Why Time Travel Is More Likely to the Future Than to the Past
Stephen Hawking spent years trying to prove that time travel can’t be accomplished. However, he couldn’t find any laws of physics that stood in the way. He eventually admitted that it might be possible, even if not practical.
Time travel to the future is likely because it doesn’t break any laws of physics. However, going back to the past is doubtful because we can’t change what had already occurred.
To comprehend the concept of time travel, a little knowledge of quantum physics will shed light on the process. We also need to understand how time is considered as the fourth dimension. So let's begin with those explanations.
Quantum Leaps in Time
Quantum physics shows that there is a means of moving within our three-dimensional space without the passage of time.
Scientists have been able to make particles move from one physical location to another without ever existing in-between. That's why it's called a quantum leap.
If we could do that in the fourth dimension, that would mean moving from the present to the future without existing in-between. Yes, we would call that time travel. It’s a fascinating subject that has enchanted people throughout the ages.
Why Time Is Considered the Fourth Dimension
The following explanation should help understand why time is the fourth dimension.
- Imagine a two-dimensional world (such as a drawing on a flat surface).
- Now imagine other two-dimensional worlds, all parallel to the first. Their existence implies that there must be three dimensions for all of them to exist within.
- Taking this a step further, imagine more three-dimensional worlds, parallel to the first. That implies a fourth dimension, and all the three-dimensional worlds exist within it.
The fourth dimension represents time. The three-dimensional worlds within it are images of all past periods, our present, and all future periods. Each one is a snapshot of a present moment in time, progressing linearly through the fourth-dimension.
How One-Way Time Travel May Be Possible
The existence of a second three-dimensional universe implies that there must be four dimensions for both of them to exist simultaneously.
I don't mean simultaneously in space. I mean simultaneously in time.
If that were so, perhaps there is a connection between the two of them, a path from one to the other. This connection is what was meant by the Einstein-Rosen Bridge,1 a wormhole that connects from one three-dimensional universe to another.
Time travel from one point in time to another is similar to moving from one point in space to another. When we travel from point A to point B, a certain amount of time goes by. We don’t ever end up at the destination at the same instant as when we left. And most certainly, we don’t arrive at the destination before we left.
Traveling through a wormhole might transport one back or forward in time. Although going backward would be improbable, as I'll explain in a moment.
The Concept of Moving Through Time
To understand the concept of traveling through time, you have to relate everything in our three-dimensional world to the fourth-dimensional world of “time.”
You can make that easy to imagine with this exercise:
- Take a piece of paper. That paper has only two dimensions—length and width.
- Draw two dots on that paper, one on each edge.
- Think of those dots as inhabitants of this two-dimensional world.
- Now fold the paper, so the two dots meet.
- You have just bent a two-dimensional world and made the inhabitants of different points in that space meet at a single location.
If we were to do the same with time, which is separated in four dimensions, and bend it over onto itself, we would make the inhabitants at different periods in time meet at a single point in time.
Proof That Backward Time Travel Will Never Happen
Here’s proof that backward time travel will have had never been discovered in the future. (Note the weird grammar when writing about past events in the future).
If future generations will have had found a way to travel back to the past, we would be aware of visitors from the future now, suddenly appearing before us when they weren’t here a moment earlier! Wouldn't you agree?
Besides, these visitors would have the ability to change our present and their history. That would mean that we would cause massive changes to their future. That is clearly explained with the butterfly effect.
How the Butterfly Effect Disrupts Time Travel
If one were to go back in time, anything he or she does would drastically change the future from which they came.
Anything we do, any small action, can have an enormous effect on the future. Future behavior is highly sensitive to past events.
This sensitivity is known as the butterfly effect2 derived by Edward Lorenz. The flapping of the wings of a butterfly can eventually affect some future event that is much more forceful, such as a hurricane.
Small initial differences can yield widely diverging outcomes many years later. When you step on a bug and kill it, your action could cause a whole new variety of species thousands or millions of years later. That is because you eliminated that single insect’s hereditary evolution.
Looking at it the other way around, every species on Earth today evolved due to conditions in the past. If one were to go back in time to our past and stepped on a bug, the world today would be affected. Maybe we’d have different types of mosquitoes—possibly savage mosquitoes that eat humans.
So you see, the point is that if we were able to go back in time, we would be able to create a change to the past that drastically affects our existence.
All Things Considered
I think it’s possible that someday our advancing human race will discover how to travel forward in time. That doesn't interfere with recorded history. Forward time travel is conceivable for that reason.
We are already traveling through time at a constant speed of one second per second. If you want to go to tomorrow, just sit in your favorite comfy lounge chair and wait 24 hours.
Okay, what we want is advancement through time at an accelerated rate. Or, better yet, an instant transfer.
A method of quickly moving forward in time may one day be discovered. As I mentioned earlier, quantum physics already shows examples of particles that move from one place to another without ever existing in the space between the two points. So we may one day have Quantum Time Travel, a leap into the future.
If it were possible for a particle to leap through three-dimensional space, why wouldn't it be possible to leap through the fourth dimension? That is, through time.
If science ever provides a method for forward time travel, the process might be useless because we need time to achieve our goals.
If we could leap to the future without any development to our society or our personal growth, what will we have achieved? The entire concept would be quite impractical. We need to stay where we are and put effort into working on creating our future.
“Time travel may be possible, but it is not practical”— Stephen Hawking
© 2015 Glenn Stok