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Opinion Clickbait Isn't travelling back in time technically possible? ⏳⏪

MetalAlien

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I'd go even further with (actual) time travel to the past being destructive. You couldn't even open a pin hole and stick a camera through without destroying the present. The very act of creating a pin hole to the past would reset the randomness of the quantum state. It would be like a bomb of randomness expanding from the pinhole at the speed of light.

All the little random quantum fluctuations that effect how real life unfolds would be different because you looked into the past and every second after that moment would unfold slightly different. The present time would be wiped out.
 

Stouffers

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It is absolutely impossible you will ever fuck Scarlett Johansson while I watch. If the scenario arises where it's about to happen I promise I will close my eyes to ensure I'm technically correct
Improbable for a bunch of reasons, but not “absolutely impossible.”
 
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O-N-E

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i think shows like Rick & Morty and pop sci fi have convinced people that a lot of miraculous technology is right around the corner

like for real you will hear people talk about uploading brains and making clones of people and teleportation and stuff, as if science will make all that possible. people may not believe in magic or religion anymore but they do have a bunch of faith in a techno utopia waiting just around the corner.

as with anything, ill believe it when i see it
First of all, in no way do I believe anything like this is "around the corner". It's a thought experiment.

Second, this localized time travel seems a lot more doable to me than Morty's request from Rick to make something that can save the state of the entire universe. It seems entirely likely that the universe is part of an infinite continuum, and how are you gonna save that?

And what Morty got instead was the parallel universe consciousness version.

Instead, you can experiment on a 30 x 30 x 30 cm space for example and scale up with more resources.
 

Kamina

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That sounds nore like reverting the state of a certain perimeter‘s content. The rest of the world/universe will remain in the present, so this isnt time travel but a reconstruction.
 
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nkarafo

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I dont know what that implies though. Can you bring people back from the dead? Because if you go back in time theoretically you should be able to interract with people who are now dead.
 
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O-N-E

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I dont know what that implies though. Can you bring people back from the dead? Because if you go back in time theoretically you should be able to interract with people who are now dead.
I mean, possibly, but if we're a civilized society, we probably shouldn't do that.

That sounds nore like reverting the state of a certain perimeter‘s content. The rest of the world/universe will remain in the present, so this isnt time travel but a reconstruction.
If your idea of time travel is that everything in the universe has to be exactly reversed, I don't think that can ever be in the hands of humans. And even if it were to happen, you wouldn't be witnessing the travel, because if you exist as you are in a time before now, that means the universe wasn't accurately reversed.
 
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Kamina

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If your idea of time travel is that everything in the universe has to be exactly reversed, I don't think that can ever be in the hands of humans. And even if it were to happen, you wouldn't be witnessing the travel, because if you exist as you are in a time before now, that means the universe wasn't accurately reversed.
Its not my idead of time travel, its the only real way of time travel. You can only travel through time if time changes for you, while you don't. If you sit outside and watch time reverse in a contained environment you arent travelling. Nor is anything within the changed environment traveling, but just reversed to a previous state.
 
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O-N-E

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Its not my idead of time travel, its the only real way of time travel. You can only travel through time if time changes for you, while you don't. If you sit outside and watch time reverse in a contained environment you arent travelling. Nor is anything within the changed environment traveling, but just reversed to a previous state.
 

SKM1

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From the point of view of the subsystem which is being manipulated, the environment changes, as such it is not really traveling through time. To solve this, you would have to isolate the system and then you would be violating the 2nd law.
 

Kenpachii

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The state of matter can change due to the forces exerted on them, but if you had the computing power to analyze and store the exact state of every particle within a certain perimeter, then had the right amount of force and accuracy to change each particle's state and position back to a previous one, isn't that essentially time travel within that perimeter? The more mass, the more energy this requires and more complexity requires more computing power and accuracy.

It would certainly be an insane setup, but it seems technically possible.



I'm not going to ask an actual physicist though, cause every time I do they roll their eyes and yell about the speed of light or some shit.
No because time still moves forwards.
 

buizel

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Feb 19, 2018
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yeh obviously

say you go to france, you go back in time 2 hours.

but then say you return back but ON A FASTER PLANE like twice as fast. youve gone back in time 1 hour. not many people realise this.
 

rykomatsu

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The equation for time dilation:


t = time you as a human observe
t0 = time passed on say....Earth
v = your velocity away from earth
c = speed of light constant

In order for time to even stop (not going backwards in time), you need to hit the speed of light (actually not even...since at speed of light, you get a divide by zero error)

However! In order for you to hit the speed of light:

The equation for velocity given energy:

v = your velocity
m = your mass
E = energy
c = speed of light constant

The square root in this case MUST equal 1. The problem is, no matter how much energy you throw at your mass, the mc2/E value gets infentisimally small, but never 0. As such, the square root can never be 1 since it'll always be 0.999...999

