HOW TO EXPLAIN TIME TRAVEL TO A KID?

The word TIME TRAVEL is made of two words: Time and Travel; Let's replace the word “Time” with another word Road, it’ll now become - Road Travel. Now, what does Road Travel simply mean? To Travel on a Road. That means we can assume that Time could be a Road on which we all are travelling. At what speed we are travelling? We are travelling in Time at the rate of 1sec/sec.

Let’s say, currently, it’s 5’o o'clock; after 1 hour, it’ll be 6’o o'clock. That means we would travel 1 hour in time and 1 hour into the future. And how much time does it take to travel 1 hour in time? Yes, it took 1 hour to travel 1 hour in time. We, humans, are constantly travelling into the future, we are always Time Traveling. If that’s so then why do we need to Time Travel? Why does this fascinate most of us?

This Time Travel that we do constantly is comparatively very small in scale – travelling 1-hour forwards costing us 1 hour; however, the extreme Time Travel – travelling a greater distance in time within just no time, would be a great idea. Let’s just not go towards the extreme Time Travel yet, first, we should know what Time Travelling into the future or the past means.

What is Time Travelling?

Time Travelling refers to something that is Time Travelling, either forward or backwards. Let’s consider Time as a road with a length of “infinity”, in which we all are continuously travelling in the forward direction. Now if I ask, how much time would it take to go 10 years forward in time? The obvious answer is that it would take 10 years to go 10 years into the future.

So, we can say that we all are Time Travelling into the Future. And since the time that we took to go forward in time is equal to the distance that we covered in this time, we can say our speed of going forward in time is 1sec./sec. That means we are going 1 second forward in time and that is costing us 1 second. And to go 10 years into the future, it would take 10 years.

So now we all can say that we are always Time Travelling into the future. So, if we are time travelling all the time then, why are we so excited to build a Time Machine, to Time Travel? Well, this Time Travel, that we all are doing, is on a very small scale so small that everyone would like to neglect it. So that means if we could able to make the time duration shorter, then that will be an Actual Time Travel for all of us. This means if we can, somehow, cover a 1-year distance in time within just 1 second, then that will be a Real Time Travel for us. However, unfortunately, this is not possible “yet” at least not for us, humans, and we can’t say anything about the future yet.

Now we know about the basics of Time Travelling, and how we are continuously Time Travelling into the future. So now let’s see, what would it be like to “actually” Time Travel to the Future.

Time Travelling to the Future 

Now let’s imagine, I made a Time Machine, and with the use of that, I Time Travelled to my future to see My Future-Self. But the problem here is, even if I do so, then I wouldn’t be able to meet my future self or see My Future. Wonder Why?

At the moment when I’m gone from the present (as I would be in the future), due to my absence, from the present, my TimeLine, won’t continue forward to be able to create a future for myself, which will eventually result in No Future for me. Hence, I can never meet My Future Self or can’t even be in the Future, by Time Travelling to the Future. But what if my future self comes to visit me at my time i.e., Past for him? Will we be able to meet even then? Let See.

Time Travelling to the Past - The Never-Ending Loop 

Now visualize, the Time Machine that I had made earlier, with the use of that I Time Travelled One week to the Past. And there, in the past, I met my past self – A one-week younger past self. So now since, I travelled back in time to meet “my past self”, that means my past self after 1 week, will also Time Travel 1 week to “his” Past to meet “his past self”; since, for my past self, I’m the future that has been already decided or created. And now here comes the Never-Ending Loop-:

Now, my past self will also Time Travel, just like me, 1 week to “his past” and there will be another past self of “my past self”.

And that past self will also Time Travel just like me and “my past self”. So, we can see here, that this is creating a Loop which is Never-Ending.

Let’s understand this with the help of an example:

A person John, who made a time machine, travelled one week to his past, there he meets “his past self”, let’s call him John-P. So now after 1 week, just like John, John-P will also Time Travel to “his past”, to meet “his past self”, let’s call the past self of John-P – John-P2. Now, this whole process will continue, forever. John-P2 will meet “his past self”, say, John-P3 and John-P3 will meet “his past self” John-P4 and so on.

The Problem 

Now let’s look at the above example again, John, in the first place never actually met his future self, in “his past” (1 week past) so how would he be able to meet “his past self”? Although this hasn’t happened with John in “his actual past”.

