The topic of this essay is time travel .While in the last decades this topic has been a subject and a relevant part of sci-fi series and movies , lately scientists and physicist have started to research in order to find if in our reality is possible or not to travel trough the so called space-time continuum .Though at the moment no real experiment can be run due to the lack of technology and of a feasible energy source , we are already aware of many theoretical problems involving time travel . While some experts sustain that time travel can actually be possible, and have some theory to explain it, other simply think it is not feasible.

But time travel has to be separated in two different categories: travelling in the past and travelling in the future .The latter is theoretically “easier” to achieve, due to the fact that it only requires us to move at the speed of light, or at least really close to it. This because we have acknowledged that when a particle moves at a really high speed, its time flows faster than the space that surrounds the particle itself. But this doesn’t mean that is easy to achieve, because the speed of light is roughly 300,000 kilometers per second, and the fastest object ever produced by humans barely reaches 16 kilometers per second. Oil based fuels engines cannot fulfill the task of getting us to travel at the speed of light , and probably any material on our planet won’t be able to . It has been hypothesized that an amount of energy equal to the one possessed by a black hole, could eventually make us travel close enough to light speed .But what engraves most controversies is travelling in the past , because we are going in a time when events have already occurred . Any slight change in our past could dramatically change our future (this is also known as the butterfly effect).As an example , if someone went back in time and prevent Hitler to be born ,probably all world war 2 would have been avoided , thus changing entirely the world from when the time traveler came from. And this is where the paradoxes come in .If someone travelled in the past and prevented himself or one of his ancestors to be born (commonly known as the grandfather paradox), how is possible that he traveled through time in the first place?

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By who believe that time travel is possible, such as theoretical physicists like Michio Kaku and Stephen Hawking, the theory of Multi-verses was created . This theory implies that not only one universe exists, but an infinite number of them , with each one with slight differences from ours , and others totally different . If this is true , time travel could indeed be possible , because by travelling back in time , we won’t travel in our own past , but in the past of another reality , thus excluding the problem of paradoxes .There is also another “proof” that shows that to travel trough time is not impossible .The laws of physics currently used and generally all well received by all the scientists and physicist community , don’t exclude the possibility of time travel (The independent,2008), though it’s hardly believable that we will become capable of travelling trough time in a matter of a short time period .

On the other hand , there are many experts that think that time travel it is not feasible . One of their main proves is ,as explained before , the theoretical issue of the paradoxes .If the theory of multi-verses shows up to not be applicable to our reality , then it’s mostly confirmed that , for what at least concerns travelling in the past , is indeed not possible .The other major point of the skeptical side of the scientific community is the problem of how actually travel trough time could be done and what technology and energy source would be required .Many theories have popped of people fantasies , mostly regarding sci-fi movies and series , and some of them are strongly physics-based . One of these implies the usage of wormholes(see picture 1)to travel trough the space-time continuum to go in places far away in space and time , both in the future or in the past ,having a trip in a shorter time period than what light would have experienced . A new research has proved that , with a miniature version of our universe , that the direction of time cannot be changed , and therefore , we won’t be able to travel to the past . Another proof was give by Stephen Hawking , when he still believed that time travel was not possible . He made a simple experiment : He made a party for time travelers , but he didn’t tell anyone about it until the party was finished . After the party , he scattered around invitation , hoping that they would have lasted enough time to reach somebody who was able to travel trough time . But the result was that nobody attended the party .

These information could prove that time travel is not possible , but there are some confutation to be made : In the first case , the described ”scale model” of our universe cannot be compared to the scale of the universe itself , and therefore it can be excluded as an affordable proof . For the second case , Stephen Hawking himself later on admitted that when traveling in time , and in the case of multiple universes , also traveling through universes , the traveler might not be able do decide in which universe go ,which means that maybe somebody who was able to time travel received the invite , but simply didn’t manage to travel to our universe .

So this confutates , for the moment , some of the opinions against time travel.

At the moment there is no way the experiment a physical/relevant time travel , but we are experiencing something close with the LHG in Ginevra , by making some particles go at a speed really close to the speed of light .It might take hundreds of years , but if money and “time” are going to be involved in the research ,maybe one day humanity will eventually have an answer for the question :can we travel trough time ?

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