Is the Speed of Light variable?

[jamesfairclear]

2 hours ago, Ghideon said:

Bold by me:

How is it more meaningful? A detailed answer may bring this discussion forward.  I claim that it is not meaningful to characterize the speed of light as something that is invalid, as other members have already stated.

 

I am proposing that the standard measurement of speed resulting in c is not an objectively accurate representation of speed where there is relative motion between the emitter and the destination because the light received (red shifted or blue shifted) is qualitatively and quantitatively different from the light that was emitted. One thing is emitted and another different thing arrives at the destination. In other words apples are being compared with oranges.

This is the best analogy I can come up with at the moment to illustrate why it is in my view more meaningful to make corrections to the measured speed of light in order to account for the discrepancies in light energy transfer rates between source and destination.

Consider a 100 metre race where a competitor leaves the start line with an average chest to back measurement of 40cm which then increases to 40 metres by the time the front of his chest trips the photoelectric cell at a measured time of 11 elapsed seconds. If his back crosses the line 5 seconds later than his chest it raises considerable doubt as to whether he has run the race in 11 seconds or 16 seconds or some averaged time (say 13.5 seconds) between the 2 or indeed if he is really the same competitor that started the race.

[Strange]

5 minutes ago, jamesfairclear said:

I am proposing that the standard measurement of speed resulting in c is not an objectively accurate representation of speed where there is relative motion between the emitter and the destination because the light received (red shifted or blue shifted) is qualitatively and quantitatively different from the light that was emitted. One thing is emitted and another different thing arrives at the destination. In other words apples are being compared with oranges.

But those apples and oranges always move at the same speed. More importantly, and something you haven't really addressed, they move at the same speed according to every observer.

So not only is the speed of light constant (interesting but not very exciting) it is also invariant (very interesting and completely changes our understanding of the universe).

7 minutes ago, jamesfairclear said:

This is the best analogy I can come up with at the moment to illustrate why it is in my view more meaningful to make corrections to the measured speed of light in order to account for the discrepancies in light energy transfer rates between source and destination.

There are no "corrections" required because it is always measured to be the same.

This is such a fundamental fact that we now define the speed of light as a constant and other units (length) are derived from it.

 

[jamesfairclear]

6 hours ago, swansont said:

This is irrelevant. The source is further away when it emits the second photon. It has to travel a greater distance. That in no way means it’s traveling at a lower speed. 
 

I will reiterate what others have said: you are redefining “speed” to mean something new. You aren’t allowed to do that. It already has a definition 

 

 

Yes I agree, I am indeed proposing a small change to the definition of speed. I am not though aware of any legislation preventing me from making such a proposal 😀

I also agree with your statement "The source is further away when it emits the second photon. It has to travel a greater distance. That in no way means it’s traveling at a lower speed".

I am proposing that the standard measurement of speed resulting in c is not an objectively accurate representation of speed where there is relative motion between the emitter and the destination because the light received (red shifted or blue shifted) is qualitatively and quantitatively different from the light that was emitted. One thing is emitted and another different thing arrives at the destination. In other words apples are being compared with oranges.

As an analogy consider a 100 metre race where a competitor leaves the start line with an average chest to back measurement of 40cm which then increases to 40 metres by the time the front of his chest trips the photoelectric cell at a measured time of 11 elapsed seconds. If his back crosses the line 5 seconds later than his chest it raises considerable doubt as to whether he has run the race in 11 seconds or 16 seconds or some averaged time (say 13.5 seconds) between the 2 or indeed if he is really the same competitor that started the race.

[Ghideon]

15 minutes ago, jamesfairclear said:

This is the best analogy I can come up with at the moment to illustrate why it is in my view more meaningful to make corrections to the measured speed of light in order to account for the discrepancies in light energy transfer rates between source and destination.

 

15 minutes ago, jamesfairclear said:

Consider a 100 metre race where a competitor leaves the start line with an average chest to back measurement of 40cm which then increases to 40 metres by the time the front of his chest trips the photoelectric cell at a measured time of 11 elapsed seconds. If his back crosses the line 5 seconds later than his chest it raises considerable doubt as to whether he has run the race in 11 seconds or 16 seconds or some averaged time (say 13.5 seconds) between the 2 or indeed if he is really the same competitor that started the race.

No.

It raises the doubt why the change in measurement was not included in the rulebook in the first place. In a scientific approach in the analogy I guess the rules would be investigated, definitions tightened, equipment tuned or changed to incorporate the changing chest ot back measurements. Then there will be a re-run incorporating the new knowledge. But I don't think the scientists would redefine the concept of speed or velocity.

Edited April 8, 2020 by Ghideon
spelling

[jamesfairclear]

2 minutes ago, Ghideon said:

 

No.

