Are there really wormholes in our universe

Wormholes

 
Wormholes and warp drives could allow super-fast journeys. Do they really exist? Einstein-Rosen Bridge
Negative energy
Casimir effect
Wormhole
Warp drive
Naked singularity

Einstein-Rosen Bridge

Black holes offer us another special feature:
Already in 1935 Albert Einstein and Nathan Rosen recognized that the theory of relativity principally "bridges", Einstein-Rosen bridges called, in the space-time that we call today Wormholes describe. Such a wormhole could e.g. be created by a black hole, which corresponds to a white hole or another black hole that is located somewhere far away in the universe. It is a tunnel-shaped shortcut between distant places in the cosmos.

We could now climb into a black hole and would be drawn into its suction to the singularity, but due to the rotation we would not necessarily get there. Rotating black holes have instead of the Point singularity a annular singularity on. So our journey could lead through the connecting channel of the two holes, the wormhole, and we would come out of the white hole again. According to calculations, it is quite possible to approach very massive (> 10 000 solar masses) black holes without damage, because here the gravitational load drops to below 15 G, which means that the tidal forces would also be tolerable.

However, and already depicted in the most beautiful colors in many SF novels, this trip would unfortunately not be a pleasure.

Although it leads us directly and irreversibly into the past, one would have to hurry up, because the Einstein-Rosen Bridge (left) only has an extremely short lifespan and very quickly constricts into a singularity (right).

This was done again in the sixties of the last century by the physicists John Wheeler and Robert Fuller approved. The wormhole then collapses under its own gravity so quickly that not even light could get through, because even the smallest disturbance, even a photon, would trigger this process.


Negative energy

But there seems to be a way out of this dilemma:

In principle, wormholes can also be "constructed" without black holes that are sufficiently large and correspondingly stable. The magic word here is negative energy or. negative ground, also known as exotic matter. The matter we are familiar with has positive energy throughout and therefore causes a positive curvature of space-time. Antimatter also has positive energy and has a gravitational attraction. To stabilize a wormhole, however, you need a region with extremely negative curvature, and therefore matter with negative energy, because this corresponds to repulsive gravity. But what is this negative energy and how can it be obtained?

Here comes this to us Uncertainty relation to help quantum mechanics:
In the subatomic area it simmers violently! So-called constantly arise virtual, oppositely charged pairs of particles that soon annihilate each other again, even in an absolute vacuum! They simply borrow the energy for their formation from the vacuum and give it back when they are destroyed. If we could suppress these fluctuations somewhat, we would bring the energy density of the vacuum, which is zero to the outside world, below this "zero energy" and we would have a field with a negative energy density.

The energy density of each field, regardless of whether it is electrical, magnetic or gravitational, is according to the Heisenberg's uncertainty principle itself subject to fluctuations. At some point it can go into negative territory. However, it is compensated for by increased values ​​of the positive density. In fact, the negative pulse is overcompensated and the more so, the greater the time intervals between the pulses. This effect is called Quantum interest, the negative energy is like a loan that has to be repaid with interest. The longer the loan duration (larger time intervals) and the larger the loan amount (the negative energy), the higher the interest rate (the positive pulse). In addition, the longer the loan amounts, the shorter the term.

Casimir effect

Fields with negative energy density can be generated in the laboratory. The so-called is used for this Casimir effect, named after its discoverer, the Dutch physicist Hendrik B. G. Casimir. As early as 1948 he showed that two uncharged metal plates attract each other very closely in a vacuum.

The cause of this are the vacuum fluctuations. Even in the most perfect vacuum, virtual particle pairs of matter and antimatter are constantly created, which "borrow" the energy for their creation from the vacuum and return it after a very short time by mutually destroying each other (annihilate). Virtual particles cannot be observed; every observation would immediately turn them into real particles. However, they provide indirect proof of their existence, for example by pushing hydrogen atoms back and forth, which leads to a measurable, tiny shift in their lowest energy level.
At the moment of its creation the vacuum already has a negative energy density because it has borrowed a small amount of its energy from the particles. The virtual particles can also be used after the Wave-particle dualism see it as a wave.
However, not all wavelengths fit between the two metal plates, but only an integral multiple of certain wavelengths, while all possible fluctuations or wavelengths are allowed to exist on the outside.

In the end, more waves press against the plates from the outside than are compensated for in the space, creating a field with a negative energy density. The attraction of the plates is thus also a further proof of the existence of the virtual particles. The Casimir effect is tiny: e.g. with a distance between the plates of a millionth of a millimeter, the quantum pressure is only around a ten-thousandth of the air pressure. If you move the plates closer to each other, even fewer waves fit into the gap - the negative energy density increases further, if you pull them apart, the effect disappears. A positive energy density, embodied for example by a star, represents a gravitational source and exerts attractive forces. If we could create fields with negative energy, we would have a source of repulsive forces and could use it to stabilize a wormhole.


