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

I asked these questions because I wanted to clearly understand this experiment.
The first bewilderment was why "mirror"?
The difference between a surface matt and mirror is the reflected light directionality.
Doppler effect to happen for a mirror, must necessarily be a movement that is not in its own plan.
A mirror is placed on a table where he moves, does not have Doppler effect.
No, wrong, and so there is Doppler effect.
The measurement can not be when the light source and receiver are in the same place.
This is not true for diffuse reflection.
On the perimeter of a wheel, the movement is tangent to the wheel, is in the same plane as a "surface" of the perimeter.
If this perimeter is a mirror, you can not measure the Doppler effect, in the case when the light source is in the same place with the receiver.

I've found something interesting!

Please Register or Log in to view the hidden image!

Doppler_effect

It reminds you of something?

 

Log in or Sign up to hide all adverts.

I don't know if this debate has ended or not, but, as written, Tach has failed regardless of what interpretation he was using. Transverse movement of the wheel only allows for zero Doppler effect at a single, particular instant (which was NOT stipulated in the problem description), and longitudinal movement of the wheel towards the light source is trivially proven to induce blue-shifting.

 

Log in or Sign up to hide all adverts.

Tach didn't just fail, he was demolished by James R. At the beginning of the debate, Tach was clearly trying to prove "There is NO Doppler effect for light bouncing off moving objects." By the end of the debate, he had conceded that there is essentially only one special case where his claims even remotely hold true.

 

Log in or Sign up to hide all adverts.

I do not think even the one case is true unless the reflected photon is emitted in the instant the incoming one hits.

Any thoughts on this?

 

Hmm, my first thought was that the law of the angle of reflection would be violated if this were true.

 

Funny, Tach replied quickly to my first PM response to him but he seems to have gone quiet now, despite posting in plenty of other threads.

Tach?

TACH?!

Please Register or Log in to view the hidden image!

TTTTTAAAACCCCHHHHH!!!!!!

 

I have not yet read an argument against Tach that I consider correct.

 

But that law is not based on quantum physics but classical physics.

Does the actual process take no time? If it takes any at all, the mirror would move slightly producing a red or blue shift in the returning photon.

 

You have had all the time in the world to answer. This debate started actually much earlier, since your false claim in post 241 on Nov 5, that you found errors in my calculations on the subject. You wanted four days instead of 2 in the debate, now you are whining that you need even more days, it is time for you to either s... or get off the pot. Moderators, please lock the thread.

 

If I had to vote I'd say allowing James R the 4 days from the post edit is fine. You agreed to the 4 days rule before the debate and the point of the time limit is to provide a maximum wait for a response to an argument in the previous post. Adding material with an edit should not give the responder less time to reply than they would otherwise expect.

 

He's had enough time since Nov 5, when he made his false claims. He taunted until he got this debate going, now that he got what he wanted, he's whining for more time.

 

Fine, he doesn't have anything. He's been lying since his post 241 on Nov 5. If he had anything, he would have long posted it.
BTW, the additions to the post were done in order to address the incorrect claims by AN (really a copy of JamesR's post), pete (understood the main part, still doesn't understand the simplest detail) , Neddy Bate (a bad copy of pete's misunderstanding). Since technically I am not allowed to post in the discussions thread until the debate is over, I added material to the post in order to address the claims made by different posters in the discussion thread. If anything, that should have helped JamesR in avoiding repeating the same incorrect claims and should have resulted into a speed-up of his answer.

 

Well, there would still be a (1D?) region whose net shifting would be zero but, yes, I think I agree with you that if the process of reflection is not instantaneous then even Tach's 'special-case' argument falls apart.

 

Not really, AN has demanded and answer, see his shrill outburst. Since I couldn't give him an answer here, I added it to the post. This should also help JamesR.

 

You couldn't differentiate a radiative body (the Sun) from a reflective body (the wheel). Do you still think that you are qualified to judge the debate in an impartial manner? It is quite clear what is going on here, the moderators (possibly with prometheus' exception) have lined up behind JamesR.

Heck, JamesR broke his own rule 9 by starting the whining (post 67) that he needed more time....