Physics Time Travel - Will it ever be possible?

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Sub_Zero

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Not sure if a thread on this has been done already and tbh I couldn't be arsed looking. Been thinking about this a lot recently, will we ever have the ability to go backwards/forwards in time? I for one would kill to be able to go back in time to enjoy my greatest memories again
 

SM

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I think the closest thing to what you're longing for is a supercomputer that can store the contents of our brains, which we can then rewatch or re-experience through a simulation.
 

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emuboy

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A very strange photo from Canada in the early 1940s shows a man wearing clothes and sunglasses that look modern day, while everybody else in the photo is wearing clothes typical of that decade. Perhaps it has already happened?
 

footyfan1978

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Not sure if a thread on this has been done already and tbh I couldn't be arsed looking. Been thinking about this a lot recently, will we ever have the ability to go backwards/forwards in time? I for one would kill to be able to go back in time to enjoy my greatest memories again
The first issue you have is no one really knows or can explain what time is.
We accept it is but cannot really put our finger on it.
 

sherb

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A very strange photo from Canada in the early 1940s shows a man wearing clothes and sunglasses that look modern day, while everybody else in the photo is wearing clothes typical of that decade. Perhaps it has already happened?
That's the thing, isn't it? How do we know it hasn't happened at some point in the future? (A contradiction in the past/future tenses, but I couldn't think of a better way to put it).

How do we know that in the year 2849 for instance, time travel was finally perfected (there I go again) and people from that time onwards have been travelling into the past, on the basis that (a) they blend in with the locals so they aren't identified and (b) they don't interfere with events of the time?
 

sherb

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My introduction to the concept of time travel as a 7 yo kid, in a fictional sense at least. Of course the subject had been the subject of fiction well before this, but it was my first step into the concept - and sci-fi itself.

God I loved this show, still do, the set (mainly the tunnel itself) just amazed me when I first watched it. If you watch the full clip someone says (Lee Meriwether I think) that the set took up two sound stages.

This was all done pre-CGI of course, as were Irwin Allen's other 60s sci-fi shows (Voyage To The Bottom Of The Sea, Land Of The Giants & Lost In Space) and two blockbuster 70s films - The Poseidon Adventure & The Towering Inferno.

I guess it could be easy to look back at it now and consider it dated, but it was truly spectacular for its time.

This is Bill Mumy narrating here.

 

Summer Nights

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Well, general relativity and other related ideas in physics suggest at least “travelling” forwards in time is possible by travelling close to the speed of light (or sitting on the edge of a black hole’s event horizon) and waiting for time, relatively, to pass more quickly on earth before returning. In this way, you kind of jump ahead in time (without, necessarily, the ability to return).

In regards to travelling backwards in time, I’m not aware of any credible ideas in physics (or more broadly in science) that suggest how it could happen.

edit: a quick wiki search expands on some of these ideas.

The closest we are from an experimental perspective is at the quantum level. Have a look at the theories behind the uncertainty principle and the probabilistic nature of wave particles. While I personally don’t agree with all the ideas within quantum mechanics, the notion that a particle can move anywhere in the universe in space-time as one of many infinite paths to its destination is definitely an intriguing one. Just think, *if* a particle can go anywhere in space time, that means it could theoretically go backwards in time on its way to its destination... and if a particle can do it then can bunches of particles and objects on the macro scale do the same, one day?

Of course, to be practical and useful, you need to be able to at least test the theories, and it doesn’t look like we’re currently anywhere near the level of capability to do so.
 

emuboy

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The question that interests me most about time travel, if you go to the same place and time twice are you there twice?

For example, say I went back in time to 1962 to see John Glenn become the first man to orbit the Earth. I wasn't born in 1962, so there would obviously no chance of me seeing a younger version of myself. I really enjoy my trip back in time to 1962, so much so that six weeks after returning to 2021 I go back in time to 1962 to do it all over again, would I see myself there on my first trip?
 

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Summer Nights

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The question that interests me most about time travel, if you go to the same place and time twice are you there twice?

