A constant speed of light in all reference frames? Surely you can't be serious.
in [Relativity]
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From: Bruce Richmond on 10 Mar 2010 20:12 On Mar 10, 10:50 am, PD <thedraperfam...(a)gmail.com> wrote: > On Mar 9, 7:58 pm, Bruce Richmond <bsr3...(a)my-deja.com> wrote: > > > On Mar 9, 9:31 am, PD <thedraperfam...(a)gmail.com> wrote: > > > > On Mar 8, 11:53 pm, Bruce Richmond <bsr3...(a)my-deja.com> wrote: > > > > > On Mar 8, 1:58 am, "Inertial" <relativ...(a)rest.com> wrote: > > > > > > "Bruce Richmond" <bsr3...(a)my-deja.com> wrote in message > > > > > >news:29fd9f7d-c9b4-41e6-b33a-585c3e0e7acf(a)q23g2000yqd.googlegroups..com... > > > > > > > On Mar 7, 9:48 pm, "Inertial" <relativ...(a)rest.com> wrote: > > > > > >> "Bruce Richmond" <bsr3...(a)my-deja.com> wrote in message > > > > > > >>news:1c6a2640-39f5-4ea4-9c85-127e71f4e6a2(a)33g2000yqj.googlegroups.com... > > > > > > >> > On Mar 7, 6:58 pm, "Inertial" <relativ...(a)rest.com> wrote: > > > > > >> >> "Peter Webb" <webbfam...(a)DIESPAMDIEoptusnet.com.au> wrote in message > > > > > > >> >>news:4b943853$0$11336$afc38c87(a)news.optusnet.com.au... > > > > > > >> >> > "Inertial" <relativ...(a)rest.com> wrote in message > > > > > >> >> >news:4b942bcf$0$27789$c3e8da3(a)news.astraweb.com... > > > > > >> >> >> "Peter Webb" <webbfam...(a)DIESPAMDIEoptusnet.com.au> wrote in > > > > > >> >> >> message > > > > > >> >> >>news:4b93bf73$0$28464$afc38c87(a)news.optusnet.com.au... > > > > > > >> >> >>>>> 1) your statement: "For clarity, both effects are purely > > > > > >> >> >>>>> observational - SR presumes (ideal) clock mechanisms are > > > > > >> >> >>>>> completely > > > > > >> >> >>>>> unaffected by a clock's motion." -- I agree the physical > > > > > >> >> >>>>> mechanism > > > > > >> >> >>>>> of > > > > > >> >> >>>>> the clock is unaffected, but this is a really misleading > > > > > >> >> >>>>> statement, > > > > > >> >> >>>>> since the amount of proper time that the clock consumes is > > > > > >> >> >>>>> affected > > > > > >> >> >>>>> by > > > > > >> >> >>>>> its motion. Are you trying to say > > > > > > >> >> >>>> I was "trying to say" exactly what I did say. If you didn't find > > > > > >> >> >>>> it > > > > > >> >> >>>> clear enough, try this: relative slow-downs/speed-ups observed in > > > > > >> >> >>>> the > > > > > >> >> >>>> readings of SR's ideal clocks aren't due to changes in the tick > > > > > >> >> >>>> mechanisms of those clocks. > > > > > > >> >> >>> I still don't find it clear, as it begs the question - it says > > > > > >> >> >>> what > > > > > >> >> >>> doesn't cause the change, not what does cause the change. > > > > > > >> >> >>> The standard SR answer is much more direct - the clocks slow down > > > > > >> >> >>> due > > > > > >> >> >>> to > > > > > >> >> >>> relativistic time dilatation from them being in different > > > > > >> >> >>> reference > > > > > >> >> >>> frames. > > > > > > >> >> >>> Is that standard position of SR also your position? Or is your > > > > > >> >> >>> somehow > > > > > >> >> >>> different? > > > > > > >> >> >> SR says that the difference in clock sync (clock settings) cause > > > > > >> >> >> the > > > > > >> >> >> measurement of length to be contracted and measurement of clock > > > > > >> >> >> ticking > > > > > >> >> >> rates to be dilated. > > > > > > >> >> > More or less. > > > > > > >> >> That's what it is :) > > > > > > >> >> > But I asked you about *your* position, not SR's position. > > > > > > >> >> My position is SR's position > > > > > > >> >> > Do you agree that that the clocks slow down due to relativistic time > > > > > >> >> > dilation, as predicted by SR, or not? > > > > > > >> >> They are measured as slower, just as a rod is measured as shorter. > > > > > >> >> This > > > > > >> >> is > > > > > >> >> due to the difference in simultaneity. They don't slow down because a > > > > > >> >> moving observer is looking at them any more than a rod shrinks because > > > > > >> >> a > > > > > >> >> relatively moving observer is looking at it. > > > > > > >> >> Here's a little example you might follow .. with time differences > > > > > >> >> exagerated > > > > > >> >> for clarity > > > > > > >> >> Here are six clocks, in tow rows (S and S'), all ticking at the > > > > > >> >> correct > > > > > >> >> rate, but set with different times... > > > > > > >> >> S' 10:30 11:00=A 11:30 <--v > > > > > >> >> S 11:30=C 11:00=B 10:30 -->v > > > > > > >> >> Clocks B sees the A is synchronized with it. > > > > > > >> >> Now .. the clocks are moving in opposite directions so after an hour > > > > > >> >> we > > > > > >> >> have > > > > > > >> >> S' 11:30 12:00=A 12:30 > > > > > >> >> S 12:30=C 12:00=B 11:30 > > > > > > >> >> Clock A has moved away from clock B .. but another clock (C) in S can > > > > > >> >> see > > > > > >> >> the time on it. Clock C sees that clock A is half an hour slow (A > > > > > >> >> shows > > > > > >> >> 12:00 when C shows 12:30). So according to the clocks in S, clock A > > > > > >> >> is > > > > > >> >> ticking slower. We also note that clock B now sees a *different* S' > > > > > >> >> clock > > > > > >> >> next to it as being fast (it shows 12:30 when B shows 12:00) > > > > > > >> >> If you look at the same scenario but from the point of view of the > > > > > >> >> other > > > > > >> >> row > > > > > >> >> of clocks, you get symmetric results. > > > > > > >> >> This is how clock synch affects measured ticking rates for moving > > > > > >> >> clocks > > > > > >> >> in > > > > > >> >> SR. Even though the clocks themselves do NOT change their intrinsic > > > > > >> >> ticking > > > > > >> >> rates.- Hide quoted text - > > > > > > >> > Looks good, but let's take it one step further. The observer with > > > > > >> > clock A jumps to frame S" which is traveling in the same direction as > > > > > >> > S relative to S' but at twice the velocity. > > > > > > >> > S" 1:00 12:00=A 11:00 -->2v > > > > > >> > S' 11:30 12:00=A 12:30 <--v > > > > > >> > S 12:30=C 12:00=B 11:30 -->v > > > > > > >> > Clocks A and B continue to tick at there same intrinsic ticking rate > > > > > >> > and an hour later A has overtaken B. > > > > > > >> > S" 2:00 1:00=A 12:00 -->2v > > > > > >> > S' 12:30 1:00=A 1:30 <--v > > > > > >> > S 1:30=C 1:00=B 12:30 -->v > > > > > > >> > The above provides the same situation as the twins paradox. Clock A > > > > > >> > left clock B and returned. So why doesn't clock A show less time > > > > > >> > elapsed than B? (Note the clocks in S" are further out of sync than > > > > > >> > those in S due to the higher velocity.) > > > > > > >> The three clock situation cannot be so easily drawn .. bit like trying to > > > > > >> drawing a three dimensional figure in 2d :) This sort of diagram only > > > > > >> really works for a single pair of clocks looking from a third frame in > > > > > >> which > > > > > >> they move with the same speed. Things are trickier when there is frame > > > > > >> jumping going on :):)- Hide quoted text - > > > > > > >> - Show quoted text - > > > > > > > The question still remains, if there is no change in the tick rate of > > > > > > the clock, how can clock A have fewer ticks recorded when it is > > > > > > brought back to clock B? > > > > > > Look at the Lorentz transforms to see. Its all due to clock synch.- Hide quoted text - > > > > > > - Show quoted text - > > > > > You are going to give yourself a head cold with all that arm waving.. > > > > You are saying the tick rate doesn't change, yet SR says that the > > > > returning twin's clock will show less elapsed time. You don't see any > > > > conflict there? > > > > No, there is no conflict. When you say that the tick rate does not > > > change, this is a LOCAL statement. What it means is that a process > > > measured locally with this clock will still have the same duration. > > > That is not what we were discussing. I agree that the clock continues > > to tick at a rate of one second per proper second in the rest frame of > > the clock. The question was whether the slowed tick rate measured in > > the frame of the stay at home twin is real, or an illusion due to the > > clock sync proceedure, as length contraction is. > > I don't know that length contraction IS an illusion. Length is > *defined* operationally by relying on simultaneity, and so the REAL > length according to that definition is of course frame-dependent, > because simultaneity is frame-dependent. > > > If it is an illusion > > the