!!! This is such an insignificant addition. But for a circle that is the equator, this decrease is already about 10-5, and although this is also very small, modern instruments easily measure this value.
But there are more exotic objects in space than just planets and stars. For example, pulsars, which are neutron stars (composed of neutrons). The gravity on the surface of pulsars is monstrous, and their average matter density is about 1014 g/cm3 - incredibly heavy matter! For pulsars, the decrease in this RATIO is already about 0.1!
But for black holes and wormholes the decrease in this RATIO reaches unity, i.e. the ATTITUDE itself reaches zero! This means that when moving towards the center, the circumference does not change near the horizon or neck. The area of the sphere around black holes or wormholes also does not change. Strictly speaking, for such objects the usual definition of length is no longer suitable, but this does not change the essence. Moreover, for a spherically symmetrical wormhole the situation does not depend on the direction from which we move towards the center.
How can you imagine this?
If we consider a wormhole, this means that we have reached a sphere of minimum area Smin=4π rmin2 with throat radius rmin. This sphere of minimal area is called the neck of the wormhole. With further movement in the same direction, we find that the area of the sphere begins to increase - this means that we have passed the neck, moved into another space and are moving away from the center.
What happens if the dimensions of the falling body exceed the dimensions of the neck?
To answer this question, let's turn to a two-dimensional analogy - see Figure 2.
Suppose that the body is a two-dimensional figure (a certain design cut out of paper or other material), and this design slides along a surface that is a funnel (like the one we have in a bathtub when water flows into it). Moreover, our drawing slides in the direction of the neck of the funnel so that it is pressed against the surface of the funnel with its entire surface. It is obvious that as the design approaches the neck, the curvature of the surface of the funnel increases, and the surface of the design begins to deform in accordance with the shape of the funnel at a given place in the design. Our drawing (even though it is paper), just like any physical body, has elastic properties that prevent its deformation.
At the same time, the material of the design has a physical effect on the material from which the funnel is made. We can say that both the funnel and the drawing exert elastic forces on each other.
1. The drawing is deformed so much that it will slip through the funnel, and in this case it may collapse (tear).
2. The pattern and the funnel are not deformed enough for the pattern to slip through (for this, the pattern needs to be large enough and strong enough). Then the drawing will get stuck in the funnel and block its neck for other bodies.
3. The drawing (more precisely, the material of the drawing) will destroy (tear) the material of the funnel, i.e. such a two-dimensional wormhole will be destroyed.
4. The drawing will slip past the neck of the funnel (possibly touching it with its edge). But this will only happen if you haven’t focused your design accurately enough on the direction of the neckline.
The same four options are also possible for the fall of three-dimensional physical bodies into three-dimensional wormholes. This is how illusory, using toy models as an example, I tried to describe a wormhole in the form of a tunnel without walls.
In the case of a three-dimensional wormhole (in our space), the elastic forces of the funnel material, discussed in the previous section, are replaced by gravitational tidal forces - these are the same forces that cause ebbs and flows on Earth under the influence of and.
In wormholes and black holes, tidal forces can reach monstrous levels. They are capable of tearing apart and destroying any objects or matter, and near the singularity these forces generally become infinite! However, we can assume a wormhole model in which tidal forces are limited and, thus, it is possible for our robot (or even a human) to pass through such a wormhole without harming it.
Tidal forces, according to Kip Thorne's classification, are of three types:
1. Tidal tension-compression forces
2. Tidal forces of shear deformation
3. Tidal forces of torsional deformation
Figure 3. (figure taken from the report of Kip Thorne, Nobel laureate in physics 2017) On the left is an illustration of the action of tidal tension-compression forces. On the right is an illustration of the action of tidal torsion-shear forces.
Although the last 2 types can be reduced to one - see Figure 3.
4.Einstein's general theory of relativity
In this section, I will talk about wormholes within the framework of the general theory of relativity created by Einstein. I will discuss the differences from wormholes in other theories of gravity in a subsequent section.
Why did I start my consideration with Einstein’s theory?
To date, Einstein's theory of relativity is the simplest and most beautiful of the unrefuted theories of gravity: not a single experiment to date has disproved it. The results of all experiments are in perfect agreement with it for 100 years!!! At the same time, the theory of relativity is mathematically very complex.
Why such a complex theory?
Because all other consistent theories turn out to be even more complicated...
Figure 4. (figure taken from A.D. Linde’s book “Inflationary Cosmology”)
On the left is a model of a chaotic inflationary multi-element Universe without wormholes, on the right is the same, but with wormholes.
Today, the “chaotic inflation” model is the basis of modern cosmology. This model works within the framework of Einstein’s theory and assumes the existence (besides ours) of an infinite number of other universes that arise after the “big bang,” forming during the “explosion” the so-called “space-time foam.” The first moments during and after this “explosion” are the basis of the “chaotic inflation” model.
