Relative Velocity Measurement – Frame and photon

[Uno Hoo]

OK. I get it. With the exception of the thread starter and a very few other participants, noone (see it, AN? has actually read the theory starter's book.

So you gaggle of arguers are self admittedly woefully ignorant of the theory inventor's own ideas as evidenced by his own written words. You are like a little puppy dog who blissfully chases his own tail and spins round in a dizzy circle. Until he gets too drunk and falls down.

Einstein's written words have deficient logical consistency to support both constant observed speed of light and non absolute simultaneity. You non readers rather chase your own tails than to admit Einstein's failure of logic.

Your problems are yours, not mine.

 

[AlphaNumeric]

You completely fail to retort things I've said to you Uno. Firstly someone can learn special relativity without having to read Einstein's own words. I've never read the original 'Elements' book by Euclid yet I know basic geometry. I've never read Newton's original words and yet I know Newtonian mechanics.

Secondly finding fault with Einstein is not synonymous with finding fault with special relativity. Einstein didn't understand a lot about his own works, he didn't get black hole solutions for a long time. We know the postulates of special relativity. They can be found in Einstein's books as well as books by plenty of other people. We know the form Lorentz transformations take, Einstein didn't come up with those. Now, if you can use those Lorentz transformations, which do not require any physical interpretation or for you to read Einstein's own words, to get SR to say 1=2 then you have a contradiction and SR is flawed. Finding fault with something Einstein said, if indeed there is a fault, may be nothing more than showing Einstein got something wrong in how he understood special relativity. The physical set up involved in this discussion is not new or novel, its something many people have looked at in many books and haven't just relied on parroting Einsteiin. That's the beauty of actually learning something and knowing how to derive results, you don't have to take other people's word for it. And plenty of people have worked through these physical setups time and again on their own and come up with non-contradictory results.

Rather than parroting Einstein's words and going "Look, he got it wrong" why don't you actually show SR is undeniably at fault. Your argument is that in two different places Einstein said two different things. Firstly you are relying on the fact you grasp SR well enough to interpret Einstein's words and the implications properly, which is a pretty massive leap to make since you have never displayed any working understanding of SR. And secondly you're assuming that if Einstein said it then definitely SR says it. This is not automatically true either.

Plenty of people have developed some new ideas and then used them to make incorrect conclusions. My GR lecturer told us how Hawking, having made a huge name for himself in differential geometry, then published another result on Riemannian manifolds but had relied on a previous proof by someone which only applied to pseudo-Riemannian manifolds. Don't worry that you don't know what those words mean, the point of the example is that sometimes even very bright people use their own results incorrectly. This is a fault in the application of the theory, not the theory itself.

If all you can do is say "Well you haven't read the book so you can be ignored" you're simply failing to justify your argument. I've read plenty of SR books. And GR books. And things which use SR, like QFT and string theory. So I can follow the kind of discussions in this thread on a quantitative level. Can you? I haven't seen you show any quantitative working understanding. All I see you say is "Have you read this decades old book?" as if reading it somehow gives you a more complete understanding of Einstein's work.

Hell, you don't even grasp what pi is. Why should any of us believe you can even do basic geometry, never mind Lorentzian geometry?

 

[Jack_]

Your ignorance is showing, Jack. SR most definitely tells us what happens with M' stationary.
If we know when and where the lightning strikes with M stationary, then SR tells us when and where it strikes with M' stationary, and vice-versa.

Try it. Say when and where the lightning strikes in one reference frame, and I'll show you how SR tells us when and where it strikes in the other.
If you could do this yourself, we wouldn't have to have such a drawn-out argument.


With M' stationary, yes. That was one of our agreed premises (number 5).


Yes, the experiment setup says that with M stationary. That's agreed premise number 3.

But, it is not agreed for M' stationary. This might be hard for you to understand, but it's central to understanding special relativity.

Jack, do you understand that the following two statements are not equivalent?

• For M at rest, when M' and M are co-located, lightning strikes at A and at B.
• For M' at rest, when M' and M are co-located, lightning strikes at A and at B.

Do you understand that only one of these is defined by the experiment setup?

Yes, I understand R of S past the point that I now know with M' at rest, SR is in a contradiction.

It just takes a little thinking.

Ehat you have agreed to is that A' and B' clo-locate with their partners when M and M' co-locate.

Also, when M and M' co-locate A and B are struck.

Since A' and B' are co-located at those positions, they see the light just like A and B does or causality is broken.

You claim when M and M' co-locate, B emits before A. That is your basic argument.

Is this correct?

I diosproved this silliness above.

I counter every argument you may have already. You just need to read the proofs better.

I proved a contadiction if B' records the light flash prior to A' in the frame of M'.

So, why don't you say specifically what A' and B' records in the rest frame of M'.

