Time Machine will not be invented

[DaveC426913]

And also no reason to suppose not, I suppose.

Yes there is. Occam's Razor and the Scientific Method.

We don't suppose faeries and unicorns for the same reason.

 

[Ash Small]

I don't see how that follows. We were talking about time travel technology. How did we get to an idea of particles spontaneously travelling backwards en mass?

Whatever the method of time travel, Dave, whether by machine or otherwise (the mechanism isn't important here), Pauli states that each fermion has it's own 'associated state' within space-time.

This has been accepted since 1927, and time travel would violate this principle.

 

[pallidin]

Ever notice how we seem unable to change the past, but most certainly capable of affecting the future?
The future, it seems, immutably relies on the "past' for part of it's "Now"

 

[DaveC426913]

Whatever the method of time travel, Dave, whether by machine or otherwise (the mechanism isn't important here), Pauli states that each fermion has it's own 'associated state' within space-time.

This has been accepted since 1927, and time travel would violate this principle.

Argh! Are you ADHD? Stay on freakin' topic!

If you want to talk about PEP, then there's nothing that excludes it. Find me a reference to PEP that talks about a particle traveling into its own past.



If you want to talk about particles traveling back in time, then well, what are we talking about? We went from a time machine to recreating the Big Bang in nothing flat.

 

[Studiot]

It's a long time since we heard from the OP.

Perhaps he really meant that a Time Machine will not be invented because he is a Time Lord and has already invented one.

 

[Ash Small]

Argh! Are you ADHD? Stay on freakin' topic!

If you want to talk about PEP, then there's nothing that excludes it. Find me a reference to PEP that talks about a particle traveling into its own past.



If you want to talk about particles traveling back in time, then well, what are we talking about? We went from a time machine to recreating the Big Bang in nothing flat.

I feel I'm repeating myself here Dave. The time machine would comprise of fermions and leptons. The fermions cannot violate PEP, PEP ties the fermions to one state in space-time. time travel would violate PEP.

Fermions can move in space-time, but they can't jump, either in space or in time, from one state to another.

Please come up with an argument that I haven't replied to already.

(BTW, I wasn't re-creating the big bang, I was extrapolating your earlier reply to 'explain' it.) :-)

 

[DaveC426913]

The fermions cannot violate PEP, PEP ties the fermions to one state in space-time. time travel would violate PEP.

Nothing in PEP addresses a particle moving backward in time to join its earlier self. Nothing in PEP says two particles can't exist near each other while being in the same state.

For one, PEP applies to particles in the same atom. No one says an atom traveling backward in time somehow overlaps itself physically.

You are reading far too much of PEP into this scenario.

 

[Ash Small]

Nothing in PEP addresses a particle moving backward in time to join its earlier self. Nothing in PEP says two particles can't exist near each other while being in the same state.

For one, PEP applies to particles in the same atom. No one says an atom traveling backward in time somehow overlaps itself physically.

You are reading far too much of PEP into this scenario.

Dave, If two particles were in the same state they would be super-imposed, PEP excludes this. They can be identical in all other respects, but they cannot occupy the same space at the same time.

They are each associated with their own unique state in 'space-time'.

 

[DaveC426913]

Dave, If two particles were in the same state they would be super-imposed, PEP excludes this.

Show what this has to do with what we're talking about.

They can be identical in all other respects, but they cannot occupy the same space at the same time.

Nobody said they have to.


These are both red herrings. Who claimed the particle traveling backward in time must occupy the same space as its younger self?

I have an atom in a beaker on my desk. I send it backward in time; it appears in another beaker a foot to the left of the first one. Show how PEP disallows this.

 

[Ash Small]

Show what this has to do with what we're talking about.



Nobody said they have to.


These are both red herrings. Who claimed the particle traveling backward in time must occupy the same space as its younger self?

I have an atom in a beaker on my desk. I send it backward in time; it appears in another beaker a foot to the left of the first one. Show how PEP disallows this.

PEP states that each fermion has it's own unique state associated with it in space-time (singular).

