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Time Travel Essay People often wish that they could go back to the past and correct their wrong behaviors or go to the future and see what it turns out to be like. The idea of time travel has been the topic of science fiction movies and novels, and has been studied by great scientists throughout history. â€Å"Ideas of time travel have existed for centuries, but when Albert Einstein released his theory of special relativity, he laid the foundation for the theoretical possibility of time travel. As we all know, no one has successfully demonstrated time travel, but no one has been able to rule it out either. Time has fascinated people throughout the dawn of civilization. People have spent their life thinking about these concepts and the ideas behind them† (Kulkarni,2011). Although the possibility of time travel has been criticized, a lot of modern scientists still argue that time travel is possible. This paper attempts to prove that time travel is possible. To better understand this assertion, we first need to study where this concept started and primarily the theories supporting this claim. Then, how it would be possible to travel to the future and to the past. Also, the philosophical understandings which include paradoxes and other arguments that tend to disprove the possibility of time travel. Ideas about time travel has been passed from generations to generations and it could be traced back to the years before the birth of Jesus Christ. â€Å" Time travel is the concept of traveling forward and backward to different points in time, much as we do 4 through space† ( Crystalinks, 2010). Many of the early works featuring elements of time travel have been claimed to be the earliest so there is no widespread agreement as to which written work should be recognized as the earliest example of a time travel story. Ancient folk tales and myths sometimes involved something the same to traveling to the future in time for example, in Hindu mythology, Mahabharata and Urashima Taro which is a Japanese tale. â€Å"Memoirs of the Twentieth Century† by Samuel Madden was an early story with ideas of time travel backwards. The first time travel was described through the book of Charles Dicken entitled â€Å" A Christmas Carol† , Ebenezer Scrooge, as the main character, is transported to Christmas past, present and yet to come. Two stories entitled â€Å"El Acronopete† and â€Å"The Time Machine† written by Gaspar y Rimbau and H. G. Wells respectively are the first stories to feature time travel with the aid of time machines. Again, a lot of people have been talking about the concept of time travel since years before the birth of our Lord and until now. What are the theories about time travel and what are Einsteins theories supporting it ? The answers are the most notably theories of time travel: forwards and backwards and supported by the theories of relativity: the special and general relativity. According to Brian (2001) â€Å"Einstein’s theories of general and special relativity can be used to actually prove that time travel is possible†. In 2011 Kulkarni claimed that â€Å"the special theory gives a unified account of the laws of mechanics and of electromagnetism. Einstein rejected the concepts of absolute space and time and made two postulates (a) the laws of nature are the same for all observers in uniform relative motion and (b) the speed of light is the same for all such observers†. Therefore, with the knowledge and understanding of the ideas of physics particularly on the theory of special relativity of 5 Einstein, one will be able to believe that time travel is possible. â€Å"In 1915, Einstein developed his ideas to form the General Theory of Relativity, in which he considered objects that were being accelerated with respect to one another. He compared the forces of acceleration and gravity and found them to be indistinguishable. For example, an astronaut standing in a rocket on a launch pad would feel himself pressed against the floor because of gravity. If the same rocket was in outer space and not affected by gravity, but with its engines turned on so that it was accelerating, the astronaut would again be pressed against the floor. If the acceleration due to the engines were the same as the acceleration due to gravity, the astronaut would have no way of telling whether the rocket was at rest on the earth or accelerating in outer space unless the looked out of the window. Einstein stated that the attraction to the Earth of a rocket that is resting on a launch pad is equivalent to the acceleration of the rocket. So although in three-dimensional space, the rocket remains stationary, in four-dimensional space-time the rocket is in motion along its world line. The upshot of this motion in space-time is that gravity also makes time run slower†( Kulkarni, 2011). What are the kinds of time travel and what are the ways that will help scientists prove that time travel is possible? The two kinds of time travel are time travel forwards and time travel backwards, which will be made through time dilation, time perception, the use of wormholes, and special-spacetime geometries. Studies conducted by scientists reveal that there is a possibility to time travel to the future. There are two ways presented by them in which a person can time travel forwards: time dilation and time perception. Hawking (2010) states â€Å"I do believe in time travel. Time travel to the future. Time flows like a river and it seems as if each of us is carried 6 relentlessly along by times current. But time is like a river in another way. It flows at different speeds in different places and that is the key to traveling into the future. This idea was first proposed by Albert Einstein over 100 years ago. The first course is to use the idea of time dilation. It has recently been claimed ( Cutnell and Johnson, 2006, p. 610) that â€Å"An observer who is in motion with respect to the events and