Wormhole

A wormhole is a tunnel-shaped connection between two points in space that are far apart. It is kind of an abbreviation in curved spacetime by simply bypassing the curvature. According to the theory of relativity, light cannot be overtaken, but it can be tricked with a wormhole.

One could construct hypothetical wormholes large enough to let a human or a spaceship through. You just have to have one way of providing enough negative energy. Then, for example, you could step into a wormhole on Earth and after a few steps you would be in the Andromeda Galaxy.

Normally, however, a wormhole would be microscopic, no more than 10-32 [mm] diameter. To open a hole one meter in diameter, you would have to open it with a 10-21 [m] surrounded by a thin field of negative energy. However, to extract it, you needed the total energy that 10 billion stars release in one year. So wormhole designers don't have it very easy! Stabilizing a large wormhole through which a spaceship could travel would require more energy than is available in the entire universe.

Especially since other problems arise:
Time travel would also be possible through a wormhole. It is already known that when traveling at relativistic speeds, travelers have aged significantly less than people on earth when they return. But if he took the shortcut through a wormhole, he could return before he left. But that contradicts the causality - an effect cannot occur without a cause. The other problem concerns the second law of thermodynamics, which says that the entropy of a system (its "disorder") can only remain the same or increase. However, the negative energy could violate this sentence: If we generate a steady beam of negative energy to open a wormhole, according to quantum theories, a second beam of positive energy would have to be created that we could use for other purposes. That would be that Perpetual motion machine created, which according to our physical laws (namely thermodynamics) must not exist.

Another argument speaks against the existence of wormholes today:
As we know, spacetime is flat on large scales, i.e. it corresponds to Euclidean geometry. This means that it has almost no bends! A "shortcut" through spacetime using a wormhole is therefore not possible at all ...


Warp drive

In this context, however, there is another application of negative energy:
It could be used as a futuristic propulsion system for spaceships, in the form of the vom Star Trek known Warp drive (engl. to warp = to distort, to warp).

Using negative energy, a kind of bubble could be constructed in space-time, on the front of which space-time is contracted, reducing the distance to the target. Behind the bubble in which the spaceship is located, space-time is stretched again, which increases the distance from the place of origin. The travelers in the spaceship would not see any movement, they would be at rest relative to their surroundings, while an outside observer could determine the bubble's speed as high as desired. According to Einstein, overtaking a light beam is impossible, but a warp drive would be a permissible abbreviation in spacetime, as would a wormhole.

The astronauts would have a big problem, however: they could not control or switch off the bladder; There would be a solution, however, in which the future travelers would create a kind of tunnel from modified space-time between the start and destination at sub-light speed (that would not be a wormhole, however!), On the return flight they could then pass the tunnel with overlight.


Naked singularity

The negative energy, if it were available to us, would have another interesting aspect. Because it has a repulsive effect on gravity, one could use it to open the event horizon of a black hole and thus a view of it naked singularity throw. That forbids us, however, the so-called, by the well-known astrophysicist Roger Penrose established Cosmic censorshipwhich prevents us from seeing. The singularity of a black hole is a state that we cannot describe in any way. In contrast, the area around the hole, delimited by the event horizon, is subject to the well-known laws of nature. A naked singularity would violate this limit and is therefore not permissible according to the cosmic censorship.

A pulse of negative energy directed at the black hole would therefore be followed immediately by a larger pulse of positive energy that closes the horizon again.

All of the effects mentioned here, whether wormhole, warp drive or naked singularity, are no pipe dreams, but the results of complicated calculations by many serious and well-known scientists. There is negative energy, as the Casimir experiment shows. In this microscopic range, it can exist indefinitely. In order to design macroscopic objects such as wormholes, however, unimaginably thin fields of negative energy density would be required, which cannot be generated. Because, as we have seen, every negative pulse inevitably is followed by a larger positive one got to. In addition, negative pulses are only very short. In order to construct long-term stable fields of negative energy, unimaginable amounts of positive energy would be necessary.

We are not able to develop warp drives or wormholes, but the theoretical considerations show that they are in principle possible without violating the laws of nature - including relativity theory and quantum physics. Perhaps in the meantime highly developed civilizations, whose existence can hardly be doubted, have been able to make use of these techniques and they are already happily crossing our cosmos. Humans could also achieve something similar in the indefinite future. Who knows...

Additional Information:
http://www.nasa.gov/centers/glenn/research/warp/warp.html
http://www.astro.cf.ac.uk/groups/relativity/papers/abstracts/miguel94a.html
http://casa.colorado.edu/~ajsh/schww.html