A puzzle for the SRians
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From: kenseto on 27 Jul 2010 09:50 On Jul 26, 5:57 pm, PD <thedraperfam...(a)gmail.com> wrote: > On Jul 26, 4:12 pm, kenseto <kens...(a)erinet.com> wrote: > > > Einstein's train gedanken is modified as follows: > > When M and M' are coincide with each other......two lightning strikes > > hits the ends of the train and the light fronts arrive at M' non- > > simultaneously. > > Question for the SRians: does this mean that according to the SR > > concept of relativity of simultaneity M will see the light fronts > > arrive at him simultaneously? > > Not necessarily. It depends on the speed of the train. > > But for a given pair of lightning strikes, there will be at least ONE > reference frame with an observer M" for whom the light fronts arrive > simultaneously. But there are infinite nmuber pairs of light fronts that arrive at M and M' non-simultaneously. That means that M and M' agree with each other on all non-simutlaneity events. That seem to violate the basic tenet of relativity of simultaneity. Your assertion that there is one pair of light fronts that will arrive at M" simutltaneously is irrelevant....why? because M" is not at the middle of the train. It is true that there is one pair of light fronts out of the infinite pairs of light fronts that will arrive at M' simultaneously but that pair of light fronts will also arrive at M simultaneously....why? Because the speed of light is independent of the motion of the ends of the train. A fourth grader can understand that and yet you call yourself a physics professor. <shrug> Ken Seto. > > It will also be possible to find a pair of lightning strikes such that > they arrive at M' non-simultaneously and at M simultaneously. Just > maybe not the pair you're talking about. > > > Since there are an infinite number of pairs of strikes that can cause > > the light fronts to arrive at M' non-simultaneously, does that means > > that there are infinite pairs of strikes that M will see their light > > fronts to arrive at him simultaneously????? > > No. Just one pair. > > Idiot. > > Ineducable idiot. > > Shamelessly self-immolating, ineducable idiot. > > > > > Ken Seto > > In case you thought you had some brilliant insight here, Ken, no. You > are asking a 6th grade question.
From: Hayek on 27 Jul 2010 10:04 whoever wrote: > "Hayek" wrote in message news:4c4ebce5$0$22935$e4fe514c(a)news.xs4all.nl... >> >> Inertial wrote: >> >>> Anyway .. none of that has much to do with the answer >>> to Ken's re-statement of the same old train gedanken >>> that has been dealt with by SR for almost a century. >>> >> I find a lot of flaws in these "gedanken". For instance, >> Einstein assumes that the event only takes place if you >> see the lightflash of the event in your frame of reference. > > Wrong > >> Light to me, is only an imperfect carrier of >> information, just as sound is. > > Yes it is. Among other things > >> With instantaneous communication, > > No need. And by SR not possible > >> and a correct >> definition of time, > > We have one Ok, time is what you read on a clock. Then, what is a clock ? >> and there is no such thing anymore >> as relativity of simultaneity. > > So if you make up a different theory, then you don't get it It is not about "getting" it, it is abput expaining "it". > .. but does > that theory actually work in reality? Of course, it just explains things differently. In the expectation to make further progress, to enlarge the understanding. >> Then again, I do not agree with the block universe, and >> accept the fact that the Now is the same everywhere in >> the universe. Just the clocks, just measuring inertia, >> measure higher or lower inertia, as an inertiameter >> should do. > > Clocks don't measure inertial .. they measure (or mark) time. Then, what is time ? To me, time emerges from motion. And motion is influenced by inertia. If the inertia is higher then the quartz in your clock moves slower. You do not notice it, but because at 37 centigrade body temperature, the molecules in your body also move slower. I claim that the only difference between inertial frames with different gamma is the strength of the inertia. This cannot be measured locally, since inertia influences all of physics. You have to look at a different frame with different inertia, to see the difference. Inertial field strength becomes the external variable, since all of local physics obeys it, so that locally, everything remains the same. You call it "time" which you do not define, I call it inertia, or inertial field strength and say that a clock just measures this inertia. This inertia slows down the motion of every object in a frame, and this seems to make your "time" "run" slower. But in my idea "time" just emerges from motion. So slower motion, slower "time". This explains GR, not just applies it. The effects all remain the same. Do you have another explanation ? > You can > use that to calculate other things > >> Look at the illustations under "block time" >> http://www.ipod.org.uk/reality/reality_mysterious_flow.asp >> >> I adhere to the "conventional view", were only the >> present is real. > > That's your opinion. It doesn't make it fact, of course. > >> For me, it is odd calling this "conventional" since I >> was raised with the "block universe" being omnipresent >> in everything I read and saw. Since about the end of >> 1999, I came to reject this block universe. > > Up to you, but unless you have good scientific ground, its just an > unsupported opinion I have. >> Is it possible to have RoS in the conventional view, >> according to you ? > > RoS doesn't mean a block universe. That was not the question. > Effect still follows cause. It > doesn't alter the notion of every point in the universe having a present > past and future That is not the conventional view, but rather the block universe. Uwe Hayek. -- We are fast approaching the stage of the ultimate inversion : the stage where the government is free to do anything it pleases, while the citizens may act only by permission; which is the stage of the darkest periods of human history. -- Ayn Rand I predict future happiness for Americans if they can prevent the government from wasting the labors of the people under the pretense of taking care of them. -- Thomas Jefferson. Socialism is a philosophy of failure, the creed of ignorance, and the gospel of envy, its inherent virtue is the equal sharing of misery. -- Winston Churchill.
