Is Relativity Reality?

[ChildInAZoo]

You still haven't got it. If you add velocities that occur in the same reference frame, that is legit.
The velocity of a referece frame, in it's own reference frame, is zero, not 100,000 or 200,000. I'm adding velocities that occur in the same frame.

Do you even read your own stuff?

"Now introduce one more particle, and it's travelling towards the first one at 100,000 kps so it's velocity is along the X axis. Now you have a problem. If you choose a frame for the original particle that is moving along the X axis towards the second particle and it's velocity is more than 200,000 kps, then the second particle is travelling in that frame at more than 300,000 kps, or more than the speed of light."

This is adding velocities across different reference frames.

[mistermack]

If you understand what you're saying, you're not explaining it very well. I'm saying that if you have two particles approaching each other at 250,000 kps closing velocity, the choice of valid frames is reduced. Are you saying that it's valid to choose a frame of reference that has one of these particles moving at more than c? For instance to have particle 'a' moving at 200,000 kps and 'b' catching it, moving at 450,000 kps?
I'm claiming that that scenario is invalid, ie, any SINGLE FRAME that produces this kind of scenario is invalid. I'm not bringing in a velocity from a different frame.
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[Farsight]

He certainly doesn't understand Special Relativity, mistermack. The guy is some dark-matter cosmologist, not a physicist. He's working off an ersatz "homogeneous space" version of general relativity. See Einstein's Leyden Address re the correct version where a gravitational field is inhomogeneous space.

[ChildInAZoo]

If you understand what you're saying, you're not explaining it very well. I'm saying that if you have two particles approaching each other at 250,000 kps closing velocity, the choice of valid frames is reduced.

And you are wrong.

Are you saying that it's valid to choose a frame of reference that has one of these particles moving at more than c? For instance to have particle 'a' moving at 200,000 kps and 'b' catching it, moving at 450,000 kps?

No, I am saying that no choice of reference frame gives a particle a speed of greater than c. If you would bother to actually learn SR, you would learn this.

I'm claiming that that scenario is invalid, ie, any SINGLE FRAME that produces this kind of scenario is invalid. I'm not bringing in a velocity from a different frame.

This claim does not relate to the argument on your website.

[Twiglet]

Farsight and Mistermack:

Please answer the following basic question using special relativity.

Two objects, each one metre long, are moving away from each other with a speed of 2.7x10^8m/s

How long does object B appear as observed from object A?

Next, assume Object A is at rest, and object B is moving away from it at 2.7x10^8m/s
Object B carries a clock and waits for 1 second to elapse.
How long has elapsed on Object As clock.

Assume c=3x10^8m/s
Please show working.

Thankyou.

[mistermack]

And you are wrong.

No argument offered there then.

This claim does not relate to the argument on your website.

In what way? Again no argument offered.

No, I am saying that no choice of reference frame gives a particle a speed of greater than c. If you would bother to actually learn SR, you would learn this.

Again no argument offered. This is what people say when they don't understand their own argument. '' O you haven't read the scriptures, you wouldn't understand''. Whenever you make that quip, childinazoo, I can tell it's because you're stuck. You may be right in what you're saying, but you clearly don't understand why. Reading something and understanding it are very different things.
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[mistermack]

Twiglet, I was hoping for answers, not questions. I enjoy the odd to-the-point question, but not a whole post of obscure ones. I get suspicious that people do it to avoid making a claim or statement.
I made some pretty clear claims in my first post which may well be wrong, but nobody so far has said why. If someone can say why in equally clear language, I'll happily say ''thank you very much, that's what I wanted to know''.
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[Twiglet]

And you are wrong.

No argument offered there then.

This claim does not relate to the argument on your website.

In what way? Again no argument offered.

No, I am saying that no choice of reference frame gives a particle a speed of greater than c. If you would bother to actually learn SR, you would learn this.

Again no argument offered. This is what people say when they don't understand their own argument. '' O you haven't read the scriptures, you wouldn't understand''. Whenever you make that quip, childinazoo, I can tell it's because you're stuck. You may be right in what you're saying, but you clearly don't understand why. Reading something and understanding it are very different things.
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If you understood relativity mistermack, you would be able to answer the above question within 5 or 10 minutes, and would also understand why Child in a Zoo is right, and you aren't.

The maths is trivial by the way, so don't even think of using that as an excuse.

Hostility aside, why ot try it?

Just look up time dilation and lorentz contraction on wiki, plug the numbers in and take a look at the answers. You will learn a lot in the process of just working it out. Experiments bear out the results predicted by the theory.

