Known physics defeated by simple puzzle?
in [Relativity]
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From: Sue... on 4 Apr 2010 10:49 On Apr 4, 10:28 am, "Peter Webb" > > or whether the relativistic speeds cause a sort of > > lensing effect (i.e. like putting a prism in front of one's eyes, the > > "contraction" affects only the person with the prism in front of their > > eyes) that makes everything *appear* contracted, but there is actually > > no measurable change at all in the rest of the universe. ================== > > No, its not an optical illusion, for the 8 billionth time. > > The travelling twin really is younger. > > The ladder really does fit inside the barn. In spite of recent cautions not to appeal to authority, I think you will find some important contributors to Einstein's relativity are diametrically opposed to you view. << Application of Noether's theorem allows physicists to gain powerful insights into any general theory in physics, by just analyzing the various transformations that would make the form of the laws involved invariant. For example: * the invariance of physical systems with respect to spatial translation (in other words, that the laws of physics do not vary with locations in space) gives the law of conservation of linear momentum; * invariance with respect to rotation gives the law of conservation of angular momentum; * invariance with respect to time translation gives the well-known law of conservation of energy >> http://en.wikipedia.org/wiki/Noether%27s_theorem#Applications Nina Byers (1998) "E. Noether's Discovery of the Deep Connection Between Symmetries and Conservation Laws." http://arxiv.org/abs/physics/9807044 Sue...
From: Ste on 4 Apr 2010 12:59 On 4 Apr, 15:14, "Inertial" <relativ...(a)rest.com> wrote: > "Ste" <ste_ro...(a)hotmail.com> wrote in message > > news:265c67a2-6691-4173-be60-e9e93373bf3d(a)30g2000yqi.googlegroups.com... > > > > > > > On 4 Apr, 14:15, "Peter Webb" <webbfam...(a)DIESPAMDIEoptusnet.com.au> > > wrote: > >> "Ste" <ste_ro...(a)hotmail.com> wrote in message > > >>news:9b9f09c2-c45f-4169-9aa6-ba7a107de57f(a)k19g2000yqn.googlegroups.com.... > > >> > On 4 Apr, 12:38, "Inertial" <relativ...(a)rest.com> wrote: > >> >> "Ste" <ste_ro...(a)hotmail.com> wrote in message > > >> >> > I give three people a photographic > >> >> > filter each, all different colours, and they hold it front of their > >> >> > eyes. I ask them to look at the sky, and they each comment that the > >> >> > sky has changed colour. I now ask them "has the sky really changed > >> >> > colour?". Now how would you interpret my question, and how would you > >> >> > answer that question? > > >> >> The light reaching them has different colors, because certain > >> >> frequencies > >> >> are filtered out. > > >> > So when I ask "has the *sky* changed colour?" you will say "no"? > > >> Just sticking my 2 cents worth in here. > > >> I'm not sure I understand what you mean by the term "the colour of the > >> sky" > >> in this context. You seem to want it to mean two different things. > > >> If you define it to mean the colour seen by an observer looking through > >> filters, then the colour does change. > > >> If you define it to mean the colour seen by an observer not looking > >> through > >> filters, then the colour doesn't change. > > >> So when you say "the colour of the sky", how are you defining this term > >> in > >> the context of this experiment? > > > The question of what I mean by the "colour of the sky" is not actually > > that important - it can be given its everyday meaning. The real > > question is about the cause of the change, and *what* is changed. > > Placing a filter in front of one's eyes clearly doesn't cause any > > measurable change in the colour of the sky (if it did, everybody would > > be able to see the sky turn red when just one person in the whole > > world put a red filter over their eyes). > > > And of course, the real question behind this is about "length > > contraction". I'm trying to get an idea of whether length contraction > > is real (i.e. the sky has turned red for everyone - the whole universe > > has contracted), or whether the relativistic speeds cause a sort of > > lensing effect (i.e. like putting a prism in front of one's eyes, the > > "contraction" affects only the person with the prism in front of their > > eyes) that makes everything *appear* contracted, but there is actually > > no measurable change at all in the rest of the universe. > > You seem to think that something can only be real if it is the same for > everyone .. so the pitch of a train whistle is not 'real', the velocity that > an object travels at is not 'real' etc etc. By your definition, very little > that we measure in physics is 'real'. > > I think your problem here is what you mean by 'real'. I'll avoid making a wisecrack here, but I've explained what I mean by real, and everyone seemed to agree that the spaceship on the monitor was not "really" in the sky. That is the essence of what I mean by "real" (and, conversely, what I mean by "apparent").