accumulated time on the two clocks should be the same when they > > are brought back together. The way Inertial described it, it came > > across as an illusion caused purely by clock sync. > > > I hate discussing what is "real". In a sense length contraction is > > real because the pole will fit into the barn. > > Absolutely. If I have a clear understanding of what "simultaneous" > means in a given reference frame, and I close the barn doors > simultaneously with the pole between them, and there are no marks on > the doors where the pole hit either one of them, then I can't think of > any sensible meaning of "fit" that would hold these circumstances to > be true and yet the pole does not fit in the barn in this frame. And > since the pole fits, I cannot think of any sensible meaning of > "shorter" where the pole would fit in the barn and yet be not shorter > than the barn. Careful here. I don't see how you can claim that the rod really is shorter but that the clock didn't really slow down. The fact that the rod has different measured lengths at the same time tells me that the measured length is a matter of perception, which can be distorted. But the fact that the returned clock has less elapsed time tells me that it isn't just how I looked at it. If we are to agree that length contraction and time dialation are real I'm good with that. But don't then tell me that the clock didn't slow down. It slowed in our frame but the traveling twin couldn't detect it because he used the coordinates of his new frame of reference to measure it. > > But with length > > contraction there is no accumulated length to inspect when the pole is > > brought to rest. > > This is true. The twin puzzle is a different animal that the barn-pole > paradox. In the twin puzzle, there is no symmetry in terms of inertial > motion. One twin is DEFINITELY not residing wholly in one inertial > reference frame, and that is a frame-independent observation. > > > I can see that the measured slowing of the clock is > > due to the rotation of the time coordinates when it changed frames, > > but that doesn't make it any less real. > > > > For example, if the half-life of a muon that is slow in frame A and is > > > measured with a clock at rest in A is 2.2 us, then if you make the > > > same measurement of the half-life of a muon that is slow in frame B > > > and is measured with a clock at rest in B, clock B will still show the > > > half-life to be 2.2 us. In this sense, we say that the clock tick rate > > > has not changed, because measurements of local phenomena are > > > unchanged. > > > Yes, but again you are measuring locally, more or less in the rest > > frame of the muon. We know that if we measure the half life of a fast > > moving muon it is longer, as if its personal clock was ticking slower. > > > > However, this does NOT mean that the tick rate of clock B will agree > > > with the clock rate of all other clocks, nor that it will read the > > > durations of nonlocal processes to be the same. > > > > Do you see the distinction? > > > If we set up a light clock with a vertical bouncing beam, and have it > > send a flash back to the stay at home twin every time the beam hits > > the top, we can tell just how fast the clock is ticking. The signal > > will be doppler shifted, but the total count is what it is. None of > > the flashes drifted off and avoided detection. I am not claiming this > > slowing is due to motion wrt an ether. It is due to the finite speed > > of light and how we define/construct the coordinate systems. > > The last sentence is right, but how we define/construct the coordinate > systems is constrained by the structure of spacetime (and this in fact > produces the finite speed of light). That is, there is no way to > define/construct a coordinate system in our spacetime such that these > effects go away. (You are free to try.) > > PD > > > Bruce
From: Peter Webb on 10 Mar 2010 20:13 According to both SR and LET there is no experiment that can reveal which frame is at rest WRT the ether, so there is no way to know which frame is more at rest WRT the ether. ______________________ Wrong. Only LET has this problem. There is no ether in SR, so the question of its velocity doesn't even arise.
