Known physics defeated by simple puzzle?
in [Relativity]
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From: Inertial on 5 Apr 2010 20:13 "Ste" <ste_rose0(a)hotmail.com> wrote in message news:a7d6645c-1261-4fc7-8528-69ff1cb56e33(a)v20g2000yqv.googlegroups.com... > On 5 Apr, 01:38, "Inertial" <relativ...(a)rest.com> wrote: >> "Ste" <ste_ro...(a)hotmail.com> wrote in message >> >> > Incidentally, this book (which was a link from Wikipedia) confirms my >> > statement that GR is how the paradox was apparently resolved (at least >> > by Einstein and a few others): >> >http://books.google.com/books?id=vuTXBPvswOwC&pg=PA165#v=onepage&q=&f... >> >> You CAN use GR .. which is a superset of SR. But SR 'solves' it as well > > As I say, that's not how I understand it, That is your problem. You need to learn. Not flaunt your ignorance. > and the written evidence > elsewhere (for example, in the link I've just provided) suggests that > even Einstein clearly felt that GR was necessary to explain it. But it is NOT necessary. Einstein even gave it as an example in his 1905 paper (though not with actual twins .. with moving clocks) > At the > very least, you can see that I'm subject to contradictory evidence > here, No contrary evidence. > and you can understand why I don't take your statement here at > face value. Do you need links to the many SR solutions to the twins paradox? >> >> > but >> >> > as I understand it, you need GR to account for acceleration (in >> >> > other >> >> > words, it's outside the scope of this discussion). >> >> >> Wrong .. you've had that told to you many times. SR handles >> >> acceleration >> >> just fine >> >> > As I say, the information I have suggests that GR is necessary to >> > account for the (absolute) acceleration, >> >> That is wrong >> >> > whereas SR treats >> > acceleration merely as a change of relative velocity >> >> It is a change in velocity > > Yes, but do you mean a relative change of velocity or (shall we say) > an "absolute" change of velocity? There is no difference > Remember, relative velocity can > change without absolute acceleration. No > Indeed, a bullet that flies past > your ear undergoes a dramatic change of relative velocity to you as it > passes (it approaches and then recedes), No .. it doesn't > but neither you or the bullet > undergo any application of force to cause that relative change of > velocity And there is no change in velocity either Gees. >> > (which may or may >> > not involve "real" acceleration - the kind that would be registered on >> > an accelerometer). >> >> If it is acceleration, it would register on an accelerometer >> >> You are making distinctions where there are none > > No I'm not. Yes .. you are > Clearly relative velocities can change with or without an > application of force No > - as I understand the twins paradox, it is the > application of force to the travelling twin that causes the asymmetry > of aging. It is the change of rest frame that results from the acceleration. You can have the twins paradox with NO acceleration. >> >> >> The ladder really does fit inside the barn. >> >> >> > But then it must fit inside the barn from *all* frames, >> >> >> Why? >> >> > Because "fitting" and "not fitting" are two mutually exclusive states. >> >> You haven't answered the question > > I think I have. I've insisted that the two states are mutually > exclusive, and I've elaborated on it below. You still haven't answered why 'fitting' must be absolute >> >> It doesn't have the same speed in all frames. It doesn't have the >> >> same momentum in all frames. It doesn't have the same kinetic energy >> >> in >> >> all >> >> frames. Why must it have the same length? >> >> > Because the notion of "speed", "energy" and "momentum" are all >> > inherently relative concepts. >> >> As are length and duration > > I don't see how length can be inherently relative (although its > appearance certainly can be, as I illustrated in a previous post). Because it is a frame dependent measurement. It is is your problem if you don't see how frame dependent measurements are frame dependent. >> > If I hit someone over the head with a >> > hammer, then the force applied to the skull depends on the relative >> > speed of the hammer and the skull. But all observers agree about the >> > force of the impact between the hammer and the skull - in other words, >> > I do not crack his skull wide open according to some observers, and >> > merely daze him according to others. >> >> And that is the same in SR .. either something happens or it doesn't > > Indeed, so the ladder either fits or it doesn't! 'fitting' isn't an event. It is a combination of events. All events that happen happen. Different frames give different coordinates and ordering of those events. > You can't say "it > fits according to some observers", Yes you can. Just like you can say a train whistle has different pitches for different observers > because that is absurd Its not .. its physics. It is not physics fault if you find it absurd > as saying > "he was merely dazed according to some observers". That is not equivalent >> > The same is true of this ladder problem. If the ladder contracts, then >> > it will fit in the barn, and if it doesn't contract then it won't fit >> > - but it cannot contract at the same time as not contracting, or fit >> > at the same time as not fitting. >> >> Wrong >> >> > However, it can *appear* to do so by careful timing of the doors and >> > careful placement of the observer, and so naturally I'm saying to >> > myself "this must be what you mean". >> >> No .. it really fits. You really need to understand the scenario before >> drawing conclusions from it > > I do understand the scenario. It is explained by the apparent timing > of the doors. The timing