There are few things in science fiction more exciting and fascinating than time travel.
While there are so many stories and ideas that go along with time travel, is it physically possible to travel in time? In a short answer the word is yes, but not like you may think. Travel to the future is indeed possible and actually quite easy. All we would need is a space ship that could get close to the speed of light. I say close to the speed of light because in theory nothing can travel faster, that is without some sort of warp drive, but that is getting into the realm of science fiction. (Although, there are some theoretical physicists that claim that this type of technology is possible, but for this post let’s say that it is out of our reach for the moment.) So according to Einstein’s theory of general relativity as a person on the ship approaches the speed of light time, for them, time begins to slow way down. The faster they go the slower time for them ticks away. So a second may last for minutes back on Earth, minutes may last hours, hours could be days or weeks, you get the idea. So when the person returns from his voyage perhaps only a few months will have passed according to his watch, but back on Earth five, ten, or even many more years will have passed. So in an essence the traveler has in fact time traveled to the future. Sounds easy enough right.
The above scenario is FACT and undisputed among anyone in the field and had been proved in numerous well documented experiments. What is still under some debate is time travel to the past. This is the one that almost everyone is in disagreement on. Even Hawking has changed his mind on whether or not this is possible. At first he was against it, but later said that the physical laws may not prevent it, still they are only theories at this point.
To achieve travel to the past is going to take technology that is well beyond anything we can conceive at this point in time. Theoretically we know how one MIGHT be able to do this, but it involves using dark energy, which we think exists but have never seen or detected it. So the basis of this theory rests on a thing that we have never seen before, sounds promising right…
As the video states if one could perhaps harness or use dark energy we think we could open a worm hole using the negative gravity of the dark energy. Again this is theoretically possible. Once we open this worm hole, the theory then states that we could put this worm hole on a ship and, again, fly near the speed of light out into space. The other end of the worm hole would be here on Earth. Time would pass more slowly on the ship and so that end of the worm hole, once it returned to Earth would and should be connected to the past. This sounds really bizarre and rather hard to fathom. In the video they talk about circling a black hole, which would produce the same results, as gravity is much more massive near a black hole, think of the movie Interstellar.
Again all this is physically and theoretically possible, but again hinges on the fact of finding and harnessing a particle that we have been searching for and not found yet. So again this is technically possible, but if we open this worm hole, there are still a plethora of issues that come into play. I can’t remember if it was Einstein or Hawking or both that said that worm holes to the past are possible, but there is no way that a living organism could successfully go through and come out the other side unscathed. One of the main reasons is that the massive amount of radiation that is believed to accompany the worm hole. So even if we could create a worm hole there is no guarantee that we could successfully travel through it. Some scientist think this could be a way that nature restricts anyone from traveling to the past and eliminating many of the paradoxes that accompany backwards time travel.
The above video throws out quite a few different ideas and I felt was rather hard to follow. Still there are a ridiculous philosophical question that arise if backwards time travel is possible. There is certainly the idea that free will may not actually be a real thing, meaning we do not have free will. Although when it comes to this aspect I usually follow what physicist Brian Greene says. He said something to the effect that free will is an illusion, basically it appears that we have free will, but when you really get down to it, it is just an illusion.
I don’t want to get off topic as that is more of a philosophical discussion, so I will discuss that in future posts. I also wanted to discuss our view of time. The last video touched on it, but failed to say it. The video said something like our view of reality is strange and what not, but they failed to connect the dots as to my theory. I believe that our understanding of the universe will only take us as far as our brains can handle. Meaning that despite how smart we think we are, our cognitive capacity is limited and our view of reality is molded from millions of millions of years of evolution, which could very well be wrong. Our brains evolved so that we can make sense of reality, but just because our brains make sense of it does not mean that it is right or in reality makes sense. When you take these two things into consideration it is easy to see that we may never know the most intimate details or in depth knowledge of the universe. Reality is a tough nut to crack, and the debate of whether there is something out there regardless of whether we are there to view it is still under debate.
Another interesting aspect is that time is a measurement. It flows and we know so because we can tell that things are different from one moment to the next, but again how we view time is wrong because of our limited cognitive capacity. That change means that time has passed. If all molecules and particles did not move and had lost all energy, as they may when at the end of the universe, time as far as we know it will have stopped. An observer will not be able to tell one moment from the next as nothing will have changed, with no particle movement every moment will look the exact same as the next. Because time is a measurement some think that time travel is impossible, however most scientist believe that time travel is possible and none of the mathematics involved seem to prevent it. Based on my limited knowledge of the subject I am inclined to think that it is possible, but I do not believe that we will ever achieve such a feat.