[Origin]

Unfortunately, you can't explain how you got that answer.

It has been explained, you are resisting learning.
I believe every source you have cited here says the traveling twin is the one that ages more.  That means none of your sources see a paradox, but for some reason you're not sure.

[hamdani yusuf (OP)]

Unfortunately, you can't explain how you got that answer.

It has been explained, you are resisting learning.
I believe every source you have cited here says the traveling twin is the one that ages more.  That means none of your sources see a paradox, but for some reason you're not sure.

I discussed standard twin paradox problem in someone else's thread. Basically, the common explanations employ time rotation as explained by minutephysics' video. Videos from Harvard and MIT use similar explanation.
Here I want to test the generality of that explanation. Is it still useful to explain some varieties of the problem? Where's the boundaries that the explanation stops working?
Is it compatible with other physics principles that are widely accepted?

[Halc]

Basically, the common explanations employ time rotation as explained by minutephysics' video. Videos from Harvard and MIT use similar explanation.

The time rotation thing lends itself nicely to video. It is hardly the simplest explanation, but it very much is a valid one.

But it needs to do a Lorentz rotation, not a Euclidean rotation like you're doing with all your pictures posted above. Those produce contradictory observations, as you have noted.

For instance, in your pictures in post 110, all the ships B,C,D age about 4.5 years, not 8. That's a contradiction since any observation (like everybody's age at the final event) should be a frame independent thing.

Here I want to test the generality of that explanation.

That explanation generalizes to any special relativity situtation, but not to any situation involving gravity.  The more simple explanation I posted also applies only to SR, but in the other thread you mention I gave a geometric explanation that works in all cases, but is beyond your ability to learn.

Is it still useful to explain some varieties of the problem?

Again, so long as it doesn't involve gravity.

According to A, both B and C switch their reference frame once, while D switchs twice. But they must have the same age, due to symmetry.

Pretty strong evidence that it isn't acceleration (or frame changes as you call them) that causes the age differential. That's been said repeatedly, but you don't accept it.  A ship could continuously stop and start, each time moving at 0.8c for a short time and then pausing again, hundreds of times before getting to the end.  He'll age 8 years just like all the others except A who travels at a different speed than the others.  It's about speed, and not at all about acceleration. I've said that from the beginning.

It also means that the age difference depends on the distance between the subject and the switching frame observer.

This statement is surprisingly correct. Similar to moment of inertia, the term is called moment-of-acceleration, where the effect is acceleration (in the direction of the 'subject') leveraged by the distance (as measured in the subject frame) to the acceleration event from the subject.

[hamdani yusuf (OP)]

The time rotation thing lends itself nicely to video. It is hardly the simplest explanation, but it very much is a valid one.

But it needs to do a Lorentz rotation, not a Euclidean rotation like you're doing with all your pictures posted above. Those produce contradictory observations, as you have noted.

For instance, in your pictures in post 110, all the ships B,C,D age about 4.5 years, not 8. That's a contradiction since any observation (like everybody's age at the final event) should be a frame independent thing.

My diagrams for B, C, D perspectives are only during their travelling period, which are 3 years. Non-travelling period are still 5 years.

[hamdani yusuf (OP)]

Pretty strong evidence that it isn't acceleration (or frame changes as you call them) that causes the age differential. That's been said repeatedly, but you don't accept it.  A ship could continuously stop and start, each time moving at 0.8c for a short time and then pausing again, hundreds of times before getting to the end.  He'll age 8 years just like all the others except A who travels at a different speed than the others.  It's about speed, and not at all about acceleration. I've said that from the beginning.

Your explanation seem to employ absolute reference frame which can be used to measure speeds of other reference frames.

[Origin]

Your explanation seem to employ absolute reference frame which can be used to measure speeds of other reference frames.

No where does he say or even imply an absolute reference frame.  I'm at a loss to see where you came up with that idea.

[hamdani yusuf (OP)]

Your explanation seem to employ absolute reference frame which can be used to measure speeds of other reference frames.

