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  • Barbara Jesline

Scientific post: Can we travel to the Andromeda galaxy in just a few years?

Isn't it a fascinating idea?🤩 Travelling to our closed galaxy, the Andromeda galaxy (not much just 2.5M light-years away) in just a few years. Spoiler alert, this idea is just a theory for now. We can do this with a concept namely 'WORMHOLE'!!!


What is WORMHOLE?

A wormhole is a sort of tunnel that joins distant points in space, or even two universes, via space-time curvature. Theoretically, such a tunnel could be traversed from one point in space to another without actually travelling the distance between them.

A wormhole can be visualized as a tunnel with two ends at separate points in spacetime (i.e., different locations, or different points in time, or both). Wormholes are consistent with the general theory of relativity, but whether wormholes actually exist remains to be seen. Many scientists postulate wormholes are merely a projection of a fourth spatial dimension, analogous to how a two-dimensional (2D) being could experience only part of a three-dimensional (3D) object. There is no experimental evidence for their existence.


WORLMHOLEs, also known as Einstein–Rosen bridges are connections between areas of space that can be modelled as vacuum solutions to the Einstein field equations, and that are now understood to be intrinsic parts of the maximally extended version of the Schwarzschild metric describing an eternal black hole with no charge and no rotation. Here, "maximally extended" refers to the idea that the spacetime should not have any "edges": it should be possible to continue this path arbitrarily far into the particle's future or past for any possible trajectory of a free-falling particle (following a geodesic in the spacetime).


In order to satisfy this requirement, it turns out that in addition to the black hole interior region that particles enter when they fall through the event horizon from the outside, there must be a separate white hole interior region that allows us to extrapolate the trajectories of particles that an outside observer sees rising up away from the event horizon. And just as there are two separate interior regions of the maximally extended spacetime, there are also two separate exterior regions, sometimes called two different "universes", with the second universe allowing us to extrapolate some possible particle trajectories in the two interior regions. This means that the interior black hole region can contain a mix of particles that fell in from either universe (and thus an observer who fell in from one universe might be able to see the light that fell in from the other one), and likewise, particles from the interior white hole region can escape into either universe. All four regions can be seen in a spacetime diagram that uses Kruskal–Szekeres coordinates.


Idea of WORMHOLE

Wormholes were first theorized in 1916, though that wasn't what they were called at the time. While reviewing another physicist's solution to the equations in Albert Einstein's theory of general relativity, Austrian physicist Ludwig Flamm realized another solution was possible. He described a "white hole," a theoretical time reversal of a black hole. Entrances to both black and white holes could be connected by a space-time conduit.


In 1935, Einstein and physicist Nathan Rosen used the theory of general relativity to elaborate on the idea, proposing the existence of "bridges" through space-time. These bridges connect two different points in space-time, theoretically creating a shortcut that could reduce travel time and distance. The shortcuts came to be called Einstein-Rosen bridges, or wormholes.


Wormholes contain two mouths, with a throat connecting the two. The mouths would most likely be spheroidal. The throat might be a straight stretch, but it could also wind around, taking a longer path than a more conventional route might require.


Einstein's theory of general relativity mathematically predicts the existence of wormholes, but none have been discovered to date. A negative mass wormhole might be spotted by the way its gravity affects light that passes by. Certain solutions of general relativity allow for the existence of wormholes where the mouth of each is a black hole. However, a naturally occurring black hole, formed by the collapse of a dying star, does not by itself create a wormhole.


Problems with WORMHOLE

Primordial wormholes are predicted to exist on microscopic levels, about 10^–33 centimetres. However, as the universe expands, it is possible that some may have been stretched to larger sizes. Still, there isn't any theoretical prove evident to provide such possibility. For example, an Earth-Moon wormhole whose far end is 0.5 seconds in the "past" will not violate causality since information sent to the far end via the wormhole and back through normal space will still arrive back on Earth (-0.5 + 1) = 0.5 seconds after it was transmitted; but an additional wormhole in the other direction will allow information to arrive back on Earth 1 second before it was transmitted. However, it is believed that relative time between the transmission of the information in one wormhole throat and out the other end in a ring structure will remain the same, because light wouldn't have violated local proper time, because the distance travelled by the information would take time, either by going the long way or through the wormhole. If the information (DATA) can't travel in much less time, how could we travel in such a short interval of time, where is impossible to any of present space vehicle to produce such extreme acceleration.


