The ultra-emission speed interested in people generally refers to ultra-light speed transmission energy or information. According to the narrow relativity, the ultra-light travel and ultra-photographic communication in this sense are generally impossible. At present, most of the situation is that certain things can be exceeded with speed, but they cannot communicate energy or information. However, existing theories have not fully excluded the likelihood of ultra-light speed.
First discuss the first case: is not the true sense of super-light speed.
1. The speed of speed is small in the vacuum in the Trumpkov effect medium. The propagation speed of particles in the medium may exceed the speed of the medium. In this case, radiation is radiated, called the rigonkov effect. This is not a true hypermitting speed, and the ultra-emission speed in the true sense refers to the speed of the vacuum.
2. Third observer If A is moving in East with respect to C at a rate of 0.6c, B is moved to the west relative to C at a rate of 0.6C. For C, the distance between A and B is increasing at a speed of 1.2c. This "speed" - the speed between the two moving objects relative to the third observer - can exceed the light speed. However, the motion speed of the two objects relative to each other has not exceeded the light speed. In this example, the speed of B in the coordinate system of A is 0.88c. The speed of A in the coordinate system of B is also 0.88c.
3. Shadow and spot shake your hand under the lamp, you will find the speed of the shadow to be fast than the speed. The ratio of shadow and hand sharing is equal to the ratio they go to the light. If you sway your flashlight in the moon, you can easily make the moving speed of the spot on the moon exceeds the light speed. Unfortunately, information cannot be transmitted at this way.
4. The rigid body knocked on a stick, the vibration will not immediately pass it to another? Is this not provided a super-optical speed communication method? Unfortunately, the ideal rigid body does not exist, the transmission of vibrations in the stick is carried out, and the sound speed is out of the electromagnetic action, so it is impossible to exceed the light speed. (A interesting question is that the upper end of a stick is vertical, suddenly loosen, is the upper end of the stick first began to fall or the lower end of the stick begins with the upper end. The answer is the upper end.)
5. The phase speed of phase speed light in the medium can exceed the speed of the vacuum in some frequency bands. The phase speed refers to a "propagation speed" corresponding to the phase lag after the phase lag after the medium propagating a distance in the medium in the medium. Obviously, simple sine wave is unable to pass information. To pass the information, you need to modulate a slower wave package in sine wave, and the propagation speed of this wave package is called a group speed, and the group speed is less than light speed. (Translator Note: Sodi and Buri Yuan's propagation of pulses in the media proves that the signal with start time [Zero before a certain time] The propagation speed in the medium cannot exceed the light speed.)
6. The speed of the galaxy of the supercubric speed star is likely to exceed the speed of light. This is an illusion because there is no reduction in our time from the galaxy to our time (?).
7. Relativistic Rockets Watching the Rockets is far from 0.8c, the Rockets are slower than those on the earth, 0.6 times the Earth clock. If the distance from the rocket moves in the rocket, a "speed" is 4 / 3c. Therefore, the people on the rocket are moved at a speed of "equivalent to" super light speed. For those on the rocket, the time has not slowed, but the distance between the galaxies is reduced to 0.6 times the original, so they also feel in speeds equivalent to 4 / 3C. Here the problem is that the number of times the distance from a coordinate system is not true at the time in another coordinate system.
8. Voluntary gravitational dissemination believes that the speed of the puller exceeds the light speed. In fact, the gravity is propagated in light speed.
9. EPR Paradox In 1935, Einstein, Podolski and Rosen published an ideological experiment attempt to indicate the incompleteness of quantum mechanics. They believe that there is a significant overall role in measuring the particles in Entangled State. Ebhard proves that it is impossible to use this effect to pass any information, so super-light speed communications does not exist. But there is still a controversy about the EPR paradox.
10. Dirty particles are transmitted by virtual particle in quantum. Since Hessonberg Uncertain These virtual particles can be propagated in ultra-light speed, but virtual particles are only mathematical symbols, ultra-light speed travel or communication still does not exist. 11. Quantum tunnel quantum tunnel is the effect of the particle escape from the barrier above its own energy, which is impossible in classical physics. Calculating the time of the particles pass through the tunnel will find that the speed of the particles exceeds the light speed. (REF: TE HARTMAN, J. Appl. Phys. 33, 3427 (1962)) A group of physicists did experiment with ultra-photographic communication using quantum tunneling effect: they claimed to pass 11.4cm wide potential at a speed of 4.7C Based on the 40th symphony of Mozart. Of course, this has caused great controversy. Most physicists believe that this quantum effect is ultra-light speed to transmit information due to the uncertainty of Hessonberg. If this effect is true, it is possible to deliver information to the past in a high-speed moving coordinate system.