No where does he say or even imply an absolute reference frame.  I'm at a loss to see where you came up with that idea.

That's a logical implication of Lorentz' relativity theory, which differentiate it from Einstein's special relativity.
In Lorentz' relativity, A objectively ages less than earth observer or Alpha Centauri observer. A never measure/calculate earth/Alpha Centauri observers to age less than himself.

[hamdani yusuf (OP)]

Your post was indeed not particularly offensive since it for the most part contains frame references, but then the causal language starts creeping in and you start asserting that somebody's choices has a physical effect on somebody far away, which is very much 'another theory'.

That's what's described in the videos by Minutephysics, MIT OCW, and Stanford professor. Right BEFORE the turn around, the travelling twin measured that the earth twin is younger than him. Right AFTER  the turn around, the travelling twin measured that the earth twin is older than him.

[Halc]

That's what's described in the videos by Minutephysics, MIT OCW, and Harvard professor. Right BEFORE the turn around, the travelling twin measured that the earth twin is younger than him. Right AFTER  the turn around, the travelling twin measured that the earth twin is older than him.

No video was referenced. Where is this asserted?  What video, what timestamp?
In particular, exactly what measurement does the twin perform that lets him know this, all without presuming the answer to his measurement before he performs it?  If the video does not mention a way to actually measure this, then the claim falls flat.

No where does he say or even imply an absolute reference frame.  I'm at a loss to see where you came up with that idea.

That's a logical implication of Lorentz' relativity theory, which differentiate it from Einstein's special relativity.

Yes, LET has completely different premises than does SR, making it a different theory, or different interpretation at least. Funny thing is that the simplified method I explained at the beginning of this topic works in LET just as well as it does in SR. That's not true for most explanations.

As for 'the exact cause of the dilation' as the one topic asked, dilation isn't something that is caused. It can be explained by various methods, so there is no one correct explanation, and the existence of any one alternate explanation does not in any way invalidate the others.  You seem bent on finding the most convoluted explanation out there, with bonus points if it's actually wrong.

In Lorentz' relativity, A objectively ages less than earth observer or Alpha Centauri observer. A never measure/calculate earth/Alpha Centauri observers to age less than himself.

All this is blatantly false. LET neither asserts nor concludes any of these things. I'm not saying LET is wrong. I'm only saying you are.

[hamdani yusuf (OP)]

Your post was indeed not particularly offensive since it for the most part contains frame references, but then the causal language starts creeping in and you start asserting that somebody's choices has a physical effect on somebody far away, which is very much 'another theory'.

That's what's described in the videos by Minutephysics, MIT OCW, and Harvard professor. Right BEFORE the turn around, the travelling twin measured that the earth twin is younger than him. Right AFTER  the turn around, the travelling twin measured that the earth twin is older than him.

I'm sorry, it should be Stanford, instead of Harvard. But it should not change my points.

[hamdani yusuf (OP)]

No video was referenced. Where is this asserted?  What video, what timestamp?

It's in the third video from Stanford professor, at around 9:00 time stamp.
The numeric values may be different, but the point is the same.

The videos from Stanford are longer, but they also say that you haven't even described the problem yet until it's analyzed from traveling twin's perspective, let alone providing a possible solution.

[hamdani yusuf (OP)]

As for 'the exact cause of the dilation' as the one topic asked, dilation isn't something that is caused.

It's not the cause of dilation that's asked. It's the cause of age difference. Why one twin's calculations are correct, while the other are false, when they move relative to each other without involving absolute frame of reference.

[hamdani yusuf (OP)]

All this is blatantly false. LET neither asserts nor concludes any of these things. I'm not saying LET is wrong. I'm only saying you are.

LET uses aether as frame of reference. Time dilation occurs in objects moving relative to it.
In the twin paradox case, earth and the destination star don't experience time dilation, which means they are stationary in the aether frame when analyzed using LET.