Another problem comes from stability. The predicted Einstein-Rosen wormholes would be useless for travel because they collapse quickly. Wormhole geometries are inherently unstable. The only material that can be used to stabilize them against pinching off is material having negative energy density, at least in some reference frame. No classical matter can do this, but it is possible that quantum fluctuations in various fields might be able to. "You would need some very exotic type of matter in order to stabilize a wormhole," said Hsu, "and it's not clear whether such matter exists in the universe."


Oh no! it looks like we are far from creating a wormhole.

But more recent research found that a wormhole containing "exotic" matter could stay open and unchanging for longer periods of time. Exotic matter, which should not be confused with dark matter or antimatter, contains negative energy density and large negative pressure. Such matter has only been seen in the behaviour of certain vacuum states as part of quantum field theory. If a wormhole contained sufficient exotic matter, whether naturally occurring or artificially added, it could theoretically be used as a method of sending information or travellers through space. Unfortunately, human journeys through space tunnels may be challenging. In 1991 David Deutsch showed that quantum theory is fully consistent (in the sense that the so-called density matrix can be made free of discontinuities) in spacetimes with closed timelike curves. However, later it was shown that such a model of closed timelike curves can have internal inconsistencies as it will lead to strange phenomena like distinguishing non-orthogonal quantum states and distinguishing proper and improper mixture. Accordingly, the destructive positive feedback loop of virtual particles circulating through a wormhole time machine, a result indicated by semi-classical calculations, is averted. A particle returning from the future does not return to its universe of origination but to a parallel universe. This suggests that a wormhole time machine with an exceedingly short time jump is a theoretical bridge between contemporaneous parallel universes.


How close or far are we creating a WORMHOLE?

Back in 2015, researchers in Spain created a tiny magnetic wormhole for the first time ever. They used it to connect two regions of space so that a magnetic field could travel 'invisibly' between them. Woohoo! the wormhole is already cleared, why wouldn't we travel through it yet? It wasn't the kind of gravitational wormhole that would theoretically allow humans to travel rapidly across space in science fiction TV shows and films such as Stargate, Star Trek, and Interstellar, and it wouldn't have been able to transport matter.


But the physicists managed to create a tunnel that allowed a magnetic field to disappear at one point, and then reappear at another, which is still a pretty huge deal. A wormhole is effectively just a tunnel that connects two places in the Universe. So far scientists have simulated this process, but are nowhere near creating a gravitational wormhole, as it would require us to create huge amounts of gravitational energy - something we don't yet know how to do. But what physicists are good at is generating and manipulating electromagnetic energy, and so the team from the Autonomous University of Barcelona decided to see if they could build a magnetic wormhole in the lab instead. In 2014, they managed to create tunnels that directed magnetic fields from one place to another, but these weren't true wormholes because they didn't keep the magnetic field undetectable or magnetically 'invisible' while it was travelling inside the tunnel.


This is something they managed to overcome in 2015, by using metamaterial and metasurfaces to build their tunnel. That meant that they could make the magnetic field from a source, such as a magnet or an electromagnet, appear at the other end of the wormhole with no trace of it in between. This created the illusion that the magnetic field must be travelling through some kind of extra dimension. Oddly enough, it also meant that an isolated magnetic monopole - a magnet with only one pole, North or South - appeared randomly at the end of the tunnel. "This result is strange enough in itself, as magnetic monopoles do not exist in nature," "The overall effect is that of a magnetic field that appears to travel from one point to another through a dimension that lies outside the conventional three dimensions." To be clear, the wormhole in this experiment isn't really invisible to the human eye - it's a sphere made up of an outer ferromagnetic surface, an inner superconducting layer, and then a ferromagnetic sheet rolled into a cylinder internally. But the way that it's been designed means that it, and its contents, is totally undetectable magnetically.


In other words, it's magnetically invisible from the outside. But importantly, it also teaches us more about ways we can tunnel our way through space - an endeavour that holds countless exciting possibilities. The research was published in Scientific Reports.


Today's technology is insufficient to enlarge or stabilize wormholes, even if they could be found. However, scientists continue to explore the concept as a method of space travel with the hope that technology will eventually be able to utilize them. "You would need some of the super-super-advanced technology," Hsu said. "Humans won't be doing this any time in the near future." But we can hope and work in the direction to it,