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RAGORDON2010

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  1. Strange, one of the problems I find with the structure of this Forum is , unlike Twitter, I can't go back to a single location and find all of my posts listed together, one after the other. I'm sure I mentioned the "stripped down Michelson interferometer" in an earlier post. But be that as it may, I hope to return to Einstein's analysis in a future post and be more explicit about how I interpreted the work. Also, I believe your question addressed to me - "Do you understand how science works? (Based on your posts n this thread I am not sure you even know how SR works.)" - deserves a forthright reply. And my reply is the following - I believe that the fact that under a Lorentz transformation, Maxwell’s equations retain their form tells us something very fundamental about the place of Special Relativity Theory in the construct of modern physics. In effect, it tells us that SR belongs firmly in the house of Electromagnetic Theory, including phenomena related to light itself such as the Relativistic Doppler effects - both in-line and transverse. The only substantial outlier that I can point to is the retarded decay of a speeding unstable particle. I hold that this phenomenon has not received adequate attention from the theoretical physics community. Simply to say that time dilated decay is a “kinematic” effect - that is, purely a consequence of the motion - is to invoke a paranormal influence having no bearing on legitimate science.
  2. Strange, I appreciate the Latin - The burden of the proof lies upon him who affirms not he who denies. (Google translation) Here's the problem as I see it. Einstein's attempt to demonstrate that the Lorentz transformations correctly associate his "at rest" observer observations with those of his "moving" observer observations, which I discussed in an earlier post regarding his use of a stripped down Michelson interferometer, is fundamentally flawed. The fact that he immediately jumps from there into successfully applying the Lorentz transformations to many physical problems raises real doubts in my mind about the foundations of SR. I hope to develop these thoughts in future posts.
  3. Studiot, thank you for your reply to my question - "Without invoking the mathematics of the the Lorentz transformations, is there a way to match an observation by observers in one reference frame with an observation by observers in the other reference frame?" To review, I used this question as a lead-in to my story about a charged ball on a speeding train exposed to an external magnetic field, and how the "at rest" observer sees that the ball begins to vertically loop, while the "moving" observer, riding on the train, sees that the ball begins to hop toward the rear of the train. I then wrote about how one could imagine inserting a firecracker in the ball and striking it with a laser beam to set off the firecracker. Both observers would then have a fixed point in spacetime about which they could compare notes. I had taken the idea from Einstein's light flash in his original paper. My story was part of a presentation I had developed some time back as a way of introducing high school students to Special Relativity. I worked around the idea of bringing the students into the story by having one group imagine that they were the research team in the "rest" frame that applied the magnetic field while the other group imagined that they were on the train with the ball. It turned out to be useful imagery, and I found myself falling back on it from time to time. in fact, I just referenced it again in a post I submitted last week to a thread discussing the SR twin story.
  4. md65536 - Interesting observation. I wasn't aware of this distinction. Thank you for clearing it up for me.
  5. Just a thought in passing - Twin tales have been part of the Special Relativity public-discussion canon going back to the original Einstein paper. The message is always that the observer in the “moving” frame is aging slower than the observer in the “rest” frame. In my studies of situations where I apply the Lorentz transformations to move from one frame to the other, I’ve noted that on occasion the result is reversed. Below, I present an example of each case. Application 1 - Retarded Decays of Speeding Unstable Particles Let’s imagine that the unstable particle is at rest on your train, which is moving at speed 0.8c relative to me standing on the platform. Suppose you observe that the particle decays over a time interval t’, while I observe that the particle decays over a time period t. If we position the particle at the origin of coordinates in your frame, we may set its x’-displacement equal to 0. Then the Lorentz time transformation from your frame to my frame takes the same form as the classic time dilation formula and for your decay time t’ equal to, say, 24 units of time with v = 0.8c, my decay time t equals 40 units of time. So, you, standing in the “moving” frame are aging slower than I, standing in the “rest” frame. Award One Point to the Twin Tales. Application 2 - The Exploding Ball I would like to return now to the a situation I described in another post. I am again standing on the platform while you are on a speeding train moving at 0.8c. Next to you is a charged ball containing a small firecracker. I apply a strong magnetic field across the track causing the ball to undergo a series of vertical loops as I perceive the motion, while you perceive the motion as a series of “pogo stick” hops. Once the ball starts looping as I perceive it, and hopping as you perceive it, I zap the ball with a laser beam and set off the firecracker. Pow!!! The ball explodes at an object point (t,x,y,z) in my frame and at the corresponding image point (t’,x’,y’,z’) in your frame, where the object-image coordinates satisfy the Lorentz transformations. Now let's make it easy on ourselves. Suppose I zap the ball at the bottom or top of a loop, so I have no x-displacement to deal with, and suppose my clock reads 24 units of time at the moment the ball explodes, in whatever units of time are appropriate to our measurements. Here, with a zero x-displacement, the Lorentz time transformation takes the same form as the classic time dilation formula referenced above, and so your clock will read 40 time-units. So, I, standing in the “rest” frame, am aging slower than you, standing in the “moving” frame. Deduct One Point from the Twin Tales. So perhaps the best that can be said is that whether the observer in the “moving” frame is aging slower than the observer in the “rest” frame, or vice-versa, depends on the specifics of the experiment under consideration.
