Known physics defeated by simple puzzle?
in [Relativity]
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From: Sue... on 11 Apr 2010 02:11 On Apr 11, 12:12 am, "Peter Webb" <webbfam...(a)DIESPAMDIEoptusnet.com.au> wrote: > "Ste" <ste_ro...(a)hotmail.com> wrote in message > > news:996ae2ac-6e26-46b4-9e71-21242c60c54c(a)30g2000yqi.googlegroups.com... > On 10 Apr, 13:05, "Inertial" <relativ...(a)rest.com> wrote: > > > > > "Ste" <ste_ro...(a)hotmail.com> wrote in message > > >news:db82a4dc-e7c6-4fea-a210-145c805688ef(a)z11g2000yqz.googlegroups.com.... > > > > On 10 Apr, 12:24, "Inertial" <relativ...(a)rest.com> wrote: > > >> "Ste" <ste_ro...(a)hotmail.com> wrote in message > > > >>news:25a765b8-2e31-476f-9935-34014a09438f(a)y17g2000yqd.googlegroups.com... > > > >> > On 10 Apr, 11:20, "Inertial" <relativ...(a)rest.com> wrote: > > >> >> "Ste" <ste_ro...(a)hotmail.com> wrote in message > > > >> >> >> > based on > > >> >> >> > the relative speed between the clocks? (and not based on the > > >> >> >> > direction > > >> >> >> > of relative movement?) > > > >> >> >> Yes. I've already said that. > > > >> >> > So what is the extent of the slowing, and on what variables does > > >> >> > it > > >> >> > depend? (We can speak in quantitative terms on this point.) > > > >> >> It depends on the speed. The greater the speed, the larger the > > >> >> effect > > >> >> (see > > >> >> the gamma factor). That affects the measured clock ticking rate and > > >> >> the > > >> >> measure length of a moving object. There is also the effect on > > >> >> simultaneity. > > > >> >> Its all given by the Lorentz transforms. > > > >> > Indeed. So there is always a slowing, related to speed, no matter > > >> > what > > >> > relative direction the object may be travelling in. > > > >> Yes > > > >> > In other words, if > > >> > an object is approaching you at .9c, it displays a slowing that is > > >> > the > > >> > same as if it were receding at .9c? > > > >> Yes > > > >> If by 'displays' you are not including any optical/visual/etc illusions > > >> due > > >> to propagation delays etc. > > > > Yes, I had assumed we'd accounted for those already, and are > > > disregarding those effects. > > > >> And if by 'slowing' you mean that observers at rest in your frame of > > >> reference would measure its ticking rate as slower. > > > > Ah, I've just realised another question. I was assuming that we're > > > talking about a fixed amount of "lag" in distant clock. Is that what > > > you're talking about, or are you talking about an *ongoing* loss of > > > time? In other words, the longer the distant clock is moving, the more > > > its time lags behind that of the local clock (and, yet, all this lag > > > is recouped when the two clocks return to relative rest). > > > The 'lag', as you call it, is distance and velocity dependent. When there > > is no distance between them and no difference in motion, there is no > > 'lag'. > > Yes, but the important thing (for me) to clarify is that, even if > there is only a negligible distance between them, if there is a > relativistic difference in velocity, then there will still be a fixed > amount of time lag? > > ________________________________ > SR does not impose a fixed "time lag". It says that clocks in different > inertial frames run at different "rates". This has nothing to do with the > relative position, only the relative speed. > > In the twins paradox, the difference in ages when the twin returns could be > considered the "lag". If the travelling twin travels twice as far and > returns, then the difference in ages (the lag) will be twice as much when he > returns. > > These relativistic effects are all functions of relative speed, and relative > position doesn't enter into it. ============== > A ladder travelling close to c will still be > shorter than the barn, whether it is within the barn or 1,000 kms away. This is an ether theory. You know from experience with the longest range forces, that magnets and charged balloons have little effect beyond a few cm. It is a fair technical accomplishment to simply detect a ladder or barn beyond a few metres. The ether is the only thing remaining you could have calculated a speed from. It is a bit optimistic also to think that ladders and barns would express kindness to theorists and experimenters by propping up the emission theory of light by altering their shape when they are measured. Sue...