  • To slow down time to a standstill, you must be traveling at the speed of light
  • To be traveling at the speed of light, you must be providing literally infinite energy
  • As such, the best you'll ever achieve is super super super slow forward movement of time, never a full stop nor movement backwards in time
 
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O-N-E

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The equation for time dilation:


t = time you as a human observe
t0 = time passed on say....Earth
v = your velocity away from earth
c = speed of light constant

In order for time to even stop (not going backwards in time), you need to hit the speed of light (actually not even...since at speed of light, you get a divide by zero error)

However! In order for you to hit the speed of light:

The equation for velocity given energy:

v = your velocity
m = your mass
E = energy
c = speed of light constant

The square root in this case MUST equal 1. The problem is, no matter how much energy you throw at your mass, the mc2/E value gets infentisimally small, but never 0. As such, the square root can never be 1 since it'll always be 0.999...999

  • To slow down time to a standstill, you must be traveling at the speed of light
  • To be traveling at the speed of light, you must be providing literally infinite energy
  • As such, the best you'll ever achieve is super super super slow forward movement of time, never a full stop nor movement backwards in time
Uh... this is quite complex for me, but is this really in relation to the method I was talking about?

Like for instance, you have a hamster in a controlled environment. You begin recording the state of particles in the environment. The hamster dies at day 5, you move the particles to their state at day 1. Hamster is alive now. According to what you posted above, that's impossible?
 

rykomatsu

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Uh... this is quite complex for me, but is this really in relation to the method I was talking about?

Like for instance, you have a hamster in a controlled environment. You begin recording the state of particles in the environment. The hamster dies at day 5, you move the particles to their state at day 1. Hamster is alive now. According to what you posted above, that's impossible?
That's not time travel.
 

Tesseract

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the laws are reversible but the process breaks once you establish approximate holds on position and velocity

it's not just a demon problem of quantum uncertainty, there's fundamental limits to reversing wave phase that we've not yet resolved

personal opinion is yes it's possible to nudge the information into placeholder phases that we can interact with, but the failure rate is so ugly as to make any practical approaches meaningless
 
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Tesseract

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more than likely i'd expect a kind of simulation space for time travel

failure rate will improve as more qubits are accessible

something like vr with ever increasing precision and accuracy, where events can be recreated and studied, probabilities examined and tuned as more information is culled
 

O-N-E

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That's not time travel.
What definition of time travel makes it not a paradox then? If the entire state of the universe is reversed, rather than a controlled local area, you won't notice that it was reversed. So that's not really time travel either. If you yourself somehow got a magical genie wish to insert yourself into a previous state of the universe, yet again, that's not time travel, because you weren't part of the equation of the universe you're now entering.

I'm trying to think of what seems like a more realistic approach to time travel.
 
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rykomatsu

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What definition of time travel makes it not a paradox then? If the entire state of the universe is reversed, rather than a controlled local area, you won't notice that it was reversed. So that's not really time travel either. If you yourself somehow got a magical genie wish to insert yourself into a previous state of the universe, yet again, that's not time travel, because you weren't part of the equation of the universe you're now entering.

I'm trying to think of what seems like a more realistic approach to time travel.
Maybe I'm misunderstanding you...

Even if you were to revert a set of particles to a "prior" state such that it was equivalent to say...its state 5 min ago, it's still done in the context of time moving forward.

Take a basic document revision control system
1. Save a document at t = 1:00pm
2. Edit and save document as revision 2 at t= 1:05pm
3. Restore 1:00pm revision 1 at 1:06pm

Would you consider this information to have traveled back/forward in time?
 
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O-N-E

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Maybe I'm misunderstanding you...

Even if you were to revert a set of particles to a "prior" state such that it was equivalent to say...its state 5 min ago, it's still done in the context of time moving forward.

Take a basic document revision control system
1. Save a document at t = 1:00pm
2. Edit and save document as revision 2 at t= 1:05pm
3. Restore 1:00pm revision 1 at 1:06pm

Would you consider this information to have traveled back/forward in time?
Locally, yes.

Back / forward is just a concept. Time just means things are in flux. If we remember a state and have the capability, we can return something to its prior form.

But again, what other definition of time travel isn't a paradox?
 
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Airola

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Back / forward is just a concept. Time just means things are in flux. If we remember a state and have the capability, we can return something to its prior form.
Travelling in time in every time travel movie has meant that the future things haven't happened yet to people who are in the time the time traveller travels to.
Would your concept somehow be also capable of erasing all memories and situations from between the time we travel to and the time the travel was performed in?
Even just erasing the memories and situations wouldn't cut it though, as they should become things that never even happened. Changing particles is current time doesn't do that trick.

But yes. Time travel is a paradox and an impossibility. It's not even theoretically possible in any way or form.

