Relativity Question

[CraigS]

Originally Posted by bojan

so we know the difference between the original wavelengths (or, we are assuming we know) and the received ones.

If I received one single photon with my test equipment, I must admit I wouldn't know what to do with it - apart from recording it's energy (which then directly translates into wavelength of course... and photomultiplier tube will not do this job, BTW). And that's about it. I wouldn't have a clue about process that generated that particular photon, so I can't possibly determine it's redshift.

I believe THIS was the core of the question in question.

… And I was content with the answers everyone gave me, to my original question.

I don't think anyone providing helpful answers, interpreted the basis of my original question to be in any way dependent upon a single measurement of a single photon. There is clearly a time element basis to the question. How could the last photon be interpreted as the last photon, unless there was a context (meaning a history of measuring a photon stream or spectrum, which ends up actually defining the last photon ??)

I think both questions about time dilation and redshift being interpreted on the literal basis of a single photon, were way out of context and yet, the question clearly was all about the context.

Whilst any questions in threads are usually welcomed here, standover demands for answers for out of context questions get what they deserve. Unless I'm mistaken, I don't believe anyone here is under an obligation to answer anyone's questions either. They do so out of generosity and a commitment of contributing value to the site.

Recently, I have noticed that this message seems to have been sadly forgotten (across multiple threads).

Thank you to all answerers who actually contributed to the value parts of this thread. They are much appreciated.

Cheers

[sjastro]

I believe THIS was the core of the question in question....

The fact that I have been similarly accused of not answering this question is quite interesting given that I have not been involved in this specific part of the thread.

My involvement in this thread was to point out to the "gentleman" concerned the issues of equating relativity with cosmological redshift, to which I got the "question" in response.

Now this this question has absolutely no relevance in this context. In fact it is just a blatant diversionary tactic.

So I wouldn't place any credibility on the question in the first place.
The question is loaded because irrespective of how one answers it, one will always be wrong.

The best thing is to ignore the question.

Steven

[xelasnave]

Originally Posted by sjastro

The fact that I have been similarly accused of not answering this question is quite interesting given that I have not been involved in this specific part of the thread.

My involvement in this thread was to point out to the "gentleman" concerned the issues of equating relativity with cosmological redshift, to which I got the "question" in response.

Now this this question has absolutely no relevance in this context. In fact it is just a blatant diversionary tactic.

So I wouldn't place any credibility on the question in the first place.
The question is loaded because irrespective of how one answers it, one will always be wrong.

The best thing is to ignore the question.

Steven

I had a look around Steven and there are many sites dealing with that question and I see your point.

alex

[bojan]

Originally Posted by sjastro

...
The question is loaded because irrespective of how one answers it, one will always be wrong.

The best thing is to ignore the question.

Steven

You are right in terms of intentions of the author of the question.

However, I still think the ONLY way to debunk those diversions is to answer the questions accurately, with all necessary argumentation as to why it is not relevant - without rising voice.

Ignore the intentions, not the question.

This is not for the sake of this particular author, but because of other spectators who may not know what is going on, but who will take sides, and it will be very likely the wrong one (David vs Goliath and so on...).

We may not be "official teachers" here (as Craig mentioned earlier) but this fact still does not absolve us from responsibility of allowing the in-accurate and plainly wrong ideas to spread. And, other spectators (who do not necessarily take part in discussion) will learn more from full answers (including myself).

My 2 cents...

[CraigS]

Well, just recapping, a polite answer was provided ... way back in post #4. If the answer wasn't sufficient, it doesn't take a lot of effort to politely request more info. A completely different question was posed is in post #34 and I don't consider this to be a polite request ! And then, somehow the original question was once again posed, impolitely, to the wrong person in post #49.

Seems to me the more important question here should be posed to the questioner as to why he's so impolite (??) !

Cheers

[sjastro]

Originally Posted by bojan

You are right in terms of intentions of the author of the question.

However, I still think the ONLY way to debunk those diversions is to answer the questions accurately, with all necessary argumentation as to why it is not relevant - without rising voice.
This is not for the sake of this particular author, but because of other spectators who may not know what is going on, but who will take sides, and it will be very likely the wrong one (David vs Goliath and so on...).

We may not be "official teachers" here (as Craig mentioned earlier) but this fact still does not absolve us from responsibility of allowing the in-accurate and plainly wrong ideas to spread. And, other spectators (who do not necessarily take part in discussion) will learn more from full answers (including myself).

My 2 cents...

I largely agree with you but if the author's motives are based on a personal agenda then the Science becomes irrelevant. It doesn't matter how well you the explain the problem, if the author's objective is to discredit you rather than the Science, then there is no point in engaging in any form of discussion.