Here we arrived at a paradox very similar to The Grandfather Paradox (Which will be discussed). So, the most logical explanation for this could be the following:

Explanation 1 – The Alternate TimeLine 

Let’s first understand, What & How many types of TimeLines do we have?

The Main TimeLine: It’s the TimeLine where all the events, the events that we know, happen. Once an event occurs in the Main TimeLine, it can no longer be changed, no matter what happens. However, if events on the main TimeLine are altered then there will be a creation of an Alternate TimeLine, a copy of the Main Timeline.

The Alternate TimeLine: It is the copy of the Main TimeLine, and the creation of the Alternate TimeLine will take place only when events on the Main TimeLine are altered which means, initially, there will be no Alternated TimeLine. The events that will be on the Alternate TimeLine, will not affect the events on the Main TimeLine.

Now we have all the basic knowledge of TimeLines. So, let’s jump right into the Explanation: When a person, say John, Time Travels to the past, he would travel to an Alternate Past in an Alternate TimeLine. As this moment wasn’t there in the “original past” of John in the Main TimeLine, so, there will be a creation of an Alternate TimeLine.

And, no matter what happens, this event, on the Alternate TimeLine, will not affect any events on the Main TimeLine. Now, what will happen with the Time Loop? Will it still exist? Well, it’ll depend on the following cases.

Case 1: John returns to his present with his Time Machine 

Now we know, that there are two TimeLines, and the one in which the person goes, is the Alternate TimeLine.

Now, let us consider that John returns to the present, at the time when he previously went to the Past, in the Main TimeLine. This means John, now will be travelling from an Alternate Past in the Alternate TimeLine, to his present in the Main TimeLine – From the Alternate TimeLine to the Main TimeLine.

And now since, John is back in his present, in the Main TimeLine, that would eventually mean that he never travelled back in Time, which means the Alternate TimeLine was never created, and John will never meet his past self. Hence No Time Loop will exist. John prevented the creation of the Alternate TimeLine.

Case 2: John never leaves the Alternate TimeLine 

What if John never leaves the Alternate TimeLine? Now, let us consider that John, decides to stay forever, in the Alternate TimeLine in Alternate Past. That means, now, there will be an Alternate Future (Different from the original Future on the Main TimeLine), and this Alternate Future will depend on the “Alternate Past Self” of John. This means, again we’ll be having two following sub-cases.

Case2.1: Alternate Past Self of John Never Time Travels 

If John-P (Alternate Past Self) never Time Travels, there will be no such Time Loop. The Alternate TimeLine, in that case, will go on, as usual, depending on the Alternate Past Self of John.

Case2.2: Alternate Past Self of John Time Travel to “His Past” 

If his Alternate Past Self, Time Travels to “his past” then he will be Time Travelling to an Alternate Past of his “actual past” from The Alternate TimeLine.

That means, now, this Alternate TimeLine for the Alternate Past self will act as a Main TimeLine, and whenever this Alternate Past Self Time Travels, there will again be a creation of the Alternate TimeLine, just like we have seen at the beginning. That means, in this case, there will not be a loop, but a series of Alternate TimeLines, that’ll go to infinity or will depend on the above-discussed two cases. (This has been shown in the Fig.1.)

 Main TimeLine

 

 

 Alternate-Alternate TimeLine – Main TimeLine for the next Alternate TimeLine

 

 

 Alternate TimeLine – Main TimeLine for the next Alternate TimeLine

  

Till here we have considered that there exists an Alternate TimeLine, but, what if there is no such thing as an Alternate TimeLine? What if everything that had happened in the past is all because of Time Travel from the Future? What if it is impossible to meet or interact with our past self by Time Travelling to the Past? Let’s jump right into the next explanation.

Explanation 2 – No Alternate TimeLine 

Let’s consider this time, I Time Travelled to my past to meet my past self. I successfully reached my past, but I cannot communicate or interact with my past self. This means I cannot do “certain” things which will affect my future or My TimeLine in any way; here, I’ll still be on the Main TimeLine in my “actual past”. However, in my actual past, my future self was indeed there with me but wasn’t able to communicate or interact with me, and there would be no change in the Timeline.