of the doors is PART of the scenario. It states that they shut (briefly) at the same time according to any observer (or observers) at rest wrt the barn. The pole fits between them when they are simultaneously shut >> >> > including the >> >> > rest frame of the ladder. And I know that is not what SR predicts. >> >> >> But you are insisting that only things that are frame independent are >> >> real >> >> (which rules out a large amount of what we measure and work with in >> >> physics). >> >> > No, I'm insisting that observations/changes can have a "real" basis, >> > or an "apparent" basis, at least for the purposes of this argument . >> >> So velocity, momentum etc do not have a real basis, according to your >> logic > > I didn't say that. You said that for anything to be real, it must be the same for all observerse .. so yes .. you did >> > And indeed, a lot of the things you may be working with and measuring >> > in physics are "apparent" and not "real". And I will state the >> > definition of "apparent": "appearing as such but not necessarily so". >> >> So velocity, momentum etc do not have a real basis, according to your >> logic > > I didn't say that. You said that for anything to be real, it must be the same for all observerse .. so yes .. you did >> > So when we talk of "clocks slowing down", we need to be clear about >> > whether we're talking about the clock *appearing* to slow down (but >> > continuing to tick at the normal rate), or whether it is *really* >> > slowed down. (More on this below.) >> >> Depends on what you mean by 'real'. Your usage is problematic, as you >> are >> excluding a wealth of things that are considered 'real' by reasonable >> people >> and physics > > The problem, once again, is that this discussion is degenerating into > a discussion between philosophers who share no common language. Then learn physics before your discuss it >> >> So if you stand on the the highway and a car travelling at 100km/h >> >> runs >> >> into >> >> you, you don't need to worry, because it isn't really travelling fast >> >> (velocity isn't real by your standard), and doesn't really have a >> >> large >> >> amount of momentum and kinetic energy (momentum and kinetic energy >> >> isn't >> >> real by your standard) that it imparts into you and your death isn't >> >> real. >> >> > But I will be apparently dead. ;) >> >> So you die from apparent causes and not real ones. > > No, I was just joking, as indicated by wink and the follow-on > "seriously though"... But the point remains .. these things that are not 'real', according to your defintion, really can kill you. >> > Seriously though, I didn't say velocity was "not real", >> >> Yes .. you did .. when you said something is only real if it is the same >> for >> all observers > > Yes, indeed. And the hammer hits the skull with the same velocity, the > same force, and with the same effect, according to all observers. I > really don't see what is difficult about this. But the velocity of the hammer is different in different frames .. and so, by your definition, is not real >> > but it is a >> > relative concept (that is, it is an interaction of two objects, not a >> > property of one object; and it is still invariant across all frames, >> > in that the car hits the person with the same force, and the same >> > effect, no matter where you look at it from). >> >> Just like a pole fitting in a barn .. that is an interaction of two >> objects > > Well, you can either think of the property of "fitting" as a property > of one object (i.e. the entire ladder and barn setup). And it is, like velocity and momentum and energy etc, a frame-dependent property > Or, you can > think of it as an interaction between two objects that all observers > agree about (and which is not relative, like the skull-cracking > scenario). No .. they do NOT all agree about it, because it is, like velocity and momentum and energy etc, a frame-dependent interaction > There is no room, as it were, in physics to talk about an interaction > between two objects that all observers don't agree on. Of course there is. We deal with frame dependent measurement all the time >> > Also, I'd be interested to return to a discussion >> >> I'm sure you would, as your current postition on 'real' has been shown as >> rather silly. > > Because as I told you, I didn't want to get into a philosopher's > discussion about the precise meaning of the words. Not when it shows your position to be silly. > I wanted to work > with what I see as their common sense and everyday, But its not common sense .. its silly > if slightly vague, > meaning, and actually get some meaningful communication between us. Then don't use silly definition for things. >> > about my "speaking >> > clock" - I had previously said that it ticked loudly, but let's make >> > it even more easy to imagine by saying that it consists of just black >> > box with an audio speaker, and it "speaks" the time out loud every >> > second. Do you not accept that the faster you move away from the >> > speaking clock, the slower the clock appears to go? >> >> That's an audio illusion (or optical if you are reading the time) due to >> delays in signal. >> >> That is NOT what happens in SR when we say clocks are measured as running >> slow. > > Well, do you accept that this is at least *one* of the causes of why a > clock will appear to run slow? That you can ALSO have optical (and audio) illusion does not mean that that is the cause of the SR effect being discussed >> You really need to understand what SR actually says before making >> conclusions about it. > > That's what we're trying to do here. Then you need to listen and think more, and assert less, and avoid attempts at scoring 'points' against those trying to help you understand.
