Einstein's Theory Of Special Relativity: How Viable Is Time Travel?

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How viable is time travel?

Time; it organizes our lives and universe into an ordered series of moments. At first thought, time is one of the most fundamental aspects of our lives and the world we know. However, time is in fact incredibly subjective; everyone experiences this indefinable concept differently.

Einstein's Theory of Special Relativity is based upon the idea of frames of reference. A frame of reference is where an observer is situated. In order to develop a universal concept of time, one would need an absolute frame of reference in the universe; however such a thing does not exist as there is no point in the universe which is completely stationary. The Second Postulate of the Special Theory of Relativity is that the speed of light
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Einstein conducted a famous 'thought experiment' surrounding the concept of time dilation and its effects; known commonly as the 'Twin Paradox'. This clearly demonstrates the nature of time travel due to time dilation. Einstein thought of a set of twins, naming one Al and the other Bert. Al embarks on a journey close to the speed of light in a rocket whilst Bert stays at home, therefore Bert is a frame of reference to Al. When Al returns home, he is significantly younger than Bert. The exact age difference depends on how long Al travelled for, but it could be that Al is half a year older than his age at departure whereas Bert is 30 years older. This is caused by time dilation; as Al was travelling close to the speed of light, the clock on board the rocket slowed down enormously compared to the clocks back on Earth. Therefore Bert lived 30 years in the time Al lived 6 months. We would therefore say that Al has travelled forwards in time. (http://www.pbs.org/wgbh/nova/einstein/hotsciencetwin/, …show more content…
[7 Everyday Things That Happen Strangely in Space] (Adam Hadhazy, April 2009, http://www.livescience.com/19582-time-travel.html/). Einstein's equation E=mc² tells us that a massive object cannot reach or exceed the speed of light. The equation tells us that the mass of an object increases as its speed increases, and also that some of the energy given to speed the object up gives it more mass. Therefore, as the object gets faster and therefore more massive, it requires more energy to speed it up. This means that it would require more than the total energy in the universe to be able to speed it up to the speed of light. So it is impossible to travel at the speed of light. Although it has been determined that the effects of time dilation are significant at speeds close to the speed of light, the energy requirements to reach these speeds will still be enormous due to E=mc² and so such a journey would be incredibly difficult to achieve, not to mention expensive and

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