Yesterday I saw a game/movie called "Quantum Break" on YouTube and I was hooked till the end. It revolves around a literal "End of Time" scenario with main characters having strange superhuman abilities and has time travel thrown in the mix. It was pretty exciting to watch, and as good movies (or games) tend to have that lasting effect, I kept on thinking about the "how" and "what-if's" of the concept until I slept. This post contains a few of my thoughts concerning the entire episode that I thought I'd share with you guys. I am in no way an expert in this field, just a wide-eyed kid with too much free time on his hands :) So, I present to you : In My Honest Opinion - Time Travel.
Whenever we talk of time travel, the word "Paradox" always crops up somewhere. Merriam-Webster defines Paradox as "an argument that apparently derives self-contradictory conclusions by valid deduction from acceptable premises" We'll visit this word soon enough.
So, Time Travel. Let us say that time is divided in 3 distinct parts - Past, Present and Future. (Some may say present is also past, but that is an argument for another time - no pun intended :p). Time usually follows a linear fashion, with present being our window of actions. This windows flows linearly in a consistent manner which is measured with units like Seconds, Minutes, Hours etc. When someone goes "out" of this window into the past or the future, that someone is said to have traveled through time. Simple enough? Then let's dive further into the intricacies of time travel.
Consider the first part of time - The Past. Say you have traveled into the past. But what would happen if you do something that hadn't happened before, in the original past? There are several theories that sprout from here. One theory suggests that whatever changes you make would just result in formation of a New Timeline. (Think Back to the Future or X-Men - Days of the Future Past) This means that an ENTIRE UNIVERSE is formed, a fully refreshed future that accommodates for the changes you made. But the question then arises, what would happen to you in the future of other timeline? You would've just vanished. Which is against the law of conservation of mass (assuming the universe is an Isolated System). Maybe the old timeline universe ceases to exist, but if that is so, then how could you have possibly traveled back to the past since you didn't exist there? That my friends, is a paradox. Let's put a pin on New Timeline theory for now.
Another theory suggests that whatever you do, you've already done. Yeah, seems a bit heavy, right? But it actually makes a little more sense; and also becomes scary/hopeless at the same time. See, whatever the future holds, it is fixed. In other words, Been There Done That theory says that time cannot be altered. You may go back in the past and raise a pandemonium, but those actions would result in the exact consequences that form the future you come from. (Think Predestination or HP - Prisoner of Azkaban) The one caveat in this theory is "how did it all START?" Say, in Present P, a person X comes from the Future F and warns his P-self not to eat today's pasta as it could upset his stomach. P-self goes on with his day, doesn't eat the pasta and at F, goes back in the past to send the warning. The loop is complete, no problem here. But what about the FIRST X? Did he eat the pasta and had a bad day? Not possible since it results in a Paradox again (events in time cannot be altered). WHO came and warned HIM if he was the FIRST? Quite a predicament...
Finally we have the theory which suggests that when you go back in the past, you do so in an Ethereal form. Like a ghost - but much less scary. What Ethereal theory says that you are basically an Audience with a fully 360 view of Reality, as it was. Since you cannot interact with anything, there is no question of a paradox, although it does raise the question of the state of matter forming your body. Or perhaps you just enter with your "consciousness"? That would take us in the realms of meta-physics of soul and mind which is quite interesting in it's own aspect, but not directly related to the topic at hand. Assuming you could gain such an Audience-type Form, the Ethereal theory makes sense.
Besides from these theories, we have others, like one suggesting that when you travel to the past, you actually just jump to ANOTHER timeline in a vast array of Multiverses (probably infinite). We will talk about Possible Past time travel later on.
We all would like to know the Future. Until we do.
Those words hold a powerful sentiment. I'm not sure where I saw/heard those words, but they have become stuck in my brain. Say you travel to the future and saw your dog die. Coming back to the present with knowledge of his death would naturally make you do things that would avoid that possibility. BUT... what if your actions in the present are what really triggers the death of your dog? You don't know. You do something and it kills your dog - you live with his blood on your hands. You do nothing and it kills your dog - you forever regret not doing anything. You'd wish you hadn't traveled to the future ("Until we do"). This Absolute Future theory is a lot similar to the BTDT theory of Past and also avoids paradoxes.
But not all theories are so grim and hopeless. A Possible Future theory suggests that what you see is just a possibility of what can be. It can be changed. You saw you Dog dying and you took measure to prevent his death, which worked. The future you saw was based on the state of Universe at the point of time in which you traveled, so in the Past when your other self travels to the future he/she would see the same future of your Dog dying. This means there is no paradox here. But then, it also means that whatever future you see, isn't really going to happen. Every time you see it, it changes. Unless the future you see is from another universe, which goes similar to the jumping between timelines of Possible Past theory. Oh well, as long it saves the Dog ;)
Remember the Possible Past theory? Well, that (and Possible Future Theory too) assumes that there are many other universes similar to ours (probably infinite) but with a few changes in events here and there (See Injustice - Gods among Us). And these Multiverses aren't isolated from each other but are somehow connected via "tunnels" through which exchange of certain primitive matter and energies takes place. (Think Worm-Holes) Unfortunately as of now, I have just enough understanding for this theory that I can think of time travel from it's perspective. But to comprehend true Infinity? I believe Human Beings aren't capable of it. I know I ain't.
Anyways, now that you have a (say, an infinite) number of timelines with all possibilities existing together (Yes, it even happens on a quantum scale everywhere!), whenever you travel through time, you just jump into another timeline, a timeline where whatever changes you've made have been accommodated for and the future is not affected irrespective of what you do or don't do. If so, then what parameters determine that you travel to such a timeline? You'd have to know what you're going to do before hand, which is not possible; Then what base does this theory has? Probably... Probability? The Universe behaves in extremely strange ways, more so at the Quantum Level, and there's sooooo much that we simply don't know.
As far as I can assume, the multiple timeline theory holds true in many aspects where others do not. Our reality is fraught with uncertainties and anything "Absolute" in primitive perspective is a mere possibility with highest chance of occurring. So the "Possible Past/Future" Theories of Time Travel could also mean you travel through vastness of space into other universes... Unless all universes are superimposed upon each other. That'd be something, eh? Guess we'll never know. All I know is that I had a lot of fun dreaming away about the exciting consequences of such unconventional travel, and I hope you guys had as much fun reading my amateurish view on same. I'd love to know your take on this matter, so feel free to comment down below. Until Next Time. Cheers.