You show me where it says otherwise, and says a fermion can exist in two states in space-time.

 

[DaveC426913]

PEP states that each fermion has it's own unique state associated with it in space-time (singular).

You show me where it says otherwise, and says a fermion can exist in two states in space-time.

I don't disagree.

Now you show me how my two atoms, a foot apart, are in the same place.

 

[Ash Small]

I don't disagree.

Now you show me how my two atoms, a foot apart, are in the same place.

They are not in the same place, but they violate the space-time component of PEP.

PEP states that each fermion occupies it's own unique state in space-time (singular)

(if A occupies x, then B occupies y, A cannot occupy y if it occupies x anymore than A and B can occupy x at the same time.)

 

[DaveC426913]

They are not in the same place, but they violate the space-time component of PEP.

PEP states that each fermion occupies it's own unique state in space-time (singular)

The two atoms (actually, particles) do not violate this.

One particle is at [x y z t] while the other is at [x' y z t]. Those are, indeed, unique places in spacetime (singular). I'm really not sure why you are not getting this.

 

[pallidin]

Uh, I would assume that going back-in-time violates a whole host of contemporary theories.

 

[pallidin]

Look, we have a clue in reality.
The past is observationally possible, but NOT interactive.

 

[Time Machine]

Yes there is. Occam's Razor and the Scientific Method.

We don't suppose faeries and unicorns for the same reason.

Aren't parallel universes in the same realm as faeries and unicorns. I'm sure a clever mathematician could conjour some ammusing calculations. The only reason it was mentioned by me was to do with an earlier comment in the thread that made a humerous remark relating to parallel universe. It was quite a long time ago.

Any-one got anything to say about my comment that did involve time travel?

 

[JaredJames]

Am I the only one who can see the logic in DaveC's view?

The PEP may say that two particles cannot occupy the same space-time, but if particle A was at [x,y,z,t] and also at [x',y,z,t] it isn't in the same space-time location. So it doesn't violate the rule.

I literally know nothing regarding this topic, but I can see what DaveC is saying. So far, none of the counter-arguments address this and simply restate the same point over and over.

 

[DaveC426913]

So far, none of the counter-arguments address this and simply restate the same point over and over.

Yyyep.

 

[DaveC426913]

Uh, I would assume that going back-in-time violates a whole host of contemporary theories.

I don' t think so, no. None that I can think of.

I mean, time travel might end up violating some theories, and thus may finally not work, but I don't know of any theories that a priori rule it out.

 

[Time Machine]

I had actually been following the dialogue about fermions but having nothing to add to this conversation about "particle physics" apart from perhaps making the suggestion that you guys are in the wrong thread or pointing out the fact that whilst the Big Bang Theory is wildly popular it is to all intents and purposes only a concept in itself and an abstract one at that.
Not an input that would have been welcomed too much no doubt.

Dave, you have complained that input has been off-track concerning this thread yet you continue to talk to me about a flip parallel universe comment that I have repeatedly told you was not serious, have no interest in and has nothing to do with this thread other than some-one else had brought it up, when the choice was there to respond to comment that I made that is related to this thread of "time travel".
Dave, I do realize that my approach to physics is unconventional and that my use of language is unusual. I see no reason that this should invalidate my input. I can assure you that I have extremely valid reasons behind this fact. If you care to contact me privately then I would be happy to explain.

Getting back to time travel, incase any-one visiting this thread is interested in my input! It occurs to me that if a potential time traveler used slow time/gravity variables to travel through faster time/gravity variables, that it actually would indeed be possible to arrive back at the place of your journey's start in your own past. Obviously it is debatable as to whether or not this is physically possible. If not then potential time travelers would probably avoid such occurances happening in their calculations when mapping out their journey.
The benefits of the time travelers time going slow whilst time outside the craft is going quicker, apart from getting to your destination in less time, would mean that engine revs could be kept down in slower speeds affording a more fuel efficient journey.
The difficulties that I mentioned before concerning containing a gravity field:
Perhaps somewhere in the work of Thompson Townsend Brown there lies a clue to the answer. If the walls of the craft were electrically charged: in an inward direction with slow time/gravity variables, in an outward direction with fast time/gravity variables and cancelling out charges were directed at each other between the inside and the outside of the walls that stopped each field leaking into the other, then perhaps this problem could be overcome.