From: mpc755 on 10 Mar 2010 20:16 On Mar 10, 8:13 pm, "Peter Webb" <webbfam...(a)DIESPAMDIEoptusnet.com.au> wrote: > According to both SR and LET there is no experiment that can reveal > which frame is at rest WRT the ether, so there is no way to know which > frame is more at rest WRT the ether. > > ______________________ > Wrong. Only LET has this problem. There is no ether in SR, so the question > of its velocity doesn't even arise. "According to the general theory of relativity space without ether is unthinkable" - Albert Einstein So, Albert Einstein said there is no aether in SR but GR without aether is unthinkable? I don't think so. The pressure associated with the aether displaced by massive objects is gravity. A moving particle has an associated aether wave.
From: Inertial on 10 Mar 2010 19:48 "Dono." <sa_ge(a)comcast.net> wrote in message news:93040dcd-34f5-47d6-a183-27829c29223e(a)x12g2000yqx.googlegroups.com... > On Mar 10, 9:36 am, waldofj <wald...(a)verizon.net> wrote: >> On Mar 10, 10:11 am, "Dono." <sa...(a)comcast.net> wrote: >> >> >> >> >> >> > On Mar 10, 7:04 am, "Inertial" <relativ...(a)rest.com> wrote: >> >> > > "Dono." <sa...(a)comcast.net> wrote in message >> >> > >news:ae269f15-4a97-4e9b-9529-002823bd2ca6(a)n7g2000prc.googlegroups.com... >> >> > > > On Mar 10, 6:54 am, "Inertial" <relativ...(a)rest.com> wrote: >> >> > > >> > Because the "multiple aethers" would need to >> > > >> > have contradictory properties. >> >> > > >> They probably would. Why can't multiple aethers have different >> > > >> properties? >> >> > > > Because the properties in cause are CONTRADICTORY , imbecile. You >> > > > keep >> > > > missing that. >> >> > > The claim was that an aether for gravity would have different >> > > properties for >> > > one for EMR. There is no contradiction in that .. they can simply be >> > > different aethers with different properties. >> >> > How can they? Their properties would not only be different but also >> > CONTRADICTORY. >> >> > > If there is no contradictions >> > > (or not enough for aetherists to assert their way out of it) then the >> > > same >> > > aether can be used. >> >> > If your grandmother had wheels she would have been a bus. The point is >> > that there IS contradiction. Fallacious thinking will not take you >> > very far. >> >> > > It doesn't really matter which approach they take, but >> > > a determined aetherist can get out of the refutations put forward so >> > > far >> > > quite easily (as has happened in the past). >> >> > You are a prime example. >> >> My understanding of the aether of LET is: >> it must have very great stiffness (i.e. very high modulus) so waves >> will propagate at the speed of light. >> It interacts with matter to cause a compression in the direction of >> motion. >> And yet, it does not cause any drag on matter moving through it so, >> for example, the earth can orbit the sun for 4.5 billion years in a >> nearly stable orbit. >> >> Now, if that last property isn't contradictory, I don't know what is. >> >> I think the point Inertial is trying to make is that the concept of an >> aether is already ad-hoc and self contradictory so it doesn't matter >> what else you pile on to it > > No, quite the contrary, Inertial doesn't admit that the concept of > aether is self-contradictory. LET isn't contradictory .. though for it to 'work' it has a bizarre set of properties .. properties that no other substance has. It certainly is ad-hoc .. that's why it survived as long as it did .. more properties were added after the fact to make it consistent with experimental results. And it may not extend well to other forces (eg gravity) .. but LET itself doesn't cover those forces. > See his exchanges with Jerry. In the > process, he keeps contradicting himself. Liar. I have not said anything self-contradictory. > It is a waste of time > discussing with him. Both Jerry and I have given up on this idiot. Liar. Jerry understands. You don't. You really need to learn about SR and LET, and how these theory make the same predictions about what is measured because they use the same math. That is why every test for the SR passes, LET passes as well. This is very well known facts .. why are you unaware of it (and worse, claiming it is untrue) ??