At these moments, primary space-time tunnels (relict wormholes) may appear, which probably persist after inflation. Further, these relict wormholes connect various regions of our and other universes - see Figure 4. This model was proposed by our compatriot Andrei Linde, who is now a professor at Stanford University. This model opens up a unique opportunity to study the multi-element Universe and discover a new type of objects - entrances to wormholes.
What conditions are necessary for the existence of wormholes?
A study of wormhole models shows that exotic matter is required for their stable existence within the framework of the theory of relativity. Sometimes such matter is also called phantom matter.
Why is such matter needed?
As I wrote above, strong gravity is needed for the existence of curved space. In Einstein's theory of relativity, gravity and curved space-time exist inextricably from each other. Without enough concentrated matter, curved space straightens and the energy of this process is radiated to infinity in the form of gravitational waves.
But strong gravity alone is not enough for the stable existence of a wormhole - this way you can only get a black hole and (as a consequence) an event horizon.
In order to prevent the formation of a black hole's event horizon, phantom matter is needed. Usually, exotic or phantom matter means a violation of energy conditions by such matter. This is already a mathematical concept, but don’t be alarmed - I will describe it without mathematics. As you know from a school physics course, every physical solid body has elastic forces that resist the deformation of this body (I wrote about this in the previous section). In the more general case of arbitrary matter (liquid, gas, etc.) we speak about the intrinsic pressure of matter, or more precisely about the dependence of this pressure on the density of matter.
Physicists call this relationship the equation of state of matter.
So, in order for the energy conditions of matter to be violated, it is necessary that the sum of pressure and energy density be negative (energy density is mass density multiplied by the speed of light squared).
What does it mean?
Well, firstly, if we consider positive mass, then the pressure of such phantom matter must be negative. And secondly, the pressure of phantom matter in modulus should be large enough to give a negative value when added to the energy density.
There is an even more exotic version of phantom matter: when we immediately consider negative mass density and then pressure does not play a fundamental role, but more on that later.
And even more surprising is the fact that in the theory of relativity the density of matter (energy) depends on the frame of reference in which we consider them. For phantom matter, this leads to the fact that there is always a reference frame (moving relative to the laboratory frame almost at the speed of light) in which the density of phantom matter becomes negative. For this reason, there is no fundamental difference for phantom matter: whether its density is positive or negative.
Does such matter even exist?
And now it’s time to remember the discovery of dark energy in cosmology (do not confuse it with the concept of “dark matter” - this is a completely different substance). Dark energy was discovered in the 90s of the last century, and it was needed to explain the observed accelerated expansion of the universe. Yes, yes - the universe is not just expanding, but expanding with acceleration.
7. How wormholes could have formed in the Universe
All metric theories of gravity (and Einstein's theory among them) affirm the principle of topology conservation. This means that if a wormhole has one topology, then over time it will not be able to have another. This also means that if a space does not have the topology of a torus, then objects with the topology of a torus will not be able to appear in the same space.
Therefore, ringholes (wormholes with a torus topology) cannot appear in an expanding Universe and cannot disappear! Those. if during the “big bang” the topology was disrupted (the process of the “big bang” may not be described by a metric theory - for example, Einstein’s theory), then in the first moments of the explosion, in the “space-time foam” (I wrote about it above - ringholes, which can then turn into impassable wormholes with the same torus topology, but they will no longer be able to disappear completely - that’s why they are called relict wormholes.
But wormholes with the topology of a sphere in Einstein’s theory can appear and disappear (though in strictly topological language this will not be the same topology of a sphere as for wormholes connecting different universes, but I won’t go deeper into these mathematical jungles here) . I can again illustrate how the formation of wormholes with the topology of a sphere can occur using the example of a two-dimensional analogy - see figures No. 5 - 7 in Figure 1. Such two-dimensional wormholes can “inflate” like a child’s rubber ball at any point in a flat rubber “universe.” . Moreover, in the process of such “inflation” the topology is not violated anywhere - there are no breaks anywhere. In three-dimensional space (three-dimensional sphere), everything happens by analogy - just as I described above.
8. Is it possible to make a time machine from a wormhole?
Among literary works you can find many different novels about a time machine. Unfortunately, most of them are myths that have nothing to do with what is commonly called the TIME MACHINE in physics. So in physics, a time machine is usually called the closed world lines of material bodies. By world line we mean the trajectory of a body drawn not in space, but in space-time!
Moreover, the length of these lines must have macroscopic dimensions. The last requirement is due to the fact that in quantum physics (in the microworld) closed world lines of particles are commonplace. But the quantum world is a completely different matter. In it, for example, there is a quantum tunneling effect, which allows a microparticle to pass through a potential barrier (through an opaque wall). Remember the hero Ivanushka (played by Alexander Abdulov) in the movie Sorcerers, where he walked through the wall? A fairy tale, of course, but from a purely scientific point of view, a large macroscopic body also has the possibility of passing through a wall (quantum tunneling).
But if we calculate this probability, it turns out to be so small that the required number of attempts (which is equal to one divided by this tiny probability) required for successful quantum tunneling is almost infinity. More specifically, the number of such attempts should exceed the number of all elementary particles in the Universe!