In this case all the author has to do is to regurgitate the same argument or introduce a totally irrelevant response.

Regards

Steven

[xelasnave]

this may be of interest

http://www.sciencedaily.com/releases...0630161834.htm

alex

[Archy (George)]

I asked how can the "redshift" of a single photon be measured

Renormalised replied "...Very easily, with a photomultiplier tube and in exactly the same way as you measure a redshifted spectrum. You look at (or determine via theory) what the original wavelength/frequency of the photon was when it left the source and compare that with what you measured at the photomultiplier."

Bojan replied inter alia

Originally Posted by bojan

...If I received one single photon with my test equipment, I must admit I wouldn't know what to do with it - apart from recording it's energy (which then directly translates into wavelength of course... and photomultiplier tube will not do this job, BTW). And that's about it. I wouldn't have a clue about process that generated that particular photon, so I can't possibly determine it's redshift.

I believe THIS was the core of the question in question.

Bojan's reply that the redshift cannot be measured contradicts Renormalised. I agree with Bojan the redshift of a single photon can't be determined. Others in the thread were unwilling or unable to answer the question. When I pressed for an answer gave wrong, irrelevant or evasive replies and cast aspersions on my motives. Gentlemen, whether you answer questions or not is your prerogative: but what you have indulged in just wastes space.

[renormalised (Carl)]

Originally Posted by Archy

I asked how can the "redshift" of a single photon be measured

Renormalised replied "...Very easily, with a photomultiplier tube and in exactly the same way as you measure a redshifted spectrum. You look at (or determine via theory) what the original wavelength/frequency of the photon was when it left the source and compare that with what you measured at the photomultiplier."

Bojan replied inter alia


Bojan's reply that the redshift cannot be measured contradicts Renormalised. I agree with Bojan the redshift of a single photon can't be determined. Others in the thread were unwilling or unable to answer the question. When I pressed for an answer gave wrong, irrelevant or evasive replies and cast aspersions on my motives. Gentlemen, whether you answer questions or not is your prerogative: but what you have indulged in just wastes space.

No, you chose one reply which was not based on anything to do with your initial and subsequent inquiries. Bojan stated that because he had no clue as to what the source of the original photon was, he couldn't measure anything other than its energy as registered on his equipment.

So, all you are trying to do here is pit one person's answer against another and try to make something of it.

My initial reply to your question was correct and is as correct as Bojan's. If you know the source of your photon, it's a simple matter of working backwards with the observation and using the appropriate redshift equations to give a redshift for that photon. And all you need is the photomulitplier tube (which will do the job, if you know how to convert the measured intensity to wavelength) to find the wavelength of the photon at detection.

Exactly the same way they read a redshifted spectrum.

If you can't understand that, then you shouldn't have asked the question in the first place.

Or, are you just out to cause arguments.

[sjastro]

Originally Posted by Archy

I asked how can the "redshift" of a single photon be measured

Renormalised replied "...Very easily, with a photomultiplier tube and in exactly the same way as you measure a redshifted spectrum. You look at (or determine via theory) what the original wavelength/frequency of the photon was when it left the source and compare that with what you measured at the photomultiplier."

Bojan replied inter alia


Bojan's reply that the redshift cannot be measured contradicts Renormalised. I agree with Bojan the redshift of a single photon can't be determined. Others in the thread were unwilling or unable to answer the question. When I pressed for an answer gave wrong, irrelevant or evasive replies and cast aspersions on my motives. Gentlemen, whether you answer questions or not is your prerogative: but what you have indulged in just wastes space.

What was the relevance of your question regarding cosmological redshift and relativity?

[CraigS]

Originally Posted by Archy

Gentlemen, whether you answer questions or not is your prerogative: but what you have indulged in just wastes space.

I learned much from the discussion .. with my being such a valuable person, I'm going to authorise this usage of the space.

Cheers

[renormalised (Carl)]

Originally Posted by CraigS

I learned much from the discussion .. with my being such a valuable person, I'm going to authorise this usage of the space.

Cheers

Where's your stamp of authorisation

(and it's got to make a big "kerchunk" noise when you stamp it down on the page)

[Archy (George)]

Originally Posted by renormalised

No, you chose one reply which was not based on anything to do with your initial and subsequent inquiries. Bojan stated that because he had no clue as to what the source of the original photon was, he couldn't measure anything other than its energy as registered on his equipment.

So, all you are trying to do here is pit one person's answer against another and try to make something of it.