For example, say I went back in time to 1962 to see John Glenn become the first man to orbit the Earth. I wasn't born in 1962, so there would obviously no chance of me seeing a younger version of myself. I really enjoy my trip back in time to 1962, so much so that six weeks after returning to 2021 I go back in time to 1962 to do it all over again, would I see myself there on my first trip?
I think you would not see a copy of yourself there because you are the one and only instance of the atoms that make up you. The way I imagine it is that because you existed as atoms in disparate forms before you were born (e.g. carbon, hydrogen etc.), by time travelling backwards you are basically taking those pre-you 1962 atoms and “assembling” them in the 2021 arrangement. Put differently, as time runs backwards from now until then, the time travel process “works” (for the purpose of this thought experiment) by maintaining the 2021 arrangement of you, when they otherwise would separate as you grow backwards towards birth and beyond.

If it was your second visit, I think those atoms would fly apart from the first you and converge as the second you.

This would naturally then act as a new divergence in time and irreversibly change the arrangement of matter at 1962 creating a butterfly effect whether you want it or not.
 

Howard Littlejohn

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I think you would not see a copy of yourself there because you are the one and only instance of the atoms that make up you. The way I imagine it is that because you existed as atoms in disparate forms before you were born (e.g. carbon, hydrogen etc.), by time travelling backwards you are basically taking those pre-you 1962 atoms and “assembling” them in the 2021 arrangement. Put differently, as time runs backwards from now until then, the time travel process “works” (for the purpose of this thought experiment) by maintaining the 2021 arrangement of you, when they otherwise would separate as you grow backwards towards birth and beyond.

If it was your second visit, I think those atoms would fly apart from the first you and converge as the second you.

This would naturally then act as a new divergence in time and irreversibly change the arrangement of matter at 1962 creating a butterfly effect whether you want it or not.
If it is because the atoms are there already, wouldn't that mean you can't go back the first time? The atoms that make up the individual would still be somewhere in 1962 - well, mostly, some may have decayed and become different elements between 1962 and either journey.
 

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No. Where are all the crowds of time tourists at important historical events?

There's also an argument that, even if time travel is allowed by the laws of physics, history will rearrange itself to prevent its invention. Every trip to the past will change history in some small way; eventually one of those changes will prevent the invention of the time machine and that's then the timeline we're stuck with.
 

mooloman

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No. Where are all the crowds of time tourists at important historical events?

There's also an argument that, even if time travel is allowed by the laws of physics, history will rearrange itself to prevent its invention. Every trip to the past will change history in some small way; eventually one of those changes will prevent the invention of the time machine and that's then the timeline we're stuck with.
Why do they have be at historical events? Maybe they’ve just come back assist in the acceleration of time travel, like help to set up the CERN or something.
 

Madas

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My son has an interesting theory
( not sure where he got it from some bizarre tic -tic or whatever thing he stares at incessantly , he claims it's his own )

Anyway goes like this :
More along the lines of teleportation than time travel ( same thing I guess ) but is focussed on copying the consciousness ( soul) and implanting that into a new physical body in a different time
It sounds feasible given how far technology has come in mapping /copying the brain but copying and then resurrecting the soul is hard to get your head around
Like the articles in the links below

Good luck young people !
Let me know when you've nailed it so I can go back and make the Dockers not So sh*t 🤣



 
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darth_timon

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Not sure if a thread on this has been done already and tbh I couldn't be arsed looking. Been thinking about this a lot recently, will we ever have the ability to go backwards/forwards in time? I for one would kill to be able to go back in time to enjoy my greatest memories again
If I can make it work, I'll tell you last week ;) As much as I'd love for there to be time travel, I'm struggling to think of any research or theories that are viable.
 

mooloman

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I think it’s prudent to be honest with ourselves. Time travel is real. But be honest with yourself, are the scientists at CERN really going to expend billions of Euros to prove it to You? Sure, you might have won the under 10’s high jump at school, but it’s safe to assume they give zero $hits. Unless you’re name’s John Connor.....
 

CD Xbow

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I think it’s prudent to be honest with ourselves. Time travel is real. But be honest with yourself, are the scientists at CERN really going to expend billions of Euros to prove it to You? Sure, you might have won the under 10’s high jump at school, but it’s safe to assume they give zero $hits. Unless you’re name’s John Connor.....
I'm afraid I don't believe travelling back in time is possible simply because the past no longer exists. Travelling forward in time, in the sense of slowing your local time down by travelling at relativistic speeds is possible, or you cheat a bit and use some future form of cryosuspension to slow your aging.
 

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