  6. I want to apologize to the Forum for the abrupt way in which I exited from this thread several months ago. Time has passed, whatever was troubling me has been resolved, and I would like to continue to offer my thoughts on Special Relativity. In particular, I would like to focus the attention of the Forum on the following question: What is the underlying physical foundation upon which SR rests? Or simply - Why does Special Relativity work so well? This will require a new thread, which I hope to begin sometime in the future.
  7. The other day, my wife and I visited a coffee house near the University of Alabama campus. As we were leaving, I noticed a young coed slowly and very apprehensively turning over the cover page of a textbook. I saw that the title of the book was “Statistical Mechanics”. “Oh”, I exclaimed. “they’re still teaching that!” The young coed immediately looked up at me with an expression bordering on total fear. I have no idea what she was thinking, but I quickly said “That was my favorite subject! Good for you!” Her face exploded in one big smile, ear to ear. So, physics isn’t so hard. It just takes a little encouragement to bite into it.
  8. Some year’s back, I had occasion to be hospitalized for 10 weeks or so while a bunch of doctors tried to figure out what ailed me. Finally, I was admitted to the Yale-New Haven Hospital in New Haven, Connecticut. The morning after my admission, a group of medical students on their rounds stopped by my room. Having been trained as a physicist and having not much else to say as they stared at me, I asked them if they had heard about Schrodinger’s cat. The reaction was “What?”. So I began to tell them about the cat, the box, the acid bath, the cyanide pill, and whether the cat was alive or dead while the box remained closed. I then explained that the probabilities that the cat was alive or dead were given by a mathematical construct know as a “wave function”, and until the box was opened, the state of the cat remained uncertain. Finally, the box is opened, the state of the cat is determined, and the wave function collapses. Needless to say, my story seemed to make little impression on the medical students. I then proceeded to explain that I was Schrodinger’s cat. I was suffering from some unknown ailment which could easily be confused with any number of ailments exhibiting similar symptoms. So, while the hospital staff considers these possible diagnoses, internally my body was moving from one disease state to the next, with relative durations set by the probabilities contained in my wave function. And then I looked directly at the medical students and told them that this state of affairs will continue until, at last, they opened me up (figuratively speaking I hoped) and arrived at a definite and correct diagnosis. At which point, my wave function will collapse, and my body will possess that and only that disease condition. Well, by and large, the students rolled their eyes, shook their heads and started for the door. As I called after them that they should read more physics, one young man stopped in the doorway and thanked me for my tale. Two days later, after the hospital staff had indeed arrived at a definite and correct diagnosis and set me up on a regimen that would keep me alive for the foreseeable future, I came across this same young student on my way out. Again he thanked me for the story and told me how much he appreciated the fact that I had brought Schrodinger’s cat to Yale-New Haven Hospital.
