What is the confusion between altering the past?

This meme has got some sense tho :-)

   Methods to travel in the past or future are already discussed here. But if time travel was to be real, it would have been easy to go to the past and erase our mistakes. But that is not easy and smooth as it looks! That is what we are going to discuss today. Can we alter the past? What is the problem possibly? And what if that happens?

  Let us first discuss an easy to understand outcome. If I travel in the past and do some changes, I am not travelling in my own past, but a copy of it. Thus, it won't reflect in our universe or our dimension. And this is where multiverse theory again steps in! So it was a very nice explanation, but things aren't this easy!

  There is something called as temporal causality loop. This loop occurs when the actions of a person traveling back in time becomes part of his past events, and may ultimately cause the event he is trying to prevent to take place. The best example is the Nobita disappeared? episode of Doraemon. 

  In the "Nobita disappeared?" episode, Nobita and Doraemon go into the past to help his future dad pursue his dream of becoming an artist. But by doing so, he seemed to change the past by which his mom and dad would have never met and Nobita wouldn't exist, similar to the Grandpa Paradox. Doraemon fears this would happen and both of them try their best to make his mom and dad meet. But they fail. Yet, his dad ends up meeting his mom anyway and they fall in love. Now the point here to note is that Nobisuke meets Tamako while leaving Kaneko's house and probably would never have been there if Nobita would have never interfered in the past. Source

   And this concept of temporal causality loop is called as predestination paradox. Sounded complicated? Imagine that your near ones dies in a hit-and-run car accident, and you travel back in time to save him/her from her fate, only to find that on your way to the accident you are the one who accidentally runs him/her over. Your attempt to change the past has therefore resulted in a predestination paradox.

  One way of handling this sort of paradox is to assume that the version of events you've got experienced are already built into a self-consistent version of reality, which by trying to change the past you'll only find yourself fulfilling your role in creating an event in history, not altering it.

  With this circular loop of events ensuring that history isn't altered by the time traveler, which any attempts to prevent something from happening within the past will simply lead to cause itself, rather than stopping it. This paradox suggests that things are always destined to show out an equivalent way, which whatever went on must happen. This is a straightaway and easy thing if understood. And also, this paradox is the base of many Doraemon episodes, the coin one, Suneo's kidnap etc.

  But now imagine this: You are a famous book writer. You write a book before the invention of time machine. Then time machine is invented and you travel to past and provide the book to your own past self! Now there is an ambiguity about where did the book content originate! This is a type of paradox in which an object, person, or piece of information sent back in time results in an infinite loop where the object has no discernible origin, and exists without ever being created. That's the Bootstrap Paradox.

  The first law of thermodynamics says that the energy can neither be created nor be destroyed. But this time travel paradox allows you to create energy or mass which violates the laws of physics. Source

 

  And that's the reason even though we create time machine, we will not be able to travel to the past with assurance or guarantee of its possible outcomes! And we all know another good reason for this- the grandpa paradox!

Posts before October 2021 have been marked as "Old Posts". Less likely, but they might have out dated or incorrect information, ugly looking bits of code, no labels, etc. Don't get me wrong, many of these posts are top-notch and interesting too.

I thought it would be better not to delete or revamp these posts, even if they suck. The bitter truth is that old works always suck, but I take that as a positive tool to convey that I am growing. Besides there's no better way to showcase my journey without these old, messy, poorly written posts!

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