This is roughly the same situation with the attempt to create a time machine from a quantum loop - almost unbelievable.
But we will still return to the issue of creating a time machine using a wormhole. For this (as I already said) we need closed world lines. Such lines, by the way, exist inside rotating black holes. By the way, they exist in some models of the rotating Universe (Godel’s solution).
But in order for such lines to appear inside wormholes, two conditions must be met:
Firstly, the wormhole must be a ringhole, i.e. connect different areas of the same universe.
And secondly, this wormhole must rotate quickly enough (in the right direction).
The phrase “fast enough” here means that the speed of matter moving in it should be close to the speed of light.
That's all? – you ask, will we be able to travel to the past and back? Physicists today cannot answer this question mathematically correctly. The fact is that the mathematical model that needs to be calculated is so complex that it is simply impossible to construct an analytical solution. Moreover: today there is not a single analytical solution for ringholes - there are only approximate numerical calculations made on computers.
My personal opinion is that even if it is possible to obtain a closed world line, it will be destroyed by matter (which will move along this loop) even before the loop is closed. Those. a time machine is impossible, otherwise we could go back in time and, for example, kill our grandmother there even before her children were born - an obvious contradiction in logic. Those. It is possible to obtain only time loops that cannot influence our past. For the same logical reason, we will not be able to look into the future while remaining in the present. We can only be transported entirely into the future, and it will be impossible to return from it if we have already entered it. Otherwise, the cause-and-effect relationship between events will be broken (and in my opinion this is impossible).
9. Wormholes and perpetual motion
Actually, wormholes themselves have no direct relation to perpetual motion, but with the help of phantom matter (which is necessary for the stationary existence of a wormhole), in principle, it is possible to create a so-called perpetual motion machine of the third kind.
Let me remind you of one of the amazing properties of phantom matter (see above): there is always a reference frame (moving relative to the laboratory frame almost at the speed of light) in which the density of phantom matter becomes negative. Let's imagine a body with negative mass (made of phantom matter). According to the law of universal gravitation, this body will be attracted to an ordinary body with positive mass. On the other hand, an ordinary body will have to repel from a body with negative mass. If the absolute masses of these bodies are the same, then the bodies will “chase” each other to infinity.
The principle of operation of a perpetual motion machine of the third kind is based (purely theoretically) on this effect. However, the possibility of extracting energy (for the needs of the national economy) from this principle has not been rigorously proven to date either mathematically or physically (although such attempts have been made several times).
Moreover, scientists did not and do not believe in the possibility of creating a perpetual motion machine, and this is the main argument against the existence of phantom matter and against wormholes... Personally, I also do not believe in the possibility of creating a perpetual motion machine, but I admit the possibility of the existence of certain types of phantom matter in nature.
10. The connection between wormholes and black holes
As I wrote above, the first relic wormholes that could have formed in the Universe after the “big bang” could ultimately turn out to be impassable. Those. passage through them is impossible. In mathematical terms, this means that a “trapping horizon” appears at the wormhole, sometimes also called a space-like visibility horizon. Even light cannot escape from under the trapped horizon, and even less so can other matter.
You may ask: “What, horizons are different?” Yes, there are several types of horizons in theories of gravity, and when they say that a black hole has a horizon, they usually mean an event horizon.
I will say more: a wormhole must also have a horizon, this horizon is called the visibility horizon, and there are also several types of such horizons. But I won't go into that here.
Thus, if a wormhole is impassable, then outwardly it is almost impossible to distinguish it from a black hole. The only sign of such a wormhole can only be a monopole magnetic field (although the wormhole may not have it at all).
The phrase “exclusive field” means that the field comes straight out of the wormhole in one direction, i.e. the field either comes out of the wormhole on all sides (like the needles of a hedgehog), or enters it from all sides - see Figure 6.
The existence of a monopole magnetic field in a black hole is prohibited by the so-called theorem “On the absence of hair in a black hole.”
For an electric monopole field, this property usually means that there is an electric charge inside the surface under which the field enters (or leaves). But magnetic charges have not been found in nature, so if a field enters a wormhole at one of the inputs, then it must leave it at the other entrance of the wormhole (or vice versa). Thus, it is possible to implement an interesting concept in theoretical physics, this concept is called “charge without charge”.
This means that a magnetic wormhole at each of its inputs will look like a magnetic charge, but the charges of the inputs are opposite (+ and -) and therefore the total charge of the wormhole inputs is zero. In fact, there shouldn't be any magnetic charges, it's just that the external magnetic field behaves as if there are - see Figure 6.
Passable wormholes have their own characteristic features that can be used to distinguish them from black holes, and I will write about this in the next section.
If a wormhole is impassable, then using phantom matter it can be made passable. Namely, if we “water” an impassable wormhole with phantom matter from one of its entrances, then it will become passable from the opposite entrance, and vice versa. True, the question arises and remains: how can a traveler (who wants to go through an impassable wormhole) inform his assistant at the entrance of the wormhole opposite him (closed from him by the horizon) that he (the traveler) is already near his entrance and it’s time to start “watering” ” the opposite entrance with phantom matter, so that the wormhole becomes semi-passable in the direction desired by the traveler.
