Researchers at Princeton University have established the conditions necessary to create wormholes large enough to transport humans through space-time.
3D illustration of a wormhole. Credit: Rost9
It is common throughout history for reality to borrow material from science fiction and vice versa, feeding back each other. In this case, a study led by Argentine Juan Maldacena and published on the prepress server arXiv, brings to the table a new theory that transforms wormholes into something suitable for humans, as seen in series and space movies.
The theoretical exercise alludes to a type of cosmic object whose existence had already been considered feasible, although only in quantum physics and in microscopic dimensions. But … “With a catch: the time it takes to travel through the wormhole is greater than the time it takes to go from one mouth to the other outside,” the authors clarify.
However, in this new work they show that, if there were a series of additional particles – in addition to those that our instruments “see” – and theoretically possible according to some models of matter, these cosmic objects could form under conditions such that a being human could go through them. Moreover, in doing so, for relativistic purposes, it would also travel to the distant future.
Einstein – Rosen
At first glance, wormholes look like two black holes connected to each other. However, they differ in a key fact:
“They do not have a horizon, a border beyond which, if one passes, one cannot get out again,” Maldacena explains. “In the case we are studying, the tube of one is connected to that of the other, and one can enter through one mouth and exit through the other, and can even exit from the other side, jump back and exit through the original entrance. They are like tunnels that would connect two very distant places in our universe, thousands of light years away”
“The idea of these cosmic curiosities dates back to 1935,” says Gastón Giribet, a professor at the University of Buenos Aires and a researcher in theoretical physics, black holes and string theory. “Einstein and Rosen, who were also working together at Princeton, realized that there was a solution to the equations of the theory of general relativity that made it possible to build a kind of tunnel in space-time.”
‘Both ends of this object look like black holes, and they can be in different universes or even the same universe, but they share their interior. This is something very surprising. Then that was studied a lot. Physicists like Stephen Morris or Kip Thorne considered an important distinction between two types of black holes: non-traversable and traversable. When you began to play with this idea, it was speculated that one could now enter one of the second type and exit, for example, in 1947. But the question is: does general relativity allow it? Well, the answer that one would have given a while ago is “no”, because for this to happen, exotic energy and matter would have to exist, which violated some physical conditions; for example, the energy should not be negative, the speed of sound of a wave on them should not exceed the speed of light. Science is a game with rules,” he says.
As Giribet explains, the possibility of microscopic wormholes has been studied for a long time.
“These can exist in the simplest theory we have (the standard model of matter), which describes all currently known particles,” Maldacena highlights. «If one assumes that there are no others, they could exist but very small; the distance between the two mouths would be the size that the Large Hadron Collider is exploring.’
Human tailor
Together with his colleague Alexey Milekhin, Maldacena explored the possibility that, contrary to what classical physics assures, these objects could occur in larger sizes, even human-sized.
“The reason why they are ‘forbidden’ in classical physics is more or less the following,” Maldacena illustrates. “Einstein’s equations relate geometry to energy or density of matter, and in order to have a geometry of this type, the energy in the tunnel has to be negative. In classical physics, these energies are positive, but if one considers quantum mechanics, there is a “Casimir effect” that allows for a little bit of negative energy. In this case, the object could exist thanks to that negative energy. It is a solution that involves quantum effects.
For such a geometric distortion of space-time to occur, one would have to assume that there is a type of matter that is theoretically possible, but has not yet been detected – massless particles, but that interact weakly with the known mass, which would give rise to quantum effects. that would make this solution possible. Scientists also failed to elucidate what processes in the universe could give rise to such a rarity.
According to the parameters that Maldacena and Milekhin studied in their work, each mouth of the wormholes would be about 10,000 km wide, comparable to the diameter of the Earth.
“If you were to jump through that place, you would come out on the other side after approximately one second and it would be approximately 10,000 light years away,” Maldacena says.
But from the point of view of someone who was left out, the time that would have elapsed would be a little longer. That is, it would allow time travel, but only into the future. One could travel 10,000 years in one second. To go and return, it would take 20,000 years.
Lonely journey
Of course, it would be a somewhat lonely trip, since very large objects could not enter.
“The wormhole is a bit fragile, in the sense that if you want to send too much stuff, it is destroyed and a black hole is formed; then, you can no longer go out, “he stresses. “It’s a bit of an unstable setup; the correct word is ‘metastable’: in principle, it can exist, but if you put too much matter inside it, you destroy it.
As Francisco Villatoro explains in the magazine Naukas, “A safe trip would require a completely empty space-time at zero temperature, since any type of radiation that entered through both throats could accumulate inside it producing a positive energy that would compensate for the negative energy of Casimir; if that happened during the trip, it would be deadly for the traveler, since he would end up inside with no possibility of going out again.
Although the idea is so disruptive, this solution looks a bit like the one described by the physicist and mathematician Karl Schwarzchild, the first to conceive of black holes and baffled Einstein with his conclusions. ‘If you study it properly, it actually describes what we would call two black holes that are connected inside. A kind of wormhole, nothing more than in that case the geometry does not allow one to go from one side to the other. The connection opens and closes in such a way that one cannot send a signal from one side to the other, but it cannot be crossed,” Maldacena says.
“If you go in, space collapses before you can get out and you have the unusual vision that you fall into the singularity. Later it was seen that through certain quantum effects one can delay the collapse and make it open and close more slowly, which allows one to pass from one side to the other, if pulled at the right time. The solutions we are discussing now are similar versions, nothing more than this connection remains open for an arbitrarily long time, as long as one wants,” he explains.
The scientist warns that it is not likely that we will soon find a wormhole that can transport us through our galaxy without the need for a ship. ‘Surely matter would enter and black holes would form. I don’t see a very practical way to tell them apart. For me, the interesting thing is that these configurations can exist, that in principle the structure of space-time can be changed in this way. They are a curious solution, but I don’t think they exist in real life.
However, Einstein said something similar about black holes almost a century ago and already we even have a picture of one of those cosmic beasts.
Source: New Scientist