We can make elaborate 'stage plays' with authentic sets and everything but that isn't time travel in any sense of its meaning.



All that said, I believe in the actual existence of ideas. There is a realm of ideas and ideas of potential future situations and ideas of past situations that have happened. Getting an access to that can allow these faux time travel things, where you could see future situations and see what happened in the past. You couldn't interact with them though and it wouldn't be actual time travel. But that's one way I could imagine something at least a bit close to time travel happening.
 

Rentahamster

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I’m going to say going back in time is possible and I don’t believe in multiverses.

In fact you can see the past when looking up at the night sky and you wouldn’t even know it. The further objects are away from you the further back in the past they actually are.

Scientists have claimed that aliens 65 million light years away could look at Earth today (providing they had some damn good telescopes) and see Dinosaurs still roaming.

I believe there is something in that which if the past can be seen then it is only a matter of time to figure out how it can be reached.
You're gonna have to overcome the speed of light, which at this point, barring some creating outside thinking, is considered impossible.
 
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V4skunk

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With an inertial mass reduction device, like the one in the US Navy patents! FTL travel could be possible.
 

Airola

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But it’s not a still image is it? It’s a physical look into the past.
No, it's you seeing light that is not the situation, but an illumination. It is just a photograph (or moving pictures if you will) imprinted in space, moving forwards at a certain speed and you are able to take a look in that. The actual situation that you see is long gone. It is a memory of a past thing, the way a picture is. You can perhaps see several pictures in a row, but that just makes it like a movie, many pictures in a row. The actual situation doesn't exist anywhere. At best you are looking at a documentary that happened by accident.
 
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bitbydeath

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No, it's you seeing light that is not the situation, but an illumination. It is just a photograph (or moving pictures if you will) imprinted in space, moving forwards at a certain speed and you are able to take a look in that. The actual situation that you see is long gone. It is a memory of a past thing, the way a picture is. You can perhaps see several pictures in a row, but that just makes it like a movie, many pictures in a row. The actual situation doesn't exist anywhere. At best you are looking at a documentary that happened by accident.
But that means there is a memory there to begin with and not a straight timeline with no way back. Seeing the past is miraculous in of itself.
 

Rentahamster

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But isn't mass the reason why FTL cannot be achieved?
Well, I don't know if there's any one problem, like mass. The only thing that travels as fast as light is light, which has no mass. Tachyons, which are only hypothetical, might have negative mass? However the hell that's supposed to work.

Mostly, according to physics as we know it, it takes infinite energy to travel at the speed of light, so that's a problem. Depending on how you look at the equation, it's also a problem of infinite mass. So unless you have some way to reduce mass to zero, I don't see how we're getting anywhere.

Stretching and altering spacetime seems like a more plausible way of getting anywhere at FTL speeds, but even that is crazy outlandish with our current understanding of the universe.
 
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To be able to travel back through time would require history physically existing somewhere.

You could perhaps create a copy of the state the world used to be in, if there would be some way to change atoms at your will, but you would still be in this current time. It's not time travel, it's just some really obnoxiously autistic way to make a fully accurate period piece setup.
This may be the greatest /thread of all time
 
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SKM1

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Well, I don't know if there's any one problem, like mass. The only thing that travels as fast as light is light, which has no mass. Tachyons, which are only hypothetical, might have negative mass? However the hell that's supposed to work.

Mostly, according to physics as we know it, it takes infinite energy to travel at the speed of light, so that's a problem. Depending on how you look at the equation, it's also a problem of infinite mass. So unless you have some way to reduce mass to zero, I don't see how we're getting anywhere.

Stretching and altering spacetime seems like a more plausible way of getting anywhere at FTL speeds, but even that is crazy outlandish with our current understanding of the universe.
Tachyons have imaginary mass, negative squared mass. If I recall correctly, there are indeed tachyonic particles but they are virtual. They only appear in intermediate process described by Feynman diagrams. They come to existence and decay rapidly, in accordance to Heisenberg's uncertainty principle for energy and time. Now, this is quantum mechanics (quantum field theory to be precise). In the context of special relativity, people claim that incorporating tachyons lead to inconsistencies in the theory. Some people claim that that is not the case and so the problem of tachyons has been extensively studied.
 
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V4skunk

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Well, I don't know if there's any one problem, like mass. The only thing that travels as fast as light is light, which has no mass. Tachyons, which are only hypothetical, might have negative mass? However the hell that's supposed to work.

Mostly, according to physics as we know it, it takes infinite energy to travel at the speed of light, so that's a problem. Depending on how you look at the equation, it's also a problem of infinite mass. So unless you have some way to reduce mass to zero, I don't see how we're getting anywhere.

Stretching and altering spacetime seems like a more plausible way of getting anywhere at FTL speeds, but even that is crazy outlandish with our current understanding of the universe.
But this solves the problem.
And this will make the speed possible among other things.