From: Ste on 4 Apr 2010 13:17 On 4 Apr, 15:28, "Peter Webb" <webbfam...(a)DIESPAMDIEoptusnet.com.au> wrote: > "Ste" <ste_ro...(a)hotmail.com> wrote in message > > news:265c67a2-6691-4173-be60-e9e93373bf3d(a)30g2000yqi.googlegroups.com... > > > > > > > On 4 Apr, 14:15, "Peter Webb" <webbfam...(a)DIESPAMDIEoptusnet.com.au> > > wrote: > >> "Ste" <ste_ro...(a)hotmail.com> wrote in message > > >>news:9b9f09c2-c45f-4169-9aa6-ba7a107de57f(a)k19g2000yqn.googlegroups.com... > > >> > On 4 Apr, 12:38, "Inertial" <relativ...(a)rest.com> wrote: > >> >> "Ste" <ste_ro...(a)hotmail.com> wrote in message > > >> >> > I give three people a photographic > >> >> > filter each, all different colours, and they hold it front of their > >> >> > eyes. I ask them to look at the sky, and they each comment that the > >> >> > sky has changed colour. I now ask them "has the sky really changed > >> >> > colour?". Now how would you interpret my question, and how would you > >> >> > answer that question? > > >> >> The light reaching them has different colors, because certain > >> >> frequencies > >> >> are filtered out. > > >> > So when I ask "has the *sky* changed colour?" you will say "no"? > > >> Just sticking my 2 cents worth in here. > > >> I'm not sure I understand what you mean by the term "the colour of the > >> sky" > >> in this context. You seem to want it to mean two different things. > > >> If you define it to mean the colour seen by an observer looking through > >> filters, then the colour does change. > > >> If you define it to mean the colour seen by an observer not looking > >> through > >> filters, then the colour doesn't change. > > >> So when you say "the colour of the sky", how are you defining this term > >> in > >> the context of this experiment? > > > The question of what I mean by the "colour of the sky" is not actually > > that important - it can be given its everyday meaning. The real > > question is about the cause of the change, and *what* is changed. > > Placing a filter in front of one's eyes clearly doesn't cause any > > measurable change in the colour of the sky > > If by "measurable change in the colour of the sky", you mean the colour > measureed by people not wearing glasses, then yes. No, what I mean is that there is some inherent attribute to the sky (it's "colour"), and that attribute is not changed by the placing of a filter between the eye and the sky. In other words, nothing happens to the sky (as a concrete object in the external world) when you put a filter in front of your eyes. > > (if it did, everybody would > > be able to see the sky turn red when just one person in the whole > > world put a red filter over their eyes). > > > And of course, the real question behind this is about "length > > contraction". I'm trying to get an idea of whether length contraction > > is real (i.e. the sky has turned red for everyone - the whole universe > > has contracted), > > No, "real" is not the same as "is observed the same by everyone" I didn't say it was. The essence of "real" is about describing the fundamental attributes of some object (in this case, "the colour of the sky"). My intention is not to argue all day about what I mean by "the sky" or "the colour". I think there is already a sufficient common understanding between us in respect of what I mean when I refer to "the sky" and "its colour", and if you are a materialist as you claim to be then this shouldn't be a problem. > If you choose to interpret as "real" only those things which are observed > the same by everyone, then "lengths" are not "real". And nor are sound > frequencies; as they depend on the speed of the observer. And nor for that > matter is the colour of the sky real, because different observers see it > differently (depending on whether they are looking through filters). No, what is "real" has *nothing to do* with observation. That's the essence of materialism versus idealism, as regards this question. Materialists hold that there is an external world, that has a concrete existence with form, properties, and attributes, that are totally independent of observation and independent of any observer. That is why we say the spaceship on the monitor is not "real", because we know that the "sky" (as an object depicted on the monitor) does not *really* contain a spaceship. And yet, it *appears* that there is a spaceship in the sky, so we say it is *apparent*. > > or whether the relativistic speeds cause a sort of > > lensing effect (i.e. like putting a prism in front of one's eyes, the > > "contraction" affects only the person with the prism in front of their > > eyes) that makes everything *appear* contracted, but there is actually > > no measurable change at all in the rest of the universe. > > No, its not an optical illusion, for the 8 billionth time. > > The travelling twin really is younger. We agreed last time that if the two twins both go into space, in opposite directions, and then return, then they remain the same age as each other (technically, they both end up younger by the same amount, than a person who stayed on Earth). This is due to acceleration, but as I understand it, you need GR to account for acceleration (in other words, it's outside the scope of this discussion). > The ladder really does fit inside the barn. But then it must fit inside the barn from *all* frames, including the rest frame of the ladder. And I know that is not what SR predicts.