From: Ste on 5 Apr 2010 20:15 On 5 Apr, 22:57, PD <thedraperfam...(a)gmail.com> wrote: > On Apr 5, 4:29 pm, Ste <ste_ro...(a)hotmail.com> wrote: > > > I do not see how this can work, > > unless the clocks themselves fall out of synchronisation (and hence > > are not actually measuring the same periods of time as each other). > > The clocks' synchronization can be (and is) checked both before and > after the operations described above and verified to still hold, so > your supposition of what must have happened is ruled out. Not necessarily. If both slowed in the middle of the operation, then they would still be synchronised with each at the end, but it would utterly confound any calculation about simultaneity, unless you also knew by how much the other clock had slowed and when. To give you an example, if I have two clocks stationary relative to each other and ten light-seconds apart, and I suddenly slow both clocks to half-speed (in other words, ticking once for every two previous ticks), then according to each clock, the other one speeds up to double speed, because for a period of 10 seconds (the time it takes for the change of rate to propagate), there is only one "local" tick for every 2 "received" ticks. If you did a simplistic correction for propagation delays, then according to this model, the other clock will have actually *leaped ahead* in time. Let's use some concrete times. The clocks are 10 light seconds apart, and stationary. We set them both going from 00:00. Obviously this setup is entirely symmetrical, so I'll simply talk about the "local" clock, and the "distant" clock. I use the word "really" to describe what the clock shows for a local observer, and I use the word "apparently" to describe what that clock actually shows for a distant observer. At 00:11 local, the distant clock apparently reads 00:01. We let them go until it's 00:20 local, and apparently 00:10 distant. At that point, I slow them both down (obviously, I'm pretending to play God here, but if you need a specific explanation for how I slow them down, let's just say I programmed their circuitry in advance to both slow down when they displayed 00:20 local). So, with the clocks running at half speed, it is now 00:21 local, and 00:12 distant. By 00:25 local, the distant clock apparently shows 00:20. Reasoning that it takes 10 local seconds for that information to reach us, that means the distant clock "really" reads 00:30. Except it doesn't. The distant clock really reads 00:25, the same as the local clock - they were never out of real synchronisation for even a moment. Now, would you say that this explanation appears to suffice for at least *some* of what is observed in SR? > I want to > emphasize that this is observational reality, even if you are stymied > to explain how it can be, given your presently held concept sets about > how nature works. I think the explanation I've just given in the paragraph above suffices. I'm not stymied by it. I'm just not blown away by it - the effects seem quite straightforward to me, but every time I offer that explanation, posters here say the explanation is inadequate and faulty.
From: paparios on 5 Apr 2010 20:28 On 5 abr, 17:19, "Sue..." <suzysewns...(a)yahoo.com.au> wrote: > On Apr 5, 4:59 pm, "papar...(a)gmail.com" <papar...(a)gmail.com> wrote: > > > > > On 5 abr, 16:47, Ste <ste_ro...(a)hotmail.com> wrote: > > > > On 5 Apr, 17:37, PD <thedraperfam...(a)gmail.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". And I ask "so a > > > person riding the ladder would see the barn expand", and the answer > > > comes back "no, no, the person riding the ladder would see the barn > > > *contract*". So I say, "well clearly in the latter case the ladder > > > cannot possibly fit with both doors shut, so it must be a visual > > > effect". "No, no" comes the reply, "the ladder *really* does fit > > > according to a person standing in the barn, and it *really* doesn't > > > fit according to the person riding the ladder". And I say, "well, it > > > can't do both at once", and the reply that is merely asserted in > > > response is "well, it does!". > > > > And that sums up thousands of words in probably hundreds of posts > > > exchanged between me and a quite a few posters on the ladder and barn > > > paradox. It always comes back to a plain assertion that "this is how > > > it works", but there is no attempt to explain *why*, or any attempt to > > > show how a mere visual explanation would not suffice for some or all > > > of the observed effects. > > > There are plenty of places where this so called "paradox" is > > explained. For instance,http://hyperphysics.phy-astr.gsu.edu/HBASE/Relativ/polebarn.html > > > The relevant part is that the fact that two events are simultaneous in > > one frame of reference does not imply that they are simultaneous as > > seen by an observer moving at a relativistic speed with respect to > > that frame. > > < Einstein's relativity principle states that: > > All inertial frames are totally equivalent > for the performance of all physical experiments. > > In other words, it is