Any comment on time travel?

 

[ZapperZ]

At some point, a thread on this topic inevitably leads to posts that are highly speculative and violates our https://www.physicsforums.com/showthread.php?t=414380" that everyone had agreed to. If this thread does not get back to discussion using valid physics AND back up unusual claims with proper citation, this thread (and this topic) will be closed.

Zz.

 

[Ash Small]

The two atoms (actually, particles) do not violate this.

One particle is at [x y z t] while the other is at [x' y z t]. Those are, indeed, unique places in spacetime (singular). I'm really not sure why you are not getting this.

Ok Dave, one last time, If fermion A is at point (x,y,z) at time t it can't also be at point (x',y,z) at time t. PEP states that each fermion has it's own unique state at anyone point in time.

Please show me where you think PEP says that a fermion can occupy TWO STATES AT THE SAME TIME?

I have read and re-read PEP and and all it says is that each fermion has it's own unique state (singular) at anyone point in time.

 

[Time Machine]

It's a long time since we heard from the OP.

Perhaps he really meant that a Time Machine will not be invented because he is a Time Lord and has already invented one.

No doubt this is one of posts you are referring to Zapper Z. There is nothing in mine that violates any rules and there are no "Holy Cows" in theoretical physics.

 

[DaveC426913]

I had actually been following the dialogue about fermions but having nothing to add to this conversation about "particle physics" apart from perhaps making the suggestion that you guys are in the wrong thread...

It is highly relevant. The claim is that time travel of any form, would violate PEP. If true, this thread topic is stopped in its tracks. But Ash has not made his case on this one.

or pointing out the fact that... whilst the Big Bang Theory is wildly popular it is to all intents and purposes only a concept in itself and an abstract one at that.

This is not true. It is a well-established and accepted theory that is virtually uncontested by any competent scientist except in the details. Make no mistake, we understand the formation of our universe back to within microsceconds of its creation.

Dave, you have complained that input has been off-track concerning this thread yet you continue to talk to me about a flip parallel universe comment that I have repeatedly told you was not serious, have no interest in and has nothing to do with this thread other than some-one else had brought it up, when the choice was there to respond to comment that I made that is related to this thread of "time travel".

All right. Consider it dropped then.

Dave, I do realize that my approach to physics is unconventional and that my use of language is unusual. I see no reason that this should invalidate my input.

I can assure you that I have extremely valid reasons behind this fact. If you care to contact me privately then I would be happy to explain.

If you didn't want it discussed, you wouldn't have put it out there. By ptuting it out there, you are expecting it to be challenged. I'll assume you'ree retracting it. No prob.

Getting back to time travel, incase any-one visiting this thread is interested in my input! It occurs to me that if a potential time traveler used slow time/gravity variables to travel through faster time/gravity variables, that it actually would indeed be possible to arrive back at the place of your journey's start in your own past.

No. No matter how much you slow a car down, it will never be slow enough to arrive back home.

Time travel, OTOH, is a reversal of direction.

The benefits of the time travelers time going slow whilst time outside the craft is going quicker, apart from getting to your destination in less time, would mean that engine revs could be kept down in slower speeds affording a more fuel efficient journey.

...despite the fact that it's a one-way trip in time.

If you let 100 years go by while you take only 6 years to travel to Gliese 581, all your loved ones are dead forever.

The difficulties that I mentioned before concerning containing a gravity field:
Perhaps somewhere in the work of Thompson Townsend Brown there lies a clue to the answer. If the walls of the craft were electrically charged: in an inward direction with slow time/gravity variables, in an outward direction with fast time/gravity variables and cancelling out charges were directed at each other between the inside and the outside of the walls that stopped each field leaking into the other, then perhaps this problem could be overcome.

Any comment on time travel?