From: PD on 27 Jul 2010 10:09 On Jul 27, 8:50 am, kenseto <kens...(a)erinet.com> wrote: > On Jul 26, 5:57 pm, PD <thedraperfam...(a)gmail.com> wrote: > > > On Jul 26, 4:12 pm, kenseto <kens...(a)erinet.com> wrote: > > > > Einstein's train gedanken is modified as follows: > > > When M and M' are coincide with each other......two lightning strikes > > > hits the ends of the train and the light fronts arrive at M' non- > > > simultaneously. > > > Question for the SRians: does this mean that according to the SR > > > concept of relativity of simultaneity M will see the light fronts > > > arrive at him simultaneously? > > > Not necessarily. It depends on the speed of the train. > > > But for a given pair of lightning strikes, there will be at least ONE > > reference frame with an observer M" for whom the light fronts arrive > > simultaneously. > > But there are infinite nmuber pairs of light fronts that arrive at M > and M' non-simultaneously. Not for a given pair of lightning strikes there aren't. > That means that M and M' agree with each > other on all non-simutlaneity events. What? No. You mean that for some pairs of strikes M and M' will both say the strikes are nonsimultaneous? Yes, that's true, but the two observers will say there is a different amount of time between them. So the "agreement" is pretty shallow. > That seem to violate the basic > tenet of relativity of simultaneity. I don't know what you think the basic tenet of relativity of simultaneity is. Did you think that the basic tenet of relativity of simultaneity is that if one observer says two events are non-simultaneous, then another observer will say they are simultaneous? If that's what you thought it said, you're wrong. It doesn't say that at all. > > Your assertion that there is one pair of light fronts that will arrive > at M" simutltaneously is irrelevant....why? because M" is not at the > middle of the train. Yes, it is. > > It is true that there is one pair of light fronts out of the infinite > pairs of light fronts that will arrive at M' simultaneously but that > pair of light fronts will also arrive at M simultaneously....why? > Because the speed of light is independent of the motion of the ends of > the train. > A fourth grader can understand that and yet you call yourself a > physics professor. <shrug> > > Ken Seto. > > > > > > > It will also be possible to find a pair of lightning strikes such that > > they arrive at M' non-simultaneously and at M simultaneously. Just > > maybe not the pair you're talking about. > > > > Since there are an infinite number of pairs of strikes that can cause > > > the light fronts to arrive at M' non-simultaneously, does that means > > > that there are infinite pairs of strikes that M will see their light > > > fronts to arrive at him simultaneously????? > > > No. Just one pair. > > > Idiot. > > > Ineducable idiot. > > > Shamelessly self-immolating, ineducable idiot. > > > > Ken Seto > > > In case you thought you had some brilliant insight here, Ken, no. You > > are asking a 6th grade question.- Hide quoted text - > > - Show quoted text -
From: Hayek on 27 Jul 2010 10:25 Daryl McCullough wrote: > Hayek says... > >> I find a lot of flaws in these "gedanken". For instance, >> Einstein assumes that the event only takes place if you >> see the lightflash of the event in your frame of reference. > > He makes no such assumption. > >> Light to me, is only an imperfect carrier of >> information, just as sound is. >> >> With instantaneous communication, and a correct >> definition of time, and there is no such thing anymore >> as relativity of simultaneity. > > That's exactly right. Relativity of simultaneity is > a consequence of there being an upper bound to communication > speed. If there is no upper bound, then relativity is wrong. Brilliant remark. But suppose that someone finds a way to send instantaneous messages, by means of Quantum effects. This is not even far fetched, as the Aspect experiment, now even some 10 miles apart, indicate that entangled photons seem to send information about their polarization across that distance. But let's not start that discussion again. Suppose we have instant messaging, what about relativity would be wrong ? Time would still dilate, rods shrink, and even RoS would still apply if you only used light as communication. Ok, mutual time dilation would have to go, but that was not of much use anyway, SR would look more like LET, but what was the difference anyway ? For one there was no absolute reference, and for the other it was not measurable. And since instant messaging would be a non-local phenomenon, it would still hold true that the laws of physics remain locally the same. It would be just "a next step" for physics, all the old physics remaining correct, just in some cases some blanks were filled in, just as Einstein replaced Newton. And then you could also usenet-chat with alien morons, or were we doing that already ? Uwe Hayek. -- We are fast approaching the stage of the ultimate inversion : the stage where the government is free to do anything it pleases, while the citizens may act only by permission; which is the stage of the darkest periods of human history. -- Ayn Rand I predict future happiness for Americans if they can prevent the government from wasting the labors of the people under the pretense of taking care of them. -- Thomas Jefferson. Socialism is a philosophy of failure, the creed of ignorance, and the gospel of envy, its inherent virtue is the equal sharing of misery. -- Winston Churchill.