It raises the doubt why the change in measurement was not included in the rulebook in the first place. In a scientific approach in the analogy I guess the rules would be investigated, definitions tightened, equipment tuned or changed to incorporate the changing chest ot back measurements. Then there will be a re-run incorporating the new knowledge. But I don't think the scientists would redefine the concept of speed or velocity.

Stranger things have happened 😀

13 minutes ago, Strange said:

But those apples and oranges always move at the same speed. More importantly, and something you haven't really addressed, they move at the same speed according to every observer.

So not only is the speed of light constant (interesting but not very exciting) it is also invariant (very interesting and completely changes our understanding of the universe).

There are no "corrections" required because it is always measured to be the same.

This is such a fundamental fact that we now define the speed of light as a constant and other units (length) are derived from it.

 

Yes indeed the apples and oranges do move at the same speed. I have never disputed this and have addressed this in more than one post e.g.

"Light emitted from a light source moving away from an observer at a speed v would intuitively be expected to be travelling at a speed (c – v) but is in fact still measured to be moving at a speed of c. The measurement of speed is based on the time interval between the light being emitted and the light being initially detected at the destination."

It is the fact that apples and oranges are not the same things that is relevant to my proposition to make a small change to the definition of speed.

[taeto]

46 minutes ago, jamesfairclear said:

my proposition to make a small change to the definition of speed.

It could be handy for anyone facing speeding charges in traffic court.

[studiot]

1 hour ago, jamesfairclear said:

I am proposing that the standard measurement of speed resulting in c is not an objectively accurate representation of speed where there is relative motion between the emitter and the destination because the light received (red shifted or blue shifted) is qualitatively and quantitatively different from the light that was emitted. One thing is emitted and another different thing arrives at the destination. In other words apples are being compared with oranges.

 

You still have not addressed my question about the difference in measurement between two frames.

Note that since relativity, whether newton-galileo or einstinian, use conventional definitions of 'speed' you cannot invoke these.

I still expect to see some mathtematics demonstrating and supporting you proposal. So far there has been none whatsoever.

[jamesfairclear]

2 hours ago, taeto said:

It could be handy for anyone facing speeding charges in traffic court.

😀

[studiot]

3 hours ago, jamesfairclear said:

It is the fact that apples and oranges are not the same things that is relevant to my proposition to make a small change to the definition of speed.

If you are proposing to define or redefine anything the correct procedure is to clearly define your new object in terms of already known objects, preferabky by way of a mathematical equation.

For example here is a definition of the moment of a force about a point.

Moment = Magnitude of the force x the perpendicular distance from the point to the line of action.

You have not done the equivalent for your new object (and keep avoiding doing so)

So we have nothing to put numbers into to test your proposal.

Edited April 8, 2020 by studiot
spelling

[Ghideon]

3 hours ago, jamesfairclear said:

I am proposing that the standard measurement of speed resulting in c is not an objectively accurate representation of speed where there is relative motion between the emitter and the destination because the light received (red shifted or blue shifted) is qualitatively and quantitatively different from the light that was emitted.

What supporting arguments would you like to provide? Repeating a flawed analogy is not enough. 

3 hours ago, jamesfairclear said:

Stranger things have happened 😀

I guess some people thought that Special Relativity was "strange" when first presented .

But more seriously; Einstein did not just wave his hands when he introduced his postulates and models, his mathematics are supported by observations. 

[jamesfairclear]

15 minutes ago, studiot said:

If you are proposing to define or redine anything the corect procedure is to clearly define your new object in terms of already known objects, preferabky by way of a mathematical equation.

For example here is a definition of the moment of a force about a point.

Moment = Magnitude of the force x the perpendicular distance from the point to the line of action.

You have not done the equivalent for your new object (and keep avoiding doing so)

So we have nothing to put numbers into to test your proposal.

Quantitatively there is less energy per second arriving at the destination from a receding light source than light from a relatively stationary light source.

Energy emitted per second = E

Energy received per second = (E – e)

Energy discrepancy e received in t seconds.

Energy emitted in T seconds = ET

Energy received in T seconds = (E – e) x (T)

Energy received in (T + t) seconds = ET

Measured speed of light over distance D for time T1 = D/T1 = c

Adjusted speed of light  = D/(T1+t) < c

[Strange]

1 minute ago, jamesfairclear said:

Quantitatively there is less energy per second arriving at the destination from a receding light source than light from a relatively stationary light source.

Energy emitted per second = E

Energy received per second = (E – e)

Energy discrepancy e received in t seconds.

Energy emitted in T seconds = ET

Energy received in T seconds = (E – e) x (T)

Energy received in (T + t) seconds = ET

Measured speed of light over distance D for time T1 = D/T1 = c

Adjusted speed of light  = D/(T1+t) < c

But that is mixing two different things. Apples and oranges, if you will.

