Questions about Special Relativity

[Johnny5]

LCF system:2 ends cannot coincide simultaneously

 

Galilean: 2 ends can coincide simultaneously

 

That's the way it is. You can see it clearly from the argument which is being developed here.

[J.C.MacSwell]

That's the way it is. You can see it clearly from the argument which is being developed here.

 

Yep, Lorentz and Galileo. Clearly there ain't enough room in this town for the two of them.

 

Now, a kinder, gentler town (read lower the relative speeds of them yardsticks). I can see maybe they might get along a little better there. (not perfectly though)

[Johnny5]

Yep' date=' Lorentz and Galileo. Clearly there ain't enough room in this town for the two of them.

 

Now, a kinder, gentler town (read lower the relative speeds of them yardsticks). I can see maybe they might get along a little better there. (not perfectly though)[/quote']

 

Yes, Lorentz vs Galileo.

 

If there isn't any error in the derivation, then simultaneity really is absolute.

 

So is there an error in the derivation?

 

All the measuring devices were at rest in inertial reference frames when the measurements were made.

 

 

PS: In another thread, entitled, "Photon frequency" Phi for all gave me this link to a different derivation of the time dilation formula, but I like the "light clock" better. I knew it by heart.

[swansont]

Yes' date=' Lorentz vs Galileo.

 

If there isn't any error in the derivation, then simultaneity really is absolute.

 

So is there an error in the derivation?

[/quote']

 

Yes. At no point did you prove that simultaneity is absolute. Assuming it is, and then concluding that events have to be sumultaneous is indeed circular reasoning.

[swansont]

Before going any further, did you follow my derivation of the time dilation formula? If you had an objection to any step, I want to hear it.

 

No. Your first line stopped me, since the light clock in no way depends on length contraction. I did notice the incorrect assumption of absolute simultaneity, which would fatally flaw any derivation. I didn't look for any others.

 

So, what are your objections to the light clock?

[Johnny5]

Yes. At no point did you prove that simultaneity is absolute. Assuming it is, and then concluding that events have to be sumultaneous is indeed circular reasoning.

 

I agree completely. If you assume your conclusion, then you have made a reasoning error, but I didn't assume that simultaneity was absolute. What I assumed was this... I assumed the Lorentz contraction formula is true. <---- that's what I assumed.

[Johnny5]

No. Your first line stopped me, since the light clock in no way depends on length contraction.

 

My first line stopped you???

 

Umm, the first thing I did was explain the simplest experiment conceivable, that can measure the speed of light. So which specific line are you referring to?

[Johnny5]

No. Your first line stopped me' date=' since the light clock in no way depends on length contraction.

[/quote']

 

When you say that the light clock in no way depends upon length contraction, I'm not sure what you mean.

[Johnny5]

I did notice the incorrect assumption of absolute simultaneity' date=' which would fatally flaw any derivation.

[/quote']

 

I didn't assume that simultaneity is absolute, what makes you think that?

[Johnny5]

So' date=' what are your objections to the light clock?[/quote']

 

I have no objections to the light clock, the "light clock" gives a simple way to derive both the length contraction formula, and the time dilation formula.

 

Regards

[swansont]

My first line stopped you???

 

Umm' date=' the first thing I did was explain the [i']simplest experiment conceivable[/i], that can measure the speed of light. So which specific line are you referring to?

 

I concluded that the length contraction formula is false.

 

The light clock is a geometric argument, and length contraction doesn't play a part, as I said in post #88.

[swansont]

I didn't assume that simultaneity is absolute, what makes you think that?

If simultaneity is absolute, then A` coincides with A simultaneously to B` coinciding with B in all frames of reference.

 

Gee, I don't know what could have made me think you were assuming absolute simultaneity...

[swansont]

I have no objections to the light clock' date=' the "light clock" gives a simple way to derive both the length contraction formula, and the time dilation formula.

 

Regards[/quote']

 

So when you answered "No" to my question, "Do you agree that the light clock runs slow, according to the other observer?" in post 85, what did you mean?

 

The two times do not agree, and the moving clock runs slow. In both frames.

[swansont]

I agree completely. If you assume your conclusion, then you have made a reasoning error, but I didn't assume that simultaneity was absolute. What I assumed was this... I assumed the Lorentz contraction formula is true. <---- that's what I assumed.

 

And the consequence of that is that the events are not simultaneous. Where is the contradiction?

[Johnny5]

If simultaneity is absolute' date=' then A` coincides with A simultaneously to B` coinciding with B in all frames of reference.

[/i']

 

Gee, I don't know what could have made me think you were assuming absolute simultaneity...

 

Oh sorry. Umm i know what happened, though it will be hard to explain, but i know what happened.

 

I am going to try to explain...

 

There are a lot of different ways to use "if then"

 

Take mathematical definitions for example.