From: Ste on 4 Apr 2010 13:36 On 4 Apr, 15:35, "Sue..." <suzysewns...(a)yahoo.com.au> wrote: > On Apr 4, 10:00 am, Ste <ste_ro...(a)hotmail.com> wrote: > =========== > > > > > That is the whole point here. Simultaneity is a function of the > > reference frame, because simultaneity is also a function of your > > actual position relative to the events being measured. Sound waves > > also have a "relativity of simultaneity", that works in exactly the > > same way as SR. > > <<There is only one demand to be made of the > definition of simultaneity, namely, that in > every real case it must supply us with an > empirical decision as to whether or not the > conception that has to be defined is fulfilled. > That my definition satisfies this demand is > indisputable. That light requires the same time > to traverse the path A > M as for the path B > M > is in reality neither a supposition nor a hypothesis > about the physical nature of light, but a stipulation > which I can make of my own freewill in order > to arrive at a definition of simultaneity.>>http://www.bartleby.com/173/8.html > > Stipulations and freewill definitions sounds > a bit like something that humans rather than > electrical charges would enjoy doing. > > Nevertheless, H. Minkowski found a way > to formalise them. > > http://www.bartleby.com/173/17.html > > So you have endless fodder for debate about what is > real and imaginary 'till you learn enough GR to > manage the concepts formally. > > Sue... As I've said before, the easiest definition of "simultaneous events" is "those events which would have occurred at the same time if information about their occurrance had travelled instantaneously across space". This is basically the common sense definition that people use anyway. If I sit with family at 7 o'clock the evening and I ask "what time did you have breakfast this morning", I'm not interested in when the information is actually conveyed to me (i.e. long after breakfast time). That is, I would not expect to be told "I've just had breakfast", and when I query this I would not expect to be told that "I had breakfast 5 seconds ago, when information of its occurence first reached your ears". What I would expect to be told, when I ask "when did you have breakfast", is "I had breakfast at 9 o'clock this morning". The problem with this nonsense definition of simultaneity that the physics community seem to be using is that nothing is held to have ever happened until you actually measure it, and because it takes time for information to travel, that means not everyone necesarily measures the same event at the same time. And according to this definition of simultaneity, the family member above had breakfast at 7pm in the evening, because it took until 7pm for the information to reach me!
From: Sue... on 4 Apr 2010 17:49
On Apr 4, 1:36 pm, Ste <ste_ro...(a)hotmail.com> wrote: > On 4 Apr, 15:35, "Sue..." <suzysewns...(a)yahoo.com.au> wrote: > > > > > On Apr 4, 10:00 am, Ste <ste_ro...(a)hotmail.com> wrote: > > =========== > > > > That is the whole point here. Simultaneity is a function of the > > > reference frame, because simultaneity is also a function of your > > > actual position relative to the events being measured. Sound waves > > > also have a "relativity of simultaneity", that works in exactly the > > > same way as SR. > > > <<There is only one demand to be made of the > > definition of simultaneity, namely, that in > > every real case it must supply us with an > > empirical decision as to whether or not the > > conception that has to be defined is fulfilled. > > That my definition satisfies this demand is > > indisputable. That light requires the same time > > to traverse the path A > M as for the path B > M > > is in reality neither a supposition nor a hypothesis > > about the physical nature of light, but a stipulation > > which I can make of my own freewill in order > > to arrive at a definition of simultaneity.>> http://www.bartleby.com/173/8.html > > > Stipulations and freewill definitions sounds > > a bit like something that humans rather than > > electrical charges would enjoy doing. > > > Nevertheless, H. Minkowski found a way > > to formalise them. > http://www.bartleby.com/173/17.html > > > So you have endless fodder for debate about what is > > real and imaginary 'till you learn enough GR to > > manage the concepts formally. > > > Sue... > > As I've said before, the easiest definition of "simultaneous events" > is "those events which would have occurred at the same time if > information about their occurrance had travelled instantaneously > across space". This is basically the common sense definition that > people use anyway. That is not too far from Einstein's definition but it is of little consequence. He declared the right to define to suit his own purpose. He succeeds by hiding Newton's light-corpuscle on an imaginary axis. No crime in that. The apparent-power of a big industrial mill lives on an imaginary axis but its real component can be seen on the capacitor banks outside, near the step-down transformers. Some eagle-eyed EE will probably criticise me for calling the capacitors real but a 90 rotation of the coordinate system, fixes it by swapping reals with imaginaries. > > If I sit with family at 7 o'clock the evening and I ask "what time did > you have breakfast this morning", I'm not interested in when the > information is actually conveyed to me (i.e. long after breakfast > time). That is, I would not expect to be told "I've just had > breakfast", and when I query this I would not expect to be told that > "I had breakfast 5 seconds ago, when information of its occurence > first reached your ears". > > What I would expect to be told, when I ask "when did you have > breakfast", is "I had breakfast at 9 o'clock this morning". > > The problem with this nonsense definition of simultaneity that the > physics community seem to be using is that nothing is held to have > ever happened until you actually measure it, and because it takes time > for information to travel, that means not everyone necesarily measures > the same event at the same time. And according to this definition of > simultaneity, the family member above had breakfast at 7pm in the > evening, because it took until 7pm for the information to reach me! A.Einstein: "That my definition satisfies this demand is indisputable." The author doesn't sound like he is amenable to using other peoples' definition but if want to dig him up and present your case be my guest. :-)) He put it on a complex system so if you don't like if just learn some complex numbers and you can rotate it out of sight and out of mind. (loosely speaking of course. Power factor capacitors and the finite speed of light are both quite real) Sue... |