You keep claiming to know.

Take any stand, I have already countered it.

Make sure you read my proof though so you can avoid silly mistakes.



Read it again.

 

[Pete]

Jack, do you understand that the following two statements are not equivalent?

• For M at rest, when M' and M are co-located, lightning strikes at A and at B.
• For M' at rest, when M' and M are co-located, lightning strikes at A and at B.

Which one do you use in your proof?
Which one is defined by the experiment setup?

 

[Pete]

Ehat you have agreed to is that A' and B' clo-locate with their partners when M and M' co-locate.

Also, when M and M' co-locate A and B are struck.

Jack, how many times do I need to point out that "when M and M' co-locate A and B are struck" is only true with M stationary?

With M' stationary:

B is struck before M and M' meet.
A is struck after M and M' meet.
B' does not get struck - lightning strikes B before B reaches B'.
A' does not get struck - lightning strikes A after A reaches A'.​

Is that really so hard for you to grasp?

 

[Jack_]

Jack, how many times do I need to point out that "when M and M' co-locate A and B are struck" is only true with M stationary?

With M' stationary:
B is struck before M and M' meet.
A is struck after M and M' meet.

Is that really so hard for you to grasp?

Oh, you finally got to it.

Show me the math for this. Since SR is consistent, you will be able to show this.

I can't wait to see this.

I am waiting with my proof.

So, do it.

 

[Pete]

I finally got to it? You haven't been paying attention at all, have you Jack?
I posted this pages ago:

Here's the bottom line, Jack.
With M' stationary:
If A' meets A when lightning strikes A, then A' meets A after M' meets M.
If A' meets A when M' meets M, then A' meets A before lightning strikes at A.

I'm glad you've caught up.

And I posted the maths for transforming the lightning strikes to the rest frame of M' back in post 87 (if you read it, be sure to note that in that post, A' and B' are placed at the lightning strikes, rather than at d/γ from M' as we have since agreed).

The result:
Lightning strikes B at t' = -γvd/c²
M meets M' at t'=0
Lightning strikes A at t' = γvd/c²

 

[Pete]

And you still need to answer this:

Do you understand that the following two statements are not equivalent?

• For M at rest, when M' and M are co-located, lightning strikes at A and at B.
• For M' at rest, when M' and M are co-located, lightning strikes at A and at B.

Which one do you use in your proof?
Which one is defined by the experiment setup?

 

[Jack_]

I finally got to it? You haven't been paying attention at all, have you Jack?
I posted this pages ago:


I'm glad you've caught up.

And I posted the maths for transforming the lightning strikes to the rest frame of M' back in post 87 (if you read it, be sure to note that in that post, A' and B' are placed at the lightning strikes, rather than at d/γ from M' as we have since agreed).

The result:
Lightning strikes B at t' = -γvd/c²
M meets M' at t'=0
Lightning strikes A at t' = γvd/c²

so uhhhh why doesn't this apply to the M rest frame?

Let me teach you.

LT does not work for light emissions.


It only applies for light receptions.

I am sorry, but your term γvd/c² is actually,

(γv(d/c))/c which is a distance over light speed.

You have concluded some distance occured at the instant of light emission.
Obviously, that is false.

It is a common error of an SR beginner.

 

[Jack_]

And you still need to answer this:

Do you understand that the following two statements are not equivalent?

• For M at rest, when M' and M are co-located, lightning strikes at A and at B.
• For M' at rest, when M' and M are co-located, lightning strikes at A and at B.

Which one do you use in your proof?
Which one is defined by the experiment setup?

This is not my logic, this is:

For M' at rest, when M' and M are co-located, lightning strikes at A' and at B'.

 

[Pete]

so uhhhh why doesn't this apply to the M rest frame?

Why doesn't what apply to the M rest frame?
You don't have a hope of teaching anyone if you can't be clear, Jack.

 

[Jack_]

Why doesn't what apply to the M rest frame?
You don't have a hope of teaching anyone if you can't be clear, Jack.

your logic simply does not apply for light emissions.

you must use other methods.

I should not have said that because your logic implies you can collapse the interval with the point, meaning the point of light emissions.

LT requires an interval.

I was not being nice.

 

[Pete]

This is not my logic, this is:

For M' at rest, when M' and M are co-located, lightning strikes at A' and at B'.

So your logic is based on:

• For M' at rest, when M' and M are co-located, lightning strikes at A and at B.

But, the experiment setup says:

• For M at rest, when M' and M are co-located, lightning strikes at A and at B.

Remember our agreed premises, Jack? Did you even read them? Are you now disagreeing with them?

We can agree that:
In the rest frame of M, two points A and B are each a distance d from M.
In the rest frame of M, M' moves past M at velocity v.
In the rest frame of M, when M' and M are co-located, lightning strikes at A and at B.