Thus, in order for an impassable wormhole to become completely passable, it must be “watered” with phantom matter from both of its entrances simultaneously. Moreover, there must be a sufficient amount of phantom matter; what exactly is a difficult question; the answer to it can only be given by an accurate numerical calculation for a specific model (such models have already been calculated earlier in scientific publications). In astrophysics there was even an expression that phantom matter is so terrible that it even dissolves black holes in itself! To be fair, it should be said that a black hole, having dissolved, does not necessarily form a wormhole.
Ordinary matter in sufficient quantities, on the contrary, “locks” the wormhole, i.e. makes it impassable. Thus, we can say that in this sense, the interconversion of black holes and wormholes is possible.
11.Black and white holes as a type of wormhole
I assume that until now the reader has been under the impression that black holes are objects from which nothing can ever come out (including even light). This is not an entirely true statement.
The fact is that in almost all black holes, the singularity repels matter (and light) when it flies too close to it (already below the horizon of the black hole). The only exception to this phenomenon could be the so-called Schwarzschild black holes, i.e. those that do not rotate and have no electrical charge. But for the formation of such a Schwarzschild black hole, its constituent matter requires such initial conditions, the measure of which is zero on the set of all possible initial conditions!
In other words, when any black hole is formed, it will definitely have rotation (even if very small) and there will definitely be an electric charge (even if it’s elementary), i.e. the black hole will not be Schwarzschild. In what follows I will call such black holes real. Real black holes have their own classification: Kerr (for a rotating black hole), Reisner-Nordström (for a charged black hole) and Kerr-Newman (for a rotating and charged black hole).
What happens to a particle that is repelled by a singularity inside a real black hole?
The particle will no longer be able to fly back - this would contradict the laws of physics in a black hole, because the particle has already fallen under the event horizon. But it turns out that the topology inside black holes turns out to be non-trivial (complex). This leads to the fact that after falling under the horizon of a black hole, all matter, particles, and light are thrown out by the singularity into another universe.
In the universe where all this flies out, there is a white hole - it is from it that matter (particles, light) flies out. But all the miracles don’t end there... The fact is that in the same place in space where there is this white hole (in another universe) there is also a black hole.
Matter that falls into that black hole (in another universe) experiences a similar process and flies out into the next universe. And so on... Moreover, movement from one universe to another is always possible only in one direction: from the past to the future (in space-time). This direction is associated with the cause-and-effect relationship between events in any space-time. By virtue of common sense and logic, scientists assume that the cause-and-effect relationship should never be broken.
The reader may have a logical question: will there necessarily be a white hole in our universe - where there is already a black hole, and from where matter could fly out to us from the previous universe? For experts in the topology of black holes, this is a difficult question and the answer to it is “not always.” But, in principle, such a situation may well exist (when a black hole in our universe is also a white hole from another - previous universe). Unfortunately, we cannot yet answer the question - which situation is more probable (whether a black hole in our universe is at the same time a white hole from the previous universe or not).
So, such objects - black and white holes - also have another name: “dynamic wormholes”. They are called dynamic because they always have a region under the horizon of the black hole (this region is called the T-region) in which it is impossible to create a rigid frame of reference, and in which all particles or matter would be at rest. In the T-region, matter isn't just moving all the time—it's moving at varying speeds all the time.
But between the singularity and the T-region in real black holes there is always still a space with an ordinary region, this region is called the R-region. In particular, space outside a black hole also has the properties of an R-region. So, the repulsion of matter from the singularity occurs precisely in the internal R-region.
Figure 7. (the author took the Carter-Penrose diagram for the Reisner-Nordström black hole as the basis for the figure) The figure on the left schematically depicts a space with a non-trivial (complex) topology of the Reisner-Nordström black-and-white hole (Carter-Penrose diagram). On the right is the passage of a particle through this black-and-white hole: outside the black circle is the outer R-region, between the green and black circles is the T-region, below the green circle is the inner R-region and the singularity.
For these reasons, it is impossible to calculate and construct a single trajectory of a particle crossing a black-and-white hole in both universes at once. For such a construction, it is necessary to divide the desired trajectory into two sections and “sew” these sections together in the internal R-region (only there this can be done) - see Figure 7.
As I've written before, tidal forces can tear matter apart before it reaches another universe. Moreover, inside a black-and-white hole, the maximum tidal forces are achieved at the point of minimum radius (in the inner R-region). The closer a real black hole is in its properties to a Schwarzschild one, the greater these forces will be at their maximum, and the less chance matter has to overcome the black-and-white hole without destruction.
