Time travel is very likely possible, we know that time is relative to speed and moving at extremely fast speeds, slows down the progression of time for the object/person who is traveling. We also know that time can be dilated around singularities such as black holes. What this tells us is time is mutable, and if time is mutable, it is likely time travel is possible. I am not going to get into the specifics, all I care about at this moment is that time travel is possible and if what we think we know about the universe is true, then time travel is possible.
The popular hypothesis on time travel is if someone travels back in time and changes the events of the past, this creates an alternate timeline, nothing changes in the original time lin. The person traveling forward to their original time, would find nothing had changed. If the person travels forward in the alternate time line, they would find an alternate version of themselves who lived the alternate life. This is a convenient, clean method of discussing time travel.
Another hypothesis is changes to the time line directly impact the future, this was best shown in the Back to the Future movie series, where the protagonist accidentally interferes with his own mother and father getting together, which causes him to start to fade from the time line. Under this premise, if time travel is ever actually achieved and people are going back in time to alter things, this would mean the time line is in flux.
The first hypothesis does not interest me much, it is basically “Nothing changes” idea. The second hypothesis does interest me. The idea that the time line is in flux would mean things as we remember them may not actually have been true a few minutes ago. Our whole perception of history could be changing from moment to moment and we would have no idea, or would we? The human brain is a complex organ and so is the nerve system that make up or sensory inputs, seeing, hearing, smelling, taste and touch. We can perceive things and not know conscientiously that we are perceiving. For instance very low or very high pitched sounds can affect humans emotionally, even though these sounds are outside of our range of hearing. We see and hear things all the time that we do not notice at the time, but remember them later. What if we can perceive these changes in the time line but only on a subconscious level?
Think about it, we all have had a sense of deja vu, the sense that we have been here before, but don’t remember it. We have all just met people that we feel like we have known all our lives. We all have these strange memories of events that never happened, parties we never attended, conversations we never had, TV shows that never actually aired. You can find reports of these things all over the internet. Memory is a funny thing and plays tricks on us all the time. On top of that, think about past life memories and premonitions of the future, rather than being just general weirdness, perhaps it is our brains dealing with alterations in the time line.
Mind you, I am making no claims here, I am not saying that feelings of deja vu are proof of time travel. All I am doing here is speculating, asking myself questions and considering possibilities. Let me ask this question, have you ever had a day dream that seemed to be out of your control? A day dream where your mind generated exacting details about events that never happened and places your have never been? A day dream where you are having a deep conversation with someone you only met once or have not seen in years or never met at all? Sure this could just be an over developed imagination, but maybe it is your mind remembering events that were take from the time line.