From: Peter Webb on 11 Apr 2010 02:19 "Timo Nieminen" <timo(a)physics.uq.edu.au> wrote in message news:899a661a-3a01-4ed0-9396-7e18c7eed862(a)11g2000yqr.googlegroups.com... On Apr 11, 5:35 am, Edward Green <spamspamsp...(a)netzero.com> wrote: > On Apr 6, 7:30 pm, Timo Nieminen <t...(a)physics.uq.edu.au> wrote: > > > 3. Can the observer see the Lorentz contraction of the pole? > > Not cleanly. What the observer will see will be the "optical illusion" length, which includes the effect of Lorentz contraction. A full answer to this part would mean finding out whether or not the Lorentz contraction is a visibly significant part of the total effect. Some guess as to visual acuity might be needed. __________________________________________ You can see the Lorentz contraction of the pole "cleanly" by designing your experiment correctly. Have the ladder travelling at exactly the right speed to exactly fit into the barn, so the ends of the ladder exactly line up with the doors at either end. Take your photo when that happens. If you take a photo from the centre of the barn, then the distance from the photographer to the front of the ladder, the back of the ladder, the first barn door and second barn door are all identical and hence the propagation delay is the same for each. So the propagation delay drops out of the equation, and what you photograph reflects exactly what is happening. If the ladder is moving faster than the speed which is required to make it exactly fit into the barn, then the propagation delays from the ends of the ladder will be different to those for the light from the barn door, and would need to be compensated for if you want to know the "real" position when the photo was taken. In other words, by carefully controlling the experimental design so that the front end of the ladder reaches the second barn door at exactly the same time (in the barn's frame) as the back-end reaches the first door, and you take the photo from the centre of the barn, then all propagation delays are identical, and there is no "optical illusion" in the photo.
From: Sue... on 11 Apr 2010 02:32 On Apr 11, 2:19 am, "Peter Webb" <webbfam...(a)DIESPAMDIEoptusnet.com.au> wrote: > "Timo Nieminen" <t...(a)physics.uq.edu.au> wrote in message > > news:899a661a-3a01-4ed0-9396-7e18c7eed862(a)11g2000yqr.googlegroups.com... > On Apr 11, 5:35 am, Edward Green <spamspamsp...(a)netzero.com> wrote: > > > On Apr 6, 7:30 pm, Timo Nieminen <t...(a)physics.uq.edu.au> wrote: > > > > 3. Can the observer see the Lorentz contraction of the pole? > > > Not cleanly. > > What the observer will see will be the "optical illusion" length, > which includes the effect of Lorentz contraction. A full answer to > this part would mean finding out whether or not the Lorentz > contraction is a visibly significant part of the total effect. Some > guess as to visual acuity might be needed. > > __________________________________________ > You can see the Lorentz contraction of the pole "cleanly" by designing your > experiment correctly. Have the ladder travelling at exactly the right speed > to exactly fit into the barn, so the ends of the ladder exactly line up with > the doors at either end. Take your photo when that happens. If you take a > photo from the centre of the barn, then the distance from the photographer > to the front of the ladder, the back of the ladder, the first barn door and > second barn door are all identical and hence the propagation delay is the > same for each. So the propagation delay drops out of the equation, and what > you photograph reflects exactly what is happening. > > If the ladder is moving faster than the speed which is required to make it > exactly fit into the barn, then the propagation delays from the ends of the > ladder will be different to those for the light from the barn door, and > would need to be compensated for if you want to know the "real" position > when the photo was taken. > > In other words, by carefully controlling the experimental design so that the > front end of the ladder reaches the second barn door at exactly the same > time (in the barn's frame) as the back-end reaches the first door, and you > take the photo from the centre of the barn, then all propagation delays are > identical, and there is no "optical illusion" in the photo. Magicians use hoops to expose this sort of thing. Some of us have the opinion that a fast magician will sever the head and foot from the levitated lady if he drops his hoop over her length, regardless of how fast she zips from stage left to stage right. Sue...