impossible to perform a physical > experiment which differentiates in any fundamental sense > between different inertial frames. By definition, Newton's > laws of motion take the same form in all inertial frames. > Einstein generalized this result in his special theory of > relativity by asserting that all laws of physics take the > same form in all inertial frames. >> > > What is simultaneous in one inertial frame > is simultaneous in a relativity moving frame. > > The ad hoc definition you are trying to use > is stated to have no physical significance: > > <<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 > > Now wondering why I bother writing to someone > who has already stated it is a matter of > religion for him, but why waste keystrokes. > send. > > Sue... > You have demonstrated all these years, quite efficiently by the way, that you don't have the slightest idea of what you are talking about. So leave Einstein rest in peace and return to your rotten eggs cooking. We know you cook worst than you talk about physics. Get a life and a wealthy idiot who is willing to support you. Miguel Rios
From: paparios on 5 Apr 2010 20:38 On 5 abr, 19:33, Ste <ste_ro...(a)hotmail.com> wrote: > On 5 Apr, 21:59, "papar...(a)gmail.com" <papar...(a)gmail.com> wrote: > > > > > On 5 abr, 16:47, Ste <ste_ro...(a)hotmail.com> wrote: > > > > On 5 Apr, 17:37, PD <thedraperfam...(a)gmail.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". And I ask "so a > > > person riding the ladder would see the barn expand", and the answer > > > comes back "no, no, the person riding the ladder would see the barn > > > *contract*". So I say, "well clearly in the latter case the ladder > > > cannot possibly fit with both doors shut, so it must be a visual > > > effect". "No, no" comes the reply, "the ladder *really* does fit > > > according to a person standing in the barn, and it *really* doesn't > > > fit according to the person riding the ladder". And I say, "well, it > > > can't do both at once", and the reply that is merely asserted in > > > response is "well, it does!". > > > > And that sums up thousands of words in probably hundreds of posts > > > exchanged between me and a quite a few posters on the ladder and barn > > > paradox. It always comes back to a plain assertion that "this is how > > > it works", but there is no attempt to explain *why*, or any attempt to > > > show how a mere visual explanation would not suffice for some or all > > > of the observed effects. > > > There are plenty of places where this so called "paradox" is > > explained. For instance,http://hyperphysics.phy-astr.gsu.edu/HBASE/Relativ/polebarn.html > > > The relevant part is that the fact that two events are simultaneous in > > one frame of reference does not imply that they are simultaneous as > > seen by an observer moving at a relativistic speed with respect to > > that frame. > > As far as I'm concerned Miguel, I already understand the paradox. Even > the page you reference says quite clearly: > > "From the pole point of view, the front gate closes just as the back > of the pole enters. The surprising result is that the back gate is > seen to close earlier from the pole framework, before the front of the > pole reaches it. The gate closings are not simultaneous, and they > permit the pole to pass through without hitting either gate." > > As it says, the simple explanation is that the gates don't close at > the same time according to the pole, and hence the pole sails straight > through. That is totally correct. It means the paradox is not a paradox at all, since events that are simultaneous on one frame of reference (the barn) are not simultaneous on the other frame of reference (the one of the pole). Piece of cake.... Miguel Rios
From: spudnik on 5 Apr 2010 20:39
Death to the lightcone -- long-live Minkowski!... yeah; and, the photon is *still* dead, no matter what herr Albert said about it! > > <<pseudoscientists rarely revise. The first edition of > > Principia Mathematica, a product of a committee, > > the Royal Society, after "the MS burnt in an alchemical > > process that set the trunk in which it was resting, afire," > > has had several editions, the latter of which take pains > > to omit mention of Robert Hooke. The sole calculus is > > is a rectangle, dxdy, in Book 2, Section 2, Paragraph 2.>> thus: as a student of Bucky Fuller -- an army of one, I say -- you've bit- off more than you should want to chew, with the n-hole spin on fullerenes; and that is my clue, because a fullerene should have a very large manifestation of polarization, not unlike in a game of futbol. I mean, just becaus the ball went through only one slit, why wouldn't it be affected by the total symmetry of the instrumentation?... all of it, down to teh electronics etc. my main thing was, though, that you should at least *try* to consider the theory of light using only waves, which can still be pieced-together from almost any "undergrad" textbook, post-Copenhagen, especially older ones. or, just stick with Einstein's refurbishment of Newton's crappy "theory," nothing of which