  9. When I joined this forum, I was hoping for the chance to engage in an intelligent conversation about issues in Special Relativity that have confused new students for decades. Instead, I have found myself talking to walls. So I will be exiting from this forum, but I want to leave three parting thoughts: Thought 1 - Despite how many people say it for other people to hear, despite how many people write it for other people to read, despite how many people key it for other people to link to - The Fact of Nature that the speed of light is the same in all inertial frames plays NO role in explaining the successful application of Special Relatively to solving physical problems! It is a Red Herring! There is another Fact of Nature at work here. What other Fact of Nature? Well, I’ve hidden it in plain sight in Thought 2. Thought 2 - "Slip slidin' away. Slip slidin' away. The nearer your destination, The more you're slip slidin' away." - Paul Simon I've been hoping to offer some thoughts on "relativistic mass" - the notion that mass increases with increasing speed. It's common to come across the statement that accelerating a particle becomes more difficult as particle speed approaches c because "particle mass approaches infinity". I prefer to state the issue differently. I would say that accelerating a particle becomes more difficult as particle speed approaches c because the external field responsible for the acceleration loses effectiveness as the particle speed approaches the speed at which the field mechanisms function. This, of course, offers an explanation for why light speed forms a limiting speed in nature. An old boot can travel no faster through the water than the maximum speed at which the fisherman can reel in the line. Whenever I think about this phenomenon, Paul Simon's song comes to mind. The speeding particle slips and slides away from the grasp of the external field. Thought 3 - I can’t leave this forum without saying something about time dilation. It has always puzzled me that while the physics community easily accepts that time dilation effects in General Relativity relate in some way to the interaction between the time-keeping system and the surrounding gravitational field, the analogous time dilation effects in Special Relativity are viewed as “just so”. Well, I have never cared much for a “just so” story. But I do hold the view that Nature does not care at all for a “just so” story. Something is going on out there! In the most dominant example - the retarded decays of unstable particles moving at speeds close to light speed - I again must fall back on my belief that these effects are in some way a consequence, in ways not at all understood, of the rapid motion of the particles through surrounding electric and magnetic fields. I hold (and this is where Special Relativity exhibits its most severe vulnerability as it is commonly described) that no physical effect can occur as a consequence of merely moving at a uniform speed in an inertial frame of reference. And now, from sunny Alabama (a state in the USA, refer Rand McNally maps, circa 1934), I happily say GOODBYE, Y’ALL!! ROLL TIDE!!
  10. Studiot, I appreciate your attempt to educate me on the history of Special Relativity. We all need occasionally to fill in gaps in our knowledge. However, I have been delving among the ins and outs of SR for maybe 5 decades now, and I'm afraid me ideas are pretty well set. There is a comment of yours, though, that I do wish to expand upon, to wit: [If you only have one frame of reference than you have the difficulty that Fitzgerald (and Lorenz) faced with the results of practical measurements on the propagation of light. This was that the Lorenz-Fitzgerald contraction was introduced as a mathematical formula which accounted for but did not explain the results of these experiments (in particular the Michelson and Michelson -Morley ones) Length contraction of the apparatus arms was a pretty heretical explanation. Einstein on the other hand, deduced the selfsame formulae from purely geometrical considerations of observing the same sequence of events in two frames.] Studiot, I have been "looking over Einstein's shoulder", in a manner of speaking, for some time now, and I want to call your attention to the manner in which he introduces the Lorentz transformations in his1905 original paper. (I have found the English translations of his 1905 papers in the book "Einstein's Miraculous Year - Five Papers That Changed the Face of Physics", Edited by John Stachel and Published by Princeton University Press, 1998, to be particularly helpful.) One almost has to read between the lines, but it soon becomes clear that Einstein is working with a central device consisting of two sticks joined at the ends to form a right angle, one vertical and the other horizontal, with a mirror at the free end of each stick. He also needs a source of light, say, a match. (Please note that there is more than a passing similarity here to Michelson's interferometer.) Einstein imagines that the device is placed in a "moving" frame labeled Frame k with the horizontal stick pointing in the direction of motion. The device is accelerated up to a speed v on the order of light speed and allowed to pass an observer in a "rest" frame, Frame K. When the vertex of the device comes up even with the Frame K observer, the match is struck. The observers in Frame k and Frame K, let's label them Observer k and Observer K, must then measure the times for the light rays emanating from the match to reach the two mirrors and the times for the reflected beams to return to the vertex of the device. As Einstein describes events, it appears that Observer k has the easier task. It is as if she struck the match. In fact, it's as if she is not moving at all. As she perceives the rays, one travels straight up to the vertical mirror and the reflected ray returns straight down to the vertex, the other ray travels in a straight line to the horizontal mirror and the reflected ray exactly retraces the path and returns to the vertex. Observer K has the more difficult task. It is as if he struck the match. As he perceives the rays, they must catch up to the moving mirrors, and the reflected rays must then meet up with the moving vertex. Einstein now sets out to demonstrate that the data obtained by the two observers satisfies the Lorentz transformations. In other writings, I have described Einstein's analysis as "unnecessarily and uncharacteristically opaque". After plunging into the depths of an argument that I have never been able to parse, he finally breaks through the surface of the water proudly holding in his hand a Lorentz-Fitzgerald contracted horizontal stick as perceived only by Observer K. I have often wondered why the editors of the journal where this work was published didn't insist that he take a clearer approach in his analysis. I do intend to suggest one possibility in a future post, but there is no avoiding his conclusion that the horizontal stick as perceived by Observer K is Lorentz-Fitzgerald contracted. This is Michelson-Morley all over again! Nothing new here! That Einstein was able to proceed from this point and create his magnificent Special Relativity Theory is a tribute to his genius.
