Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The Peripatetic Albert - Warmup Lap

  1. Apr 11, 2004 #1
    (I apologize in advance for the length of this message. I will endeavor to be more brief in the future. The advanced reader may skip the first few paragraphs, or read the paragraphs of my message in reverse order to facilitate rapid assimilation of the point at question.)

    So, in the first 4 sections of Relativity, Dr. Einstein begins to build the ladder which he will climb and, eventually, kick out from under himself. Section I invokes Euclid's geometry, building the foundation of linear measurements relative to rigid bodies. Section II innovates a coordinate system relative to a rigid body. Section III reviews the concepts of space and time in classical mechanics, Section IV presents the relationship between Netwonian inertia and the coordinate system from Section II, and Section V lifts the corner on the theory of Special Relativity.

    In the unveiling of this last, Dr. Einstein offers us this contemplation:

    Economically stated, and Dr. Einstein easily accomplishes his goal of disabusing us of any vestiges of bias whereby we might choose to consider ourselves "at absolute rest" and all other things, "in motion." This challenges us to take the first rung of the ladder which will eventually lead us to the theory of special relativity. Dr. Einstein continues:

    A reversal of thought is necessary here. We begin by believing (quite naturally) that the embankment is "really" at rest, and the train "really" in motion. But, after considering this chapter, and especially after folding in such concepts as the rotation and revolution of the earth, rotation of the galaxy, possible rotation of the galactic cluster, etc., we then reverse ourselves and say, "Yes, of course - the embankment is no more likely to be 'really' at rest than the train or the earth or anything else."

    But a second reversal of thought might also occur to the reader: Is it really true that the organ pipe must sound different on one orientation than another, even supposing a thought system which features (somewhere) a true K0? What forces would cause such a distinction? We understand that Dr. Einstein must provoke us to consider the impact of motion on wave phenomena for the sake of later considerations. But would sound waves really be affected as Dr. Einstein suggests? And if so, how?

    Of course, this point is not critical to Dr. Einstein's postion. We are simply warming up as we consider his explanation of relativity. And, we are not going to pick at every little thread which might appear to be hanging out. But can anyone justify Dr. Einstein's assertion? He seems to have offered an experimental method of verifying or disproving special relativity. But has he really? Will this experiment really yield different results in the event that special relativity is not true?

    As far as I can tell, the answer is No. But others, wiser, more experienced than I, can surely clear this matter up.
  2. jcsd
  3. Apr 12, 2004 #2


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    1) If you're going to try to disprove relativity, this is not the correct place to do so.

    2) If you're going to try to disprove relativity, don't take Einstein's writing too seriously; you might get caught up in a semantic issue with the language he used. Many of these semantic issues are well-known. Many books which better explain relativity have been written in thecentury since the introduction of the theory. You should read one of those instead. I should also remind you that the best language to discuss relativity is, of course, not a language proper -- it's mathematics. No matter how good an author's English "translation" of relativity theory may be, it's probably not perfect. It's plainly foolish to argue relativity with arguments written in English.

    3) If you're going to try to disprove relativity, and you're going to take Einstein's writing seriously, don't take quotes out of context. The passage to which you refer is preceded by:
    In other words, the passage you quote has already presumed special relativity is false.

    If relativity is false, an organ pipe "really moving" must sound different than an organ pipe "really not moving," since, as we all know from listening to passing ambulances, the velocity of the ambulance has a lot to do with how its siren sounds.

    - Warren
  4. Apr 12, 2004 #3
    Dear Warren,

    First, as I have already said, I am not trying to prove relativity wrong. Such an endeavor would certainly be premature on my part, who am only a tyro. As I have said, I am looking to examine some of Dr. Einstein's views critically (in a positive sense) so that I may fully comprehend the relativistic model. Only then would I assay to make critique. For now, I am assuming that my questions have good (and probably well-known) answers. These answers are what I seek.

    Second, yes, I am aware that Dr. Einstein is proposing a scenario in which SR is false. I had thought that my original message made that clear. I believe that a careful reading of my first message will show that I am completely accepting Dr. Einstein's argument, and asking for information which fleshes it out.

    Correct me if I am wrong, but it seems to me that Dr. Einstein offers us a simple experiment, a sonic equivalent to the Michelson-Morley experiments, whereby one might easily demonstrate the validity of the SR proposition.

    Without critiquing SR, I believe that one might still ask, "Does this experiment accomplish Dr. Einstein's purpose?"

    I don't think that it does. And, I believe that the ambulance siren (though an obvious first contemplation) is not a good analogy to the organ pipe on the train car.

    In this thread series, I am hoping to consider these questions carefully and at some depth. I am aware that this sort of board usually lends itself to a thrust-and-riposte mentality. I am hoping to avoid this mentality, and I earnestly request that those who are kind enough to assist me adopt a contemplative mentality as we engage in discussion.

    Finally, I am not afraid of math, and am willing to consider and evaluate mathematical propositions. My math is a little rusty, but my peregrinations with Dr. Einstein has been improving my facility.

    In any case, thank you for taking the time to respond. I am hopeful that you will be able to effect my improvement as time goes by.
    Last edited by a moderator: Apr 12, 2004
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook