Which is the true Time Travel scenario?

Many shows have used the Time travel concept in their stories, but which concept would be the most likely if Time Travel actually was possible?

The prevailing theory is that when a character travels back to a specific point in the past and does something while there (stomping on a flower, stopping a specific event from happening, etc) that one action can cause a ripple effect that would alter the course of history.

But there are some shows that imply that this is actually not possible; that the past truly cannot be changed. Those are the shows that suggest that even if the characters went back in time and purposefully tried to change history, history would somehow manage to correct that change and the timeline would remain unaltered: Gargoyles had four episodes that established that history cannot be changed and Static Shock, Teen Titans and Justice League Unlimited implied that as well (Static Shock and JLU both had characters from the past see what was going to become of Batman, including Batman himself, yet the Batman Beyond Timeline remains undamaged and canon to the rest of the DCAU. Teen Titans had the episode "How Long is Forever" where the villain explains that a specific treasure went missing because he went back in time to steal, which was because the treasure went missing in the first place)

What do you think?

I always liked the concept of "Voyagers!" (not animated though, but I wouldn't mind an animated remake of it). It mostly worked for me because the travellers were working outside time, and instead of trying to change it, they were fixing history (why history was on the verge of going wrong was never explained, though). Either way, if you time travel and change your past, wold you even know that you did? After all, your own reality would be change alongside everyone else.

You Already Changed the Past seems most likely to me.

Same. Least interesting from a writing perspective, most likely from a physics perspective.

For me, the idea that the time traveler is protected from the ripple effect always seemed the most plausible, simply because most of the paradox concepts are built on one simple idea: that temporal causality is a requirement. I just don't think it is. I don't think physics care about temporal consistency as far as time travel is involved.

I don't think going into the past has any kind of invisible tether binding you inexorably to your original time. It's a fourth-dimensional movement. If you step outside your house, and the house is crushed by a meteor, you don't cease to exist because your third-dimensional point of origin did. Why would the fourth-dimensional point of origin be any different?

As far as time is concerned, you are not a person from the future. You are a person who sprang into existence fully-formed at the moment of your arrival, and the timeline is cool with that because it doesn't really care. It's not a sapient entity trying to rationalize the continuity. It's just a form of motion. So while your actions may change the future, and may change or even unwrite future versions of you, this ripple does not affect you because you are not in the future. You're right here, changing history. Your past is in the future, but your past doesn't matter because it already happened, even if it didn't.

Similarly, I disbelieve basically any form of paradox brought on by two versions of you existing. You don't merge with your future self, nor does your future self merge with you, because that person isn't you. New memories do not flood your brain, because that is a life you never lived. You are a wholly separate individual from whatever future version of you may come about - if one does at all, depending on the scale of your changes - and are treated accordingly.

edited 14th Nov '13 10:08:38 AM by TobiasDrake

I'm gonna go with Kamen Rider Den O's model of time travel: You can't change things in your own timeline, but you can alter other peoples' timelines. Also, the only fixed points are certain people, who can also bond with time-travelling ghosts from the future to become superheroes.

IMO, the time travel that causes the least issues is simply having time flow at a different "rate" for you than for others. So you can arrive at a distant future faster. That of course only allows you to go into the future, not past.

Time traveling to the future is easy. I do it every time I sleep.

In Primer and some other stories, time travel to the past only reverse the flow of time one to one, so if you wanted to go to yesterday, you'd have to sit in your time machine for 24 hours.

I don't underatnd why people like primer. I mean, I tried watching it, but it was kind of slow and I couldn't understand what they were talking about. Please don't hurt me I'm actually a very smart guy and I watched it because I heard about how it was a 'primer' for time travel. But I just couldn't get it

The characters themselves don't get it either. The real point of Primer isn't understanding how the different timelines and Abes and Aarons fit together, but the facts that (A) time travel makes everything hella confusing, and (B) time travel is power, and power corrupts.

edited 20th Nov '13 12:06:29 PM by MetaFour

I recall writing a story about this, involving time travel and the physics problems that came with it. A couple of the rules were:

1. The travelers could only go to the past with the machine and not the future. The past has existed, the future technically doesn't yet. Later, however, they find a loophole to travel to the future: relativistic flight ("The faster you go, the slower time affects you.")

2. Traveling to the past erases the present. What was once "the present" is now "the future" and so doesn't exist yet. It can exist again provided the-past-now-present goes the same, though.

3. The machine, which is controlled by an AI, can't travel through space. It can only take them to the exact spot that it was at that point in the past. This is because it travels by first identifying a memory of the time and place and "running it through the timeline of the universe" to find the result. It compares it to pasting a sentence in a search engine, looking for the closest match. It also can't take them to before the AI was built. No memories from then, obviously.

4. Which Me?, Time-Travel Tense Trouble, and Cloning Blues don't occur because of conservation of matter. Since matter can't be created or destroyed, the universe compensates for the arrival of you by "deleting" your past self and using his/her matter to construct your own body that just arrived. Because of this, it's highly recommended to not travel to your own lifetime, or your arrival will kill your past self. Any arrival before then will still delete matter to make room for you, but it will probably just be random molecules or food minerals. Probably.

edited 21st Nov '13 11:26:21 AM by Tuckerscreator

I subscribe to the Many-Worlds Hypothesis; "time travel" is simply stepping into / creating a different universe-branch.

edited 20th Nov '13 6:25:56 PM by TheAirman

I don't mean I couldn't follow the science, I mean I could t follow the plot

Hardly anybody could. Hence all the charts◊. Note how little of it is yellow, i.e. actually seen in the move.

edited 21st Nov '13 11:22:56 AM by Tuckerscreator

They may seem random, but if you were to trace those matter particles through time, you'd probably find they'd eventually come together to be you.

Indeed. Just random in the sense that they're not connected to a human yet, or maybe even spread out in many objects versus one single object.

It made me wonder if you'd accidentally kill your own parents by arriving within a few days before your conception, but I'm a little scared to explore that.

edited 21st Nov '13 11:29:46 AM by Tuckerscreator

I mean , the acting. I couldn't underatnd what they were talking about , or what was happening. I had no clue what was going on besides what the thing in their garage might be