A Way to Make Time Travel Work

[Wraith_Boy]

Time Travel to the future appears to happen the closer one comes to the speed of light but this isn't really time travel, it is more akin to stasis in the objects frame of reference.

Frame Dragging is also theorized to be able to send messages back in time to the point the machine was activated.

Wormholes, if they work as predicted, would also allow time travel but time travel to the past is a stupid idea, you could never change anything that happened. You could take a nuke back to Washington DC in the year 1900 and attempt to detonate it and it would fizzle, or have total existence failure, or any number of other improbable events would happen to ensure that the nuke never goes off.

It is time travel though. You leave at one point in time go on a short journey then come back 100's or 1000's of years in the future.

As to the whole paradox thing, how exactly does anybody know for certainty that you could go back to the time of Hitler, try to snipe him & the gun would jam. Try to set off a bomb & it fails to explode.

How do you not know it could actually work say like in the movie 'Timecop'. You go back, change the past, then when you come back to your own timeline, the changes you made will have happened. Only you don't know what they were exactly but everybody else does.

It could even happen like in the movie 'Frequency', where you change the past, then get hit with a whole set of new memories showing the changes in your life.

You could even change the past then move to another reality in which a brand new timeline has been created & your original one which you came from & remember is gone forever.

For the whole grandfather paradox thing, where you go back & kill him. Meaning your father was never born, so you couldn't have possibly been. Maybe the minute you kill him, you instantly disppear from existence. Perhaps you live on, when you go back to your own timeline, your old life never existed. You have no family, nobody remembers you at all etc.

I seriously doubt there will be this thing that prevents you from changing history if youa re able to go back. You fire a gun & it jams. You step on a spider & it repels your foot, or your foot is unable to lift off the ground. You buy a winning lottery ticket & the till jams or lottery machine breaks down. If it broke down, then nobody else in the queue behind you would be able to get their tickets, which they did originally. So history will have already been changed from what it was. What happens if you try to tell someone in your family winning numbers or the winners to a sporting event. Will your lips shut up., If you write it down, the ink doesn't work or the paper disappears from existence. If you were able to go back in physical form, then you shouldn't be able to touch or speak to anyone or anything because that simple act could change history. So unless your shifted to another dimension like 'Arthur's Mantle' where you can see & hear everything, but nobody can see or hear you. Then you should be able to go back & change things to whatever you wanted. Of course you would have to be very specific in what changes you made because it could affect your own life & when you go back it could be very different from the one you left.

Say you worked in timetravel for the government. You go back change something, say to affect any of those repsonsible for creating & approving the study of time travel in the 1st place. The project is never started. You go back, then you were never in the job, you appear in a secret government facility. Nobody knows who you are & you get arrested, then locked in a a black project holding facility & studied, questions & hidden from the world for the rest of your life.

You could go back & make yourself win the lottery. However when you go back, the money may have went to the head of your younger self, women, cars, drugs, booze etc. You find your life totally different from the one you left.

The biggest one that makes me laugh comes from people like Stephen Hawking & co. If time travel were possible then why haven't we met visitors from the future. Perhaps Stephen because they don't want to draw attention to themselves & change their own timeline. If they arrived in an uber future ship. Waved to the world that they are time travelers from the future, the givernemtn would nab them, then interrogate them on how to build, operate the ship. As well as examine their ship. Do you honestly think people will wave them off back on their merry way & continue life as usual.

The moment any government or rich individual/corporation(s) knew it was possible they would all put more money into research. To get the technology & use it to change history for their own ends. Meaning the time travelers go back to a world that was different from the one they left. Perphaps one of their grandfathers was the key behind the discovery. Maybe his father left him enough money to start the research in the 1st place. However upon hearing about time travel the great-grandfather decides to use the money to start the research himself rather than leaving it all to his young son. He gets it, then time has changed from the original one. Instead of their grandfather, it was the great-grandfather. The grandfather may have had nothing to do with the project. So perhaps never met his wife who was working for him on the research project. End result, they never got together. So the guy goes back & nobody has a clue who he is. Another one - a government develops it. It's leaked that they can go back & alter the timeline at will. Do you think other countries will allow this to happen, of course not. They'd fear the worst & a war would start. The time travelers go back, perhaps their father was killed before he was conceived. He's erased from the timline & all the rest. That's the reason that if time travel were possible that we aren't being visited by people from the future. The slightest change or alteration of the timeline could have disastrous consequences to their own timeline & it could be totally different from the one that they left. Just because they aren't boasting in public about how great & advanced theya re. Doesn't mean that it isn't being done today by future visitors. Heck even the whole ufo thing, may not be Aliens, but advanced ships from the future.