It is important to keep in mind that there is dilation in only one direction. You can slow time via GR but you cannot speed it up. Free space, away from massive bodies is the fastest time is going to travel. Moving into a gravity well will slow time for you, but there'e no counterpart. There is no flatter space or negative curvature.

 

[DaveC426913]

Ok Dave, one last time, If fermion A is at point (x,y,z) at time t it can't also be at point (x',y,z) at time t. PEP states that each fermion has it's own unique state at anyone point in time.

Please show me where you think PEP says that a fermion can occupy TWO STATES AT THE SAME TIME?

Boy, you just really don't get this time travel concept do you?


Please show me how any object can be in two places at the same time. It can't. Right?


Your argument really has nothing to do with PEP. Look, I'll use the exact same argument on a macroscopic object.

By the definition of person - a person cannot be in two places at once. Right? That doesn't require PEP; it is just common sense. In every way meaningful, one object cannot be in two places at once. Period. PEP is smply a specious argument that applies to atomic particles and their states.

The point here is that PEP does not add anything to the discussion about uniqueness of objects. If an object cannot be in two places the same time, then it can't be in two places at the same time, PEP or no PEP. Full stop.



Now we add time travel into the mix. As soon as we allow the possibility of time travel it becomes obvious how one person can be in two places at the same time. It also becomes obvious how any particles can be in two places at the same time - if we allow for time travel. It also becomes obvious that PEP has nothing to say about - this because PEP - like all our other sans-time-travel statements - doesn't account for time travel. PEP (like all the rest of physics) assumes that one particle exists only once at any point in time.

But with the advent of time travel, that is now a false assumption. PEP is now inadequate to describe our new situation.

 

[Ash Small]

I had actually been following the dialogue about fermions but having nothing to add to this conversation about "particle physics" apart from perhaps making the suggestion that you guys are in the wrong thread or pointing out the fact that whilst the Big Bang Theory is wildly popular it is to all intents and purposes only a concept in itself and an abstract one at that.
Not an input that would have been welcomed too much no doubt.

Dave, you have complained that input has been off-track concerning this thread yet you continue to talk to me about a flip parallel universe comment that I have repeatedly told you was not serious, have no interest in and has nothing to do with this thread other than some-one else had brought it up, when the choice was there to respond to comment that I made that is related to this thread of "time travel".
Dave, I do realize that my approach to physics is unconventional and that my use of language is unusual. I see no reason that this should invalidate my input. I can assure you that I have extremely valid reasons behind this fact. If you care to contact me privately then I would be happy to explain.

Getting back to time travel, incase any-one visiting this thread is interested in my input! It occurs to me that if a potential time traveler used slow time/gravity variables to travel through faster time/gravity variables, that it actually would indeed be possible to arrive back at the place of your journey's start in your own past. Obviously it is debatable as to whether or not this is physically possible. If not then potential time travelers would probably avoid such occurances happening in their calculations when mapping out their journey.
The benefits of the time travelers time going slow whilst time outside the craft is going quicker, apart from getting to your destination in less time, would mean that engine revs could be kept down in slower speeds affording a more fuel efficient journey.
The difficulties that I mentioned before concerning containing a gravity field:
Perhaps somewhere in the work of Thompson Townsend Brown there lies a clue to the answer. If the walls of the craft were electrically charged: in an inward direction with slow time/gravity variables, in an outward direction with fast time/gravity variables and cancelling out charges were directed at each other between the inside and the outside of the walls that stopped each field leaking into the other, then perhaps this problem could be overcome.

Any comment on time travel?

i agree that using relative speeds and gravity it is possible to slow time down, but this is not the same as time travel.

There is an argument that anti-matter travels backwards through time, but when it meets it's corresponding matter both are annialated, releasing energy.

While you could, theoretically, set out in a spacecraft on a ten year trip and arrive back here after 50 years had passed here, essentially traveling into the future (or your own future relative to others who stayed here) you could not arrive back here before you left.

It could possibly be argued that 'anything that travels backwards through time is antimatter' and will therefore be annhialated as soon as it comes into contact with matter, which travels forwards in time.