These properties of real black holes are determined by the measure of their spin (this is their angular momentum divided by the square of their mass) and the measure of their charge (this is their charge divided by their mass). Each of these properties (these measures) cannot be greater than one for real black holes. Therefore, the greater any of these measures is to one, the less tidal forces will be in such a black hole at their maximum, and the greater the chances for matter (or a person) to overcome such a black and white hole without destruction. Moreover, no matter how paradoxical it sounds, the heavier the real black hole is, the less tidal forces will be at its maximum!
This happens because tidal forces are not just gravitational forces, but a gradient of gravitational force (i.e., the rate of change of gravitational force). Therefore, the larger the black hole, the slower the gravitational forces change in it (despite the fact that the gravitational forces themselves can be enormous). Therefore, the gravitational gradient (i.e. tidal forces) will be smaller in larger black holes.
For example, for a black hole with a mass of several million solar masses (at the center of our galaxy there is a black hole with a mass of ≈ 4.3 million solar masses), the tidal forces on its horizon are small enough for a person to fly there and, at the same time, nothing I wouldn’t have felt it the moment it passed the horizon. And in the Universe there are also much heavier black holes - with a mass of several billion solar masses (as, for example, in the quasar M87) ... I will explain that quasars are the active (brightly glowing) nuclei of distant galaxies.
Since, as I wrote, matter or light can still fly from one universe to another through a black-and-white hole without destruction, such objects can rightfully be called another type of wormhole without phantom matter. Moreover, the existence of this particular type of dynamic wormholes in the Universe can be considered practically proven!
Original video by the author (from his publication), illustrating the free, radial fall of a dust sphere into a black and white hole (all dust particles on the sphere glow monochrome green). The Cauchy horizon radius of this black-and-white Reissner-Nordström hole is 2 times smaller than the radius of the outer horizon. The observer also falls freely and radially (following this sphere), but from a slightly greater distance.
In this case, initially green photons from dust grains of the sphere reach the observer with a red (and then violet) gravitational shift. If the observer remained motionless relative to the black-and-white hole, then after the sphere crossed the visibility horizon, the red shift of photons for the observer would become infinite and he would no longer be able to observe this dust sphere. But thanks to the free fall of the observer, he can see the sphere all the time (if we do not take into account the strong red shift of photons) - incl. and the moments when the sphere crosses both horizons, and while the observer himself crosses these horizons, and even after the sphere passes through the neck of this dynamic wormhole (black-and-white hole) - and the exit of dust particles into another universe.
Below is a radius scale for the observer (marked with a yellow mark), the point of the dust shell closest to the observer (marked with a green mark), the point of the dust shell that is furthest away from the observer from which photons come to the observer (marked with a thin white mark), as well as the location of the horizon black hole (red mark), Cauchy horizon (blue mark), and throat point (purple mark).
12.Multiverse
The concept of the Multiverse is usually identified with the non-trivial topology of the space surrounding us. Moreover, in contrast to the concept of “multiverse” in quantum physics, they mean sufficiently large spatial scales on which quantum effects can be completely neglected. What is a non-trivial topology? I will explain this with simple examples. Let's imagine two objects molded from plasticine: an ordinary cup with a handle and a saucer for this cup.
Without tearing the plasticine and without gluing the surfaces, but only by plastic deformation of the plasticine, a saucer can be turned into a ball, but it is in no way possible to turn into a cup or a donut. For a cup it’s the other way around: because of its handle, the cup cannot be turned into a saucer or into a ball, but it can be turned into a donut. These common properties of a saucer and a ball correspond to their common topology - the topology of a sphere, and the common properties of a cup and a donut - the topology of a torus.
So, the topology of a sphere (saucer and ball) is considered to be trivial, and the more complex topology of a torus (cup and donut) is considered to be non-trivial, although there are other, even more complex types of non-trivial topology - not only the topology of a torus. The Universe around us consists of at least three spatial (length, width, height) and one time dimensions, and the concepts of topology are obviously transferred to our world.
Thus, if two different universes with the topology of a sphere are connected by only one wormhole (dumbbell), then the resulting universe will also have a trivial topology of a sphere. But if two different parts of one universe are connected to each other by a wormhole (weight), then such a universe will have a non-trivial torus topology.
If two different universes with the topology of a sphere are connected by two or more wormholes, then the resulting universe will have a non-trivial topology. A system of universes connected by several wormholes will also have a nontrivial topology if there is at least one closed line that cannot be pulled together to one point by any smooth deformation.
For all their attractiveness, wormholes have two significant drawbacks: they are unstable and their existence requires the presence of exotic (or phantom) matter. And if their stability can still be realized artificially, then many scientists simply do not believe in the possibility of the existence of phantom matter. Based on the above, it may seem that without wormholes the existence of the Multiverse is impossible. But it turns out that this is not so: the existence of real black holes is quite sufficient for the existence of the Multiverse.
As I already said, inside all black holes there is a singularity - this is an area in which the density of energy and matter reaches infinite values. In almost all black holes, the singularity repels matter (and light) when it gets too close to it (already below the horizon of the black hole).