I believe if you can go back in the 1st place, then you can change or alter it just like you can in normal life. Simply that it'd be impossible to make any real changes because what could happen as a result of the tinkering. There is far too much to take into account for even the slightest change.

For example - You go back & shoot a bird. Birds are stupid, so what possible change could that make. Say in the original timeline, this bird mated, one of it's generational offspring, flies into the garden of one of the scientists working on the original time travel project. He somehow got inspired by the bird, so because it isn't flying in every day. He doesn't get this inspiration, never comes up with the critical advancement to make time travel possible. You go back & they never managed to complete & make it work. Too much at stake for the most minute changing of the timeline, even if you only changed it to try & do something good with the technology!

[Jimbo-DR]

As for your last example, clearly you haven't read, "A Sound of Thunder".

[TheBigFlush]

The only way to keep the timeline constant is for the nuke not going off. You will still go back in time but you will never accomplish what you set out to do.

By that logic, you never would have been able to travel through time to begin with. The mere act of going back would change something, even if only something small and seemingly insignificant.

In the grand scheme of things, the universe doesn't differentiate between major and minor changes. The universe doesn't care about anything.

[Orii]

Our current understanding of cosmology, relativity, and quantum mechanics does paint a picture that allows time travel, with a few important stipulations (some of which have been mentioned before):

(1) you can only travel back to times during which the "machine" existed. However, there are a few potential naturally occurring cosmological events that might exist in the universe which would function as the core of a time travel machine, and allow travel to any time during which that phenomenon existed. Relativity allows this. Wormholes are in essence the core of a time travel device (as well as space travel), but the type of energy required to make that work may not be physically possible (seems to be possible in theory, and the math works out, but it seems unlikely it is anything other than a mathematical curiosity... we'll see one day perhaps).

(2) you don't travel back to a past "time" in "this universe" but rather travel to another universe as described in the multiverse interpretation of quantum mechanics. This effectively removes any paradox problems. So you go back in time and kill your grandmother... fine. She isn't "your" grandmother, as she isn't from your specific multiverse progression, but rather is the grandmother of an "alter-you." This interpretation allows there to be more than one of you in a given universe at a given time. Weird, but not paradoxical. Kill yourself if you wish, doesn't change anything but that universe. The catch is that it seems unlikely that you could return precisely to the universe from which you left. Maybe, the math is a bit fuzzy (as if the whole subject isn't to begin with!). This interpretation also removes the information paradox problem... you know, you develop a time machine and send the plans into the past... so the machine gets built earlier and the information seemingly came into existence "from nowhere." Well, it is clear that the information has to be created in one universe, and still exists there, even if sent to another time-slice of another universe. This also allows for the bulk transfer of matter and energy from one universe to the next.

Seen in that light, time travel is just a subset of "interdimensional" travel as popularly used in sci-fi. They are one and the same.

(3) energy types and requirements and/or space-time configurational requirements are wacky, and not likely to ever be realized. Mathematically sound proposals involve something like the following... create a stable wormhole (requires an exotic form of negative energy), drag one end of it (assuming that is possible) at speeds near that of light (assumes we have also developed that kind of propulsion capability)... etc. Or another goes like "find a rotating cylinder of extreme density and nearly the length of the diameter of the universe..." (erm, sure, I'll pick one up from wal-mart tonight) and fly around it at near the speed of light (there's that propulsion requirement again). Possibly less exotic proposals involve the universe having a rotation, but we don't know yet whether that is the case or not, and it still requires the fast propulsion. Another alternative is to use a cosmic string fragment (not sure if those exist, but the math works out if they do) as a substitute for the huge cylinder thing, and then go get in your super-fast space ship.

Looks like time travel will never be possible by using a cool looking box that sits on the dash of your puddle jumper. But at least it isn't completely impossible... yet.

[Zatarc]

Some very good idea here on the thread but a lot are based on the idea that time is linear, i.e that changing the past will have a direct affect on the future that change came from. The latest theories on time travel posit that time is amde up of several different 'timelines' and that when one travels back in time they are in fact creating a new timeline where the future the traveler has come from has not happened yet. So, any changes the traveller would make would just affect that timeline. When the traveller goes forward, they go forward in that timewline and therefore the affects would be evident.

Of course as many ahve emntioned there are so many theories on time travel that no one is 'right', but it is generally accepted that the Grandfather paradox, although interesting, is outdated.

[Emperor Tippy]

And their is absolutely no evidence to support that the multiple timelines theory is correct. Their is also no evidence to say that its not. Until we start time traveling it is impossible for us to know which si true.