From: Inertial on 10 Mar 2010 19:48
"PD" <thedraperfamily(a)gmail.com> wrote in message news:2c0f2867-095d-4582-8275-a41dcd7ca574(a)g11g2000yqe.googlegroups.com... > On Mar 10, 12:11 pm, "Dono." <sa...(a)comcast.net> wrote: >> On Mar 10, 9:36 am, waldofj <wald...(a)verizon.net> wrote: >> >> >> >> > On Mar 10, 10:11 am, "Dono." <sa...(a)comcast.net> wrote: >> >> > > On Mar 10, 7:04 am, "Inertial" <relativ...(a)rest.com> wrote: >> >> > > > "Dono." <sa...(a)comcast.net> wrote in message >> >> > > >news:ae269f15-4a97-4e9b-9529-002823bd2ca6(a)n7g2000prc.googlegroups.com... >> >> > > > > On Mar 10, 6:54 am, "Inertial" <relativ...(a)rest.com> wrote: >> >> > > > >> > Because the "multiple aethers" would need to >> > > > >> > have contradictory properties. >> >> > > > >> They probably would. Why can't multiple aethers have different >> > > > >> properties? >> >> > > > > Because the properties in cause are CONTRADICTORY , imbecile. You >> > > > > keep >> > > > > missing that. >> >> > > > The claim was that an aether for gravity would have different >> > > > properties for >> > > > one for EMR. There is no contradiction in that .. they can simply >> > > > be >> > > > different aethers with different properties. >> >> > > How can they? Their properties would not only be different but also >> > > CONTRADICTORY. >> >> > > > If there is no contradictions >> > > > (or not enough for aetherists to assert their way out of it) then >> > > > the same >> > > > aether can be used. >> >> > > If your grandmother had wheels she would have been a bus. The point >> > > is >> > > that there IS contradiction. Fallacious thinking will not take you >> > > very far. >> >> > > > It doesn't really matter which approach they take, but >> > > > a determined aetherist can get out of the refutations put forward >> > > > so far >> > > > quite easily (as has happened in the past). >> >> > > You are a prime example. >> >> > My understanding of the aether of LET is: >> > it must have very great stiffness (i.e. very high modulus) so waves >> > will propagate at the speed of light. >> > It interacts with matter to cause a compression in the direction of >> > motion. >> > And yet, it does not cause any drag on matter moving through it so, >> > for example, the earth can orbit the sun for 4.5 billion years in a >> > nearly stable orbit. >> >> > Now, if that last property isn't contradictory, I don't know what is. >> >> > I think the point Inertial is trying to make is that the concept of an >> > aether is already ad-hoc and self contradictory so it doesn't matter >> > what else you pile on to it >> >> No, quite the contrary, Inertial doesn't admit that the concept of >> aether is self-contradictory. See his exchanges with Jerry. In the >> process, he keeps contradicting himself. It is a waste of time >> discussing with him. Both Jerry and I have given up on this idiot. > > I don't think there's anything to admit. > > An aether that is supposed to have certain qualifiers to it -- such as > solidity, where solidity means that it carries the expectation that it > behaves like OTHER solids -- can certainly be said to be self- > contradictory. > > This, in fact, is where a lot of aether types have been ruled out. > Aethers that behave exactly like gases are ruled out. Aethers that > behave exactly like solids have been ruled out. > > But what isn't necessarily ruled out is an aether that is UNLIKE any > other substance previously known. This is the kind of aether that > Inertial has been referring to, and in fact is similar to the kind of > aether that Einstein mentioned is still permissible in relativity. > > The problem with the latter is that it is too slippery to pin down, > and therefore impossible to experimentally test, and therefore > scientifically useless. It is like invisible and very clever fairies > that are the cause of momentum conservation but are perfectly adept at > masking their presence and covering their tracks. There is no way to > say that such fairies are self-contradictory, but on the other hand, > there is no way to prove either that they exist or that they don't > exist. Exactly |