[hamdani yusuf (OP)]

In particular, exactly what measurement does the twin perform that lets him know this, all without presuming the answer to his measurement before he performs it?  If the video does not mention a way to actually measure this, then the claim falls flat.

It's a thought experiment, hence every stated measurement is actually a calculation based on chosen model and assumptions.
It seems that your understanding of twin paradox is not mainstream among current physics community.

[Origin]

It's the cause of age difference. Why one twin's calculations are correct, while the other are false, when they move relative to each other without involving absolute frame of reference.

That has been answered. 

[hamdani yusuf (OP)]

It's the cause of age difference. Why one twin's calculations are correct, while the other are false, when they move relative to each other without involving absolute frame of reference.

That has been answered. 

Do you agree with mike's answer from his thread?

[Mod edit: Topic split from https://www.thenakedscientists.com/forum/index.php?topic=86033
Please do not post personal relativity conjecture in the main sections of the forum]

The Twin "Paradox" is very simple to analyze.  Here is how to do it:

The home twin is older that the traveling twin at their reunion.  The home twin (she) is ALWAYS inertial, so she can immediately compute the traveling twin's (his) current age from the time dilation equation (TDE): she says his current age is equal to her current age, divided by gamma:

  gamma = 1 / { sqrt [ 1  -  ( v * v ) ]  } .

For example, for v = +-0.866 ly/y, gamma = 2.0 .

So SHE says that, during his entire trip, he is always ageing half as fast as she is.  So, in the case where he ages by 20 years on each of the two legs of his trip, she says that he is 40 at their reunion, and she is 80.  And everyone must agree with that.

But how does HE describe their ages DURING the trip?  He obviously has to  agree with her about their respective ages at the reunion (because they are standing together right there, motionless, looking at each other).  But what does HE say about their two ages at other times during his trip?  Everyone DOES agree that he is 20 years old during his turnaround.  But what does HE say about her age immediately BEFORE and immediately AFTER his turnaround?

He can also use the time dilation equation (TDE) immediately before his turnaround.  From that, he concludes that, since he is 20 years old then, she is 10 years old then.

He also knows that, since he ages 20 years during his return trip, she must age 10 years during his return trip.  So, if that were all that happens to her age during his trip (according to him), she would only be 20 years old at their reunion, when he is 40 years old.  But she's NOT 20 years old then ... he can see with his own eyes that she is 80 years old then.  Somewhere during his trip, she HAD to age an additional 60 years, according to him.  WHERE did that extra ageing by her, according to him, occur?  There is only one possible place it could have occurred: it HAD to have occurred during his instantaneous turnaround, because during ALL the rest of his trip, he knows she was ageing only half as fast as he was.

For this simplest scenario, that's all you need to know to solve "the paradox".  More complicated scenarios require that you know how to COMPUTE her instantaneous age-changing (according to him).  There is a simple equation that allows you to do that (and also a graphical technique that you can use to do it), but neither of those is needed for this simplest scenario.

[Origin]

Do you agree with mike's answeranswer from his thread?

Sure that is one explanation.

[hamdani yusuf (OP)]

Do you agree with mike's answeranswer from his thread?

Sure that is one explanation.

Good. That's an important step to discuss the case described in this thread.
Can we use that explanation for the cases described in this thread? What does it predict?

[Origin]

That's an important step to discuss the case described in this thread.
Can we use that explanation for the cases described in this thread?

Please pay attention, I just said you could in my last post!

What does it predict?

Seriously?  It predicts the same answer that has been shown several times in this thread.

[hamdani yusuf (OP)]

The time rotation thing lends itself nicely to video. It is hardly the simplest explanation, but it very much is a valid one.

But it needs to do a Lorentz rotation, not a Euclidean rotation like you're doing with all your pictures posted above. Those produce contradictory observations, as you have noted.

For instance, in your pictures in post 110, all the ships B,C,D age about 4.5 years, not 8. That's a contradiction since any observation (like everybody's age at the final event) should be a frame independent thing.

How should the Lorentz' rotation be drawn? How could it avoid producing contradictory observations?