It is a common time-travel trope that if you wander backwards in time, you will have the chance to meet the younger version of your self which, in some scenarios, could cause irreparable harm to the fabric of time and the universe itself. In fact, many fictional narratives have been written on alternative timelines in which the story’s hero travels back to a time period in order to carry out some task (such as killing baby Hitler) that will invariably improve the future. Simply look at the entire Terminator franchise. In those stories, Sarah Connor is constantly fighting against agents sent from the future who wish to kill her son in order to change the course of events in their time period. Of course, all of these fictional narratives fail to explain the concept of time travel. How does one move through time? Is it a stream? Is it linear? Is it sequential? And let’s not even talk about the amount of energy it might take to accomplish such. Still, there have been countless stories where time travel has played a central part in the narrative (my recent favorite is Looper, although Deja Vu is also a well-done version). But I’m going to suggest something a bit different. Drawing on prevailing thoughts within the field of physics, a little application of established natural law, and a thought experiment or two, I’ll argue that we are already living in every possible timeline and that it’s impossible to meet another version of yourself in a different universe.
Understanding Time
Before we can jump into a discussion about how it’s impossible to meet yourself through time-travel, we need to agree upon how time works. One of the oldest models of time travel, around which much of fictional narratives are spun, is the linear time model. In this model, time flows from the start to an infinite horizon. There is no thought of time ever stopping (or reversing). It just keeps moving forward, forever aging the universe (and those of us unfortunate enough to live with its confines). But this model also makes the time travel narrative, from H.G. Wells The Time Machine to Back to the Future, possible: you can travel back through time, find what you need to change, and then return to your time where the change will have taken effect. But many modern theories in physics (I need examples here), seem to undermine this simplistic model. Time is not linear. It is not a line from our past to our future. A more prevailing theory is branching theory, in which time, like a river, can branch off depending on things that affect its flow. For example, let’s say that you go back in time and kill someone. At that point, not the killing, but your traveling back, you have created a branch. Your future is now the future of that branch and returning to your previous time is actually returning to a different branch in which what you did to affect the past will not have happened. In fact, in this model, one can return to an event in the past over and over again, carrying out the same action, but producing an infinite number of branches (as it’s impossible to predict the impact of changing a single event). The branching theory of time travel actually plays a lot into the multiverse theory in which each branch created is actually creating a different parallel universe. This supposes, of course, that time is the underlying construct of any universe, whether ours or a parallel one.
A Quantum Approach to Time
Rather than seeing time as a dimension of the universe (in a four-dimensional framework), perhaps it can be seen simply as a byproduct of the physical model of the universe. It is not a force in-and-of-itself. It is, instead, a by-product of quantum interactions. Consider the following: instead of “traveling through time” (which suggests that time is a variable to manipulate), one simply adjusts their quantum representation to coincide with a different universe. In this way, time is now a representation of quantum state. So something doesn’t “age” because it exists for a specific period of time. The matter itself never changes. Rather, the matter moves through quantum states (billions, maybe trillions), each one in appropriate balance to the amount of matter and energy in the universe, until it no longer exists. ‘Traveling” through time then, is all about adjusting a specific object to a different quantum time state. Imagine it’s like a radio dial moving through an infinite number of frequencies except this dial “tunes” you to a specific quantum state rather than filling speakers with the voices of NPR.
The REAL Issue With Time Travel
Although there are numerous issues with time travel in the current model of time (whether linear or branching), the primary one is about the conservation of matter. In traditional physics, matter is never created or destroyed. When the universe came into existence (both the one we inhabit and the infinite number of others), all of the energy and matter was created. You can’t add more energy into the system or any more matter. When we create something, we are simply transforming one form of matter into another, or one form of energy into another. So let’s say that you travel back into time and meet yourself. How is that possible in consideration of that fundamental physical law? This would create a situation in which additional matter, you, has been introduced into the universe where a version of you is already accounted for in the physical model. Of course, that’s impossible and, as such, breaks any model of time travel, especially one in which you meet yourself.
Fixing Time Travel with Quantum Time
One of the fundamental tenants of the Quantum universe is entanglement. Particles can basically exist in two places at the same time (or multiple places if you subscribe to a 10-dimensional model of the universe such as proposed in M-Theory and Calabi-Yau manifolds) until some of their quantum properties, like spin, are observed at which time they exist in only one location. So let’s pretend that, in a Quantum-time model, that the present version of us, such as the me sitting here typing this, is entangled with all of the other versions of myself across an infinite number of parallel universes. There is only one me. I just exist across the multiverse in a Quantum state. Maybe the me in a different universe is sipping tea instead of typing. Regardless, we are entangled at all times, with an infinite number of possible states, therefore granting us an infinite version of me across an infinite number of universes. Time travel, then, is less of “traveling” than it is of existing in a different quantum state. We wouldn’t be moving through a time continuum. Rather, we would occupy different states in the physical world. This easily solves the issue I raised before about the conversation of matter in traditional time travel scenarios. Of course, it brings up a lot of other questions as well, some of which I will address below.