 

A if and only if B

 

So when you are given a definition like this you know...

 

If A then B AND if B then A

 

Because definitions are stipulated to be true, you can play around with it as much as you want.

 

HOWEVER

 

When we really reason in real time, we use the IF to denote something which we don't know the truth value of.

 

So i guess the lesson is this.

 

When a reasoning agent is reasoning, the IF part will probably indicate uncertainty.

 

But not always.

 

I guess what I was doing, was attempting to give meaning to the phrase "simultaneity is absolute"

 

It has the form of a statement, and it also has meaning.

 

I wasn't hypothesizing that simultaneity is absolute. I've already concluded it is. So my reasoning phase is beyond that now.

 

But you don't accept that it is.

 

Regards

[Johnny5]

So when you answered "No" to my question' date=' "Do you agree that the light clock runs slow, according to the other observer?" in post 85, what did you mean?

 

The two times do not agree, and the moving clock runs slow. In both frames.[/quote']

 

Let me say this right now: This is a very delicate argument.

 

[if the time dilation formula is true, then the amount of the time in the two frames are different.] <---- the previous "if then" statement is true.

 

But I am not saying that the antecedent is true. I am saying the antecedent is false. The conditional as a whole is true, but I am using the Philonian conditional.

 

AB If A then B

00 1

01 1

10 0

11 1

 

You can see that in case two above, it is possible for the antecedent to be false, but the conditional as a whole is true.

 

The point is, that in the Philonian conditional, knowing that the conditional as a whole is true, doesnt mean you simultaneously know the truth value of the antecedent.

[Johnny5]

And the consequence of that is that the events are not simultaneous. Where is the contradiction?

 

There was only ONE event in the light clock example, so I am not sure what you mean by saying 'events.'

 

I am not saying that the light clock experiment can be used to invalidate SR, maybe it can I don't know, but what I am saying is this:

 

The light clock example allows a derivation of both the following formulas, under the assumption that the speed of light is the same in both frames (of the example)

 

1. Lorentz contraction formula

2. Time dilation formula

 

So by understanding this example, one is sure to know that the following statement is true:

 

If the speed of light is the same in every inertial reference frame then LCF is true and TDF is true.

 

As far as proving that simultaneity is absolute, you need a different argument for that.

[swansont]

If the speed of light is the same in every inertial reference frame then LCF us true and TDF is true.

 

As far as proving that simultaneity is absolute' date=' you need a different argument for that.[/quote']

 

Yes. You need for c not to be a constant in all frames. We could probably test that experimentally. Oh, wait...we already have.

 

Pretty much all your objections flow back to whether or not c is a constant.

 

c being constant has certain ramifications, and makes specific predictions. When we do the experiments to confirm them, we find that the predictions are correct. Anybody not in denial from argument from incredulity concludes that relativity is correct.

[Johnny5]

Yes. You need for c not to be a constant in all frames. We could probably test that experimentally. Oh' date=' wait...we already have.

 

Pretty much all your objections flow back to whether or not c is a constant.

 

c being constant has certain ramifications, and makes specific predictions. When we do the experiments to confirm them, we find that the predictions are correct. Anybody not in denial from argument from incredulity concludes that relativity is correct.[/quote']

 

Let me ask you one question.

 

Do the experiments prove that c is constant in all inertial reference frames.

OR

 

Do these experiments prove that the speed of any photon relative to that which emits it, is c, regardless of material.

 

Which one?

[Johnny5]

Swansont I just had an idea.

 

But first, please answer my question in the other thread enititled "Question about General Relativity Theory."

[Janus]

Let me ask you one question.

 

Do the experiments prove that c is constant in all inertial reference frames.

OR

 

Do these experiments prove that the speed of any photon relative to that which emits it' date=' is c, regardless of material.

 

Which one?[/quote']

 

The first one.

[Johnny5]

The first one.

 

Name that experiment.

 

(Just a play on name that tune).

 

 

Which experiment are you referring to? Or which experiment would swansont refer to.

 

Give me the best experiment.

[swansont]

Swansont I just had an idea.

 

But first' date=' please answer my question in the other thread enititled "Question about General Relativity Theory."[/quote']

 

I've made my comment. I don't believe the question can be answered, from a physics standpoint.

[Johnny5]

I've made my comment. I don't believe the question can be answered, from a physics standpoint.

 

What does this mean, that it cannot be answered from a physics standpoint?

 

Do you mean that the statement is not empirically verifiable?

[swansont]

Give me the best experiment.

 

Why just one? There are so many, and it's the breadth of the evidence that is impressive. I'm doing one experiment right now: There is relative motion between me and a light source, and yet I can still see - the light is still a solution to the wave equation (Maxwell's equations). That can only be true if c is constant in both frames. Also, my car radio still works even when it's moving.