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Author Topic: What is the basis of the twin paradox and general relativity?  (Read 4454 times)

Offline Alan McDougall

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http://home.earthlink.net/~owl232/twinparadox.pdf

This is worth a read.

''According to STR, different intertial reference frames (RFs) can disagree on the time that
elapses between two events, as well as on the length of an object. These discrepancies are
described by the Lorentz Transformation equations:''


No they can't disagree on length of an object or disagree on the elapsed time between events,


They can agree the visual length angle of light is different to give an illusion of a different length object and agree that their measurements of time are different and their clocks are not synchronised constants.
You are 100% wrong.

All theories are 100% wrong unless they are 100% correct. 

No, you are wrong, present information may say I am wrong by their subjective thinking, but my objective thinking says that they are wrong, so who's thinking is correct?

Answer = neither of us, because it is both subjective to our thoughts,

The objective reality which you call the subjective reality, is different to the subjective reality you call the objective reality. It is not me who has it backwards according to definition.


Subjective - influenced by the mind or personal feelings /  belief


Objective - uninfluenced by personal feeling or belief,   (that which I use)

It is a misnomer  to call it a paradox because in reality both twins in their respective time frames are moving into the future.
 

Offline granpa

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I have found the question below in an old thread about the twin paradox. I could not get an answer at that thread or from other sources. The problem for me is: if the situation is totally simmetric, both twins return at the same age. But isn't it against SR theory?
I assume that all acelerations and desacelarations are the same for both the traveller twins, so GR should not explain any difference.


Things get interestinger when you have triplets, one stays on the ground, one goes off in a spacecraft to the celestial north, the other off to the celestial south, and both later return. What are their relative ages, and why?


https://commons.wikimedia.org/wiki/File:Twin_paradox.png



 

Online hamdani yusuf

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I have found the question below in an old thread about the twin paradox. I could not get an answer at that thread or from other sources. The problem for me is: if the situation is totally simmetric, both twins return at the same age. But isn't it against SR theory?
I assume that all acelerations and desacelarations are the same for both the traveller twins, so GR should not explain any difference.


Things get interestinger when you have triplets, one stays on the ground, one goes off in a spacecraft to the celestial north, the other off to the celestial south, and both later return. What are their relative ages, and why?


https://commons.wikimedia.org/wiki/File:Twin_paradox.png


how can someone in the rocket see the clocks run backward without moving faster than light?
photons arranged to show prior to 12:00 have already pass the rocket, so to see them again, the rocket must catch them up faster than photon's speed.
 

Offline granpa

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Draw A Spacetime diagram. Let the x-axis a space and the y-axis be time. Draw clocks on the x-axis at time equals zero.

Then draw a diagonal line representing 1 simultaneous moment from the point of view of the rocket.



How to draw a spacetime diagram:
https://www.physicsforums.com/threads/how-to-draw-a-spacetime-diagram.314080/
 

Online hamdani yusuf

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Draw A Spacetime diagram. Let the x-axis a space and the y-axis be time. Draw clocks on the x-axis at time equals zero.

Then draw a diagonal line representing 1 simultaneous moment from the point of view of the rocket.



How to draw a spacetime diagram:
https://www.physicsforums.com/threads/how-to-draw-a-spacetime-diagram.314080/
IMO, a clock can be said to run backward if at one instance it shows a particular time reading, and then later on, the same clock shows the reading of time prior to that instance. For example, at start a clock shows 12:00, but later on, it shows 11:59.
Your spacetime diagram doesn't show this case.
 

Offline granpa

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When the rocket is stationary then 1 simultaneous moment now is represented by the x-axis. When they work it starts moving then the line representing one one moment now becomes a dog and a lion. The faster the Rock and moves them or Tilted the line is. You can obviously see that Clark's further away will seem to be more out of sync. Just consider the case of a park that is millions or billions of light-years away from the rocket. Consider how far out of sync it must become.
 

Offline IAMREALITY

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When the rocket is stationary then 1 simultaneous moment now is represented by the x-axis. When they work it starts moving then the line representing one one moment now becomes a dog and a lion. The faster the Rock and moves them or Tilted the line is. You can obviously see that Clark's further away will seem to be more out of sync. Just consider the case of a park that is millions or billions of light-years away from the rocket. Consider how far out of sync it must become.

Not a clue what you just tried to say.

What I do know, is that the theory above is wrong.  Under no circumstance in physics would the clock on the left suddenly be 11:59 unless almost 24 hours has elapsed and it's showing the time for the next day.  But no, a clock that once read 12:00 am will under no circumstances tick backwards to 11:59, no matter what you do.  Period.
 

Offline granpa

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I didn't say it would take backwards. I said from the point of view of the rocket it would seem to be.
 

Offline IAMREALITY

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I didn't say it would take backwards. I said from the point of view of the rocket it would seem to be.

Wouldn't that mean they would see 11:59?  That's what your diagram shows.  but if they left when it was synchronized at 12, it's an impossibility for it to then show 11:59, which would in fact be ticking backwards.

The point of view of the rocket could never see any of the clocks show anything prior to 12 am, if they started at 12 am.
 

Offline granpa

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 What would a o'clock at infinity say from the Rockets point of view? What would a o'clock at negative infinity say?
 

Offline IAMREALITY

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What would a o'clock at infinity say from the Rockets point of view? What would a o'clock at negative infinity say?
It would say "warning: fatally flawed logic ahead".

