Time travel is a topic many people are familiar with and a topic many people find fascinating (especially me).  It has been the focal point of many movies and shows in the past, but is it possible? There are many variables that have to go into time travel. Moving freely throughout time and space like on screen is unrealistic but there are several theories that might make it a possibility.

      Before we can get into the actual travel part, we have to first cover the basics. You have to understand time. Time is a dimension, kind of like length, width and height. When you move on the earth, like to school, you are traveling forward in spatial dimensions but you are also moving forward in time (4###sup/sup### dimension). You are able to move freely forwards, backward, up and down in the first three dimensions but the 4###sup/sup### dimension only allows you to move forward.

        Now that we have that out of the way we have to cover one more thing. Traveling to the future or to the past are two very different things. The past being the more complicated of the two. However, there are many theories for them.

Future

       Traveling to the future is possible based on Einstein’s Theory of Special Relativity and it has actually happened. I know, it is crazy but hear me out. First off, the Theory of Special Relativity says that if time and space were the same thing there is a speed limit (300,000 kilometers/per second). When something travels the speed of light, and they are passing through space and time, time actually goes slower. However, this effect will not be known until they return to normal speed.

       One theory is to travel to the future you have to achieve light speed. Assuming you construct a ship that can travel the speed of light you could possibly travel to the future. Time would be slow relative to the people on earth that are going normal speed (1 hour per hour). You would be going fast while the clock would be going slow. So you could travel a year in light speed and when you got back to earth you only aged a year but earth has gone through many years (depends on how close to the speed of light you got). Sadly, to get a ship that could travel light speeds is nearly impossible and the effect of light speed on people for an extensive amount of time is unknown and, almost certainly, fatal.

     Another theory involves black holes, also theorized by Einstein. If you sat at the edge of a black hole for a while, time would pass slower. The effect would be the same as traveling at the speed of light. You would return to an earth that has aged many years while you only aged the amount of time you sat next to the black hole.

      Amazingly, Serial ISS resident Sergei Kirkalev has already time traveled. He holds the record for the longest time in space. He was on the ISS for 803 days, 9hours, and 39 minutes.  The ISS has a speed of 7.66 km/s around the earth. Since Sergei was on the ISS for as long as he was, he actually arrived back to earth 0.02 seconds in the future. He achieved this by a phenomenon known as dilation. The time on the ISS ran a fraction of a millisecond faster than on earth. The time dilation is due to gravity, even though earth’s gravity is weak astronauts travel a little bit into the future when they arrive back to earth. It might not be impressive that he only traveled a fraction of a millisecond into the future, but it is still time travel.

Past

      Traveling to the past is a whole other story. Even if time travel was possible, you could only travel back to the time the machine or the object that did the time traveling existed or else the machine would not exist and you could not be in the past. I know, it’s complicated and confusing but it makes perfect sense. Let’s say you wanted your parents never to meet so you went back and broke them up. This causes you to never be born so you couldn’t have traveled through time to break them up. This goes with the theory that time and space are one.

     One theory for traveling to the past is with wormholes or a tunnel connecting to places in space-time. This could also be a theory for future time traveling. The wormholes could theoretically connect two worlds or two different places in time. They could go anywhere is the galaxy. However, the energy needed to cut a hole in the fabric of time would take the energy of a star. That technology is not available today.

      Another theory is the Cosmic Strings theory. Cosmic strings are energy tubes that streak across space that were left over from earlier cosmos. They are suspected to contain a lot of mass and are able to warp space-time. They are either a string or a loop, there are no ends. If two cosmic strings were parallel to each other, the force would be able to bench space and time and theoretically make time travel possible. Again, this is far beyond our technology today.

      For now, time travel is too advanced for today’s technology. Traveling to the past is not completely ruled out. Maybe in the future, time travel will be possible. Until then we are stuck living in the present.

Resources:

Martin, Sean. "Time travel IS possible and has ALREADY happened, say esteemed physicists." Express.co.uk. Express.co.uk, 01 Apr. 2016. Web. 30 Mar. 2017.

NASA. NASA, n.d. Web. 30 Mar. 2017.

 Goudarzi, Sara. "You Can't Travel Back in Time, Scientists Say." Live Science. N.p., 7 Mar. 2007. Web. 3 Mar. 2017. .