A constant speed of light in all reference frames? Surely you can't be serious.
in [Relativity]
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From: PD on 5 Mar 2010 11:02 On Mar 5, 2:55 am, Ste <ste_ro...(a)hotmail.com> wrote: > On 4 Mar, 18:12, PD <thedraperfam...(a)gmail.com> wrote: > > > > > On Mar 4, 12:04 pm, Ste <ste_ro...(a)hotmail.com> wrote: > > > > On 4 Mar, 17:46, PD <thedraperfam...(a)gmail.com> wrote: > > > > > On Mar 4, 11:17 am, Ste <ste_ro...(a)hotmail.com> wrote: > > > > > > On 4 Mar, 16:49, mpalenik <markpale...(a)gmail.com> wrote: > > > > > > > On Mar 4, 11:45 am, Ste <ste_ro...(a)hotmail.com> wrote: > > > > > > > > On 4 Mar, 16:32, mpalenik <markpale...(a)gmail.com> wrote: > > > > > > > > > On Mar 4, 11:28 am, Ste <ste_ro...(a)hotmail.com> wrote: > > > > > > > > > > On 4 Mar, 16:20, mpalenik <markpale...(a)gmail.com> wrote: > > > > > > > > > > > On Mar 4, 10:31 am, Ste <ste_ro...(a)hotmail.com> wrote: > > > > > > > > > > > > On 4 Mar, 13:40, mpalenik <markpale...(a)gmail.com> wrote: > > > > > > > > > > > > > On Mar 4, 3:12 am, Ste <ste_ro...(a)hotmail.com> wrote: > > > > > > > > > > > > > > On 3 Mar, 20:01, mpalenik <markpale...(a)gmail.com> wrote: > > > > > > > > > > > > > > > On Mar 3, 12:52 pm, Ste <ste_ro...(a)hotmail.com> wrote: > > > > > > > > > > > > > > > > No. In SR, clocks *appear* to run slower as you are increasing your > > > > > > > > > > > > > > > distance from the clock. The effect is entirely apparent in SR. > > > > > > > > > > > > > > > You must just go through the entire thread and not pay any attention > > > > > > > > > > > > > > to what anybody says. Ever. > > > > > > > > > > > > > > > 1) What you've stated above is not an effect of SR. It is an effect > > > > > > > > > > > > > > of propagation delay, which was used to calculate c from the motion of > > > > > > > > > > > > > > the moons of jupiter hundreds of years ago. > > > > > > > > > > > > > > Ok. > > > > > > > > > > > > > > > 2) If you were to move TOWARD the clock, it would appear to run > > > > > > > > > > > > > > faster. But SR says nothing about whether you are moving toward or > > > > > > > > > > > > > > away from an object. > > > > > > > > > > > > > > <suspicious eyebrow raised> Ok. > > > > > > > > > > > > > > > 3) The amount that the clock would appear to slow down is DIFFERENT > > > > > > > > > > > > > > from the amount that SR predicts the clock *actually* slows down > > > > > > > > > > > > > > Really? I'm growing increasingly suspicious. In what way does SR > > > > > > > > > > > > > predict the "actual" slowdown, as opposed to the "apparent" slowdown? > > > > > > > > > > > > > And for example, if we racked up the value of 'c' to near infinity, > > > > > > > > > > > > > would SR still predict an "actual" slowdown, even though the > > > > > > > > > > > > > propagation delays would approach zero? > > > > > > > > > > > > > With what you have described, I checked just to be sure, even though I > > > > > > > > > > > > was already pretty sure what the answer would be, the time you read > > > > > > > > > > > > moving away the clock would be: > > > > > > > > > > > > > t2 = t - (x+vt)/c = t(1-v/c) - x > > > > > > > > > > > > > and when you move toward the clock > > > > > > > > > > > > > t2 = t + (x+vt)/c = t(1+v/c) + x > > > > > > > > > > > > > so moving away from the clock: > > > > > > > > > > > > dt2/dt = 1-v/c > > > > > > > > > > > > and toward > > > > > > > > > > > > dt2/dt = 1-v/c > > > > > > > > > > > > > Special relativity predicts that the moving clock will always slow > > > > > > > > > > > > down as > > > > > > > > > > > > dt2/dt = sqrt(1-v^2/c^2) > > > > > > > > > > > > > What