Known physics defeated by simple puzzle?
in [Relativity]
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From: Sue... on 6 Apr 2010 19:59 On Apr 6, 7:09 pm, "Sue..." <suzysewns...(a)yahoo.com.au> wrote: > On Apr 6, 6:52 pm, Edward Green <spamspamsp...(a)netzero.com> wrote: > > > > > On Apr 6, 11:39 am, Ste <ste_ro...(a)hotmail.com> wrote: > > > > On 6 Apr, 16:28, PD <thedraperfam...(a)gmail.com> wrote: > > > > > On Apr 5, 6:41 pm, Ste <ste_ro...(a)hotmail.com> wrote: > > > > > > On 5 Apr, 22:10, PD <thedraperfam...(a)gmail.com> wrote: > > > > > > > On Apr 5, 3:47 pm, Ste <ste_ro...(a)hotmail.com> wrote: > > > > > > > > I'm happy to make concessions, but I have to be able to ask questions > > > > > > > and get meaningful answers. The ladder in the barn is a prime example. > > > > > > > I'm told "the ladder contracts to fit in the barn". > > > > > > > It contracts to fit the barn in the rest frame of the barn, which is > > > > > > why the ladder makes no marks on the barn doors when the doors are > > > > > > shut at the same time. In the rest frame of the ladder, the ladder > > > > > > does not contract and indeed does not fit inside the barn at all. In > > > > > > the rest frame of the ladder, the reason why there are no marks on the > > > > > > barn doors when they are shut is that they were not shut at the same > > > > > > time in this frame. > > > > > > This logic is easily defeated Paul, because if we contracted the > > > > > ladder's length *just* enough so that it marked the door in the barn > > > > > frame (in other words, the ladder has contracted just enough to manage > > > > > an interference fit with both doors shut), then this cannot be > > > > > accounted for in the ladder frame (because, in the ladder frame, if > > > > > the ladder is *even larger* relative to the barn than when it started, > > > > > then the ladder could not possibly mark the doors in the same way). > > > > > I'm not sure what the fuss is. The observation is that the doors are > > > > shut and open without striking the pole, and this is true in both > > > > reference frames examined (as well as any other inertial reference > > > > frame). The account in the ladder frame is, however, not because the > > > > ladder fits inside the barn. It is exactly as I described above. Why > > > > is this difficult? > > > > It isn't difficult for me. I can explain it, in its entirety, in terms > > > of a "visual effect" and the careful timing of the doors. It's other > > > people here who keep insisting that it is not a visual effect, and > > > hence the fuss > > > Taking you at your word (that you can explain it), I wonder if your > > "visual effect" is not an alternate formulation of SR. But perhaps > > that has been ruled out already. ==================== > About 1907 the formulation changed to a [visual] > derivation. This is why the Quacks will only > refer to the 1905 paper. Its well documented > here if you can read as fast as you post: > > http://en.wikipedia.org/wiki/Lorentz_ether_theory Timo's post suggest that visual is not the right term. I have to agree. because it implies an image. Einstien's 1920 paper *judges* clocks and endpoints on the rod from the relative moving frame with a light path delay. That still in no way implies Lorentz's instruments or barns that fortuitously change shape. Sue... > > Sue...
