# Discussion: Zero Doppler effect for reflected light from a rolling wheel

Discussion in 'Formal debates' started by James R, Nov 10, 2011.

1. ### TrippyALEA IACTA ESTStaff Member

Messages:
10,890
And we're already off to a poor start.

Allow me to repeat myself:

But this time, I have emphasized the salient clause for you.

3. ### TachBannedBanned

Messages:
5,265
Yes, we are saying the same thing. Go ahead.

5. ### OnlyMeValued Senior Member

Messages:
3,914
Only in an idealized and theoretical hypothetical. (BTW I did not wind up having Pauli's book and the Bateman reference is not readily available. I put both on my list but the list is not short.)

What you have been arguing can only occur in practice when there is no difference in the speed of the reflecting surface relative to the light source and camera. Again assuming the reflecting surface is moving parallel to the plane of the source and camera. If not moving parallel any relative velocity will result in a Doppler effect. (Have to keep stating this so it is clear.)

Again,
You keep saying you understand what others are saying but I have yet to see anything in your posts that demonstrates that.

Tach, sometimes what you call word salad is necessisary to make clear the involved conditions. You seem to continually address an idealized hypothetical with only extremely limited aplication to any practical situation. All the while any reference to any praticale example, seems to be ignored.

Again, light is never reflected from any surface instantaneously. There are no real world ideal mirrors that do reflect light instantaneously. If the parallel motion of an object relative to an observer is small, yes the Doppler effect will be trivial. That in no way suggests that it will not occur, IN A REAL WORLD PRACTICAL SITUATION.

7. ### PeteIt's not rocket surgeryRegistered Senior Member

Messages:
10,167
No, your logic is quite general. You said so explicitly in [post=2860270]post 195[/post]:
Your angle transformation argument is also general enough to apply to an arbitrary plane mirror.

Yes, in the rest frame of the axle, each element of the spinning mirror wheel moves parallel to itself.

We can also agree that for a plane mirror aligned with the y-axis, each elementary mirror moves parallel to itself in a reference frame in which the mirror is moving parallel with with y-axis. Yes or no?

Think through the consequences carefully before you continue, Tach.
Have you derived how to properly transform the angle between a surface and an arbitrary velocity vector yet, or would you like me to post mine?

Last edited: Nov 22, 2011
8. ### TachBannedBanned

Messages:
5,265
Good, so we agree that in the axle frame the plane of the mirror makes a zero angle with its velocity. Next step: do you agree that the zero angle as measured in the axle frame transforms into a zero angle in the ground frame? Yes or no?

9. ### TachBannedBanned

Messages:
5,265
But you have already given ample proof that you don't understand the idealized case, why would you engage in a more complicated case that you know nothing about?

I ignore your word salads because they are a mix of innuendo with downright errors and misunderstandings. This is what I call "mixed greens".

So, how does this result into a Doppler effect? Can you write down the formalism explaining it? You pretend to have studied physics.

Prove it.

10. ### OnlyMeValued Senior Member

Messages:
3,914
So Tach,

You are saying that a Doppler effect only occurs when there is relative motion between the light source and observer? And is unaffected by the motion of an object in motion, parallel to the plane of the source and observer?

11. ### TrippyALEA IACTA ESTStaff Member

Messages:
10,890
And you wonder why people are rude to you?

12. ### OnlyMeValued Senior Member

Messages:
3,914
I don't think he does. But really it does not matter. I am just having fun with him.

He hates that I won't get into the math. And I wonder if he actually fully understands English.

13. ### Neddy BateValued Senior Member

Messages:
2,514

Tach has also stipulated that the object must be moving between the light source and the camera. He doesn't like it when the light source and the camera are both on the same side of the moving object. I think he added that stipulation some time after James R's rebuttal, though.

14. ### TachBannedBanned

Messages:
5,265
Actually it amuses me. Especially since you pretend to have studied physics, yet you cannot quantify any of your statements.