you *measure* is a combination of the actual slow down predicted > > > > > > > > > > > > by SR (sqrt(1-v^2/c^2) and whatever changes occur due to propagation > > > > > > > > > > > > delays (which depend on the direction of motion). > > > > > > > > > > > > Ok. So let us suppose that we take two clocks. Separate them by a > > > > > > > > > > > certain distance, synchronise them when they are both stationary, and > > > > > > > > > > > then accelerate them both towards each other (and just before they > > > > > > > > > > > collide, we bring them stationary again). Are you seriously saying > > > > > > > > > > > that both clocks report that the other clock has slowed down, even > > > > > > > > > > > though they have both undergone symmetrical processes? Because there > > > > > > > > > > > is obviously a contradiction there. > > > > > > > > > > > Yes, that is correct. Both will report a slow down. And in fact, > > > > > > > > > > which ever one breaks the inertial frame to match speed with the other > > > > > > > > > > is the one that will be "wrong". This is still within the realm of > > > > > > > > > > SR, not GR. > > > > > > > > > > What if they both "break the inertial frame"? > > > > > > > > > Then whichever frame they both accelerate into will be the one that > > > > > > > > has measured the "correct" time dilation. > > > > > > > > So in other words, the clocks will register the same time, but will > > > > > > > have slowed in some "absolute sense"? > > > > > > > Yes--assuming they both accelerated by the same amount (that is to > > > > > > say, assuming they both broke the inertial frame in a symmetric way). > > > > > > Otherwise, they will register different times. > > > > > > Agreed. > > > > > > So let's explore an extension of this scenario. Let's say you have two > > > > > clocks, and you accelerate both of them up to a common speed, and > > > > > after they have travelled a certain distance, you turn them around and > > > > > return them to the starting point. The only difference is that one > > > > > clock goes a certain distance, and the other clock goes twice that > > > > > distance, but they *both* have the same acceleration profile - the > > > > > only difference is that one clock spends more time travelling on > > > > > inertia. > > > > > > Obviously, one clock will return to the starting point earlier than > > > > > the other. But when both have returned, are their times still in > > > > > agreement with each other, or have they changed? > > > > > Agreement. Both of them will agree, but will be showing a time earlier > > > > than a third clock that was left behind at the starting point. > > > > Oh dear. Mark contends otherwise. > > > Right. I misunderstood. He's right. I was wrong. > > Ok. So what you're (both) saying is that time dilation (in SR) is a > simple function of speed and distance, so that the quicker you travel > the more time dilates, and the further you travel the more time > dilates? And, to boot, you're saying that it's only *relative* > distance and speed that counts (i.e. there is no absolute measure of > movement in space)? The time dilation *factor* (by what factor is the clock moving more slowly) is a simple function of relative speed. The difference in the time *elapsed* between the two clocks is also a function of the relative distance. This should make perfect sense to you. If a clock is running 2% slower, then it is running 2% slower regardless of distance. But if, as a result of running 2% slower, it falls behind 6 minutes after running a certain amount of time, then it will fall behind 12 minutes after running for twice as long.