[Orii]

There is evidence to support one of the following: multiple universes exist simultaneously, or multiple versions of particles/objects/etc. exist simultaneously until observed at which point the multiples collapse to a singular.

Between the two possibilities, the "big picture" painted by the multiverse interpretation is much more beautiful and compelling, and integrates in a more pleasing way with other areas of knowledge such as computation theory, biology, and evolution.

[Zatarc]

There is evidence to support one of the following: multiple universes exist simultaneously, or multiple versions of particles/objects/etc. exist simultaneously until observed at which point the multiples collapse to a singular.

Aaah yea, almost forgot about the observer theory. Very interesting, read a Stephen Baxter novel that explained that a bit...hmmm, would be interesting to see if it were tru, of course no way to do that unless you were the final observer

[escyos]

My theory is that you cannot move through time in your own universe. THere are actually an infinite number of universes that are of a differnt time. Think of it like a bunch of bricks stacked on top of each other, the middle one is our universe, the next one up is +1 sec, the one below is -1 second.

so you can travel to a differnet universe and do whatever you want in that timeline, because it cannot affect you

[thekillman]

quantum physics does not disallow time to travel backwards.


but seriously, time travel is possible, but unfortunately it'll probably kill you or eternally trap you.

[K^2]

First of all, I want to say that everything time travel that I have seen from most sci-fi shows and movies are so far off that it is laughable. Most of this is due to the fact that they are taking matter and energy from one time in the universe and sending it to another, disrupting the natural balance that the universe established, which I believe would have disasterous results.

It's not so much about disastrous results as that you simply can't do it. You can't just pull matter out of now and put it into then. Hence all the problems with time travel. We already know how to make microscopic sub-systems in which time flows backwards. It's almost trivial. Problem is, you can't even put some information in without disrupting the time flow.

There are ways to make it work, but the discussion goes way beyond what would be reasonable for this thread.

[Angarsk]

Ok, I don't know a lot of physics, quantums, relativity, etc. but:

Time "travel" to the future: possible, through time dilation.
Time travel to the past: no way... we're not dealing with a movie here, one you can rewind, fast forward, pause or eject... no, whatever happened, it's gone, it already happened and ceased to exist, giving way to the present, even as I write this post, each keypress changes the "universe" and backspace only changes it again, but never un-does what already happened.

Am I making any sense? I mean, there is no "place" called "past" that you can just go there, you can't.

No parallel universes either, if we have parallel "trees" for example, and not 1 is equal to another, how would an entire universe be exactly like ours, with humans on earth and actually copies of ourselves? my bet is IF there are other universes, they're totally different to ours.

[Aer'ki]

Is time travel possible in reality? No.

Can it make sense in scifi? Yes.

In Stargate the one that has made sense was when Jack and Teal'c get sent back in time in "window of opportunity." There is no 'double matter' paradox here, they are sent back to their original places and original bodies with their memories intact. This, on a basic level, makes sense...enough for scifi anyway. Time 'rewound' and then replayed. The only problem was it was said that this didn't happen everywhere, but only a small number of stargates. That was a big writing flaw. In order for time to rewind it should mean the entire universe. Paradoxes abound if only a small section of space rewinds...like what if a ship happened to pass into and out of that space.

All the other time travel instances in stargate haven't made much sense.

[K^2]

Aer'ki, even if you don't want to think of time as dimension, time travel is still possible. We can set up microscopic systems where time flows backwards. (basically, everything is sent in reverse, and all dynamics is identical to reversed time) It has been done. Problem is that you cannot read/write information from these systems without upsetting the time flow. But there are ways to circumvent that, which can allow small quantities of information to be read before it is written. There is a little bit of quantum physics involved, but only stuff that has been experimentally checked. (I've seen a quantum computer run with my own eyes, so if you'll tell me you don't believe in that, I'll have to e-smack you.)

[Aer'ki]

Aer'ki, even if you don't want to think of time as dimension, time travel is still possible. We can set up microscopic systems where time flows backwards. (basically, everything is sent in reverse, and all dynamics is identical to reversed time) It has been done. Problem is that you cannot read/write information from these systems without upsetting the time flow. But there are ways to circumvent that, which can allow small quantities of information to be read before it is written. There is a little bit of quantum physics involved, but only stuff that has been experimentally checked. (I've seen a quantum computer run with my own eyes, so if you'll tell me you don't believe in that, I'll have to e-smack you.)

Read before it is written...seriously! Have you tried not writing it after it is read, just to see what happens? I don't think the universe has imploded from the paradox yet.