Time TravelFirst of all to give you a better concept of time I will use a personal theory of mine. When you look at the sky at night, at the stars, what do you see? Do you think star collage really exists? Most of them don't. When you look at the sky at night you are seeing the past because it takes an obscene amount of time for the light from those stars to reach the earth, and in that time those stars may have disappeared. It works both ways. When an inhabitant, if there is one, on a planet around the star you are looking at looks at our sun, he or she is also seeing the past. So here we are at the main idea of ​​my speech: the possibility of different times and time travel. The main question here is: how do these 2 times connect? Well, the key is to go faster than light, which is 186,283 miles per second - or about the same as circling the earth seven times in one second. If you're having trouble understanding that going faster will double you, I can put it more simply: motion slows down time. This was proven in 1971. In that year American physicists took 4 atomic clocks, left 2 on the ground, and put each of the others on airplanes flying in opposite directions around the earth at 621 mph. When the planes returned, scientists were happy to find that the planes' clocks were a few billionths of a second slower than those left on the ground. (theage.com.au) Unfortunately, according to Einstein (who has yet to be disproved), you cannot go at the speed of light because whatever solid object you used to do so (for example: the spaceship) would create a vortex behind it which it would drag all matter... planets, stars, galaxies, etc. To put this into perspective, think about when... middle of the paper... the mother would be born, meaning the time traveler would be born and in fact could still go back in time and kill his grandmother.Dr. Preston has two solutions to this. The first is that it is not possible to alter the course of history, so the time traveler would have endless misadventures in trying to kill his grandmother. The second is that when he killed her he immediately created a parallel universe in which the young grandmother never existed and where he was never born, but our original universe remains. Time travel seems to be a thing only for science fiction movies, but it could have been invented in the future and the course of history has already been changed. While we are here now, all our feelings, thoughts and memories may have simply been reset and we are in a different universe. Neither you nor I would have any memory of it.