is needed for relativity & so on. anyway, one simply does not need to analyze a phenomenon by *both* its wavey & bullety aspects -- at the same time; once you have proven a theorem in projective geometry e.g., you do not have to give the "2nd column proof," unless you're just learning it, for the first time! > http://en.wikipedia.org/wiki/Louis_de_Broglie > any moving particle or object had an associated wave." thus: a-ha, I was correct: say "half," with respect to the beamsplitters, please (as I comprehend, they generally split the "photon" into "two photons" of half the energy, I think of a different frequency, not amplitude -- although the "photon" is really more akin to a phonon, such as the audible "click" of the geiger-counter. the *proviso* with these experiments is that the waves are highly modified in the LASER apparatus, so that some folks more easily think of them as "rocks o'light." it could have been worse; lots of more-or-less literate folks use "of" in the place of "have" -- to be or not to be owned, that is this particualr question! > http://en.wikipedia.org/wiki/Delayed_choice_quantum_eraser#The_experi... > Alter the experiment. When the downgraded photon pair are created, > have each photon interact with its own double slit apparatus. Have > detectors at one of the exits for each double slit apparatus. When a > photon is detected at one of the exits, in AD, the photon's aether > wave still exists and is propagating along the path exiting the other > slit. When a photon is not detected at one of the exits, the photon > 'particle' along with its associated aether wave exits the other slit. > Combine the path the aether wave the detected photon is propagating > along with the path of the other photon and its associated aether > wave. An interference pattern will still be created. This shows the > aether wave of a detected photon still exists and is able to create > interference with the aether wave of another photon, altering the > direction the photon 'particle' travels. thus: if you let go of the empty notion of "photon," there isn't any difficulty, at all, with a geometrical picture. Death to the lightcone -- long-live the lightcone-heads (because, Minkowski was only one of them, by haphazard default/death). yes, I know, that *photonics* is a whole field of engineering; thank you, herr doktor-professor E., for unburying Newton's bogus corpuscle and attendant "theory," that Young had successfully popped! thus: on the wayside, if you are really going to set so much store in a two-hole procedure for fullerenes, maybe you shouold read the original article, and try to question its purpose. as it is, I'd guess that English is not your mother-tongue, which can sometimes prove difficult in *using* it; so, that's why I always suggest Shakespeare, becuase *no* one can *begin* to comprehend English, til he *tries* to read the bard. (he also had a hand in translating the KJV of the Bible .-) thus: NB, quaternions are not "quadrays" (for an amateur attempt at homogenous co-ordination), but you can "do" special rel. with them (according to Lanczos .-) thus: The "cap & trade" omnibus bill -- what Waxman-Markey should be known as, being so fundamental to the Stupid, economy -- is at least as old as Waxman's '91 bill to ameliorate acid rain. One must really stop and consider, just who really opposes this "last hurrah" for Wall Street (like- wise, the healthcare bill, also under Waxman's House committee, and which, after all, is geared toward funding a smaller aspect of the S-- the economy, already tremendously leveraged by the "voluntary" cap & trade, which the bill would essentially mandate, a la the much-larger, market- making EU scheme). Not so long ago, there was a guest-editorial in the WSJ, which mentioned that an actual carbon tax would achieve the same thing, more or less, as the total "free" market apporach of cap & trade; oh, but, there're certain, so- called Republicans, who refer to the bill as "cap & tax!" Well, before any "reform" of the financial system, why would one put all of one's eggs into such a casino -- especially considering that the oil companies have not bothered to release the carbon-dating "fingerprints" that they use, to determine whether two wells are connected, underground; so, guys & gals, how old is the stuff, on average, anyway? Surely, the green-niks who lobby for "renewable" energy, do not think that oil comes only from dinosaurs, and their associated flora -- all, from before the asteroid supposedly offed them (I refer them to the recent issue of Nature -- several articles that may be related!) Finally, note that, in a sense, the whole world is going a) nuclear, and b) into space, while we are essentially frozen into '50s and '60s techniques in these crucial frontiers. (While some folks dither about Iran's nuke-weapons policy, they are rapidly achieving a full-scale nuke-e and process-heat capbility for industry & infrastructure.) --yr humble servant, the Voting Rights Act o'65 (deadletter since March 27, 2000, when Supreme Court refuzed appeal in LaRouche v. Fowler ('96)) |