Time travel and how can we achieve it

Time travel

There is a concept of movement between certain points in time travel time, using an imaginary device, commonly known as a time machine, in accordance with the movement between different points in space by an object or person. Time travel is a widely recognized concept in philosophy and fiction. Time machine idea H. G. The 1895 novel The Time Machine by Welles made popular.
It is uncertain that if traveling in the past is physically possible. Forward time travel, outside of common knowledge of the notion of time, is a widely observed phenomenon and is well understood within the framework of special relativity and general relativity. However, it is not possible to advance or delay a body more than a few milliseconds in comparison to any other body. For backwards time travel, it is possible to find solutions in general relativity which allow for it, but solutions require situations that can not be physically possible. There is limited support in arbitrary travel theoretical physics in spacetime, and is usually associated with quantum mechanics or wormhole, also known as Einstein-Rosen bridges.

Time dilation

According to the theory of relativity, the dispersion of time differs in the elapsed time measured by two observers, either because of the velocity difference relative to one another, or because it is located separately relative to the gravitational field. As a result of the nature of spacetime, a clock that is moving relative to a supervisor, will be measured to be slower than a clock, which is comfortable in the supervisor's own frame. A clock that occurs in the influence of a strong gravitational field compared to the observer, which will be measured to keep the supervisor slower than its clock.

For example, repeated dispersion has been demonstrated, for example, after one of the pairs of atomic clocks, one of them is sent on space travel after minor inequalities, or watches on the earth by clocks on the space shuttle, or GPS But there is a bit slower than the clocks and the Galileo satellites are running at a slightly faster pace. The spread of time has also been the subject of the works of science fiction, because it technically provides means for travel ahead of time.

Ways to Time travel according to physics

Some theories, especially special and general relativity, suggest that allow space-time or specific geometrical time and specific time of motion to allow time in the future if these geometry or motion was possible. In the technical paper, physicists discuss the possibility of discontinued timelike curves, which are world lines that form the closed loops in spacetime, allowing objects to return to their past. Such general relativity is known to solve equations that describe spacetime, which have closed timelike curves, such as Gödel spacetime, but the physical impairment of these solutions is uncertain.
Many people in the scientific community believe that travel time of backward time is not very likely. Any theory that will allow time travel will present potential problems of work-causes. The classic example of a problem related to work-causes is "Dada Paradoxes": What if someone goes back prematurely and killed his own grandfather before imagining his father? Some physicists, such as Novikov and Deutsch, suggested that these kinds of cosmic contradictions can be avoided by the translation of Novokov Self-Consumption Theory or the change of interpretation of many world with the world that talks.

general relativity

Traveling time for the past is theoretically possible in some general relativity spacetime geometries that allow speed of light, such as cosmic strings, transversal wormhole and alkobier drive to travel faster. The theory of general relativity suggests a scientific basis for the possibility of traveling backwards in some unusual scenarios, although the arguments of half-yearly gravitation show that when the quantum effect is included in general relativity, then these flaws are closed. can go. Due to these semiconductor arguments, Stephen Hawking made chronological conservation estimates, stating that the fundamental rules of nature prevent the journey of time, but physicists are involved in quantum mechanics and general relativity, without regard to the principle of gravity, on this issue Can not take a definite decision. Fully Integrated Theory

Various spacetime geometry

The theory of general relativity describes the field of the universe under a system of equations that determine the metric, or distance function, spacetime. The exact solutions of these equations are present, including closed time-like curves, which are the lines of the world that intersect themselves; Due to the line of the world, due to some point in the future it is also in the past, a situation which is similar to time travel. Such a solution was first proposed by Kurt Gödel, a solution known as Gödel metric, but their (and others) solutions require the physical characteristics of the universe which does not seem to be That is, such a lack of rotation and Hubble expansion. Does general relativity fall like all the time for realistic situations, still being researched.

Wormholes

Wormhole is a fictional dictatorship that is allowed by general relativity Einstein field equations. Using the travelable workhouse, the proposed time-travel machine will work in a fictitious manner: one end of the wormhole is accelerated to some significant components of the speed of light, perhaps with some advanced propulsion system, and then at the back point Is brought. Original. Alternatively, another way is to take an entrance door of the Vermohol and take it within the gravitational field of an object in which there is more gravity than the other entrance, and then return it to the position near the second entrance. . For both of these methods, due to the spread of time, the cause of the end of wormohol, which has been taken for the short life, or "youth" became, seen by the external observer compared to the stable end; However, the timing connects from the outside of the Virhamhole differently, so that the clocks synchronized at both ends of the Vermohole should always be equal to the things seen by a supervisor passing through Worthhole, even though the two ends. This means that a supervisor who enters the "youth" end will get out of the "old" end at that time, when it was a "young" age, it was effectively going back to time as it was from outside A supervisor had seen it. A significant limitation of such a time machine is that it is possible to return only in the form of the initial construction of the machine; In essence, it is more of a path through time because it is an instrument that progresses through time itself, and in this time the technology will not allow itself to move backwards.

According to the current principles on the nature of wormhole, the construction of a traversal wormhole will require the existence of a negative energy substance, which is often known as "foreign substance". More technically, Wormhole Spacetime requires the distribution of energy which violates various energy conditions, such as the weak, strong and major energy conditions, as well as the state of the weak energy. However, it is known that quantum effects can lead to small violations in the state of null energy, and many physicists believe that the negative energy required in quantum physics can actually be possible due to negative energy. Although initial calculations suggested that a large amount of negative energy would be required, later calculations showed that the amount of negative energy can be minimized arbitrarily.

In 1993, Matt went to argue that with such an induced clock gap, two mouths of a wormhole can not be brought together without stimulating the quantum area and gravitational effects, which would either destroy the wormhole or both mouth Remind one another. Because of this, both mouths can not be closed so that work-due violation can occur. However, in a paper 1997, Viscer estimated that the configuration of a complex "Roman ring" (named after Tom Roman) of Vermohol, arranged in a symmetrical polygon can still function as a time machine. , Although his conclusion is that it is more likely. In classical quantum gravity theory there is evidence rather than fault that causality is possible.

Warp drive

A warp drive is a fictional fast-to-light (FTL) spacecraft propulsion system that works in many science fiction, most notably Star Trek. A spacecraft equipped with a warp drive can travel more speed than light by several orders of magnitude. Unlike some other fictional FTL technologies, such as a jump drive or hyperdriver, the warp drive does not allow immediate travel between two points, but it involves a mediocre time that is conducive to the concept. The spacecraft will continue to interact with objects in the "normal space" at warp velocity. The general concept of "WPP Drive" was presented by John W. Campbell in his 1931 novel Islands of Space.

The theory of Einstein's special relativity states that energy and mass are interchangeable, and the speed of light travel is impossible for physical objects overweight. The problem of a physical object over the speed of light is that in order to actually travel at the speed of light, an infinite amount of kinetic energy will be required. To do this, instead of increasing the kinetic energy of the object, the space can be resolved in principle to move an object to move. In comparison to light travel problem, such a solution leads directly to two opposing approaches for the journey of light-motion in science fiction: first, the spacecraft is brought to the speed of light and beyond it; In the second place, not yet built for the ship to be in the local place, while the ship runs at the speed of the light.