Ref: w. Heitmann and G. Nimtz, Phys Lett A196, 154 (1994); A. Enders and G. NIMTZ, Phys REV E48, 632 (1993) Terence Tao believes that the above experiment does not have persuasiveness. The signal is not 0.4 nanoseconds with a distance of 11.4 cm through 11.4 cm, but the acoustic signal of up to 1000 nanoseconds can be predicted by simple interpolation. Therefore, there is an experiment that the high-frequency random signal is required to be supercapsomy.
12. Casimir effect When two blocks of chargeless conductors are very close, they will have very weak but still measurable power, which is Kassimi effect. The Kassim effect is caused by vacuum energy. The calculation of Scharnhorst shows that the speed of photons in the lateral movement between the two metal plates must be slightly larger than the radius (for one nano gap, this speed is 10-24, which is larger than the light speed. Under specific cosmology conditions (for example in the Camine String [Cosmicstring] Nearby [If they exist]), this effect will significantly significantly. But further theoretical studies have shown that it is impossible to use this effect to perform ultra-light speed communication.
Ref: k. Scharnhorst, Physics Letters B236, 354 (1990) s. Ben-Menahem, Physics Letters B250, 133 (1990) Andrew Gould (Princeton, Inst. Advanced Study). IASSNS-AST-90-25Barton & Scharnhorst, J Phys A26, 2037 (1993)
13. The universe expansion Hubble stated that the galaxies of the distance D were separated by the speed of HD. H is a constant that is independent of the galaxy, called Hubble constant. The sufficiently far-depth galaxies may be separated from each other with speeds of the light speed, but this is the separation speed relative to the third observer.
14. The moon is rotating at the speed of ultra-light speed!
When the moon is on the horizon, we assume that we take a circle in a speed per second, because the moon is 385,000 kilometers away from us, the moon is 121,000 kilometers per second, about four times more than the speed of light! This sounds quite ridiculous, because in fact, we are rotating, but saying that the moon around us. However, according to general relativity, any coordinate system including the rotating coordinate system is available. Isn't this the moon in motion?
The problem is that in general relativity, the speed of different locations cannot be directly compared. The speed of the moon can only be compared to other objects in its local inertia. In fact, the concept of speed is not much used in general relativity, and it is difficult to define what "super-speed" is very difficult in general relativeism. In general relativity, even "Einstein does not need to explain. Einstein I said" Relativity: Narrow and General Aory "on page 76" Light Express "is not always correct. At the time and distance there is no absolute definition At the time, how to determine the speed is not so clear. Nevertently, modern physics believes that the radius of the broad relativeism remains unchanged. When the distance and time unit links through the light speed, the speed of light is unchanged as a non-self-clear system. Definition. In the previous example, the speed of the moon is still less than the speed of light, because at any time, it is located within the future light cone from its current location.
15. Clarify the definition of super-light speed
The first part of the various examples of the "super-optical speed" example indicates the difficulty of defining "super-optical speed". The "super light speed" of the shadow and spot is not true ultra-light speed, then what is the true super-light speed? "World Line" in the relativism is an important concept, we can use the "World Line" to give "super-speed" next clear definition.
What is "World Line"? We know that all objects are composed of particles, and if we can describe the position of the particles at any time, we describe all of the "history" of the object. Imagine a four-dimensional space consisting of a three-dimensional plus time of space. Since a particles can only be in a specific location at any time, all of its "history" is a continuous curve in this four-dimensional space, which is "World Line". The world line of an object is a collection of world lines that make up all of its particles.
The history of non-optical particles can form the world line, some people defined "things" history can also form the world line, such as shadow and spot. The shadow can be defined in its border. These points are not true particles, but their positions can be moved, so their "history" also constitutes the world line.
One point in the four-dimensional time and space is an "event", that is, three spatial coordinates plus a time coordinate. Any two "events" can define a space distance, which is the square of the spatial distance between the two events to reduce its time interval and the layers of the light-speed product. The narrow relativity proves that this time and space is not related to the coordinate system, so there is physical significance.