My initial reply to your question was correct and is as correct as Bojan's. If you know the source of your photon, it's a simple matter of working backwards with the observation and using the appropriate redshift equations to give a redshift for that photon. And all you need is the photomulitplier tube (which will do the job, if you know how to convert the measured intensity to wavelength) to find the wavelength of the photon at detection.

Exactly the same way they read a redshifted spectrum.

If you can't understand that, then you shouldn't have asked the question in the first place.

Or, are you just out to cause arguments.

My you are all riled up. The original question started and ended thus

Originally Posted by CraigS

Ok all you relativists out thar......

There is some flaw here, but where is it … ??...

Answerers welcome.

Cheers

Perhaps you are riled because the flaw in your postulate is that although you can measure the wavelength/frequency of the photon when it arrives, it is impossible to determine what the original wavelength/frequency of the photon was when it left the source, though you may speculate what it was.

Therefore you cannot determine the relative ages of photons X and Y

Giving facile or abusive responses tends to cloud the issue.

Gentlemen, Goodnight

[sjastro]

What was the relevance of your question regarding cosmological redshift and relativity?

I'm still waiting on your answer.

[renormalised (Carl)]

Originally Posted by Archy

My you are all riled up. The original question started and ended thus

Being "smart" about it will not make your reply any less puerile.

Originally Posted by Archy

Perhaps you are riled because the flaw in your postulate is that although you can measure the wavelength/frequency of the photon when it arrives, it is impossible to determine what the original wavelength/frequency of the photon was when it left the source, though you may speculate what it was.

Therefore you cannot determine the relative ages of photons X and Y

Let's make it clear right from the start....the relative ages of any photon have nothing to do with the question that you specifically asked. Your question has nothing to do with the original question of Craig's.

Your responses show a clear lack of understanding either our answers or any of the physics involved. I doubt very much if you'd understand the original question that was posed.

Originally Posted by Archy

Giving facile or abusive responses tends to cloud the issue.

Gentlemen, Goodnight

Don't try and sound all reasonable. It doesn't work. Yours is a case of the pot calling the kettle black.

[CraigS]

Originally Posted by Archy

although you can measure the wavelength/frequency of the photon when it arrives, it is impossible to determine what the original wavelength/frequency of the photon was when it left the source, though you may speculate what it was.

Therefore you cannot determine the relative ages of photons X and Y

Well, ok .. so that doesn't really provide me with any insights into explaining anything I observe …

So I'm now in alignment with Steven's question … how is this relevant in my quest to explain what I might see ?

Cheers

[avandonk]

Originally Posted by CraigS

Bert;
Are you tellin' me that we can't gain any understandable knowledge of the physical world from the Science of Astronomy ?

Bear Grylls beats around bushes … and he's a living legend !

Cheers

I should have answered more informatively.

A very smart lecturer taught me years ago

One observation was just a point.
Two observations only imply a trend.
Three may give you a straight line trend.

It is only through many observations with all available means can we work out how things tick. These observations should fit any theory and be self consistent across all scientific fields. Like QM and gravity!

Astronomy is not an isolated science. Of course this is stating the bleeding obvious but it needs to be said.

A gedunken experiment based on two photons with the dubious honour of being the last from their respective sources will never give any insight no matter how carefully 'measured'.

Our reality is the constant interaction of uncountable energy interactions that all affect each other and further interactions ad infinitum. When the interactions stop reality stops. All of us come from the dust and gases from many stars and supernovae. The coldest places in our galaxy are even now accreting dust and gas for new stars and planets. Gravity can only collect this nebulous material when it slows to a crawl.

I wish I could explain my ideas better but like most humans I am limited by my own ignorance and time and space on this forum. My interpretation of the Universe changes as I get older and all are 'correct' as they are all equally wrong!

Bert

[CraigS]

Originally Posted by avandonk

A gedunken experiment based on two photons with the dubious honour of being the last from their respective sources will never give any insight no matter how carefully 'measured'.

I'm beginning to see that in order for it to do so, there needs to be a commonality of background understanding. (Which perhaps, may be partially absent in this case).

Cheers

[avandonk]

Originally Posted by CraigS

I'm beginning to see that in order for it to do so, there needs to be a commonality of background understanding. (Which perhaps, may be partially absent in this case).

Cheers

There are only questions and any good answers lead to more better questions.

If at any point one becomes smug and think one has all the answers one is doomed to mediocrity! This is known as dogma.

Bert

[CraigS]

Originally Posted by avandonk

There are only questions and any good answers lead to more better questions.

If at any point one becomes smug and think one has all the answers one is doomed to mediocrity! This is known as dogma.

Bert

Sure Bert !
Bring on the answers that lead to the better questions, I say !

Cheers