change in past = change in future

Discussion in 'Physics & Math' started by Jagdwuf, Jun 19, 2001.

  1. kmguru Staff Member

    Let me understand this

    I am more confused than ever. Here is my question:

    You have a time machine. You get a pound of gold. You put it on the table. Then 10 minutes later you put it in the time machine and send it back ten minutes. Does this mean that at (T-10) minutes you see two pounds of gold?

    Irrespective of whatever time line you are talking about, you will have two pounds of gold, correct? And if you keep repeating it, then soon you will have a ton of gold.

    That means, you are creating matter out of nothing, or did I miss something here?
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  3. Crisp Gone 4ever Registered Senior Member

    Hi kmguru,

    Good one, I think you've just added another example to the "paradoxes with timetravel" list! With that reasoning you could - as a thought experiment - double the universe's mass if you'd just transfer enough matter, indeed violating the conservation of matter/energy.


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  5. kmguru Staff Member

    Hi Crisp:

    Thank you for agreeing with me. My opinion on time travel is like perpetual machine, impossible because it violates the most fundamental and easy to understand rule of the Universe.

    In the past, people came up with an excuse that time will branch out and hence no paradox. It is the same story with perpetual machine that the machine will draw energy from the universe.

    In my example, time branch excuse does not work.

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  7. Bebelina Valued Senior Member

    I don´t agree

    Well, this is very complicated, I agree, and we can never be certain until we have actually tried it. But I believe that an alternative reality is created everytime you intend to break the time, and therefore you will never see the gold you send back, because you, who you are in that particular instant , is not the same you that exists 10 minutes back in time. So if you send the gold back, you will loose it completely. The same goes if you try to send gold to the future.
  8. KneD Le Penseur Registered Senior Member

    Let's use the gold example:

    I think that if you put the 10 cm next to the 'old' gold, then the 'old' gold will dissapear, you will only have the gold that you transported.

    I know it sounds a little stupid, and in the gold example it is a little strange.
    But when we think of transporting human through time, we never speak about another 'double' people.
    I won't meet myself in 1999 I think, I will be myself again.
    So the gold won't be duplicated....
  9. Bebelina Valued Senior Member


    I wondered about that too, and the more I think the more I come to the conclusion that you will actually meet yourself in the future, the future you, not you as you are now, but a different future you. Because you, as you are now, will always be in the present of your present reality, and if you go to another present by braking through time, you will meet another version of a possible future self. But then, you could also become yourself, just as the gold would become itself.
  10. Crisp Gone 4ever Registered Senior Member


    Hi KneD, Bebelina,

    The idea is the following: you have a room where you have one bar of gold, and a timemachine. The bar of gold is on a table at 10 am. You sit nicely in a chair. This is a static situation. No way you turn it, at 10 am on that day you are sitting in chair, staring at a bar of gold that lies on the table - you cannot change the past by an action in the future. We'll call this copy of you "You@10:00am".

    At 10:10am you, who we now call "You@10:10am" take the bar of gold and travel back in time to 10 am with the goldbar in your hand. You arrive, just to see You@10:00am sitting in that chair, staring at that bar of gold. The freshly arrived You@10:10am puts the goldbar next to the one on the table.

    At that very instant, You@10:10am has two gold bars where You@10:00am only had one.

    Now comes the tricky part, the part of "seperate timelines" (and we're going highly hypothetical here, let me remind you

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    ). If there would only be ONE timeline, then there would be a contradiction, since the You@10:00am will travel back in time at 10:10am, becoming You@10:10am. But since You@10:10am already travelled back in time, there would suddenly be two You@10:10am's at 10:00am (okay, this starts to get confusing

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    ). This proces repeats itself ad infinitum, but since there's only one timeline, all processes have to take place. This means that at 10:00am, all of the sudden an infinite number of You@10:10am's would pop up having a new gold bar in their hands. This simply sounds absolutely absurd so we are lead to think that timelines seperate at the moment a decision is made.