From: rotchm on 5 Mar 2010 11:27 > > and I consider them two > > interpertations of the same thing. > > Not at all. Very different as far as how they explain reality Note that he said "and I consider...interpretations...". He did not say taht they are the same thing. he interprets them to be the 'same" or "equivalent". Nonetheless, LET and SR have identical predictions (for kinematical/ optical) effects. > LET has and required a fixed (theoretically undetectable) aether in a fixed > absolute frame. > SR does not specify nor require anything about an aether True. That is a reason why SR confuses many; there is not a "master reference". > LET has objects physically compressed due to absolute motion thru the aether True. this can be taken as a postulate of LET or deduced via field eqs. > SR has no absolute motion, so objects are not affected by such motion That is why SR confuses many: The objects are not affected yet they shorten (measured length diminishes). Some call it "real", "physical", "visual", "projection" etc. In LET, there are no such confusions. > LET has processes physically slowed due to absolute motion thru the aether True. This can be taken as a postulate in LET or deduced as above. > SR has no absolute motion, so processes are not affected by such motion That is why SR confuses many. The processes are not afected by such motion yet clocks slow down. In LET, clocks are affected and is the "cause" of the slowing down of clocks. > LET has a side-effect of the speed of light being measured as the same in > all frames of reference, due to measuring with compressed rulers and slowed > clocks, True. From highschool kinematics one deduces that although the speed of light is not iso in i-frames, a (two way) measurement will always give c. A simple highschool exercise. > SR has no absolute compression and slowing, and the speed of light really is > c SR has the side effect that the speed of light is c for all observers, contrary to other type of waves, contrary to common kinematics. That is why SR confuses many. > LET has a side-effect of an appearance of the lorentz transforms holding on > measured values, due to measuring with compressed rulers and slowed clocks. > SR has no absolute compression and slowing, so the lorentz transform hold As above... > > The LET interpertation had the > > advantage, for me, of showing how c + or - v could end up being > > measured c in all frames. I too prefer that model. The LET model has advantages as the SR model has its advantages. I use both but prefer "LET". > > Given that was possible I no longer had any > > problem accepting the second postulate. Eventually I became aware > > that the second postulate wasn't so much an assumption as a > > stipulation. We will consider the speed of light to be our standard. > > No .. it is an observed fact. Not a stipulation It is a stipulation. In fact it is a "defintion". What ever the behavior of light, it is used as a standard to measure lengths. Length has an operational defintion that uses the integer 299792458. This definition implies/makes the speed of light constant. Who owes me 2 cents now ? :)
From: Y.Porat on 5 Mar 2010 11:41 On Mar 5, 1:51 pm, "Inertial" <relativ...(a)rest.com> wrote: > "Y.Porat" <y.y.po...(a)gmail.com> wrote in message > > news:868926cb-233d-417e-86c8-cd8987c43419(a)q16g2000yqq.googlegroups.com... > > > > > On Mar 4, 7:44 pm, PD <thedraperfam...(a)gmail.com> wrote: > >> On Mar 4, 11:09 am, Ste <ste_ro...(a)hotmail.com> wrote: > > >> > On 4 Mar, 16:48, mpalenik <markpale...(a)gmail.com> wrote: > > >> > > On Mar 4, 10:19 am, Ste <ste_ro...(a)hotmail.com> wrote: > > >> > > > On 4 Mar, 12:19, "Inertial" <relativ...(a)rest.com> wrote: > > >> > > > > "Ste" <ste_ro...(a)hotmail.com> wrote in message > > >> > > > > > Not really, because if the total acceleration is small, then so > >> > > > > > is the > >> > > > > > speed. > > >> > > > > That is a nonsense argument. Acceleration can be small and > >> > > > > speeds very > >> > > > > large. > > >> > > > When I went to school, you could not have a large change of speed > >> > > > with > >> > > > only a small amount of total acceleration. > > >> > > The problem is your use of the term "total acceleration". If by > >> > > total > >> > > acceleration, you mean integral(a dt), then yes, you are correct. > >> > > However, there is already a word for integral(a dt) -- it's called > >> > > "the change in velocity". The term "total acceleration" isn't > >> > > actually defined. Acceleration is defined, velocity is defined, > >> > > deltav is defined. But "total acceleration is not". > > >> > Essentially, I'm defining "total acceleration" as something akin to > >> > total force, so that even though the force may be small, if