The starry universe is fraught with many mysteries. According to the general theory of relativity (GR), created by Einstein, we live in four-dimensional space-time. It is curved, and gravity, familiar to all of us, is a manifestation of this property. Matter bends, “bends” the space around itself, and the more, the denser it is. Space, space and time are all very interesting topics. After reading this article, you will probably learn something new about them.
Idea of curvature
Many other theories of gravitation, of which there are hundreds today, differ in detail from GR. However, all these astronomical hypotheses retain the main thing - the idea of curvature. If the space is crooked, then we can assume that it could take, for example, the shape of a pipe connecting the areas that are separated by many light years. And perhaps even eras far from each other. After all, we are not talking about space, familiar to us, but about space-time, when we consider the cosmos. A hole in it can appear only under certain conditions. We offer you a closer look at such an interesting phenomenon as wormholes.
The first ideas about wormholes
The distant cosmos and its riddles attract. Thoughts about the curvature appeared immediately after the publication of general relativity. L. Flamm, an Austrian physicist, already in 1916 talked about the fact that spatial geometry can exist in the form of a hole that connects two worlds. The mathematician N. Rosen and A. Einstein in 1935 noted that the simplest solutions of equations in the framework of general relativity, which describe isolated electrically charged or neutral sources that create gravitational fields, have the spatial structure of a “bridge”. That is, they connect two universes, two almost flat and identical space-time.
Later, these spatial structures became known as “wormholes”, which is a rather loose translation from English of the word wormhole. A closer translation is “wormhole” (in space). Rosen and Einstein did not even exclude the possibility of using these "bridges" to describe elementary particles with their help. Indeed, in this case, the particle is a purely spatial formation. Therefore, the need to simulate a source of charge or mass does not specifically appear. And the remote external observer, if the wormhole has microscopic dimensions, sees only a point source with charge and mass when it is in one of these spaces.
Einstein-Rosen Bridges
On the one hand, electric lines of force enter the hole, and on the other, they exit without ending and starting nowhere. J. Wheeler, an American physicist, said on this occasion that it turns out "charge without charge" and "mass without mass." It is not necessary at all in this case to assume that the bridge serves to connect two different universes. No less appropriate would be the assumption that at the wormhole both “mouths” emerge into the same universe, but at different times and at different points in it. It turns out something resembling a hollow "pen" if it is sewn to an almost flat familiar world. The lines of force enter the mouth, which can be understood as a negative charge (for example, an electron). The mouth from which they exit has a positive charge (positron). As for the masses, they will be the same on both sides.
Einstein-Rosen Bridging Conditions
This picture, with all its attractiveness, was not widely used in elementary particle physics, for which there were many reasons. It is not easy to attribute to the Einstein-Rosen “bridges” quantum properties, which cannot be dispensed with in the microworld. Such a “bridge” does not form at all with the known values of the charges and masses of particles (protons or electrons). An “electric” solution instead predicts a “bare” singularity, that is, the point where the electric field and the curvature of space become infinite. At such points, the concept of space-time, even in the case of curvature, loses its meaning, since it is impossible to solve equations having an infinite number of terms.
When does GTR not work?
By itself, general relativity definitely states when it stops working. On the neck, in the narrowest place of the "bridge", a violation of the smoothness of the connection is observed. And it should be said that it is quite nontrivial. From the position of a distant observer, time stops at this neck. What Rosen and Einstein considered the neck is now defined as the event horizon of a black hole (charged or neutral). Rays or particles from different sides of the "bridge" fall on different "sections" of the horizon. And between the left and right parts, relatively speaking, there is a non-static region. In order to pass the area, one cannot help but overcome it.
Inability to get through a black hole
A spacecraft that is approaching the horizon of a rather large black hole relative to it, as if freezes forever. Signals from him are getting less and less ... On the contrary, the horizon in ship clocks is reached in a finite time. When a ship (a ray of light or a particle) passes it, it will soon run into a singularity. This is the place where curvature becomes infinite. In a singularity (still approaching it), an extended body will inevitably be torn and crushed. This is the reality of the black hole device.
Further research
In the years 1916-17. Reisner-Nordstrom and Schwarzschild decisions were obtained. Symmetric electrically charged and neutral black holes are spherically described in them. However, physicists were able to fully understand the difficult geometry of these spaces only at the turn of the 1950s and 60s. It was then that D. A. Wheeler, known for his work in the theory of gravity and nuclear physics, proposed the terms “wormhole” and “black hole”. It turned out that in the Reisner-Nordstrom and Schwarzschild spaces there are indeed wormholes in space. They are completely invisible to the remote observer, like black holes. And, like them, wormholes in space are eternal. But if a traveler penetrates beyond the horizon, they collapse so quickly that neither a ray of light, nor a massive particle can fly through them, not just a ship. To fly to another mouth, bypassing the singularity, you need to move faster than light. At present, physicists believe that supernova velocities of the movement of energy and matter are fundamentally impossible.
Black holes Schwarzschild and Reisner-Nordstrom
Schwarzschild's black hole can be considered an impenetrable molehill. As for the Reisner-Nordstrom black hole, it has a slightly more complicated structure, but is also impassable. Nevertheless, it is not so difficult to come up with and describe the four-dimensional moleholes in space that could be passed. One has only to choose the necessary type of metric. The metric tensor, or metric, is a set of quantities, using which it is possible to calculate the four-dimensional intervals existing between event points. This set of quantities also fully characterizes the gravitational field and the space-time geometry. The geometrically traversable wormholes in space are even simpler than black holes. They have no horizons that lead to cataclysms with the passage of time. At different points, time can go at a different pace, however, it should not be infinitely stopped or accelerated.
Two directions of research of wormholes
Nature has put a barrier to the appearance of wormholes. However, a person is designed so that if there is an obstacle, there will always be those who wish to overcome it. And scientists are no exception. The works of theoreticians who study wormholes can be conditionally divided into two areas that complement each other. The first deals with their consequences, presuming in advance that wormholes actually exist. Representatives of the second direction are trying to understand from what and how they can arise, what conditions are necessary for their occurrence. There are more works in this direction than the first and, perhaps, they are more interesting. This direction includes the search for models of wormholes, as well as the study of their properties.
Achievements of Russian physicists
As it turned out, the properties of matter, which is the material for the construction of wormholes, can be realized due to the polarization of the vacuum of quantum fields. Russian physicists Sergei Sushkov and Arkady Popov, together with Spanish researcher David Hochberg, as well as Sergey Krasnikov recently came to this conclusion. The vacuum in this case is not a void. This is a quantum state characterized by the lowest energy, that is, a field in which there are no real particles. In this field, pairs of “virtual” particles constantly appear, disappearing before the devices detect them, but leaving their mark in the form of an energy tensor, that is, an impulse characterized by unusual properties. Despite the fact that the quantum properties of matter are mainly manifested in the microworld, the wormholes generated by them, under certain conditions, can reach significant sizes. One of Krasnikov’s articles, by the way, is called “The Threat of Wormholes”.
The issue of philosophy
If wormholes ever manage to be built or discovered, the field of philosophy associated with the interpretation of science will face new challenges and, it must be said, very difficult ones. For all the seemingly absurdity of time loops and difficult problems regarding causality, this area of science will probably someday deal with this. Just as we dealt in due time with the problems of quantum mechanics and the theory of relativity created by Einstein. Space, space and time - all these questions have always been of interest to people and, apparently, will always interest us. It is hardly possible to fully understand them. Space exploration is unlikely to ever be completed.