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

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

  1. Emil Valued Senior Member

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    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!

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    Doppler_effect

    It reminds you of something?
     
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  3. RJBeery Natural Philosopher Valued Senior Member

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    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.
     
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  5. Neddy Bate Valued Senior Member

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    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.
     
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  7. hardalee Registered Senior Member

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    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?
     
  8. RJBeery Natural Philosopher Valued Senior Member

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

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    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?!

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    TTTTTAAAACCCCHHHHH!!!!!!
     
  10. James R Just this guy, you know? Staff Member

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    I note that Tach has edited his most recent post in the Debate thread since he originally posted it.

    I am somewhat busy at the moment, so I propose to take my 4 day time limit for my next reply from the time of Tach's last edit, and not from the time he posted the original version of his latest Debate post (whatever that was).

    If anybody (especially Tach) has a problem with this, please let me know ASAP. If there is a dispute over the time, we will need to have this independently adjudicated.

    I intend to reply in detail to Tach's latest post, and to respond to the content of his file from the first post. But right now, I just don't have the time.
     
  11. Aqueous Id flat Earth skeptic Valued Senior Member

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    I have not yet read an argument against Tach that I consider correct.
     
  12. Trippy ALEA IACTA EST Staff Member

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    Sounds fair and reasonable.
     
  13. hardalee Registered Senior Member

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    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.
     
  14. Tach Banned Banned

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    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.
     
    Last edited: Nov 16, 2011
  15. prometheus viva voce! Moderator

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    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.
     
  16. Tach Banned Banned

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    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.
     
  17. Trippy ALEA IACTA EST Staff Member

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    And you agreed to four days instead of two.

    I see no whining involved.

    When you alter your post 47 hours after you make it, it seems fair and reasonable that your interlocuter is granted an additional 47 hours to respond.
     
  18. Tach Banned Banned

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    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.
     
    Last edited: Nov 16, 2011
  19. RJBeery Natural Philosopher Valued Senior Member

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    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.
     
  20. Trippy ALEA IACTA EST Staff Member

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    Well then, that was just silly, wasn't it - modifying your post to address statements that have no bearing on the debate you're supposed to be having.

    And yet, here you are doing precisely that.

    Hence the granting of the extra time for James to review his response, ensure it adequately covers any counter points that he may wish to make and addresses the new material you added.

    The claims made by the different posters in this thread are irrelevant to your debate with James R.

    If this was a formal, spoken team debate, I'm fairly sure that addressing points made by the audience discussing the debate amongst themselves would cost your team points.
     
  21. Trippy ALEA IACTA EST Staff Member

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    Incidentally, my post precisely addresses the topic of this thread, and this discussion - a wheel rolling down a hill, and presents no mis understanding of the issue.
     
  22. Tach Banned Banned

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    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.
     
  23. Tach Banned Banned

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    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....
     
    Last edited: Nov 16, 2011

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