Time Travel – It is one of those things that is most likely not possible but most wish it was. Back To The Future, The Flash, Rick and Morty – Science Fiction is chock full of Time Travel and it’s a wondrous and equally dangerous thought.
Often Time Travellers are shown in popular fiction to do drastic things to make impacts on ‘the future’. And the result of those drastic actions are drastic differences in the ‘new future’ or splitting of time lines or something along similar lines.
In this article, I would not be even touching on the possibility and practicality of time travel. That is a completely separate topic, about which, frankly, I am not equipped in knowledge to discuss.
I think that if Time Travel was possible in the future, owing to chaos theory, all that needs to be done to make huge changes is just changing something small or minute.
Things in the future are theoretically predictable – but because of the abundance of unknown variables and their complex interdependencies, practically we have not been able to do so. However, if the current progress in Artificial Intelligence, Quantum Computing and Machine Learning continues, then we could relegate this process of accurate (or as close to accurate as possible) prediction of the past or the future to them. This means that they could also predict the smallest incident that may have resulted in sparing (or taking) the life of a person.
For example, Adolf Hitler was saved from drowning by a local priest. We don’t have to go back to kill the priest, we just have to delay him by a couple minutes . For example, time teleport a nudie mag (or something intensely distracting) on his path and Hitler would have been dead at 4. World history would have been very different.
The butterfly effect might lead to small incidents like these drastically changing the world as we know it. While this creates innumerable paradoxes and whether this is truly feasible or not is unknown (to me atleast) at this point, but this means that changing the course of history may not be as dramatic as shown in fiction.
The fundamental assumption in this is that time is direction less. That a small change somewhere in the time stream will directly propagate in that direction. However, there also a possibility that time is like a river – with a direction. And throwing in a rock somewhere will make events go around that disturbance, not change their course completely. Due to the dependence of almost everything on almost everything, this is a good possibility as well. In that case, either major events in the past are unchangeable, or the rock in the time stream needs to be enormous (in which case fiction might just be closer to reality). (Even in this case, there are many interesting questions that arise – who decides what event is major? What if a minor event is the cause of a major event in the far future? What effect does the changed minor event have on a major event? What if changing anything leads to time travel never taking place? etc.)
There is yet another, a little disturbing thought. What if this has happened already? That killing Hitler or Stalin or Genghis Khan led to events that destroyed humanity or some other similar catastrophe ? Future humans understood this and decided to create the course of history as we know it? That future humans looked at their past (our immediate past, the present and the immediate future) and decided that avoiding that terrorist attack would lead to a dangerous unintended consequence in the future (maybe a victim of a terrorist attack is responsible for creating Skynet?).
Worse even, what if the future is dystopian thanks to a number of interventions by future mankind in the past? (And the terrorist attack was prevented to protect that single guy/girl who rules/destroys mankind.)
These are some of many hypothesis. And as of now, there is very little we know.
P.S.: All of this is based on the assumption that time travel is possible. But at the same time, concluding that time travel is not possible might be a simple and elegant theory – there is no definitive proof so far.