The only exception to this phenomenon could be the so-called Schwarzschild black holes, that is, those that do not rotate at all and which have no electric charge. A Schwarzschild black hole has a trivial topology. But for the formation of such a Schwarzschild black hole, the matter that forms it requires such initial conditions, the measure of which is zero on the set of all possible initial conditions!
In other words, when any black hole is formed, it will definitely have rotation (even if very small) and there will definitely be an electric charge (even if elementary), that is, the black hole will not be Schwarzschild. I call such black holes real.
A Schwarzschild black hole has a singularity inside a central sphere of infinitesimal area. A real black hole has a singularity on a ring that lies in the equatorial plane under both horizons of the black hole. It is worth adding here that, unlike the Schwarzschild black hole, a real black hole has not one, but two horizons. Moreover, between these horizons the mathematical signs of space and time change places (although this does not mean at all that space and time themselves change places, as some scientists believe).
What will happen to a particle that is repelled by a singularity inside a real black hole (already below its inner horizon)? The particle will no longer be able to fly back: this would contradict the laws of physics and causality in a black hole, since the particle has already fallen under the event horizon. This leads to the fact that after falling under the inner horizon of a real black hole, any matter, particles, light are thrown out by the singularity into another universe.
This is because, unlike Schwarzschild black holes, the topology inside real black holes turns out to be non-trivial. Isn't it amazing? Even a slight rotation of a black hole leads to a radical change in the properties of its topology! In the universe where matter then flies out, there is a white hole - everything flies out of it. But all the miracles do not end there... The fact is that in the same place in space where there is this white hole, in another universe, there is also a black hole. Matter that falls into that black hole in another universe undergoes a similar process and flies out into the next universe, and so on.
Moreover, movement from one universe to another is always possible only in one direction - from the past to the future (in space-time). This direction is associated with the cause-and-effect relationship between events in any space-time. By virtue of common sense and logic, scientists assume that the cause-and-effect relationship should never be broken. Such an object is usually called a black-and-white hole (in this sense, a wormhole could be called a white-white hole). This is the Multiverse, which exists thanks to the existence of real black holes, and the existence of wormholes and phantom matter is not necessary for its existence.
I assume that for most readers it will be difficult to imagine that in the same region of space (within the same sphere having the horizon radius of a black hole) there would be two fundamentally different objects: a black hole and a white hole. But mathematically this can be proven quite strictly.
I invite the reader to imagine a simple model: the entrance (and exit) of a building with a revolving door. This door can only rotate in one direction. Inside the building, the entrance and exit near this door are separated by turnstiles, allowing visitors to pass in only one direction (entry or exit), but outside the building there are no turnstiles. Let's imagine that inside the building these turnstiles divide the entire building into 2 parts: universe No. 1 for exiting the building and universe No. 3 for entering it, and outside the building there is universe No. 2 - the one in which you and I live. Inside the building, the turnstiles also only allow movement in the direction from No. 1 to No. 3. Such a simple model well illustrates the action of a black-and-white hole and explains that outside a building, visitors entering and exiting can collide with each other, but inside a building they cannot because of the unidirectionality of movement (just like particles of matter in the corresponding universes).
In fact, the phenomena that accompany matter during such an ejection into another universe are quite complex processes. The main role in them begins to be played by gravitational tidal forces, which I wrote about above. However, if the matter that gets inside the black hole does not reach the singularity, then the tidal forces acting on it always remain finite and, thus, it turns out to be fundamentally possible for a robot (or even a person) to pass through such a black-and-white hole without harming it. Moreover, the larger and more massive the black hole is, the smaller the tidal forces will be at their maximum...
The reader may have a logical question: will there necessarily be a white hole in our Universe where there is already a black hole, and from where matter from the previous Universe could fly out to us? For experts in black hole topology, this is a difficult question, and the answer is “not always.” But, in principle, such a situation may well exist - when a black hole in our Universe is also a white hole from another, previous universe. Answer the question “Which situation is more likely?” (whether the black hole in our Universe is also a white hole from the previous Universe or not), we, unfortunately, cannot yet.
Of course, today and in the near future it will not be technically possible to send even a robot to a black hole, but some physical effects and phenomena characteristic of wormholes and black-and-white holes have such unique properties that today observational astronomy has come close to detecting them and , as a consequence, the discovery of such objects.
13.What a wormhole should look like through a powerful telescope
As I already wrote, if a wormhole is impassable, then distinguishing it from a black hole will be very difficult. But if it is passable, then through it you can observe objects and stars in another universe.
Figure 9. (original drawing by the author)
The left panel shows a section of the starry sky observed through a circular hole in the same universe (1 million identical, evenly distributed stars). The middle panel shows the starry sky of another universe, viewed through a static wormhole (1 million different images from 210,069 identical and evenly distributed stars in another universe). The right panel shows the starry sky of another universe as seen through a black-and-white hole (1 million different images from 58,892 identical and evenly distributed stars in another universe).