    Now this scenario has a problem aswel: the moment the timeline seperates/branches from the original timeline is when You@10:10am arrives at 10am after the timetravel. At that moment a new timeline has to be created to prevent the problem mentioned above. In our example this means that You@10:00am sees You@10:10am arrive and has two choices: You@10:00am can choose to travel back in time at 10:10, leading to two You@10:10am's travelled back in total, adding another branchline, ... proces repeats... yedda yedda... Or he can choose not to travel back in time, leaving just You@10:10am and the original You@10:00am at 10:11 (since nobody travelled back in this timeline - this is starting to sound like a cheap SciFi show you know

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    The later scenario leads to another problem, being that you've introduced new mass into the universe@10:00am... Instead of a bar of gold, you could also decide to transport the entire universe back in time (thought experiment), - kinda violating the principle of conservation of mass/energy.

    Now I can hear you argue: "but perhaps these laws aren't valid for timetravel", well, then you can't timetravel at all since if one law breaks down, then why shouldn't all the others ?

    Conclusion: timetravel might not be possible after all.


  11. kmguru Staff Member

    Thank you Crisp for explaining that to our readers, I could not have done any better. Here is another monkey wrench you might want to add. Just in case someone will complain about sending someone or the gold back to exactly 10:00 am, let us send each time to T plus 1 millisecond(T being the last time transfer). So every millisecond one guy pops up with one gold bar or if the time machine is big enough a BMW....

    Or instead of the guy, we could send Bebelina. In short order we will have a planet full of beautiful Bebelinas.....and name our planet the Eve Planet....(I am kidding Bebelina....)

    Now the guys are thinking...where can I get one of these machines.....
  12. Bebelina Valued Senior Member


    I remember an episode of old Star Trek involving an Eve Planet...?

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  13. free_thinker Registered Member

    I'm 14 and I found this forum. It looks cool This is my first post so don't criticize me if I'm wrong. I read in an article in discover magazine about how he thinks that alternate universes with copies of us exists. If this is true then when you time travel you would be in fact traveling to another world and altering that one instead. Even if you gave Shakespeare his plays (the example they use in the article) they still would have been by Shakespeare in another reality. Then again I didn't really understand the article all that well.
  14. kmguru Staff Member

    Welcome to sciforums free_thinker. Alternate universe, many dimensions, time travel are wild ideas that should keep your mind open for possibilities. Who knows someday you may find something that have practical applications...
  15. amaroq Registered Member

    coming back to "could time travel to the past alter it?" i know that i have supported this paradox before in another thread, but i find that it makes a lot of sense...maybe not when i explain it, but just to think about its meaning. this would be the grandmother paradox. One may pose the question "what if you went back in time and killed your grandmother before she gave birth to your mother?" the problem this would create would be that if you have killed your grandmother, then your mother would have never been born, and going further yet- you never would have been born. yet, if you were never born you couldn't possibly have gone back in time and been able to kill your grandmother. this same thing applies to the fact that what has happened happened and will not change. when you travel back in time you become part of the past as well as the present time which you came from. If you were to travel back in time and cross your own world line you could shake hands with a younger version of yourself. this younger version of yourself would eventually come to the point in time where you will travel back in time and shake hands with a younger version of yourself continuing a cirlce through time. there is no real beginning to the cycle and no end. one could also apply this to the sinking of the titanic. you could travel back and try to warn the captain of the ship that he was going to hit an iceberg. this attempt would be ignored because obvioulsy the ship has already crashed in the past and your attempts failed then, the same as they will now, but you are only just now aware of your time travel to the past since you have been living in the present and not your future. according to these theories, it is physically impossible for someone to change the past through time travel. my explanations are very poor, but i hope that someone can pick through them enough to understand the main idea.
  16. Stryder Keeper of "good" ideas. Valued Senior Member

    Kmguru's Gold pile

    Looking at the facts you have to take into consideration the "Schrodinger's Cat Experiment", after all the experiment involves an understanding that the cat in a box becomes a multiversal victim of foul play, either with a universal tampering where the cat lives or "Murder" where the cat dies.