If two cars take the same time to drive the same distance, but one of them uses twice as much gas/petrol, does that mean that the one that had the greater energy difference was going faster, even though they were both travelling at the same speed?

No, obviously not.

You can't just combine random quantities and get a sensible answer.

[swansont]

4 hours ago, jamesfairclear said:

Yes I agree, I am indeed proposing a small change to the definition of speed. I am not though aware of any legislation preventing me from making such a proposal 😀

I also agree with your statement "The source is further away when it emits the second photon. It has to travel a greater distance. That in no way means it’s traveling at a lower speed".

we already have a definition for speed. Call it something else.

4 hours ago, jamesfairclear said:

I am proposing that the standard measurement of speed resulting in c is not an objectively accurate representation of speed where there is relative motion between the emitter and the destination because the light received (red shifted or blue shifted) is qualitatively and quantitatively different from the light that was emitted. One thing is emitted and another different thing arrives at the destination. In other words apples are being compared with oranges.

Relativity has beat you to the notion. We already know that the frequency depends on the frame of reference, and I’m not the first to point this out.

 

4 hours ago, jamesfairclear said:

As an analogy consider a 100 metre race where a competitor leaves the start line with an average chest to back measurement of 40cm which then increases to 40 metres by the time the front of his chest trips the photoelectric cell at a measured time of 11 elapsed seconds. If his back crosses the line 5 seconds later than his chest it raises considerable doubt as to whether he has run the race in 11 seconds or 16 seconds or some averaged time (say 13.5 seconds) between the 2 or indeed if he is really the same competitor that started the race.

Repeating an explanation/analogy without responding to questions about it is poor form

[studiot]

12 minutes ago, jamesfairclear said:

Quantitatively there is less energy per second arriving at the destination from a receding light source than light from a relatively stationary light source.

Energy emitted per second = E

Energy received per second = (E – e)

Energy discrepancy e received in t seconds.

Energy emitted in T seconds = ET

Energy received in T seconds = (E – e) x (T)

Energy received in (T + t) seconds = ET

Measured speed of light over distance D for time T1 = D/T1 = c

Adjusted speed of light  = D/(T1+t) < c

So let me try this with some figures.

 

A Wild distomat DI 10 laser distance meter has an emitted power of 0.08mW at a wavelength of 875 nm.

What is your predicted change in wavelength when used to measure the length of the Obridge Viaduct at a target 360m distant?

 

Edited April 8, 2020 by studiot

[Bufofrog]

18 minutes ago, jamesfairclear said:

Measured speed of light over distance D for time T1 = D/T1 = c

Adjusted speed of light  = D/(T1+t) < c

This is where your conceptual error lays.

D is actually the distance the first photon travels to the receiver.  Which is the beginning of the light pulse.

Your "adjusted speed" is the end of the light pulse, the time is (T1 + t).  So you have the wrong distance 'D'.  The distance should be, D + v/t.

So you second equation should be: (D + v/t)/(T1 + t) = c

[studiot]

2 minutes ago, Bufofrog said:

D + v/t.

Aw you spoilt the surprise.

[jamesfairclear]

3 hours ago, swansont said:

we already have a definition for speed. Call it something else.

Relativity has beat you to the notion. We already know that the frequency depends on the frame of reference, and I’m not the first to point this out.

 

Repeating an explanation/analogy without responding to questions about it is poor form

What questions do you have about this analogy?

[jamesfairclear]

2 hours ago, Bufofrog said:

This is where your conceptual error lays.

D is actually the distance the first photon travels to the receiver.  Which is the beginning of the light pulse.

Your "adjusted speed" is the end of the light pulse, the time is (T1 + t).  So you have the wrong distance 'D'.  The distance should be, D + v/t.

So you second equation should be: (D + v/t)/(T1 + t) = c

No there is no conceptual error.

With a receding light source and measuring a given quantity of light energy E emitted over a time T the distance D implicitly represents a known range of distances D1 to D2 that can be factored into the calculation with the same values at both source and destination thus effectively cancelling out to the simpler expression D.

On the basis that D1 to D2 are known fixed values and that the light energy once emitted is no longer affected by the receding emitter it is known that the emitted light energy E will travel at a speed of c to the destination and will arrive there in a less energetic form due to the Doppler effect.  The quantity of light energy emitted E over time T will take a longer time (T + t) to be received at the destination. Thus the only relevant parameter to the adjusted speed calculation is the additional time t taken for the energy discrepancy e to be received at the destination.  

[Bufofrog]

Too bad, I was hoping you were willing to learn a little.  Oh well, it's your choice.

[Mordred]

1 hour ago, jamesfairclear said:

No there is no conceptual error.

With a receding light source and measuring a given quantity of light energy E emitted over a time T the distance D implicitly represents a known range of distances D1 to D2 that can be factored into the calculation with the same values at both source and destination thus effectively cancelling out to the simpler expression D.

