A wormhole is something that exists theoretically. At least until the time of this writing, the wormhole is only on theoretical paper or appears in science fiction films and books. The existence of a wormhole, in theory, began when Albert Einstein introduced the Theory of General Relativity. Einstein showed that mass can make the space (time) curved / folded, the greater the mass, the more curved space (time). Hard to imagine huh?
In 1919, Arthur Eddington proved, when at that time there was a Total Solar Eclipse; the stars around the Sun are observed in a position that shifts from the position it should be. Of course, during the eclipse, stars can be observed during the day. And the evidence shows that Einstein was right. How can a star shift from its proper position? Because the sun's gravitational field deflects the direction of the star's light.
But the evidence of bending light by the Sun at the time of the eclipse has nothing to do with the wormhole. The evidence by Eddington shows that Einstein's theory of Relativity is true. From that theory, one fundamental thought that we know then is that the mass affects space (and time). In general, gravity is closely related to geometry, how the direction of light can turn, it was not imagined before. Simply put, how the relationship of gravity and geometry can be described as the following picture.
It should be understood that before Einstein, space and time were two separate entities, but Einstein's theory states that space and time are the sole, indivisible entities. Thus, the geometry here needs to be understood as a time-space relation.
Back in Einstein's work, Einstein's theory used a mathematical theory known as the Einstein field equation, and the solution was known as the Schwarzschild solution. The solution of this theory describes the gravitational field on a spherical-symmetry mass, not rotating. This solution is the embryo of a black hole (Blackhole Schwarzschild).
In 1916, not long after Einstein introduced the theory of Relativity; Ludwig Flamm realizes that Einstein's equation has another solution, known as the White Hole and that both solutions describe the two regions in the spacetime (flat) connected (mathematically) by the existence of a 'space' space-time. Because the theory has not yet said where the realm of time-space is in the real world, so it could be the black-hole as the entrance and the white hole as the exit, but it could be in the same world we (the space of time we can understand), or in space and other times (other universes, parallel universes, past, present, future?). However, White Hole violates the 2nd Law of Thermodynamics, thus, the existence of the White Hole is difficult to accept easily.
In 1935, Albert Einstein and Nathan Rosen studied further the connection of Black Hole and White Hole; that from the formulation of the theory of General Relativity, the curved spacetime-structure can connect two regions from a distant time-space, through a similar form of an alley, as a shortcut in space. This work is formally known as the Einstein-Rosen bridge. The goal is not to study the faster journey of light or the journey between the universe, but rather to seek explanation on fundamental particles (such as electrons) in space-time. Einstein-Rosen Bridge is also known by other names, such as Lorentzian Wormhole or Schwarzschild wormhole.
In 1962, John Wheeler and Robert Fuller pointed out that the wormhole of the Einstein-Rosen bridge type is unstable, causing no light to pass through it for a moment as a wormhole is formed. Then, whether the wormhole cannot be passed? (Traversable)? We will review about traversable wormhole later.
Thus, since then, the theory of wormhole has been continuously studied; likewise, urban legends about the wormhole are present in society, especially in science fiction literature.
The scientific theory of wormhole continues to grow: all have the same principle, that is, the mathematical solution of the geometric relationship between one point in space-time to another, where the relationship can behave as a 'shortcut' in space-time.
How is a wormhole formed? Back to the picture illustration of Earth. If there is the curvature of spacetime at a point and is connected with curvature in other spacetime, then the wormhole image exists. As in the following illustrations, taken from the Stargate S1 movie, it is as if everything is beautiful and fun. Like the door of Doraemon, we open the door, then we reach a place far away. Ah, the beauty of science fiction.
Wormhole related to the relationship in space-time, known as Laurentzian wormhole. The relationship here is of course said to be a shortcut, because: If the journey from Gate to Moon, it can be done much faster, even faster than the speed of light through normal path. (Of course, it's faster than this speed of light because it uses a shorter path, not because it's 'faster than the speed of light'). That is of course if the trip can indeed be done through the wormhole.
But complexity arises, because, can we determine the end of our journey? Are we going to come out on the other end, in the same universe? Or in a parallel universe? Or do we show up at the same time? Do we show up in our time? Or in the past? Or the future? Of course all is possible, because Laurentzian wormhole is a product of the General Theory of Relativity which states that all move in both space and in time.
Lorentzian wormholes fall into two types:
There is also another wormhole known as Euclidean wormholes, which, in this wormhole is in a very micro-process, because it is the main concern of quantum field theorists. Thus this type of wormhole, at this time will not be discussed, and Laurentzian wormhole is the wormhole we discussed.
Back to the question, is it possible we travel through the wormhole? Kip Thorne and Mike Morris in 1988 suggested that the wormhole could be maintained in its stability using exotic material (matter that is still theoretical, and yet undiscovered in the world, with behavior like a negative mass or denying gravity, rather than obeying Newton's law of gravity). This theory model is known as the Morris-Thorne wormhole. Theories that were later developed to maintain the stability of the wormhole, so that it can be traversed, until now guided by the argument that, no matter that we know can play a role to maintain stability because it requires the existence of negative energy.
Although the wormhole is still a theory discourse (and urban legend), there is no evidence to support its existence, either from observation or experimentally. Will the wormhole then be impossible? Or could a wormhole be made?
In theory, we can build a wormhole. How? In order for space-time to be folded, it takes extraordinary material and energy, so we live looking for a very dense matter in space there, say, from the neutron star. Why a neutron star? The neutron star is a type of star whose mass reaches 1.35 to 2.1 times the mass of the Sun, but with a radius of only 20 to 10 km, reaching 30 thousand to 70 thousand smaller than the Sun. Thus, the weight-type of neutron stars reaches from 8 × 1013 to 2 × 1015 g / cm3.
How many? "Sufficiently" - until it can form a giant ring the size of Earth's orbit around the Sun. Then, make another ring on the other end. After the construction of the gigantic ring at both ends is completed, provide very high electrical voltage, at both ends, rotated until it reaches the speed of light - both, and voila, traveling across space-time instantaneously.
The fact that the journey passes through time, when it jumps into the future is acceptable, because it does not contradict the Theory of Special Relativity, but if his trip backwards in time? It becomes controversial, elusive, even paradoxical.
If, one end of the wormhole that has been created is driven at a rate reaching the speed of light, and according to the theory of Special Relativity, the rate of an object reaches the speed of light, the running time becomes slow; Such relative motion creates a time difference between the two. In such a way as to create a corridor that ends at different times. If from a silent tip, a person moves deep into the future, but the opposite, from the moving end, he will return to the past!
Here is the controversy, if someone returns from the future, then kills his parents before he is born, then how can he 'exist' and carry out the mission of killing his parents? With knowledge of Quantum theory, Stephen Hawking introduces 'Conjecture Protection Chronology', which can 'protect' the journey between these times. Because theoretically, in the antiparticle-particle pairs the cores are continuously created and mutually exclusive, so the energy overflows with the utmost, even exceeding the exotic energy required to open the wormhole gate. And, wormhole will be disrupted and closed, even before the time machine is created. Then is it then that time machine is impossible?
Whatever may actually happen, does the wormhole as a time machine exist? Could occur? Or as an inter-space portal? All still open, still have to wait a long, because still have to look for understanding and unification theory of quantum mechanics and gravity. There is still much to be learned, and if it is interested in learning it, much has not been understood; while waiting, let the science fiction author tell you about the wormhole exotica, or we enjoy the movie The Flash series.
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