Question #1: What Happens When We Die?
This is the most obvious question. If time is not a linear stream but, instead, just different quantum states, then what happens when we die? One answer is that we disappear all together. If the multiple versions of me across infinite universes is never governed by more than a single consciousness (because, remember, the only consciousness that can exist at a given time is the one that is observed, although the quantum nature of it provides for the simultaneous existence of an infinite number of consciousnesses), then when I die, all of the other possible quantum states of me cease to exist as well. As such, matter is conserved. But another answer might be that, in dying, one of the other versions of me, across the multi-verse, becomes the “me of record” within the universe and I continue to exist but within a different universe. In that sense, we never die but are infinitely reincarnated as ourselves across an infinite number of universes. I am likely to ascribe to the former rather than the later.
Question #2: If I Change Quantum State, Does That Mean the Universe Changes Too?
So let’s say that you figure out how to make the “time-changing radio dial” and tune yourself to a different quantum-time state. Does that mean the universe changes as well? The answer, of course, is yes because you are now observing the universe from a different quantum-time and therefore locking in all the rest of the entanglement. You might ask, “well, what happens if someone else does the same thing at the same time but tunes themselves to a different state as mine?” The key here is in the infinite nature of quantum-time. You would go to your time, the other person would go to theirs, each one inhabiting a parallel universe. There are an infinite number of possible universes, all existing simultaneously, all entangled which supports everyone moving through quantum-time states simultaneously.
Question #3: Is It Possible to Travel Forward in Time (Or Predict the Future)?
The short answer to this is, yes. That’s because in a quantum-time-state-model, there is no “forward” or “backward” in time. The universe (or rather, you) is simply existing in a different quantum-time state. Of course, one could argue that quantum-time states which have already existed are “in the past” and those which have not yet been observed are “in the future.” But those terms, past and future, are ultimately relative to the observer and, as such, don’t really have a basis in a quantum-time approach to the universe. It is possible to utilize a super-fast computer to predict all of the possible quantum-time states that haven’t yet been observed but perhaps some of those time states could represent states which were not observed “in the past.” Consider this: if a tree in the forest is never observed to age, does it grow old? How would you know? Unless someone watched it grow old, there’s no way to prove that the tree’s current state, when it is finally observed, isn’t the state it’s always been in. And predicting the future? Perhaps that’s possible, again, with computer simulation. When we understand the quantum-time nature of matter, we can produce models of the universe that exist in a specific state. But, again, that state would only apply to the observer(s), those doing the tuning, and they would begin to exist in an alternate universe in which their observation of certain quantum-time states existed.
The Universe-of-Record
This is the most complicated part to understand. The universe in which we currently reside, in which I am typing this, is my universe. There is no single universe, no “starting point,” for matter and energy. The universe, as we know it, is really a container for an infinite number of universes with a certain balance of matter and energy already established. But the “container” universe is just a framework of physical and quantum rules and a “ledger” of matter and energy. It’s not full of more planets and stars and space. The physical manifestation of matter and energy is repeated throughout the multiverse, with each alternate universe having an accurate representation of the ledger and being governed by the over-arching framework. So there is no “true” universe. They exist and operate simultaneously, entangled with each other until observed.
The Philosophical vs. The Empirical
Yes, this is largely a philosophical exploration into science. None of what I have talked about, the possibility of a quantum-time state of matter and energy, can be proven empirically. It borrows heavily from M-theory and other quantum concepts. But exploring these ideas is what forces us to look for the science to answer the tough questions. Time is particularly troubling to physics, both quantum and classical, because it appears to be an aspect of matter and energy (as a fourth dimension) but it can’t be quantified outside of arbitrary mathematical notation. Positing that time is a by-product of quantum state is a way to give time some mathematical basis although it requires us to ask even harder questions, like “is there a time-like variable of particles then, like spin or direction, which dictates the current temporal existence of matter?” Unfortunately, we do not have the scientific instrumentation or capabilities to even detect that, let alone know what to look for. Still, exploring alternate models of the universe, which seems to definitely be affected by time, is important in understanding how we, as conscious beings, affect the world around us. If quantum theory regarding observable states continues to hold true, which has largely been proven, why can’t one state of matter be related to time just like spin and direction? Right now, I don’t even think we could comprehend a term to describe such. Maybe it’s a particles “shake” (this relates to other thoughts I have about vibrational properties of strings in a superstring framework) or perhaps a kind of motion that, again, we can’t observe without better equipment and mathematics.