Time and space distance can be divided into three categories: class distance: spatial interval is less than the product of time interval and light speed; type light distance: spatial interval is equal to the product of time interval and light speed; Empty distance: Spatial interval is greater than the time interval and light speed.
Below we need to introduce the concept of "local". A smooth curve, "local", very similar to a straight line. Similarly, the four-dimensional time and space is partially straight, the world line is locally similar, that is, the speed can be described, which is the instantaneous speed of the particles. On the world of photons, the distance between adjacent events is light. In this sense, we can speak the world line of the photons as light.
Any world line of particles at a speed at a speed of speed, is partially, and the distance between adjacent events is time. In this sense, we can say this world line as a class. The particles or artificial "points" defined by ultra-light speed movement are empty. Here, the world line is empty, refers to local, and the spatial distance of adjacent events is empty.
Because there is a possible time and space, there may be such a world line: Locally, the distance between adjacent events is class, the particles do not have a super-light speed; but there are two events that are far away, their space space The distance is empty. This is not a super-light speed?
The meaning of this problem is that it can define local "super-optical speed" or define global "super-optical speed". Even if the local supercuminance is impossible, the possibility of global super-light speed is not excluded. Global super light speed is also worth discussing. All in all, "super-optical speed" can be defined by empty world lines, which is the case where the two objects are moved relative to third observes with "super-speed" movement.
Let's consider what we think that ultra-light speed transmission is "something", the main purpose is to eliminate things that "shadow" and "spot" are useless. Particles, energy, charge, spin, information is our wondering. One question is: How do we know what is transmitted or the original thing? This problem is better, for a particle, we observe its world line, if the world line is continuous, and no other particles are separated from this particle, we can think that this particle is still that particle.
Obviously, transmitting the entire object is more difficult to say more than the transmission information. Now we have no difficulty in transmitting information without difficulty. In essence, we only have to re-read the information on the time series of the information in the photon and reachabilia to the time series from the photon, and the speed of the photon is naturally light speed.
Similarly, if a fast child (TACHYONS, theoretically predicted ultra-photometer) really exists, we only need to find a technique that controls its generation and transmission direction, it can achieve supercap speed communication.
It is extremely possible that the cost of transmitting different particles is extremely different, and more economical is to use replication technology. If we can get all the information about an object, and we have mastered the technology of copying the original object from this information, then super-optical communication and super-light travel are equivalent.
Science fiction has long been there, called a long-distance fax (Teleport). Simply put, it is like a fax, then copy a copy there, and then destroy the original one, it is equivalent to passing the people. Of course, the problem is whether the conscious complex object of people can be copied.
16. Unlimited energy
E = MC ^ 2 / SQRT (1 - v ^ 2 / c ^ 2)
The above formula is the energy of the stationary mass to M. Energy when the speed V is moved. Obviously, the higher the speed, the greater the energy. Therefore, it is necessary to allow particle acceleration to do it, and the work is equal to the increase in particle energy. Note When V is approxishes C, energy tends to be infinite, so that the particles reach the light speed in a usually accelerated manner, not to mention super light speed.
However, this does not exclude the possibility of ultra-light speed of particles in other ways. The particles can decay into other particles, including photons moving at a light-speed (the stationary mass of the photon, so that the energy is moved, the energy thereof may also be a limit, and the above formula is invalid for photons). Details of the decay process cannot be described in classic physics, so we cannot negate the possibility of producing ultra-photographic particles by decay (?)
Another possibility is that the speed is always above the particles of the radius. Since there is a photon that is always at a speed of light, there is a particle that is always at a speed at a speed of the speed speed, why will there be a particle that is always at a speed higher than the speed of the speed? The problem is, if V> C is in the above formula, either energy is imaginary, or the quality is imaginary. If there is such particles, there is no physical significance of energy and quality? How should I explain their meaning? Can I launch a observable prophecy? As long as the evidence of this particle is found, the method of detecting such particles is found to find a method of deflecting the movement of such particles to achieve ultra-light speed communication.