    This led me to think two possible conclusions:

    1: when you create a parallel from one world, all the energy within it does't actually double, it motions towards the one with a higher quanta level atomically (Thus creating your perceptional world, and making the other parallel unseen from your observation position)

    2: As Kmguru mentioned in another topic and has been written within the book "The Holographic Universe by David Deutsch".
    Parallels when created split the universal quanta into a fraction of the number of parallels that are created. This would of course mean any studies into the smallest quanta of an atom would be of little use since they will just be a decimal place further in a measurable scale ad the quanta itself would be more like a holographic fractal.

    (This when added to my conclusion of atoms being created from photon acceleration through gravity pockets would tie it together.
    In english: If a blackhole exists and light from stars accumilates at it's mouth, the light accelerates to the narrow-end of a funnel where it becomes an Energy packet from its spin. This would conclude why their is a photoelectric effect.)


    If the first assumption is correct, then some universe somewhere is going to lose it's piles of gold. If the second assumption is correct then you wouldn't need the gold to begin with you could just make it out of light.

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  17. ogster Registered Member


    when ever someone goes into the past its nearly always to kill there gran (poor thing).
    anyways, time traveling is to take into account the following
    1.time travel is possible
    2.when you travel into the past, which past is it you go into? there one time line or is there infinite possibilities at any instant in time (if one time line, 2 doesn't apply
    4.when reaching the past where or what is the further (home where you left from)
    thus at any instant in time, there must be a place, a time, a space time were you are. like a cosmic pointer. the stepping on the ant example, there are infinite possibilities (could have missed), which direction do our self follow, how do we know if we are who we were,before the disesion?
    i tend to belive that there are infinite possibillities, and that time is not in a line, but in a circle (quantum theory).
    these are just a few thoughts i have while reading through the whole of this form. feel free to disagree

    -sorry about the spelling
  18. Alpha «Visitor» Registered Senior Member

  19. ogster Registered Member

    Im a friend of oggie im borrowing his name to give my views. If u went back in time and altered it in some way my personal belief is that such an action could thoretically permantly disrupte the time/space contiuium forceing it to collaspe in opon itself resulting in another “bigbang” and stsrting over again,a time loop if u will.
    This throey ignore ths possibiltys of paerell universer (which might also happen) to concentrate on the fact that space time cannot(in my view) be tampered with becauase if it was such playing with time must of already happened beforre hand in order to maitain spacetime cohosion which again creates a loop.
  20. Alpha «Visitor» Registered Senior Member

    I remember thinking the same thing a few years ago. But I came to the conclusion that if you altered the timeline in the past it violates relativity. I don't remember exactly how I came to that conclusion though. Something about when you go back in time, the timeline is altered, so the effect alters the timeline at the speed of light, correcting everything. I don't remember where, but there's a contradiction in there.
    Last edited: Dec 6, 2001
  21. Stryder Keeper of "good" ideas. Valued Senior Member

    I did kind of mention this as a hypothesis.

    I of course didn't broaden upon it, or write it in a way that might seem legible.

    If you went back and created a difference, you would create a parallel, all the quanta within that world is infused with quantum entangement. All quanta is positioned with regard to the forces around it. When you make a change those forces move (although there would be a world somewhere that was ghosted with the original timelines forces in their position).

    Since the parallel/timeline/world you exist in has "stronger" more relevant forces, your world follows those forces ruling in comparison to that of the original timeline.

    (If you existed on the original timeline, you would be following it's global forces in comparison to that of the now ghosted parallel.)

    This is why parallels don't merge. (Unless there is a frequency fluctuation but this would make more sense if you studied the "Schrodingers Cat Experiment". This is when you create a MULTIWORLDS OBSERVATION, where something can be viewed from one but exist in the other.)
  22. Hevene Registered Senior Member

    Time paradox

    When we go back in time and change the past, at that instant, another quantum universe opens up and time splits into two parts with each one leading to a new universe. So if we go back in time and change something, the universe we came from will stay unaltered (Our past cannot be altered). We merely changed the future in some other quantum parallel universe.

    Comments recommanded
  23. Chagur .Seeker. Registered Senior Member

    Hevene ...

    It would appear logical ... if time travel to the past were possible.

    Interesting aspect though: 'You', as the time traveler, would then be bound
    to the new 'time line' since in 'your' past, the change occurred.

    Most interesting. "You can't go home again" takes on a new meaning.

    Take care.

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