If you want to learn, then try engaging in the learning process rather than verbal slanging.

Go ahead and try it.

[mistermack]

Twiglet, if you want to help, answer a much simpler question, with a clear explanation :
Is any and every frame of reference you can choose ( an infinite choice ) valid for every particle in the Universe? If yes, why, if no, why not?
If you can give a clear answer to that, we're getting somewhere.
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And no hostility felt or meant, by the way. I just react if people try to talk down to me. If Einstein talked down to me, he would get the same response, so you lot are a cert.

[Twiglet]

Twiglet, if you want to help, answer a much simpler question, with a clear explanation :
Is any and every frame of reference you can choose ( an infinite choice ) valid for every particle in the Universe? If yes, why, if no, why not?
If you can give a clear answer to that, we're getting somewhere.
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And no hostility felt or meant, by the way. I just react if people try to talk down to me. If Einstein talked down to me, he would get the same response, so you lot are a cert.

That's a philosophical question, not a scientific one mistermack.

All I can say is that the results predicted by relativity are consistent with experiment, which doesn't mean the theory is true.

The thing is, if you are going to criticize relativity scientifically, then you really should understand for your own sake what relativity means. People learn in different ways, but the questions you have asked about particles travelling at different speeds - thats a question which can easily be plugged into the equations, and produce a result which not only can be tested experimentally, it repeatedly has been.

ChildinaZoo is right when he says you cannot simply add the velocities together (in relativity). If you go through the question I posed, you will learn why,

If you actually want to learn, but the understanding isn't handed to you on a plate mistermack, you actually need to go through the process. I am not appealing to my greater knowledge here, I am telling you how you can go about calculating what relativity predicts. When you understand that, you'll be a lot further forward. IMO quite a lot further forward than farsight too.....

[JimC]

Twiglet, if you want to help, answer a much simpler question, with a clear explanation :
Is any and every frame of reference you can choose ( an infinite choice ) valid for every particle in the Universe? If yes, why, if no, why not?
If you can give a clear answer to that, we're getting somewhere.
.
And no hostility felt or meant, by the way. I just react if people try to talk down to me. If Einstein talked down to me, he would get the same response, so you lot are a cert.

That's a philosophical question, not a scientific one mistermack.

All I can say is that the results predicted by relativity are consistent with experiment, which doesn't mean the theory is true.

The thing is, if you are going to criticize relativity scientifically, then you really should understand for your own sake what relativity means. People learn in different ways, but the questions you have asked about particles travelling at different speeds - thats a question which can easily be plugged into the equations, and produce a result which not only can be tested experimentally, it repeatedly has been.

ChildinaZoo is right when he says you cannot simply add the velocities together (in relativity). If you go through the question I posed, you will learn why,

If you actually want to learn, but the understanding isn't handed to you on a plate mistermack, you actually need to go through the process. I am not appealing to my greater knowledge here, I am telling you how you can go about calculating what relativity predicts. When you understand that, you'll be a lot further forward. IMO quite a lot further forward than farsight too.....

+1

Without the maths, it might as well be new age woo...

[mistermack]

That's a philosophical question, not a scientific one mistermack.

No, it's a perfectly clear phyics question.
I'll pare it down even more. In the first part of my argument 1, I postulated a 'sphere' diagram of possible vectors for valid inertial frames for a single particle in otherwise empty space.
Is that right, or wrong, and why?

And Jimc, that's an awful lot of quoted text for such a pointless little comment.
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[Twiglet]

That's a philosophical question, not a scientific one mistermack.

No, it's a perfectly clear phyics question.
I'll pare it down even more. In the first part of my argument 1, I postulated a 'sphere' diagram of possible vectors for valid inertial frames for a single particle in otherwise empty space.
Is that right, or wrong, and why?
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You initial question was flawed, as others pointed out to you.

You need to consider the frame of reference *from the perspective of an observer*, whether that is at particle A, B or somewhere entirely different.

The basic tenet of SR is that all frames of reference are equally valid.

Hence, to work out what particle B looks like, from particle A, you need to perform the calculation, which was the question I set you.

Are you trying to understand relativity or just make stuff up?

[Twiglet]

Sorry to double post, but here is how you can work it out for yourself mistermack:

Situation


<-------2x10^8 m/s - Particle A (observer - at rest) 2x10^8m/s--------> Particle B



My question to you: Relative to particle A, how fast is particle B moving??


When you can work that out, you will be some way to understanding what relativity predicts and why.

[mistermack]

The basic tenet of SR is that all frames of reference are equally valid.

Just minutes ago Twiglet, you said that that was a philosophical question, not a scientific one.
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