Once Upon A Time

“Once upon a time,” pretty sure all of us heard this right? What comes into your mind? If you say, story, you are right, and we will venture to the world of science fiction. There are a few science fiction topics who can capture the imagination, but one idea stood the most of the time, the idea of TIME TRAVEL. You can't deny that even children captured this idea, how much more to our scientists.

To get the idea of this article, we need to at least enlighten ourselves first in some basic concepts.

What is Time?

Pretty easy to ask but difficult to define. There are a lot of explanations proposed by scientist, but we're making this easily to explain, time regarding entropy equations and some straightforward definitions. To get the idea want to express it in this way: From the time period of your life to your adolescence period seemed to be very long such that as if it must take hundreds of years to be 18 years old whereas it was only 10 years of time to be passed on.

The said example is called objective time perception and hypothesis that is proposing some brain activities running as the neuro-psychological progress. So, after puberty (let's say between 15 and 25 years old), you still couldn't understand exactly how those years passed by, so quickly. After 25, every day is incredibly elapsing too fast. You have nothing in your hands to stop or slow it down which most of us are aware or at least our mind tells us.

In addition to that, all of us are the time travelers who are tripping the time as mentioned above. We are not going to the philosophical inference yet of this idea because it will confuse a lot.

This is what Physics says about time travel.

To understand what I meant, we need to somehow touch the tip of the dimensions we have at present.

If you ask, "what are those dimensions", these are Length, Width and Height. To get the idea of these spatial dimensions, the easiest way is to look on one corner of your room, you can clearly see those three or you can draw them out since we already tackled them in our geometry class. It only shows that you can't perceive these three dimensions unless that object (wall) is not found there. Additionally, the fourth dimension was introduced by Einstein, SPACE TIME, which we can somehow imagine it like a trampoline, spacetime is much more discussed on how gravity works.

Now let us make a simple example on time-space correlation. Imagine a car is driven at a speed of 80 km/h and a person is looking at this car. From the person's point of view, the car comes towards him with a speed of 80 km/h. But let me add some different point here, I say that the time which the car is living in also changes while it is getting close to the observer. This is one key to understand the idea of Time Travel. The Faster the car goes, the longer the time which car lives according to the observer.

The said example is called time dilation which touches Albert Einstein's Theory of Special Relativity and time dilation is only true to near the light speed. As everyone is aware, Einstein's theory unlocked a lot of questions that talk about Time Travel.

So let's go back to our main question, is it possible to travel into the past or future?

Theoretically it is possible in physics, but it's not that easy also! For this to work, you need to go back on other theoretical things apart from special relativity and the general relativity itself. Time is depending on an entropic flow directed from the past towards future. For entropy, we can briefly express that it is the universe's a tendency from the disordered to the ordered state. Everything in nature goes from an ordered state to a disordered state, including our bodies.

The late Stephen Hawking postulated that it is impossible to travel to the past which makes the idea more intriguing. Hawking postulated what we called, "chronology protection conjecture,” where it postulates that time travel is prevented by the laws of physics we have at this moment, but not on micro scale or in simpler terms, quantum scale.

Travelling into the past is a philosophical question, and we're now here with these endless paradoxes. We’re all aware of the grandfather paradox, where if you travel back in time and kill your grandfather you would have never been born to go back in time to kill him.

It might be confusing here that an idea also proposed that present, past, and future are happening at the same. In much simpler context, the past, present, and future are all happening simultaneously in the present moment; similar to a loaf bread sliced into three parts, all are part of one bread yet three slices we're made. You can see, hear, smell, taste, touch everything that happened in that memory, not physically but with your senses.

I pointed out the reason we can't travel into the past because travelling into the future has a lot of methods to begin with, the famous is faster than Light or the answer lies inside a black hole. We're all aware of that but not totally into the past.

The idea of Time Travel is not anymore a work of fiction, many great scientists captured its interest, and we will continue to seek the exact answer of how and when we will achieve such technology. Time Travel will continue to travel into our minds until we shall unlock it.

Maybe the answer lies on how capable are we to break our shells.

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