  11. I too have been a teacher at various points in my life and, if on any given day, I found that I had held the attention of my students, prodded their curiosity, and possibly stimulated their imagination, I went home that night feeling that I had a very good day. I would imagine you have had days like that also. Teaching is not easy, particularly as the ideas become more abstract and removed from the students' day-to-day experiences. That's one reason I feel there is value in giving students alternative ways to view a problem. and the conceptual problems posed by Special Relativity definitely could use an alternative viewpoint. And if this viewpoint is grounded in their sense of two separate experiments conducted in the same laboratory, I believe a that good number of students would benefit from this viewpoint and find that they would be more open to arguments drawn from the conventional viewpoint of one experiment and two laboratories moving uniformly relative to each other at near-light speeds.
  12. Lately, I’ve been using “Special Relativity and Classical Field Theory”, Leonard Susskind and Art Friedman, Basic Books, 2017, as a desk reference. They state on p.57 that “proper time” and “spacetime interval” are negatives of each other, each referencing spacetime distance. I have no citation I can give you regarding the Einstein-Minkowski story. It may be apocryphal.
  13. Studiot, you are becoming one of my favorite responders because you seem to have a knack for leading me into areas I very much want to address. I am aware that Hermann Minkowski first dealt with the problems of the 4-space of t,x,y,z, i.e. "spacetime", circa 1908. His concern was how to specify a "distance" or separation between two spacetime events by building on Einstein's special relativity theory. This separation we now refer to as "proper time". I will have much more to say on Minkowski's contribution in later posts. It is worth noting here that, as the story goes, when Einstein first became of aware of Minkowski's paper, he mumbled something about mathematics muddling up good physics. (Hmm.) By "change of viewpoint" in the context of Special Relativity, I am working at a higher level of abstraction than simply relative velocities as seen by moving observers. This is what I am talking about - "We have, on one hand, the conventional scenario consisting of a single experiment and two inertial frames of reference in uniform relative motion and, on the other hand, an alternative scenario consisting of a single frame of reference and two separate but related experiments". (And, please, forget I ever mentioned the Earth and the Moon.)
  14. I apologize for confusing you with my initial remarks. I hope you will see that I've tried to be more specific in my later posts. The Earth to Moon imagery was just a way of letting the readers know that I was going to present a change of viewpoint.
  15. Thanks to all of you who have taken time to respond to my posts. The subject of Special Relativity deserves all the attention it gets. I think I’ve stumbled onto some sort of DNA test among followers of SR. We have, on one hand, the conventional scenario consisting of a single experiment and two inertial frames of reference in uniform relative motion and, on the other hand, an alternative scenario consisting of a single frame of reference and two separate but related experiments. I hold the view that both scenarios should be introduced and discussed in high school junior and senior science classes and also at the freshman university level. Let the students choose their preference according to their natural inclinations. Obviously I have my own preference but, particularly with the advent of General Relativity, the question of relationships across multiple reference frames becomes significant and must be introduced and discussed. Which brings me to the subject of scenario equivalence. Let me give an example. I pose the following question - Without invoking the mathematics of the the Lorentz transformations, is there a way to match an observation by observers in one reference frame with an observation by observers in the other reference frame? I believe Einstein wrestled with this question because he introduced the notion of the “mutually observed light flash” - a match is struck and the light flash is observed instantly by observers in both frames. Beginning with the conventional scenario, let’s not just talk about it - let’s do it, at least in thought. Let’s go back to the situation where I stand on the platform and you are on the speeding train along with the charged ball. This time, however, I want to insert a small firecracker inside the ball. Then, once the ball starts looping as I perceive it, and hopping as you perceive it, I zap the ball with a laser beam and set off the firecracker. Pow!!! The ball explodes at an object point (t,x,y,z) in my frame and at the corresponding image point (t’,x’,y’,z’) in your frame, where the object-image coordinates satisfy the Lorentz transformations. Obviously, I cannot reproduce this match-up in the related experiments scenario. I think what we have here might be what theoretical physicists refer to as a “broken symmetry”. It certainly looks like a broken symmetry to me. (Actually after re-reading the above text, I did indeed find a way to match up observations across related experiments, and I’ll describe it in a future post. In my next post, however, I want to discuss time dilation and “slow clocks”.)
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