(All the above is based on accepted scientific theory)

 

[DaveC426913]

There is an argument that anti-matter travels backwards through time...

An argument, yes. For virtual particles.

It could possibly be argued that 'anything that travels backwards through time is antimatter'

This does not follow. If all dogs are mammals, are all mammals dogs?

(All the above is based on accepted scientific theory)

Please reference this accepted scientific theory.

 

[Ash Small]

Boy, you just really don't get this time travel concept do you?


Please show me how any object can be in two places at the same time. It can't. Right?


Your argument really has nothing to do with PEP. Look, I'll use the exact same argument on a macroscopic object.

By the definition of person - a person cannot be in two places at once. Right? That doesn't require PEP; it is just common sense. In every way meaningful, one object cannot be in two places at once. Period. PEP is smply a specious argument that applies to atomic particles and their states.

The point here is that PEP does not add anything to the discussion about uniqueness of objects. If an object cannot be in two places the same time, then it can't be in two places at the same time, PEP or no PEP. Full stop.



Now we add time travel into the mix. As soon as we allow the possibility of time travel it becomes obvious how one person can be in two places at the same time. It also becomes obvious how any particles can be in two places at the same time - if we allow for time travel. It also becomes obvious that PEP has nothing to say about - this because PEP - like all our other sans-time-travel statements - doesn't account for time travel. PEP (like all the rest of physics) assumes that one particle exists only once at any point in time.

But with the advent of time travel, that is now a false assumption. PEP is now inadequate to describe our new situation.

Dave, you macroscopic analogy of PEP does hols, as we are comprised mostly of fermions ourselves (per unit mass), therefore PEP is relevant.

If we were to travel back in time, the point that we travel back to (and all points that we pass through on the way) would already contain fermions (even space isn't a complete vacuum).

We would be violating PEP for a second time if our fermions were occupying the same space as other fermions.

The only way to avoid this would be to move those other fermions (the other 'matter') out of the way first, which would involve 'changing the past'.

Before you can argue that time travel may be possible, you first have to suggest a viable mechanism, based on scientificly sound principles, by which we can achieve this, and change history after the event.

How would you attemt to overcome these obstacles?

 

[Ash Small]

An argument, yes. For virtual particles.


This does not follow. If all dogs are mammals, are all mammals dogs?



Please reference this accepted scientific theory.

Dave, I'll leave aside the points we seem unable to agree on for now, and stick to the 'common ground'.

(BTW, antimatter isn't 'virtual particles', it has been observed and is real)

If the only thing we know of that travels bacwards in time is anti-matter, then it follows that any time machine capable of traveling into the past MUST be constructed purely from anti-matter.

While this may be theoretically possible, in practice, for obvious reasons, it is impractical/impossible, as it would be annhialated, along with any matter it came into contact with.

 

[DaveC426913]

Dave, you macroscopic analogy of PEP does hols, as we are comprised mostly of fermions ourselves (per unit mass), therefore PEP is relevant.

That's kind of my point. It's not that PEP rules out things being in two places at once, it's simply our conventional non-time-traveling physics. Once we posit time travel, we have to re-examine these assumptions about two places at once.

If we were to travel back in time, the point that we travel back to (and all points that we pass through on the way) would already contain fermions (even space isn't a complete vacuum).

We would be violating PEP for a second time if our fermions were occupying the same space as other fermions.

This argument is silly. By your logic, no atom can ever move, since to do so, it might "occupy the same space" as an adjacent atom.

Again, you do not understand PEP. PEP means that two electrons in the same atoms cannot both occupy the same state. It does not say that one whole atom pushing another atom out of its way somehow constitutes these two atoms occupying the same space and being in the same state.

You're really going off the reservation now.

Before you can argue that time travel may be possible, you first have to suggest a viable mechanism, based on scientificly sound principles

No I don't. That is an engineering issue, far down the road. We first posit that time travel may be possible in pirinciple. We then try to determine if there are any existing laws that prohibit it (the is where we are in the discussion right now). So far, we know of none.