From: Hayek on 27 Jul 2010 10:37
PD wrote: > On Jul 27, 6:02 am, Hayek <haye...(a)nospam.xs4all.nl> wrote: > >> With instantaneous communication, and a correct >> definition of time, and there is no such thing anymore >> as relativity of simultaneity. >> > > I don't know why a definition of time would be more correct Any definition of time will be welcome. Then we can argue the pros and cons. > if you > presuppose a phenomenon that is specifically and unilaterally excluded > in our universe. Hold your horses. Are you certain this does not happen under uncertainty ? > It might be conceptually appealing to you, but it > wouldn't have any bearing on time AS IT APPLIES in nature as we > observe it. I beg to differ. Look at what questions the FQxi (http://www.fqxi.org) has put forward in order to obtain a grant : 1 Can physics establish or deny the flow of time? 2 If the flow of time is an illusion, how do we explain this illusion? 3 Are the laws of physics time-symmetric or time-reversible? 3 If not, how does one explain the time symmetry of some physical laws and the asymmetry of others? 4What do the theory of relativity and quantum mechanics (QM) respectively tell us about the nature of time and time travel? 5 How do we reconcile their see-mingly inconsistent conceptions of time? 6 Is the nature of time intrinsically different from that of space? 7 Can physical time be infinite? 8 Is the universe a static “block” universe? 9 Does the big bang (at least partially) explain the entropic arrow of time? 10 Is the nature of time intrinsically different from that of space? 11 Why? 12 Are there many space-time branches or timelines in addition to our own? 13 Do these theories provide us with inconsistent con-ceptions of time? 14 If we could experimentally confirm or discard any of the key specific interpretations of QM or classes of interpretation (such as collapse accounts), would we gain insight on the problems of time? 15 Can QM explain the beginning of time? 16 Is space-time itself quantized? If so, what does it mean? 17 Can we, by way of experiments employing different reference frames, experimentally confirm the existence of anything such as the need for preferred foliations, inconsistent histories, advanced action, evolving spacetime, etc., that argues against the block-universe interpretation of relativity theory? 18 Does non-locality in QM give us good reason to modify relativity? 19 Are there new QM experiments (thought or otherwise) involving weak values, pre- and post- selection, etc., that bear on the problems of time? For example, are there such experiments that are best interpreted as requiring “BCQM” or advanced action? 20 Are there any specific accounts of time-symmetric quantum mechanics, such as truly new time-symmetric dynamics, that bear on the problems at hand, suggest new predic-tions, etc.? 21 Is the Everett-Wallace-Saunders interpretation of QM truly local and consistent with “M4” and “blockworld”? 22 If so, how does this or any other view which takes the wave function as fundamental (such as GRW) recover M4 and relativity? 23 How many spatial dimensions are there? Can this question be resolved empirically or experimentally? 24 Can there be more than one temporal dimension? 25 Is the Tumulka-GRW interpretation truly covariant, and can it be extended to cases with interactions? 26 Does Bohmian mechanics require a preferred frame, and if so does that undermine the Bohmian interpretation of QM or special relativity? 27 How can time be recovered from the timeless Wheeler-Dewitt equation? Must we modify the equation? Or replace it altogether? UNQUOTE Uwe Hayek. -- We are fast approaching the stage of the ultimate inversion : the stage where the government is free to do anything it pleases, while the citizens may act only by permission; which is the stage of the darkest periods of human history. -- Ayn Rand I predict future happiness for Americans if they can prevent the government from wasting the labors of the people under the pretense of taking care of them. -- Thomas Jefferson. Socialism is a philosophy of failure, the creed of ignorance, and the gospel of envy, its inherent virtue is the equal sharing of misery. -- Winston Churchill. |