who views them as occurring at different places measures a dilated time interval. The dilated time interval is greater than the proper time interval, according to the time dilation equation†. For example, an observer might take a trip away from the Earth and back at relativistic velocities, with the trip only lasting a few years according to the observers own clocks, and return to find that thousands of years had passed on Earth†. Indeed, â€Å" once spaceships are built that could fly faster than the speed of light a day on board would be equivalent to a year on Earth. Thats because -according to Einstein- as objects accelerate through space, time slows down around them† (Hawking,2010). Cutnell and Johnson (2006, p. 60) noted, â€Å"A striking confirmation was achieved in 1971 by an experiment carried out by J. C. Hafele and R. E. Keating†. Consequently, time dilation will genuinely help time travelers to time travel to the future if they are able to travel in space. In addition, time travel to the future would be possible through time perception, where the body temperature and metabolic rate of the creature is decreased. Some scientists research on the possibility of time travel to the past and the results demonstrate that it will become true. Certainly, they displayed two possible methods which will help an individual to be able to travel backwards, these are by using wormholes and through the idea of special space time geometries. One view (Brian, 2001) is that, â€Å"Wormholes appear to be the main way that time travel into the past would be 7 possible. Wormholes are holes in the fabric of four dimensional space-time, that are connected, but which originate at different points in space and at different times†. Crystalinks (2010) asserts that â€Å"A proposed time-travel machine using a wormhole would (hypothetically) work something like this: A wormhole is created somehow. One end of the wormhole is accelerated to nearly the speed of light, perhaps with an advanced spaceship, and then brought back to the point of origin. Due to time dilation, the accelerated end of the wormhole has now experienced less subjective passage of time than the stationary end. An object that goes into the stationary end would come out of the other end in the past relative to the time when it enters†. Although, it is hard to build a time machine like a huge spacecraft, still small time machines are possible to be made enabling human beings to travel backwards. Therefore, the use of wormholes is one of the best course to enable a man to time travel to the past. Likewise, time travel to the past will be possible through the idea of special space time geometries that describes the universe under a system of field equations, and there exists solutions to this equations. What is the paradox that hinder the possibility of time travel and what is its resolution? The answer is the grandfather paradox and the Novikov self-consistency principle. Grandfather paradox is a logical contradiction of time travel. Mendham (2005) states that â€Å"This is a very simple idea with serious repercussions for the concept of time travel. Lets say that I invent a time machine and travel into the past. I meet my own grandfather when he was a boy and kill him. The result? One of my parents is never born, therefore I can never be born† . But, a resolution of this paradox was discussed. Mendham (2005) further expained that â€Å"An interesting technical approach to resolving the paradox 8 is the Novikov self-consistency principle proposed by Dr. Igor Novikov. This essentially says that paradoxes wont happen its impossible to create a paradox however hard you try. In this view the universe is in some way self-righting. If you attempt to shoot your grandfather then something will go wrong youll miss, the gun will jam, etc. Or, if you succeed, youll later learn that your father was adopted; so he still gets born and still marries your mother. This reminds me of the anthropic principle: the universe is this way because if it wasnt we wouldnt be here†. Therefore, there is always a possibility traveling forwards and backwards . In conclusion, time travel is possible even though some say it is not. Studies confirmed that time travel is possible. Although others have presented a paradox, the resolutions have also been made. The methods of traveling forwards and backwards are elaborated and they really help in a way to make time travel possible. In addition, critics didnt clearly prove that time travel will be impossible. Therefore, the issue on time travel has been solved even though no one has actually experienced time travel much as we see in movies. In the end, the future development of our technology is in the hands of our scientists and the possibility of time travel is also at them. 9 Bibliography Brian. (2001). Brians View on Time Travel and Interdimensional Voyages. Available: http://www. brianbosak. com/ Crystalinks. (2010). Time Travel. Available: http://www. crystalinks. com/timetravel. html Cutnell, J. D. Johnson, K. W. (2006 ) . Essentials of Physics (1st ed. ). USA: John Wiley Sons, Inc. Gott, J. R. (2002). Time Travel in Einsteins Universe: The Physical Possibilities of Travel Through Time. Boston: Mariner Books. Hawking, S. (2010). Stephen Hawking: â€Å" Time Travel To The Future Is Possible†. Available: http://www. dailygalaxy. com/my_weblog/2010/07/stephen-hawking-time-travel-to-the-future-is-possible. html Kulkarni, D. (2011). thus Time Travel is Possible. Available: http://www. buzzle. com/editorials/6-20-2004-55679. asp Mendham, T. (2005). Time Travel Paradoxes. Available: http://www. horology-stuff. com/time/travel/paradox. html Miller, Kristie (2005). Time travel and the open future. Disputatio Nahin, Paul J. (2001). Time Machines: Time Travel in Physics, Metaphysics, and Science Fiction. Springer-Verlag New York Inc.. Toomey, David (2007). The New Time Travelers: A Journey to the Frontiers of Physics. W. W. Norton Company.