From: PD on 11 Apr 2010 14:02 On Apr 10, 11:55 pm, Ste <ste_ro...(a)hotmail.com> wrote: > On 10 Apr, 18:24, PD <thedraperfam...(a)gmail.com> wrote: > > > On Apr 9, 6:52 pm, Ste <ste_ro...(a)hotmail.com> wrote: > > > > > There is always > > > > this loose, hand-waving out: "Maybe we only *think* there are laws of > > > > physics, but there aren't laws at all and we're just given the > > > > appearance that there are," or "I choose to believe that the laws that > > > > you've deduced are all wrong, and that there are some other laws that > > > > are at work instead. I haven't got the foggiest idea what they are, > > > > but they surely will be easier for me to accept than the ones you've > > > > found so far." > > > > Indeed. If the odds of history are anything to go by, it is always > > > best to bet against the truth of any current scientific theory. > > > Thanks, this tells me just about everything I need to know. > > And what does it tell you? > > > > > > > In which case, there is no distinction WHATSOEVER in your mind between > > > > science and religion, or for that matter any belief system including > > > > morals, customs, common opinions, fads and fancies. That is because > > > > there is no such thing as "naturalistic ideology" other than a > > > > completely subjective and capricious assignment on an item by item > > > > basis: "This is natural. This, too, is natural. This, however, is not, > > > > and neither is that over there." And in fact, you can make no > > > > distinction whatsoever between the study of the natural universe and > > > > head-scratching over whether a round belly on a woman is to be > > > > considered beautiful. Since you can make no defensible distinction > > > > between these two, or in fact, any two contentions of any variety > > > > whatsoever, I'm curious why you have an interest in science, other > > > > than as another example of mental diddling. > > > > I'm interested in science because I'm interested in the natural world, > > > Which "natural world" is only demarcated by your arbitrary and > > capricious labels. > > Which is the same arbitrary and capricious labels that everyone else > uses. I disagree that "everyone else" uses these, and I find it astonishing that you would presume to speak for, let alone think like, "everyone else". > As I've said, the only difference is that a minority continue to > insist that somehow science has no ideological content at all. > > For me, there is no useful argument to be had on, for example, whether > unicorns or angels are "natural" or not - the real question is what > sort of ideological framework do they fall into, and invariably you > find that a belief in unicorns and angels is simply ancilliary to an > ideology involving the supernatural, or ancilliary to a belief that > the world does not operate in an understandable, predictable, and > mechanistic way (which really sums up my axioms, my "ideology" in this > respect). > > In fact, the existence of unicorns would not be incompatible with my > general outlook at all. Even angels would not be, as long as they > existed within naturalistic principles of cause and effect, and some > plausible mechanism was posited for firstly how their influence > manifests and secondly for why they have any interaction at all with > humanity (or any concern for humanity). > > But once you scratch the surface, you often find that the explanations > to these questions are sorely lacking, and that there is in fact not a > great deal of concern with how it may be explained on the part of > those who posit the existence of unicorns and angels. Indeed, when you > ask where the idea even came from in the first place, the answer is > rarely (if ever!) "from personal hypothesis", "from inference", or > "from observation", but "from religious authority". Such proponents > also tend to have a general worldview that is informed entirely by > their imaginations or naive beliefs, ....such as temporally ordered cause and effect between strictly material agents... > and show a total unfamiliarity > with history, science, politics, psychology, economics, or any > systematic body of human knowledge that might offer any counter to the > mere spoken word of their priest or other religious figures, or which > may put a different slant on their beliefs. In other words, they are ignorant, uneducated, and cowing to authority. > > Indeed, for me, I also take the view that it will often be futile to > attack ideology using mere logic. Most people hold an ideology because > in some way or another because it has a concrete function for them, ....such as temporally ordered causality between strictly material agents... > never because it is wholly logical. The answer to a stubborn ideologue > is not to try and convince him otherwise, but instead to rob him of > the support of others who can be convinced otherwise (if indeed you > can rob him of his support and offer people a better ideology that is > more functional for them). > > As long as people are familiar with the conflicting ideologies of > science and religion, then it is fairly certain that most people will > continue to support science as long as science continues to deliver > the goods. For science to become overly concerned with an appearance > of objectivity, or to try too hard to repress religion, will in fact > be damaging for science - and may in fact be a reflection of the fact > that science is delivering certain answers that scientists, and their > paymasters, don't want to hear (because it conflicts with the tenents > of the prevailing political ideology, in which the scientists often > have a personal vested interest).
