Can Someone Explain to me how time travel works?

[Snowman37]

you can alter another you's future.

I only care about my past and future, not the past and future of some parallel reality.

well there's no way to say that's what happens. if anything, it's possible that the universe already exists, all synchronous, but every time there is a possibility, every possible outcome is represented by a universe.

If you can't change your own past, why are you allowed to change the past of a parallel universe? Changing the past is changing the past.

actually no. how do i put this? i think One-minute-science can do this better than me

How the universe appeared from Nothing

The simple answer: God created the universe.

Could always just travel back in time and not change anything. Witnessing historical events has an appeal

Impossible, you were never there to begin with, thus you've changed the past by simply being there even if you sat alone in a cave and went back to the future. Your present-day is intact, but you have the knowledge that you were in the past sitting in a cave, thus every trip to the past changes the past by simply being there.

But if you did change something you would need something like other universes to solve the Grandfather Paradox.

You don't need a parallel universe to solve the Grandfather Paradox. You simply embrace the Grandfather Paradox. If you go back in time and kill your grandfather and return to the present, you'll be in a world where you never existed. How can you exist? You and your time machine were in the past BEFORE the timeline began changing, thus you are a left over remnant from the timeline's previous state. That's your paradox solution right there.

[thekillman]

I only care about my past and future, not the past and future of some parallel reality

yea but how different are you from your other, 99.9999999% similar you?

the point is, that other you also cares about his/her future. you could consider the entire universe in superposition with itself across every possibility. you are you regardless of how the specifics are.

[Snowman37]

yea but how different are you from your other, 99.9999999% similar you?

I am not my 99.9999999% similar self, that is how we are different.

the point is, that other you also cares about his/her future. you could consider the entire universe in superposition with itself across every possibility. you are you regardless of how the specifics are.

What happens if the other me goes back in time and splits off into another reality, changing the future of that other reality? What if that other reality is mine? He goes back in time, and instead of erasing himself from the future, he erases me instead. He can just go home via inter-reality portal or whatever, but I'm still gone. None of this makes any sense.

[anaberration]

Time travel was discovered and was in use back in the late 1950s' and early 1960s' !

[jeri]

Time travel makes my head spin! So when asked about it I tell them It's just a story and sit back and enjoy the ride. That's this idiot's take on it.

[thekillman]

I am not my 99.9999999% similar self, that is how we are different.

don't you get it. that other you will be you in every other way. it's like an SG clone of you. similar in every way except he's a seperate being. your arguments are used by him. so if he goes back in time to change things for his betterment, it would not necessarily be for your betterment.

What happens if the other me goes back in time and splits off into another reality, changing the future of that other reality? What if that other reality is mine? He goes back in time, and instead of erasing himself from the future, he erases me instead. He can just go home via inter-reality portal or whatever, but I'm still gone. None of this makes any sense.

i don't see the part that does not make sense. if you2 goes into another reality in the past, and that reality is yours, then he can indeed kill you and go home.

[Snowman37]

don't you get it. that other you will be you in every other way. it's like an SG clone of you. similar in every way except he's a seperate being.

He's like me in every other way, accept that he is not me. I am writing a science-fiction novel with a time machine as a central plot point. The inventors of time travel are represented three times in one timeline. Their first incarnation stranded in the distant past, their second incarnation died in the 1980's, and then their third incarnation exists in the present day unaware of their prior selves' existence until someone from the past surfaces. In the story, there is no multiverse, just the one reality which can be altered into any timeline you wish, but at the cost of erasing the previous timeline back to the point of divergence. In the story, the timeline has been altered so many times that the original is seemingly unrecoverable. Each timeline's characters believe their timeline is the one that should be restored. The question is begged, which timeline is the proper timeline? Is it the original, is it the one where Earth is at it's best, or is it the one that belongs to the main character, but then... which version of that character? I don't mean to go on a tangent, but my novel-to-be is directly on subject when it comes to fiction and time travel. Take my central male character, he has three versions of him; two older versions from prior timelines and a third younger self who belongs to the current timeline. They are all the same character, yet they are not. Every subtle difference can drastically alter one's life even if it appears to be insignificant.

I say again, me in another reality could be identical, but there's that nagging issue where he isn't me... I am me. If I die, I don't wake up in his body... I'm simply dead.

your arguments are used by him. so if he goes back in time to change things for his betterment, it would not necessarily be for your betterment.

That's why I have a problem with this whole time-trave-multiverse concept. The idea of parallel worlds, OK, but rewriting a parallel world every time you go back in time? That's just wrong. What if that parallel world stopped your world's Nazis from conquering the Earth? You go back in time to change the past, you change another reality, and now the reality you came from spontaneously changes, because that reality now didn't help your own reality in the 1940's. This gets unnecessarily complicated. It can and will happen, if you truly subscribe to infinite realities.

i don't see the part that does not make sense. if you2 goes into another reality in the past, and that reality is yours, then he can indeed kill you and go home.

Well, he wouldn't be killing me if I never existed to begin with. However, the reason why this doesn't make sense... It's a simple question. Why can one alter a parallel world's past, yet not their own? The past is the past.

[thekillman]

Why can one alter a parallel world's past, yet not their own? The past is the past.

not exactly. you do change your past, but basically it "splits" into the original and the changed version. now there is no way to know if there's an infinite amount of universes running synchronously and one universe takes option 1 and the other option 2, or a universe spontaneously grows into existence.

Why can one alter a parallel world's past, yet not their own? The past is the past.

technically you'd be changing your own past, as the universes would (in option 1) run synchronous for 100%, or it would still be your universe ( a copy of it).

[Snowman37]

not exactly. you do change your past, but basically it "splits" into the original and the changed version.

Splits, as in duplicates? Since when does a time machine provide enough power to clone the entire universe for the sake of having two timelines simultaneously?

now there is no way to know if there's an infinite amount of universes running synchronously and one universe takes option 1 and the other option 2, or a universe spontaneously grows into existence.

How could you prove that the time traveler has created an alternate timeline universe? How could you prove that he's not still in his own reality and that the future he came from is simply gone? In science, the simplest solution is often the correct one.

technically you'd be changing your own past, as the universes would (in option 1) run synchronous for 100%, or it would still be your universe ( a copy of it).

It's not my universe if it's a copy.

[thekillman]

Splits, as in duplicates? Since when does a time machine provide enough power to clone the entire universe for the sake of having two timelines simultaneously?

not...exactly. watch the video on the link i posted.

How could you prove that the time traveler has created an alternate timeline universe? How could you prove that he's not still in his own reality and that the future he came from is simply gone? In science, the simplest solution is often the correct one.

until you begin to enter the realm of Quantum Physics.

how you could prove it? uhm. it would require an AR drive like in SGA's Deadalus Variations, but it's possible. although the very nature of the quantumphysical Multiverse would make it VERY difficult to distinguish two AU's from two Alternate Timeline's.

anyway, there is a simple experiment i can run.


take a box. send it back in time 1 hour. now you have two boxes at the time you sent 1 in the past. if you do not have to send one box into the past to complete the timeline, you are in an AU as otherwise you violated thermodynamics

It's not my universe if it's a copy.

i am going to abandon this train of thought as it's way too complex and way too ethical