Known physics defeated by simple puzzle?
in [Relativity]
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From: PD on 7 Apr 2010 21:39 On Apr 7, 8:21 pm, Ste <ste_ro...(a)hotmail.com> wrote: > On 7 Apr, 22:45, PD <thedraperfam...(a)gmail.com> wrote: > > > On Apr 7, 4:24 pm, Ste <ste_ro...(a)hotmail.com> wrote: > > > > But you still don't get it. "Fitting" is not a relationship between > > > obsever and ladder. It is a relationship between ladder and barn. Why > > > on Earth would the observer's presence and circumstances affect the > > > fitting of these two objects, that are totally independent of the > > > observer? > > > To help you understand this, I'd like for you to give me a very > > precise definition of what you mean when you say that one object A > > will "fit" inside object B, when A and B are relatively moving. > > Depending on the quality of your definition, I may probe it with some > > additional questions and scenarios to see if it works. > > It's relatively straightforward. "Fitting" is when the ladder is of > such length that it would be possible to close both doors on the barn, > and for the ladder to be contained completely inside. Remember the ladder is moving relative to the barn. How does one determine that the ladder is contained completely inside, exactly? For example, I could shut one door and open it, while the front of the ladder is inside the barn, and then I could walk around to the back of the barn and shut the other door, while the back of the ladder is inside the barn. But by that time, the front of the ladder may have struck the first door. Is it still true that the ladder fits inside the barn? > > > > > > > > but that's not materialism - it's going > > > > > back to saying that the tree falling in the forest only makes a sound > > > > > if an observer heard it. > > > > > Nonsense. You are the one who above pointed out the with the object moving > > > > at 50km/hr and 100km/hr you have to consider the objects you are measureing > > > > relative to (ie the frame of reference). > > > > Yes. But you only have to reference two objects to describe a closing > > > speed. You don't say "objects A and B were closing at 100kmh according > > > to Jack" and "objects A and B were closing at 50kmh according to > > > Jill", because that would be contradictory (assuming that the > > > definition of "kmh" is itself common between Jack and Jill). > > > > You could say "objects A and B were closing at 100kmh according to > > > Jack" and "objects A and B were closing at 100kmh according to Jill", > > > but since the observer has no bearing on the measurement, why > > > reference him at all? > > > But it does. Closing velocity is also frame dependent. > > Suppose you have objects A and B, and you have observers Jack (at rest > > relative to A), Larry (at rest relative to B), Mary (moving relative > > to both A and B such that A and B have equal speeds relative to Mary), > > and Nancy (moving relative to A, B, and Mary). > > I must admit I've no clear picture at all about this scenario. > > > Then what will be true > > is that the closing speeds between A and B will have the same answers > > for Jack and Larry, but that number will be different than the closing > > speed between A and B according to Mary, and all of those different > > than the one according to Nancy. > > No, I reject this. The closing speed between A and B is universal, no > matter how the observers move around relative to A and/or B.
From: Inertial on 7 Apr 2010 21:40 "Y.Porat" <y.y.porat(a)gmail.com> wrote in message news:6c0df839-574d-4ba1-bf7a-16c9f1629de6(a)g11g2000yqe.googlegroups.com... > On Apr 8, 12:01 am, no. And I suspect at this point the >> > real problem is not my lack of understanding of the paradox, but your >> > lack of understanding of what I mean by "real". >> >> Real is what can be verified by a measurement. > > -------------------- > so why is it that an idiot like you claim that > THERE IS NO SMALLEST PHOTON ENERGY !!! !?????? One could perhaps suggest Planck energy. But that is WAY too big. There is no meaningful physical or theoretical lowest value for a photon energy or frequency. If one could find a smallest possible energy, then from that you could find a smallest photon frequency using the well known and experimentally derived E = hf > CAN AN IDIOT LIKE YOU > MEASURE PHOTON ENERGY THAT IS LESS THAN PLANK TIME DURATION > EMITTED ?? All individual photons are emitted in Planck time (or less) duration. Though the processes leading up to that will take longer. Similarly photon destruction is within planck time, though the energy released may take some time to be used. How long it take for a photon to be emitted has nothing to do with measuring it some time later. Single photon energy has been measured many times. From those measurement we get the experimentally derived fact that the energy of a single photon is E = hf (where f is the frequency of the EMR). The photon energy is not duration-of-emission dependent; it is frequency dependent.
From: Ste on 7 Apr 2010 21:40 On 7 Apr, 23:01, PD <thedraperfam...(a)gmail.com> wrote: > On Apr 7, 4:39 pm, Ste <ste_ro...(a)hotmail.com> wrote: > > > > I doubt that after writing "It cannot fit and not fit at the same > > > time" you really understand this gedanken at all. > > > It depends what you mean by "understand". If you mean "have grasped > > its tenets, and can reason the conclusion from those tenets", then I > > understand it totally. If you mean "accept that length contraction > > really occurs", then the answer is no. And I suspect at this point the > > real problem is not my lack of understanding of the paradox, but your > > lack of understanding of what I mean by "real". > > Real is what can be verified by a measurement. No it isn't. This is a fundamental difference between us. I dare say there are lots of things that cannot be verified by measurement, but only by inference from other measurements. > If you believe that reality has certain traits but that those traits > are unverifiable through measurement, because the measurement is > always obscured, then one has to ask on what basis you would believe > reality has those traits in the first place. Indeed, you would have to ask that. > > > We all understand > > > that. You don't know what you are talking about and it shows. > > > When you build a model of the world such as Special Relativity, you > > > consider some building blocks (the two postulates) and continue from > > > there. You are really not interested in following that route, > > > You're right. I'm not interested in merely reasoning from the first > > principles of a particular theory, and then dusting off my hands and > > patting myself on the back. > > > I'm interested in seeing how this theory actually applies to the real > > world, and how the conclusions of the theory are to be interpreted in > > practice. For example, how "length contraction" is to be explained as > > a matter of practical reality, and not just accepted at face value > > "because the theory predicts it". > > In terms of practical reality, length contraction applies to cases > where there are high speeds involved, typically. Thus the length of > the RF cavities in a LINAC changes as the particle accelerates, at a > rate that is completely consistent with length contraction. Beyond my comprehension. > The same > goes for where you place a detector to watch a particle decay, because > time dilation of a fast moving particle means it will be further away > from its creation when it decays than what would be expected from its > speed and its rest lifetime. But how does that prove anything? Decay is measured statistically in any event, and we have no understanding of the underlying mechanism that causes decay. > Since the placement is critical for a > successful experimental design, its an excellent example of practical > application. For a living-room application, color TVs with CRTs are > effectively electron accelerators that would get electrons to > sufficiently high speed that you'd have to make a relativistic > correction to the steering voltage to get the beam to sweep to the > correct spot. Again, a practical application. Lol! I wasn't asking for "the practical applications of SR".