From: paparios on 11 Apr 2010 15:16
On 11 abr, 00:55, Ste <ste_ro...(a)hotmail.com> wrote: > On 10 Apr, 18:24, PD <thedraperfam...(a)gmail.com> wrote: > > > > I'm interested in science because I'm interested in the natural world, > > > Which "natural world" is only demarcated by your arbitrary and > > capricious labels. > > Which is the same arbitrary and capricious labels that everyone else > uses. As I've said, the only difference is that a minority continue to > insist that somehow science has no ideological content at all. > > For me, there is no useful argument to be had on, for example, whether > unicorns or angels are "natural" or not - the real question is what > sort of ideological framework do they fall into, and invariably you > find that a belief in unicorns and angels is simply ancilliary to an > ideology involving the supernatural, or ancilliary to a belief that > the world does not operate in an understandable, predictable, and > mechanistic way (which really sums up my axioms, my "ideology" in this > respect). > > In fact, the existence of unicorns would not be incompatible with my > general outlook at all. Even angels would not be, as long as they > existed within naturalistic principles of cause and effect, and some > plausible mechanism was posited for firstly how their influence > manifests and secondly for why they have any interaction at all with > humanity (or any concern for humanity). > > But once you scratch the surface, you often find that the explanations > to these questions are sorely lacking, and that there is in fact not a > great deal of concern with how it may be explained on the part of > those who posit the existence of unicorns and angels. Indeed, when you > ask where the idea even came from in the first place, the answer is > rarely (if ever!) "from personal hypothesis", "from inference", or > "from observation", but "from religious authority". Such proponents > also tend to have a general worldview that is informed entirely by > their imaginations or naive beliefs, and show a total unfamiliarity > with history, science, politics, psychology, economics, or any > systematic body of human knowledge that might offer any counter to the > mere spoken word of their priest or other religious figures, or which > may put a different slant on their beliefs. > > Indeed, for me, I also take the view that it will often be futile to > attack ideology using mere logic. Most people hold an ideology because > in some way or another because it has a concrete function for them, > never because it is wholly logical. The answer to a stubborn ideologue > is not to try and convince him otherwise, but instead to rob him of > the support of others who can be convinced otherwise (if indeed you > can rob him of his support and offer people a better ideology that is > more functional for them). > > As long as people are familiar with the conflicting ideologies of > science and religion, then it is fairly certain that most people will > continue to support science as long as science continues to deliver > the goods. For science to become overly concerned with an appearance > of objectivity, or to try too hard to repress religion, will in fact > be damaging for science - and may in fact be a reflection of the fact > that science is delivering certain answers that scientists, and their > paymasters, don't want to hear (because it conflicts with the tenents > of the prevailing political ideology, in which the scientists often > have a personal vested interest). All these thoughts of yours are so typical of a person which knows very little of how science works or is performed. It reminds me when a physicist went to my high school, several years ago, and told us that he was at one airport where he was questioned about his job. He answered "I'm a physicist" and the guy at the airport told him "so, you do physical therapy?". I have been into a university system for over 40 years now and can assure you none of your rantings have anything to do with how science is performed. Most of scientists do their research "just for the fun of it", meaning they love to explore Nature and discover its secrets. In doing so, their only required law is to follow the scientific method and produce replicable results. It also requires of them to always question the current "state of the art" and in so doing discover gaps or domains of applicability, where some improvement on the current knowledge is necessary. In many fields, such as mathematics, this game frequently results in new algorithms and theorems whose applicability are near to nil, and they will continue like that for several years or centuries (like Fermat's last theorem). And then, some of those discovered relations are re-discovered and put into work in un-expected ways. Look, for instance, Gallager's LDPC coding, which for over 30 years was sleeping in a shelve until somebody found them to be what the next generation of data communications just needed. Why you have got to think you can discuss (even in this crappy forum), without any knowledge of even simple mathematics, and very little knowledge about basic physics, theories like Special Relativity is not even funny....it is just pathetic!!! Miguel Rios |