In the rest frame of M', two points A' and B' are each a distance d/γ from M'.
In the rest frame of M', when M and M' are co-located, A is co-located with A' and B is co-located with B'.

Remember post 59, where I asked if whether you were keeping this setup the same as Einstein's?

that the strikes are still simultaneous in the rest frame of M
Yes.

Is that right, or are you changing it so that the lightning strikes are simultaneous in the rest frame of M'?

No it is simultaneous in the M frame.

This issue with M' must be proven.

 

[Jack_]

So your logic is based on:

• For M' at rest, when M' and M are co-located, lightning strikes at A and at B.

But, the experiment setup says:

• For M at rest, when M' and M are co-located, lightning strikes at A and at B.

Remember our agreed premises, Jack? Did you even read them? Are you now disagreeing with them?


Remember post 59, where I asked if whether you were keeping this setup the same as Einstein's?

I can help you think this through.

If M and M' do not mutually co-locate, then all of LT fails since the original LT thought experiment assumes this logical truth of mutual co-location.

 

[Pete]

your logic simply does not apply for light emissions.

you must use other methods.

I should not have said that because your logic implies you can collapse the interval with the point, meaning the point of light emissions.

LT requires an interval.

I was not being nice.

Jack, I'd rather use methods that work, not the methods which you've shown give inconsistent results.
The maths I showed you is how SR works.

SR very clearly says that with M' at rest:
Lightning strikes B at t' = -γvd/c²
M meets M' at t'=0
Lightning strikes A at t' = γvd/c²

You might not like it, Jack, but I'm sticking with it because it is consistent.

 

[Jack_]

Jack, I'd rather use methods that work, not the methods which you've shown give inconsistent results.
The maths I showed you is how SR works.

SR very clearly says that with M' at rest:
Lightning strikes B at t' = -γvd/c²
M meets M' at t'=0
Lightning strikes A at t' = γvd/c²

You might not like it, Jack, but I'm sticking with it because it is consistent.

No, you cannot decide light emissions based on equations.

If so, you can decide simultaneity and the lack thereof.

Therefore, you can decide absolute simulaneity.

Your equations are not mainstream because they fail immediately.

Othewise, show me the links.

 

[Pete]

If M and M' do not mutually co-locate

What precisely does "M and M' mutually co-locate" mean, Jack?

With M at rest, M and M' are co-located at a particular time.
With M' at rest, M and M' are co-located at a particular time.
Is that what you mean?

Note that this doesn't tell us when the lightning bolts strike, in either case.

Now, the setup says:
For M at rest, when M' and M are co-located, lightning strikes at A and at B.'
But your logic relies on:
For M' at rest, when M' and M are co-located, lightning strikes at A and at B.


So, it seems your "logic" relies on the lightning strikes being simultaneous for M' at rest, because it's given that they're simultaneous for M at rest?
Jack, that's what you set out to prove. This is called a circular argument, or begging the question.

 

[Pete]

No, you cannot decide light emissions based on equations.

Sure can, Jack.

If so, you can decide simultaneity and the lack thereof.

For any given frame, sure.

Therefore, you can decide absolute simulaneity.

Nope - the equations show us how simultaneity varies between frames.

Transforming back to the rest frame of M, for example, gives:
Lightning strikes B at t = 0
M meets M' at t=0
Lightning strikes A at t = 0

Hey, simultaneous again!

Otherwise, show me the links.

What, you haven't bothered to Google "lorentz transform"?

 

[Jack_]

What precisely does "M and M' mutually co-locate" mean, Jack?

With M at rest, M and M' are co-located at a particular time.
With M' at rest, M and M' are co-located at a particular time.

But, this doesn't tell us when the lightning bolts strike.

The setup says:
For M at rest, when M' and M are co-located, lightning strikes at A and at B.'
Your logic relies on:
For M' at rest, when M' and M are co-located, lightning strikes at A and at B.


So, your "logic" relies on the lightning strikes being simultaneous for M' at rest? Jack, that's what you set out to prove. This is called a circular argument, or begging the question.

What precisely does "M and M' mutually co-locate" mean, Jack?

In my world this has a precise definition.

Under SR, you have questions. If this concept fails SR fails.

So, I have cut this off and other angles.

But, this doesn't tell us when the lightning bolts strike.

Correct.

This must be proven. Look over my proofs.

 

[Pete]

In my world this has a precise definition.

What definition is that, Jack? Your world looks awfully inconsistent, so I think I'll stay with ours.

This must be proven. Look over my proofs.

Done to death, Jack.
You keep assuming without proof that in the rest frame of M', "when M and M' co-locate A and B are struck".

Your argument is circular. You assume your conclusion.