From: PD on 7 Apr 2010 21:41 On Apr 7, 8:21 pm, Ste <ste_ro...(a)hotmail.com> wrote: > On 7 Apr, 22:45, PD <thedraperfam...(a)gmail.com> wrote: > > > But it does. Closing velocity is also frame dependent. > > Suppose you have objects A and B, and you have observers Jack (at rest > > relative to A), Larry (at rest relative to B), Mary (moving relative > > to both A and B such that A and B have equal speeds relative to Mary), > > and Nancy (moving relative to A, B, and Mary). > > I must admit I've no clear picture at all about this scenario. Try making a sketch. > > > Then what will be true > > is that the closing speeds between A and B will have the same answers > > for Jack and Larry, but that number will be different than the closing > > speed between A and B according to Mary, and all of those different > > than the one according to Nancy. > > No, I reject this. The closing speed between A and B is universal, no > matter how the observers move around relative to A and/or B. I don't care whether you reject it or not. It is experimentally the case, according to measurements. By what right do you say that something is true, despite being counter to measurements? We're back to unconfirmable solipsism if you so insist. PD
From: Inertial on 7 Apr 2010 21:46
"Ste" <ste_rose0(a)hotmail.com> wrote in message news:fd597667-aad9-45d2-86f4-8d2dd6e3f67b(a)i25g2000yqm.googlegroups.com... > On 7 Apr, 22:45, PD <thedraperfam...(a)gmail.com> wrote: >> On Apr 7, 4:24 pm, Ste <ste_ro...(a)hotmail.com> wrote: >> >> > But you still don't get it. "Fitting" is not a relationship between >> > obsever and ladder. It is a relationship between ladder and barn. Why >> > on Earth would the observer's presence and circumstances affect the >> > fitting of these two objects, that are totally independent of the >> > observer? >> >> To help you understand this, I'd like for you to give me a very >> precise definition of what you mean when you say that one object A >> will "fit" inside object B, when A and B are relatively moving. >> Depending on the quality of your definition, I may probe it with some >> additional questions and scenarios to see if it works. > > It's relatively straightforward. "Fitting" is when the ladder is of > such length which is a frame-dependent notion > that it would be possible to close both doors on the barn, implicitly simultaneously, which is a frame-dependent notion > and for the ladder to be contained completely inside. So it is a frame dependent notion. Yet you insist it be absolute and invariant. Sorry, but you cannot impose your will on nature or physics. > > > >> > > > but that's not materialism - it's going >> > > > back to saying that the tree falling in the forest only makes a >> > > > sound >> > > > if an observer heard it. >> >> > > Nonsense. You are the one who above pointed out the with the object >> > > moving >> > > at 50km/hr and 100km/hr you have to consider the objects you are >> > > measureing >> > > relative to (ie the frame of reference). >> >> > Yes. But you only have to reference two objects to describe a closing >> > speed. You don't say "objects A and B were closing at 100kmh according >> > to Jack" and "objects A and B were closing at 50kmh according to >> > Jill", because that would be contradictory (assuming that the >> > definition of "kmh" is itself common between Jack and Jill). >> >> > You could say "objects A and B were closing at 100kmh according to >> > Jack" and "objects A and B were closing at 100kmh according to Jill", >> > but since the observer has no bearing on the measurement, why >> > reference him at all? >> >> But it does. Closing velocity is also frame dependent. >> Suppose you have objects A and B, and you have observers Jack (at rest >> relative to A), Larry (at rest relative to B), Mary (moving relative >> to both A and B such that A and B have equal speeds relative to Mary), >> and Nancy (moving relative to A, B, and Mary). > > I must admit I've no clear picture at all about this scenario. Its not that hard. Here's a more concrete example. Two relatively moving spaceships A and B. Jack is in one of them, Larry in the other, and Mary is in a space station half way between them. Nancy is in another rocket ship moving relative to all of them. >> Then what will be true >> is that the closing speeds between A and B will have the same answers >> for Jack and Larry, but that number will be different than the closing >> speed between A and B according to Mary, and all of those different >> than the one according to Nancy. > > No, I reject this. Tough > The closing speed between A and B is universal, So you assert .. but experiment shows that reality does not work that way > no > matter how the observers move around relative to A and/or B. See .. you insist on shoehorning reality into a Galilean/Newtonian model, which we know experimentally does not work in reality, but is just a low-speed approximation to SR. As long as you insist on things working that way, no matter what the velocities involved, you cannot accept SR or even get a consistent model of it. |