Let's consider the simplest (hypothetical) model of the starry sky: there are quite a lot of identical stars in the sky, and all these stars are evenly distributed across the celestial sphere. Then the picture of this sky, observed through a circular hole in the same universe, will be as shown in the left panel of Figure 9. This left panel shows 1 million identical, evenly spaced stars, so the image appears to be an almost uniform, circular blob.
If we observe the same starry sky (in another universe) through the neck of a wormhole (from our universe), then the picture of the images of these stars will look approximately as shown in
Stills from the movie "Interstellar" with a wormhole (2014)
The space epic “Interstellar” (we are talking about a science fiction film released in October 2014) tells about astronauts who, in search of options for saving humanity, discover the “road of life” represented by a mysterious tunnel.
This passage inexplicably appears near Saturn and in space-time leads a person to a distant galaxy, thereby providing a chance to find planets inhabited by living beings. Planets that can become a second Home for people.
The hypothesis about the existence of a movie tunnel, called a “wormhole” or “wormhole” by scientists, was preceded by a real physical theory, which was proposed by one of the first astrophysicists and a former professor at the California Institute of Technology, Kip Thorne.
Kip Thorne helped astronomer, astrophysicist, popularizer of science and one of those who initiated the project to search for extraterrestrial intelligence - Carl Sagan - to create a model of a wormhole for his novel Contact. The persuasiveness of the visual images in the film for space scientists is so obvious that astrophysicists admit that these are perhaps the most accurate images of wormholes and black holes that exist in world cinema.
There is only one “small” detail in this film that haunts the attentive viewer: flying in something like this on a space express is, of course, great, but will the pilots be able to not give up during this very interstellar movement?
The creators of the space blockbuster chose not to mention that the original theory of wormholes belonged to other leading theorists of astrophysics - Albert Einstein began to develop it together with his assistant Nathan Rosen. These scientists tried to solve Einstein's equations for general relativity so that the result was a mathematical model of the entire Universe, along with the forces of gravity and the elementary particles that form matter. In the process of all this, an attempt was made to imagine space as two geometric planes connected to each other by “bridges”.
In parallel, but independently from Einstein, similar work was carried out by another physicist, Ludwig Flamm, who in 1916, also while solving Einstein’s equations, made his discovery of such “bridges.”
All three “bridge builders” suffered a common disappointment, since the “theory of everything that exists” turned out to be unviable: such “bridges” in theory did not act at all like real elementary particles.
Nevertheless, in 1935, Einstein and Rosen published a paper where they outlined their own theory of tunnels in the space-time continuum. This work, as conceived by the authors, was obviously supposed to encourage other generations of scientists to think about the possibility of applying such a theory.
Physicist from Princeton University John Wheeler at one time introduced the designation “wormhole” into the vocabulary, which was used in the early years to study the construction of models of “bridges” according to the Einstein-Rosen theory. Wheeler noticed: such a “bridge” is painfully reminiscent of a passage gnawed by a worm in a fruit. Let's imagine an ant crawling from one side of a pear to the other - it can either crawl along the entire curved surface, or, taking a shortcut, cross the fruit through a wormhole tunnel.
What if we imagine that our three-dimensional space-time continuum is the skin of a pear, that a curved surface encloses a much larger “mass”? Perhaps the Einstein-Rosen “bridge” is the very tunnel that cuts through this “mass”; it allows starship pilots to reduce the distance in space between two points. Probably, in this case we are talking about a real mathematical solution to the general theory of relativity.
According to Wheeler, the mouths of the Einstein-Rosen “bridges” are very reminiscent of the so-called Schwarzschild black hole - simple matter that has a spherical shape and is so dense that its gravitational force cannot be overcome even by light. Astronomers have a strong opinion about the existence of “black holes”. They believe that these formations are born when very massive stars “collapse” or die out.
How substantiated is the hypothesis that a “black hole” is the same as a “wormhole” or a tunnel that allows long-distance space flights? Maybe, from a mathematical point of view, this statement is true. But only in theory: there will be no survivors in such an expedition.
The Schwarzschild model represents the dark middle of a “black hole” as a singular point or central neutral stationary ball with infinite density. Wheeler's calculations show the consequences of what happened in the event of the formation of such a “wormhole” when two singular points (“Schwarzschild black holes”) in two distant parts of the Universe converge in its “mass” and create a tunnel between them.
The researcher found out that such a “wormhole” is of an unstable nature: a tunnel first forms and then collapses, after which only two singular points (“black holes”) remain again. The procedure for the appearance and slamming of the tunnel takes place so lightning fast that even a ray of light cannot penetrate through it, not to mention an astronaut trying to slip through - he will be completely swallowed by the “black hole”. No joke - we are talking about instant death, because gravitational forces of crazy power will tear a person to pieces.
"Black holes" and "white spots"
At the same time as the film, Thorne released the book The Science of Interstellar. In this work he confirms: “Any body - living or inanimate - at the moment the tunnel collapses will be crushed and torn into pieces!”
For another, alternative option - Kerr's rotating “black hole” - researchers of “white spots” in interplanetary travel have found a different solution to the general theory of relativity. The singularity inside Kerr’s “black hole” has a different shape, not spherical, but ring-shaped.