17. Quantum field
So far, all physical phenomena except gravitational is compliant with the standard model of particle physics. Standard model is a relatively argument, which can describe three basic interactions including electromagnetic interactions, weak interactions, and strong interactions, and all observed particles. According to this theory, any operator corresponding to the physical observation of two events in an empty distance is an easy (Any Pair of Operators Corresponding to Physical Observables At Space-Time Events Which Are Separated by a Space Like Interval Commute) ). In principle, this means that any effect is impossible to spread at speeds of speed. However, no one can prove that the standard model is self-constent. It is very likely that it is actually really not self-contained. In any case, it cannot guarantee that the particles or interactions there are no discovery it cannot be described in the future. No one will extend it to include broad relativity and gravity. Many people studying quantum gravity doubt whether such simple expressions on causality and local area can be used. All in all, in the future theory, it is not possible to ensure that the speed is still the upper limit of the speed.
18. Grandfather Paradox (causality)
The best evidence against super-light speed is probably the grandfather's paradox. According to the narrow relativity, the particles in a reference system are possible in the other coordinate system in another coordinate system. Therefore, ultra-light travel and ultra-photographic communication also means back to the past or transmit information to the past. If time travel is possible, you can return to the past to kill your own grandfather. This is a powerful refutation of super-light speed. But it can't rule out this possibility, that is, we may make limited ultra-light speed travel but cannot go back. Another possibility is when we make super-speed travel, causality is destroyed in some consistent way.
All in all, time travel and ultra-light speed travel are not exactly the same but have contact. If we can return to the past, we can also achieve super-light speed travel.
Third part: the possibility of ultra-light speed unseaved
19. Tachyon
Fastum is theoretically predicted particles. It has a local speed (instantaneous speed) that exceeds the light speed. Its quality is imaginary, but energy and momentum are real. Some people think that this particle cannot be detected (the translation: What is the meaning of this prophecy :-), but it doesn't matter. Examples of shadows and spot illustrate that more than light speed can be observed.
At present, there is no experimental evidence that there is no fast child, and most people doubt their existence. Some people claim that there is evidence that there is evidence in the experiment of the Medium Quality of Tritium Petay's decline. This is very suspicious, but it is not fully excluded.
The problem of faster theory, one is violating causality, and the second is the presence of a faster to unstable vacuum. The latter can be avoided in theory, but if we cannot achieve ultra-light speed communication.
In fact, most physicists believe that the faster is the performance of the morbid behavior, and the public's interest in the faster is much more than the number of times in science fiction.
20. Wormle
A famous advice on global super-light speed travel is to use the wormhole. The insect hole is a shortcut to connect two locations in the bending time and space, and the time required to pass through the insect hole to the B-place is shorter than that of the light from A, and it needs to be shorter. Wormles are inference of classic generalized relativity, but creating a wormhole need to change the topology of time and space. This is possible in quantum gravity.
Opening a worm hole requires a negative energy area, Misner and Thorn recommend a negative energy area using the CasimiR effect on a large scale. Visser recommends using the cosmine. These recommendations are almost unrealistic. The weird substance with negative energy may not exist in the form of their requirements.
Thorn Discovery If you can create a wormhole, you can use it to construct a closed class in time and space to achieve time travel. Some people think that multiverse explains can be used to eliminate causal paradoxes, that is, if you go back, history will happen in different ways. Hawking believes that the worm hole is unstable and is therefore useless. However, insects is still a well-rich area for ideological experiments, which can be used to clarify what is possible under the known physical law of recommendations, what is impossible. REFS: WG Morris and Ks Thorne, American Journal of Physics 56, 395-412 (1988) WG Morris, Ks Thorne, And U. Yurtsever, Phys. Rev. Letters 61, 1446-9 (1988) Matt Visser, Physical Review D39 3182-4 (1989) See Also "Black Holes and Time Warps" Kip Thorn, Norton & Co. (1994) for An Explanation of The Multiverse See, "The Fabric of Reality" David Deutsch, Penguin Press.
21. Quarter Promotion (WARP Drive)
The trip proportion refers to the bending in a specific manner, thereby making the object supercapshe. MigueLalcubierre is known as a presented a time and space geometric structure that enables a trip. The bending of time and space allows objects to travel at a class while maintaining a class. Like the insect hole, the track advances also requires a weird substance with negative energy density. Even if this material is present, it is not clear how specifically, how these substances should be arranged to achieve the falling phase.