From: Ste on 6 Apr 2010 20:12 On 6 Apr, 18:28, PD <thedraperfam...(a)gmail.com> wrote: > On Apr 6, 12:14 pm, Ste <ste_ro...(a)hotmail.com> wrote: > > > > > > > On 6 Apr, 17:02, PD <thedraperfam...(a)gmail.com> wrote: > > > > On Apr 6, 10:39 am, Ste <ste_ro...(a)hotmail.com> wrote: > > > > > On 6 Apr, 16:28, PD <thedraperfam...(a)gmail.com> wrote: > > > > > > On Apr 5, 6:41 pm, Ste <ste_ro...(a)hotmail.com> wrote: > > > > > > > On 5 Apr, 22:10, PD <thedraperfam...(a)gmail.com> wrote: > > > > > > > > On Apr 5, 3:47 pm, Ste <ste_ro...(a)hotmail.com> wrote: > > > > > > > > > I'm happy to make concessions, but I have to be able to ask questions > > > > > > > > and get meaningful answers. The ladder in the barn is a prime example. > > > > > > > > I'm told "the ladder contracts to fit in the barn". > > > > > > > > It contracts to fit the barn in the rest frame of the barn, which is > > > > > > > why the ladder makes no marks on the barn doors when the doors are > > > > > > > shut at the same time. In the rest frame of the ladder, the ladder > > > > > > > does not contract and indeed does not fit inside the barn at all. In > > > > > > > the rest frame of the ladder, the reason why there are no marks on the > > > > > > > barn doors when they are shut is that they were not shut at the same > > > > > > > time in this frame. > > > > > > > This logic is easily defeated Paul, because if we contracted the > > > > > > ladder's length *just* enough so that it marked the door in the barn > > > > > > frame (in other words, the ladder has contracted just enough to manage > > > > > > an interference fit with both doors shut), then this cannot be > > > > > > accounted for in the ladder frame (because, in the ladder frame, if > > > > > > the ladder is *even larger* relative to the barn than when it started, > > > > > > then the ladder could not possibly mark the doors in the same way). > > > > > > I'm not sure what the fuss is. The observation is that the doors are > > > > > shut and open without striking the pole, and this is true in both > > > > > reference frames examined (as well as any other inertial reference > > > > > frame). The account in the ladder frame is, however, not because the > > > > > ladder fits inside the barn. It is exactly as I described above. Why > > > > > is this difficult? > > > > > It isn't difficult for me. I can explain it, in its entirety, in terms > > > > of a "visual effect" and the careful timing of the doors. It's other > > > > people here who keep insisting that it is not a visual effect, and > > > > hence the fuss. > > > > I don't believe it's a "visual effect" at all. The doors are closed > > > and opened by a common trigger, electronically. > > > > Is it your claim that the doors are "really" closed and opened > > > simultaneously, but they only visually appear to close and open > > > nonsimultaneously in the ladder frame? Then how does the 80 foot > > > ladder fit into the 40 ft barn without the doors striking the ladder, > > > if the doors are "really" closed simultaneously? > > > I would contend that the ladder never does fit, and even though it > > would *appear* observationally to be small enough to fit, any attempt > > to actually shut the doors while the ladder is inside will produce > > catastrophe. > > This is inconsistent with experiment. We've had this one before Paul. No experiment of this kind (i.e. trying to confine objects moving at relativistic speeds) has ever been performed. I even gave sources last time for this statement. > As I mentioned before, the first thing one must do in the case of an > observational science, is to not deny what is actually seen in > experiment, just because you do not immediately understand how that > outcome could arise. No one is denying what is seen. The ladder and barn paradox has never been "seen". We have merely reasoned, using the tenets of SR, that this is what we *would* see, if we were able to perform an experiment. But as I've said previously, even if this *is* what we would "see", seeing is not necessarily believing. Incidentally, I seem to remember Terrell ruled out any real observation of this contraction. > As indicated above, the doors are closed and then opened by a single > trigger and equal-length, exchangeable cables. There is no catastrophe > observed. You're asserting this. There is no experimental evidence of this being the case.