Certain models of it can give a person a chance to survive in interstellar flight, but only if the ship passes this hole exclusively through the center of the ring. Something like space basketball, only the price of a hit here is not extra points: what’s at stake is the existence of the starship and its crew.
The author of the book “The Science of Interstellar,” Kip Thorne, doubts the state of this theory. Back in 1987, he wrote an article about flying through a “wormhole,” where he pointed out an important detail: the neck of the Kerr tunnel has a very unreliable section, which is called the “Cauchy horizon.”
As the corresponding calculations show, as soon as the body tries to pass past this point, the tunnel collapses. Moreover, subject to some stabilization of the “wormhole”, it, as quantum theory says, will immediately be filled with fast high-energy particles.
Consequently, as soon as you stick into Kerr’s “black hole,” you will be left with a dry, fried crust.
The reason is “terrible long-range action”?
The fact is that physicists have not yet adapted the classical laws of gravity to quantum theory - this branch of mathematics is too difficult to understand, and many scientists have not given it an exact definition.
At the same time, Princeton scientist Juan Malsadena and his Stanford colleague Leonard Susskind suggested that wormholes are apparently nothing more than the material embodiment of entanglement at the time when quantum objects are connected - regardless of whether they are distant from each other friend.
Albert Einstein had his own name for such entanglement - “terrible long-range action”; the great physicist did not even think of agreeing with the generally accepted point of view. Despite this, many experiments have proven the existence of quantum entanglement. Moreover, it is already used for commercial purposes - it protects online data transmission, for example, banking transactions.
According to Malsadena and Susskind, in large volumes, quantum entanglement can affect changes in the geometry of the space-time continuum and contribute to the emergence of “wormholes” in the form of linked “black holes.” But the hypothesis of these scientists does not allow for the emergence of traversable interstellar tunnels.
According to Malsadena, these tunnels, on the one hand, do not provide the opportunity to fly faster than the speed of light, and on the other hand, they can still help astronauts meet there, inside, with someone “other.” There is, however, no pleasure from such a meeting, since the meeting will be followed by inevitable death from a gravitational impact at the center of the “black hole.”
In a word, “black holes” are a real obstacle to human exploration of space. In this case, what might “wormholes” be? According to Avi Loeb, a scientist at the Harvard-Smithsonian Center for Astrophysics, people have many options in this regard: since there is no theory that combines general relativity with quantum mechanics, we are not aware of the full range of possible space-time structures where wormholes may appear "
They're collapsing
But here, too, not everything is so simple. The same Kip Thorne in 1987 established the peculiarity for any “wormhole”, corresponding to the general theory of relativity, to collapse if it is not tried to be kept open due to the so-called exotic matter having negative energy or antigravity. Thorne assures: the fact of the existence of exomatter can be established experimentally.
Experiments will show that quantum fluctuations in a vacuum are apparently capable of creating negative pressure between two mirrors that are placed very close together.
In turn, according to Avi Loeb, if we observe the so-called dark energy, then these studies will give even more reason to believe in the existence of exotic matter.
A scientist at the Harvard-Smithsonian Center for Astrophysics says that “...we see how, throughout recent cosmic history, galaxies are moving away from us at an increasing speed over time, as if they were under the influence of antigravity - this accelerating expansion of the Universe can be explained if the Universe is filled with a substance with negative pressure, exactly the material that is needed to create a wormhole...”
At the same time, both Loeb and Thorne believe that even if a wormhole could appear naturally, it would require a mass of exotic matter. Only a highly developed civilization will be capable of accumulating such an energy reserve and subsequent stabilization of such a tunnel.
There is also “no agreement among the comrades” in their views on this theory. Here's what their colleague Malsadena thinks of Loeb and Thorne's findings, for example:
“...I believe that the idea of a stable traversable wormhole is not intelligible enough and, apparently, does not correspond to the known laws of physics...” Sabine Hossenfelder from the Scandinavian Institute for Theoretical Physics in Sweden completely smashes Loeb-Thorn’s conclusions to smithereens: “... We have there is absolutely no evidence for the existence of exotic matter. Moreover, there is a widespread belief that it cannot exist, because if it did exist, the vacuum would be unstable..."
Even if such exotic matter existed, Hossenfelder develops his idea, moving inside it would be extremely unpleasant: each time the sensations would be directly dependent on the degree of curvature of the space-time structure around the tunnel and on the energy density inside it. Sabine Hossenfelder concludes:
“...This is very similar to “black holes”: the tidal forces are too great and a person will be torn to pieces...”
Paradoxically, despite his contributions to the Interstellar film, Thorne also doesn't particularly believe that such a passable tunnel could ever emerge. And the possibility of astronauts passing through it (without any harm!) - and even more so. He himself admits this in his book:
“...If they [tunnels] can exist, then I very much doubt that they can arise in the astrophysical Universe naturally...”
...So then believe in science fiction films!