15. ### OnlyMeValued Senior Member

Messages:
3,914
How could that make any difference with you Tach? How many threads and total posts have been centered on this hypothetical with you now? There has been a lot of people who have argued the math with you and you either don't understand them or are unable to make sense yourself.

At least four, five.., maybe six, (I lose track) of your "opponents" seem to know their math. At least two have degrees in math. You don't seem to understand them! And they obviously have problems with your reasoning and at times your math...

Really, I have been watching from the sidelines and decided maybe a try at English, but no.., no "discussion" there either.

16. ### TachBannedBanned

Messages:
5,265
Well, at least the people arguing intelligently with me (like pete) for example:

-understand the parameters of the discussion (as you don't)
-do not make vague references to "practical" considerations that cannot be quantified (as you do)
-are able to cast their position in a formal way (as you cannot)

So far there have been two debates and two threads. People who understand physics and can talk intelligently about it, are starting to understand the subject.

17. ### TachBannedBanned

Messages:
5,265

Is this what you understood from the two threads and two debates? Or are you just in the process of building a strawman in preparation for beating it to death?

You really, really need to learn what is being discussed. Questions like this show that you don't even understand the basics. Why don't you try the local library for the Pauli book or for the Bateman paper? I think that this must be the 4-th or 5-th time I am recommending you reading them in order to clear your misconceptions.

18. ### OnlyMeValued Senior Member

Messages:
3,914
This was a simple question you could have answered.., I think.

And the discussion began in a thead before either debate or discussion thread. That's five threads... I don't think you ever understood the original discussion and it led off and into the debate/discussions here.

Why when I can just ask questions of authorities like yourself?

I really cannot believe that you are this slow... I have already posted that I was just messing with you and you keep on biting..

19. ### TachBannedBanned

Messages:
5,265
Because you are too lazy to learn and when I explain the same exact things that you could have learned if you weren't so lazy, you argue.

So, you are just trolling.

20. ### OnlyMeValued Senior Member

Messages:
3,914
I never thought of it that way and I am not sure since I don't know what that means.

I can say that had you been so inclined it could have been a discussion. As it turned out .... Maybe. Someone else will have to say. Like I said I don't even know what it is.

But I do have to say I was having fun. Then again that is always what I am doing.

21. ### PeteIt's not rocket surgeryRegistered Senior Member

Messages:
10,167
No, not for an angle between a surface and a velocity vector.

This is painfully obvious if you consider a flat surface in uniform motion.

Have you derived how to properly transform the angle between a surface and an arbitrary velocity vector yet, or would you like me to post mine?

22. ### TachBannedBanned

Messages:
5,265
I showed you through two methods that your claim is wrong. How do you define the "angle between a surface and a velocity vector"? You realize that we are talking about the velocity of the surface , not about some arbitrary velocity, right?

Yes, I actually did, so please don't talk down to me. If you are getting a different result, you must have made an error. Because, if you are saying is true, then the aberration formula, expressing the frame invariance of the zero angle between two co-linear vectors, would be falsified.
If what you are claiming were true, you would be performing the amazing feat of transforming a zero angle into a non-zero angle by simply changing frames. This would be a fantastic experimental refutation of POR.

I am curious to see what you did, so go ahead, post it.

Last edited: Nov 23, 2011
23. ### PeteIt's not rocket surgeryRegistered Senior Member

Messages:
10,167
The methods you presented are wrong.
Does this really need explaining?
Try here

No, you did not.

No, this is a qualitatively different situation to that described by the aberration formula.
POR?
It's not amazing at all.

Look:
A zero angle between two spacelike manifolds (eg rods or surfaces) is zero in all frames.
It is true that a zero angle between two timelike worldlines (eg a velocity vector) is zero in all frames.

But, we're talking about an angle between a spacelike manifold (the mirror surface) and a timelike worldline (it's velocity).

You have nowhere shown how to transform such an angle between frames.

Hang tight while I translate to tex...
(May not be until tomorrow. I'm supposed to be pulling up carpet today.)