From: Inertial on 6 Apr 2010 20:24 "Ste" <ste_rose0(a)hotmail.com> wrote in message news:f9926deb-d318-4544-ab51-00799c9522e9(a)x12g2000yqx.googlegroups.com... > On 6 Apr, 18:28, PD <thedraperfam...(a)gmail.com> wrote: >> On Apr 6, 12:14 pm, Ste <ste_ro...(a)hotmail.com> wrote: >> >> >> >> >> >> > On 6 Apr, 17:02, PD <thedraperfam...(a)gmail.com> wrote: >> >> > > On Apr 6, 10:39 am, Ste <ste_ro...(a)hotmail.com> wrote: >> >> > > > On 6 Apr, 16:28, PD <thedraperfam...(a)gmail.com> wrote: >> >> > > > > On Apr 5, 6:41 pm, Ste <ste_ro...(a)hotmail.com> wrote: >> >> > > > > > On 5 Apr, 22:10, PD <thedraperfam...(a)gmail.com> wrote: >> >> > > > > > > On Apr 5, 3:47 pm, Ste <ste_ro...(a)hotmail.com> wrote: >> >> > > > > > > > I'm happy to make concessions, but I have to be able to ask >> > > > > > > > questions >> > > > > > > > and get meaningful answers. The ladder in the barn is a >> > > > > > > > prime example. >> > > > > > > > I'm told "the ladder contracts to fit in the barn". >> >> > > > > > > It contracts to fit the barn in the rest frame of the barn, >> > > > > > > which is >> > > > > > > why the ladder makes no marks on the barn doors when the >> > > > > > > doors are >> > > > > > > shut at the same time. In the rest frame of the ladder, the >> > > > > > > ladder >> > > > > > > does not contract and indeed does not fit inside the barn at >> > > > > > > all. In >> > > > > > > the rest frame of the ladder, the reason why there are no >> > > > > > > marks on the >> > > > > > > barn doors when they are shut is that they were not shut at >> > > > > > > the same >> > > > > > > time in this frame. >> >> > > > > > This logic is easily defeated Paul, because if we contracted >> > > > > > the >> > > > > > ladder's length *just* enough so that it marked the door in the >> > > > > > barn >> > > > > > frame (in other words, the ladder has contracted just enough to >> > > > > > manage >> > > > > > an interference fit with both doors shut), then this cannot be >> > > > > > accounted for in the ladder frame (because, in the ladder >> > > > > > frame, if >> > > > > > the ladder is *even larger* relative to the barn than when it >> > > > > > started, >> > > > > > then the ladder could not possibly mark the doors in the same >> > > > > > way). >> >> > > > > I'm not sure what the fuss is. The observation is that the doors >> > > > > are >> > > > > shut and open without striking the pole, and this is true in both >> > > > > reference frames examined (as well as any other inertial >> > > > > reference >> > > > > frame). The account in the ladder frame is, however, not because >> > > > > the >> > > > > ladder fits inside the barn. It is exactly as I described above. >> > > > > Why >> > > > > is this difficult? >> >> > > > It isn't difficult for me. I can explain it, in its entirety, in >> > > > terms >> > > > of a "visual effect" and the careful timing of the doors. It's >> > > > other >> > > > people here who keep insisting that it is not a visual effect, and >> > > > hence the fuss. >> >> > > I don't believe it's a "visual effect" at all. The doors are closed >> > > and opened by a common trigger, electronically. >> >> > > Is it your claim that the doors are "really" closed and opened >> > > simultaneously, but they only visually appear to close and open >> > > nonsimultaneously in the ladder frame? Then how does the 80 foot >> > > ladder fit into the 40 ft barn without the doors striking the ladder, >> > > if the doors are "really" closed simultaneously? >> >> > I would contend that the ladder never does fit, and even though it >> > would *appear* observationally to be small enough to fit, any attempt >> > to actually shut the doors while the ladder is inside will produce >> > catastrophe. >> >> This is inconsistent with experiment. > > We've had this one before Paul. No experiment of this kind (i.e. > trying to confine objects moving at relativistic speeds) has ever been > performed. I even gave sources last time for this statement. > > > >> As I mentioned before, the first thing one must do in the case of an >> observational science, is to not deny what is actually seen in >> experiment, just because you do not immediately understand how that >> outcome could arise. > > No one is denying what is seen. The ladder and barn paradox has never > been "seen". We have merely reasoned, using the tenets of SR, that > this is what we *would* see, if we were able to perform an experiment. > But as I've said previously, even if this *is* what we would "see", > seeing is not necessarily believing. > > Incidentally, I seem to remember Terrell ruled out any real > observation of this contraction. Nope. Unless by 'observation' you mean only what the naked eye would see. >> As indicated above, the doors are closed and then opened by a single >> trigger and equal-length, exchangeable cables. There is no catastrophe >> observed. > > You're asserting this. There is no experimental evidence of this being > the case. Because it is impractical to do so. Other experiments do exist that show time dilation, differences in simultaneity etc. And indirectly show length contraction (ie get results consistent with what is predicted when length is contracted)