On the basis that D1 to D2 are known fixed values and that the light energy once emitted is no longer affected by the receding emitter it is known that the emitted light energy E will travel at a speed of c to the destination and will arrive there in a less energetic form due to the Doppler effect.  The quantity of light energy emitted E over time T will take a longer time (T + t) to be received at the destination. Thus the only relevant parameter to the adjusted speed calculation is the additional time t taken for the energy discrepancy e to be received at the destination.  

All completely incorrect. You do realize that different frequencies of light propogate at the same speed.

 We have proven this beyond doubt with spectronomy and lasers. So it makes no sense to think redshift which only alters frequency will affect the speed of light.

One day you might actually learn to examine the evidence instead of your incorrect claims.

Lol Even my 1921 physics textbook disagrees with you and it gives a chart of different tests at different frequencies of light.

[Ghideon]

Your proposal is not working, for many reasons already stated. Here is an attempt at posting some hints regarding "definition" in case you are open for learning.

12 hours ago, jamesfairclear said:

I am indeed proposing a small change to the definition of speed.

Note: bold by me

8 hours ago, jamesfairclear said:

Measured speed of light over distance D for time T1 = D/T1 = c

Adjusted speed of light  = D/(T1+t) < c

What is your new definition of speed? How does your new definition affect the measurement in first equation in the quote above? Are you trying to use two different definitions of speed at the same time, the standard definition and your own new definition?  

Your math is not just incompatible with physics of light and speed of light, it is incompatible with the concept of speed as stated by you. You need to tell the new definition of speed before incorporating it into an explanation of speed of light. 

 

Edited April 9, 2020 by Ghideon

[Markus Hanke]

20 hours ago, jamesfairclear said:

This standard method of measuring the speed of light does not take account of any discrepancies between the rates of transfer of Energy at the source and destination respectively.

That is because those “rates of transfer” are irrelevant to the propagation velocity of the radiation field, which depends only on the permeability and permittivity of the underlying medium:

\[ c=\frac{1}{\sqrt{\mu_{0} \epsilon_{0}}}\]

It cannot depend on any other quantity, since that would violate local Lorentz invariance as well as global diffeomorphism invariance.

20 hours ago, jamesfairclear said:

One thing is emitted and another different thing arrives at the destination. In other words apples are being compared with oranges.

Both emitter and receiver couple to the same radiation field; they just label events in spacetime slightly differently, because their coordinate systems are rotated by some hyperbolic angle. 

[Strange]

!

Moderator Note

I split the Canuck Chat posts off to their own thread: https://www.scienceforums.net/topic/121759-canuck-chat-split-from-is-the-speed-of-light-variable/

 

 

[studiot]

2 hours ago, Markus Hanke said:

23 hours ago, jamesfairclear said:

One thing is emitted and another different thing arrives at the destination. In other words apples are being compared with oranges.

Both emitter and receiver couple to the same radiation field; they just label events in spacetime slightly differently, because their coordinate systems are rotated by some hyperbolic angle. 

 

Yeah  I've been trying to say this in a simpler way all along. +1

James has totally ignored the first time I said this.

 

5 hours ago, Mordred said:

We have proven this beyond doubt with spectronomy and lasers. So it makes no sense to think redshift which only alters frequency will affect the speed of light.

James isn't only flying in the face of experimental experience, he has posted self contradictory 'maths' as well.

11 hours ago, jamesfairclear said:

Quantitatively there is less energy per second arriving at the destination from a receding light source than light from a relatively stationary light source.

Energy emitted per second = E

Energy received per second = (E – e)

Energy discrepancy e received in t seconds.

Energy emitted in T seconds = ET

Energy received in T seconds = (E – e) x (T)

Energy received in (T + t) seconds = ET

Measured speed of light over distance D for time T1 = D/T1 = c

Adjusted speed of light  = D/(T1+t) < c

 

Please note that since the relative velocity v does not appear in any of these equations, the presented maths clearly implies that the 'so called' effect is independent of v.
This contradicts the initial premise of a receding light source.

This is also why he has been unable to put numbers into his 'maths' to answer my very simple measurement question.

(I actually carried out the measurement in question about 1980)

 

 

 

Edited April 9, 2020 by studiot

[jamesfairclear]

5 hours ago, Mordred said:

All completely incorrect. You do realize that different frequencies of light propogate at the same speed.

 We have proven this beyond doubt with spectronomy and lasers. So it makes no sense to think redshift which only alters frequency will affect the speed of light.

One day you might actually learn to examine the evidence instead of your incorrect claims.

Lol Even my 1921 physics textbook disagrees with you and it gives a chart of different tests at different frequencies of light.

You state "All completely incorrect" without providing any explanation.

It is abundantly clear from my proposition that I assume light (of any frequency) to be propagating at c. How have you interpreted this to be otherwise?