Stick to what we're talking about.  Which is a bunch of clocks starting at 12 am and how it's impossible for the rocket to ever see a time prior to 12 am on them, regardless of your diagram saying otherwise. 
 

Offline granpa

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So you don't believe what a simple space-time diagram is telling you?
 

Offline IAMREALITY

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So you don't believe what a simple space-time diagram is telling you?

You mean the patently false diagram?  No.
 

Offline PhysBang

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What would a o'clock at infinity say from the Rockets point of view? What would a o'clock at negative infinity say?
It would say "warning: fatally flawed logic ahead".

Stick to what we're talking about.  Which is a bunch of clocks starting at 12 am and how it's impossible for the rocket to ever see a time prior to 12 am on them, regardless of your diagram saying otherwise.
You are confusing what one way of creating a system of coordinates might assign to the time of an event with what another way of creating a system of coordinates might assign to an event with what any particular clock might say at a particular event. Not every clock is synchronized.
 

Offline IAMREALITY

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What would a o'clock at infinity say from the Rockets point of view? What would a o'clock at negative infinity say?
It would say "warning: fatally flawed logic ahead".

Stick to what we're talking about.  Which is a bunch of clocks starting at 12 am and how it's impossible for the rocket to ever see a time prior to 12 am on them, regardless of your diagram saying otherwise.
You are confusing what one way of creating a system of coordinates might assign to the time of an event with what another way of creating a system of coordinates might assign to an event with what any particular clock might say at a particular event. Not every clock is synchronized.

No idea what on earth you just tried to say. 

What I know, is if the clocks displayed 12am when the rocket left, no event on the rocket would allow them to see 1157,as the diagram shows. 
 

Offline granpa

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Look at the space time diagram that I told you to draw. The x axis represents the line clocks.
Now look at the line representing one simultaneous moment from the point of view of the rocket. It's the diagonal line. Wherever that diagonal line goes below the x axis then the Clarks there will sing from the point of view of the rocket to be earlier. The only way no clock could be hurt earlier would be for the day now I can never get below the x-axis. That's obviously impossible.
 

Online hamdani yusuf

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When the rocket is stationary then 1 simultaneous moment now is represented by the x-axis. When they work it starts moving then the line representing one one moment now becomes a dog and a lion. The faster the Rock and moves them or Tilted the line is. You can obviously see that Clark's further away will seem to be more out of sync. Just consider the case of a park that is millions or billions of light-years away from the rocket. Consider how far out of sync it must become.
if a clock is billions of light years away to the left, then it will not look synchronized with the clock right next to the rocket even when it is not moving.
 

Offline granpa

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Which is why it has to be calculated not observed
 

Offline IAMREALITY

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Which is why it has to be calculated not observed
Yet your graphic above mentions nothing about calculations, seems to infer observation, and specifically shows a time on the clock face that was to be observed. If you were specifically talking about merely what might be calculated, then you should have just said so.
 

Online jeffreyH

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I must admit skipping most of the discussion but need to address a point made in a post by granpa. No clock will ever appear to run backwards unless the rocket can outrun photons coming from the clock. The clock will appear to slow down and fall behind others but it will NEVER go backwards. It matters not what metric is used the rocket will never exceed the speed of light.
 

Offline granpa

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Relativity is much more than just how things appear

Why would you think I was talking about the appearance of the clocks?
« Last Edit: 06/07/2016 20:16:18 by granpa »
 

Offline IAMREALITY

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Relativity is much more than just how things appear

Why would you think I was talking about the appearance of the clocks?

Are you for real?  Maybe because in your graphic, you specifically start off with the declaration of how "they appear"?  And the main part of the graphic is specifically how they appear?

You specifically address how 'they appear'.  You further specifically call attention to appearance by showing very specific graphics of their appearance.  You furthermore state from their "point of view", which also is therefore referencing appearance (point of view = what they would see from where they are).  What isn't found anywhere in the details of your explanation within that graphic itself though, is anything specifically mentioning Relativity (I'm not talking about the title of the graphic nor the end line conclusion.  But your actual theory and explanation within the graphic you put forth.  And it was that of which I was in disagreement.  And it is why the graphic is quite simply wrong.  Cause nothing will make the clock go backwards.)

So my advice to you would be to start the graphic over from scratch.  Cause it does a horrible job at making your case.

« Last Edit: 06/07/2016 21:44:45 by IAMREALITY »
 

Offline granpa

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I don't believe anybody could be that stupid. Why are you harassing me?
 

Offline Alan McDougall

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There is no paradox both twins are both advancing in time in the only possible direction into their relative futures, albeit at different rates, depending on their mass, gravity field, or acceleration away or towards each other.

What we do know about the "Flow" of time in our universe is that it is linear like an arrow from the past into the present and then into the future. We are all on the ride into the future, but at different rates, because time is not a fundamental constant and varies fro place to place, indeed time flows slightly faster at your feet which are nearer to the gravity field of the earth, than your head.

Thus; if you could hypothetically stand still for a few billion Earth years, the result would be that your feet would have become much younger than your head .
 
Alan
« Last Edit: 06/07/2016 21:02:52 by Alan McDougall »
 

Offline Alan McDougall

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I don't believe anybody could be that stupid. Why are you harassing me?

Report him to the moderator he likes to insult people such as calling you "Dude"

Don't let him get away with it, he persisted in insulting me in an exact manner he is doing to you!

From one Granpa to another

Great to make your acquaintance!

Warm regards from a like thinker

Alan McDougall

« Last Edit: 06/07/2016 21:06:16 by Alan McDougall »
 

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