From: Ste on 6 Apr 2010 20:27 On 6 Apr, 19:44, PD <thedraperfam...(a)gmail.com> wrote: > On Apr 5, 10:03 pm, Ste <ste_ro...(a)hotmail.com> wrote: > > > > > > You still haven't answered why 'fitting' must be absolute > > > Because of the obviousness of the concept. A thing cannot fit and at > > the same time not fit, because there is a logical contradiction in the > > meaning of those words. And nor can the state be subjective for each > > observer, otherwise that isn't materialism (and it isn't causal > > either). Or to repeat my earlier analogy, you can't hit a person over > > the head with a hammer, and merely daze him *at the same time as* > > cracking his skull wide open. > > This business about a thing fitting and not fitting being a > contradiction... > > A penny on the armrest of a plane is at rest in one reference frame > and not at rest in another reference frame. Is it not obvious to you > that there is a logical contradiction in those claims? No, because *everyone* agrees about how the penny is moving with respect to any other object. > How does the > penny change from being at rest in one frame to not being at rest in > another frame, without there being some physical interaction with the > penny to cause that change? Because it *doesn't* change from being "at rest" to "not at rest". There is no "change" at all. Both the man on the plane, and the man on the ground, agree that the penny is stationary relative to the flyer, and moving relative to the man on the ground. The penny does not "change" from being stationary to moving. What changes is the object to which you are making reference. > Penny dropping from the armrest of the plane falls down in a straight > line to the floor of the plane in one reference frame, but in another > reference frame its path is a parabolic arc. Is it not obvious to you > that there is a logical contradiction in those claims? How does the > path change from being in a straight line to a parabolic arc? It doesn't change. Both observers agree that the penny moves in the same way, with respect to any reference object. So for example, the man on the ground agrees that if the penny is dropped in the middle of the plane, then the penny maintains its position relative to each end of the plane (and, obviously, moving closer to the floor). And the man on the plane agrees with this: the penny maintained it's position relative to each end of the plane. There is no contradiction. > You see how easy it is to fool yourself with statements you believe > are contradictory... I'm not fooled Paul.
From: Inertial on 6 Apr 2010 20:34
"Ste" <ste_rose0(a)hotmail.com> wrote in message news:a38d2d91-101b-4c7e-9bcf-f3ac730927d8(a)b33g2000yqc.googlegroups.com... > On 6 Apr, 19:44, PD <thedraperfam...(a)gmail.com> wrote: >> On Apr 5, 10:03 pm, Ste <ste_ro...(a)hotmail.com> wrote: >> >> >> >> > > You still haven't answered why 'fitting' must be absolute >> >> > Because of the obviousness of the concept. A thing cannot fit and at >> > the same time not fit, because there is a logical contradiction in the >> > meaning of those words. And nor can the state be subjective for each >> > observer, otherwise that isn't materialism (and it isn't causal >> > either). Or to repeat my earlier analogy, you can't hit a person over >> > the head with a hammer, and merely daze him *at the same time as* >> > cracking his skull wide open. >> >> This business about a thing fitting and not fitting being a >> contradiction... >> >> A penny on the armrest of a plane is at rest in one reference frame >> and not at rest in another reference frame. Is it not obvious to you >> that there is a logical contradiction in those claims? > > No, because *everyone* agrees about how the penny is moving with > respect to any other object. > > > >> How does the >> penny change from being at rest in one frame to not being at rest in >> another frame, without there being some physical interaction with the >> penny to cause that change? > > Because it *doesn't* change from being "at rest" to "not at rest". > There is no "change" at all. YES !!!! > Both the man on the plane, and the man on > the ground, agree that the penny is stationary relative to the flyer, > and moving relative to the man on the ground. The penny does not > "change" from being stationary to moving. What changes is the object > to which you are making reference. You are fine with the notion of different observers measuring different velocities for a coin, but all agreeing that it is at rest wrt some given observer (the one on the plane). Yet you seem to have problems with the similar situation about the pole 'fitting in a barn'. It only 'fits in the barn' wrt the farm-based observer (for whom the barn is at rest) (just like the coin is at rest only for the plane observer). All observers agree that the farm-based observer will measure the pole as 'fitting in the barn' (just as the ground observer will agree that the coin is at rest wrt the plan observer). Why do you have a stumbling block about poles and barns, but are fine with coins and planes? |