Time should taking a longer time to saw the

Time run in one direction and time travel is a simple concept that appears in science fiction which mentioning the movement between the time. It may travel to the future or to the pass. Profuse of physics lovers may want to in touch and build it. Although it just a simple concept in science fiction, this concept occupies a privileged position in region of physics and philosophy.     In physics side, there are some theories discuss that there is a feasibility that time travel to the future is work. It is called time dilation in physics and it is base on the uncertainty of time which mentions in Relativity (Galperin:2009). And the most famous theory is Relativity. In special relativity, natural time delays are due to a limited speed of information transmittal in the equations and transformations (ibid). And this theory comes from a thought experiment by Einstein called “The Michelson-Morley clock” (Hassani:2017). This experiment consists of a source of light and a mirror. In the first figure, the tube is at rest. Set L is 1.5m and the light takes 5 nanoseconds to go from S to M and take another 5 nanoseconds to go back to S from M. So the light consumes 10 nanoseconds in total for return when the tube in rest. For the second figure, place the tube perpendicular to the direction of motion on a train moving to the right. In this experiment, there are 2 observers whose sit in the tube and another stay on the ground. Although the light source is executing the same route as the first experiment, the observers on the ground would see a different route which the light source passes through (shown in the second figure). The route that the ground observers observe is longer than the observers in the tube saw. However, it is true that speed of light is a constant, which mean the observer on the ground should taking a longer time to saw the experiment. Therefore Einstein concludes that time is related to velocity and time is relative. According to the result of the experiment (ibid), in theory, the more speed to reach, the slower time passes through. Therefore, time travel to the future may success.   Secondly, time not only affected by speed but also affected by gravity which has discussed in general relativity. According to the general relativity, the behavior of the time is entirely related to the behavior of the gravitational field. And base on the gravitational time dilation which wrote by Elbert Einstein predicted the lower the gravitational potential, the more slowly time passes (Baruk?i?a. :2011). In other words, it means that when it approaching a high-density object, the time fluid become slower.  The Pound-Rebka experiment was the first experiment successfully proof the last of the three classic proofs of a General theory was accurate (Rehak). It was carried out in the year 1959 at Harvard. The principle of this experiment was to determine the wavelength of the photons which emitted from the top of the Jefferson Tower which high 22.5 meters at Harvard campus to the bottom. According to the text, when the photons measured from the bottom at its top, the wavelengths were decreased by a small amount. On the other side, when the photons measured from the top at its bottom, the wavelengths were increased which mean red shifted (ibid). Accordingly, the spectral shift toward to red which the signal sent from the bottom of the tower does not lie in the loss of light energy. Therefore, it may prove that gravitational field was linked to the variable time (ibid). With the theory of the relativity, it may impress on the high velocity and an object with the gravitational field to accomplish the time dilation. Therefore, time travel to the future may success in theoretically.     It is certainly true that time travel to the future by utilizing the concept in the theory of relativity may be possible. However, It could be argued that time travel should not be afford to specialize in the future, but also need to consider travel to the pass. The idea of traveling back in time to change the past is probably one of the oldest scientific issues that have given rise to much imagination. Yet, time travel to the pass may not be possible as it may break the rules in the physics and it will bring out some logical problems.  First, in philosophy side, travel to the past may not be a success by reason of the paradox problem and the causal loops. It is well known that every event generally appears to have caused and that is the definition of the causation. However, if someone did travel to the pass, the relationship between the factor and the result may bring out big consequences which out of the logic. There is 2 famous theory of paradox giving an example that can explain the logic problem (Lee: 2011). The first on call grandfather paradox, it was stated that a grandfather was killed by a grandson who is a time traveler. And grandfather was killed before the grandson’s father conceived. And this leads to a paradox as the grandson would not be exist as his grandfather has been killed before born the grandson’s father (ibid). Moreover, the condition of Dentsch’s unproven theorem paradox is a time traveler went back in time to present the proof of a mathematical theory, therefore, it can record in the history which the time traveler can read in the future (ibid). These two cases consider the idea of traveling back in time, however, both may break the causation thus bring out a paradox problem. Due to this two cases, time travel back in time may not work in philosophy side. Not only philosophy side, physics side seems also not allows time travel back in time happen. A famous theoretical physicist, Steven Hawking, bring out a theory call Chronology protection conjecture in 1991. The validity of time travel is represented by the existence of closed timelike curves in exact solution to General Relativity in maths (Hawking:1991),. In other words, time travel may success in General Relativity theoretically. However, Steven Hawking holds into an opposite view. Due to Chronology protection conjecture(ibid), using quantum fields as the background, every timeline contains an independent light cone, time travel to the past may cause two light cone close to each other. Since two light cone convergence, Chronology protection conjecture will be broken down. In the other words, it suggests that when time travel back in time, space-time will resist being warped so that closed timelike curves appear. And that seem to be theoretical reasons to believe the chronology protection conjecture: The laws of physics prevent the appearance of closed time like curves. Therefore, it may not be invaded by hordes of tourist from the future (ibid). Steven Hawking says “it seems that there is a Chronology protection conjecture which prevents the appearance of closed timelike curves and so makes the universe safe for historians”. Nevertheless, both physics and philosophy side tend to not allow time traveler travel back to the past. Because of this behavior seems like trying to break the rule of physics and the concept of philosophy. To conclude, time travel may separate into two parts. The first part is travel to the future, due to the theory of relativity, approaching to a high gravitational field or increase speed close near to the speed of light will occur time dilation (Hassani:2017). Which mean the time for the traveler will much slower than the individuals who stay in rest. Therefore, utilizing this method, time travel to the future may possible theoretically. However, on the other hand, the rule of physics and the logic for the philosophy be in unison that time travel to the pass is impossible. Firstly, it will bring out some logic problem like the paradox. Grandfather paradox and Dentsch’s unproven theorem paradox illustrate that this behavior may violate the causation (Lee: 2011). Moreover, due to Chronology protection conjecture which was written by Steven Hawking, also prove that travel back in time may against the physics law. Therefore, although time travel seems like a science fiction’s classical clips, in theoretically it probably can happen.