it > >> > continues for a long time then the total force will be the same as if > >> > a large force was applied for a short period of time. In this way, if > >> > the application of force is what is causing either part or the whole > >> > of the time dilation effect, then it is the final speed that counts, > >> > not how quickly the object reached that speed. > > >> Indeed. This should tell you that it is not the details of the > >> acceleration that matter. > >> The overly simplistic statement would be, "Yes, you see that is why > >> SR's effects are based on speed, not on acceleration." > > >> In fact, there is a speed time dilation effect on GPS satellites, > >> which are going around in a circular path at constant speed, relative > >> to earth clocks, and accounting for this is crucial to their proper > >> operation. This is the same speed dilation effect, though different > >> size, as seen in muons in a circulating ring. (Since, by the way, the > >> GPS satellites are certainly not inside a magnetic ring but still > >> experience time dilation properly calculated by SR, this is another > >> good way to be sure that the magnetic ring is not what's responsible > >> for the time dilation of the muons.) > > >> Regarding something I alluded to earlier, though, what really matters > >> is how straight the path through spacetime is. We're used to thinking > >> that the shortest path through space is the straight one (and that's > >> right), but the straightest path through spacetime yields the LONGEST > >> duration. Any change in motion (such as an acceleration) introduces a > >> kink in this path (something that can be illustrated visually very > >> easily) and so lowers the duration. Why this is, has to do with the > >> structure of spacetime and we could discuss that. But this is perhaps > >> the most intuitive way (once these concepts are explained) to > >> understand why the traveling twin returns younger. > > >> > > Also, you could just be dealing with a system where the velocity > >> > > started out high and you never measured any acceleration. > > >> > Indeed. > > > ---------------------- > > (:-) > > to mix **biologic process** with > > inorganic physics > > is ridiculous!!! > > He didn't .. there was no biologic process mentioned in the above. > > > (i said it in a big understatement ...(:-) > > Y.Porat > > ----------------------- here is a quote from PD quote 'and so lowers the duration. Why this is, has to do with the structure of spacetime and we could discuss that. But this is perhaps the most intuitive way (once these concepts are explained) to understand why the traveling twin returns younger. end of quote ------------- so the tarveling twin returns younger ???!!! 2 if you dont rmind EM radiation HAS MASS! therefore it i influenced by gravity SIMILAR BUT NOT EXACTLY AS ANY OTHER MASS!! no curvature and no shmervature of space but that is again not for born parrots BYE Y.P ------------------------------
From: mpalenik on 5 Mar 2010 12:18 On Mar 5, 11:27 am, rotchm <rot...(a)gmail.com> wrote: > > No .. it is an observed fact. Not a stipulation > > It is a stipulation. In fact it is a "defintion". > What ever the behavior of light, it is used as a standard to measure > lengths. > Length has an operational defintion that uses the integer 299792458. > This definition implies/makes the speed of light constant. > This was not the definition used at the time of Einstein. This definition was put into effect many years later after it had long been observed that the speed of light does not depend on your choice of reference frame. > Who owes me 2 cents now ? :) Nobody?
From: PD on 5 Mar 2010 12:46
On Mar 5, 10:41 am, "Y.Porat" <y.y.po...(a)gmail.com> wrote: > On Mar 5, 1:51 pm, "Inertial" <relativ...(a)rest.com> wrote: > > > > > "Y.Porat" <y.y.po...(a)gmail.com> wrote in message > > >news:868926cb-233d-417e-86c8-cd8987c43419(a)q16g2000yqq.googlegroups.com.... > > > > On Mar 4, 7:44 pm, PD <thedraperfam...(a)gmail.com> wrote: > > >> On Mar 4, 11:09 am, Ste <ste_ro...(a)hotmail.com> wrote: > > > >> > On 4 Mar, 16:48, mpalenik <markpale...(a)gmail.com> wrote: > > > >> > > On Mar 4, 10:19 am, Ste <ste_ro...(a)hotmail.com> wrote: > > > >> > > > On 4 Mar, 12:19, "Inertial" <relativ...(a)rest.com> wrote: > > > >> > > > > "Ste" <ste_ro...(a)hotmail.com> wrote in message > > > >> > > > > > Not really, because if the total acceleration is small, then so > > >> > > > > > is the > > >> > > > > > speed. > > > >> > > > > That is a nonsense argument. Acceleration can be small and > > >> > > > > speeds very > > >> > > > > large. > > > >> > > > When I went to school, you could not have a large change of speed > > >> > > > with > > >> > > > only a small amount of total acceleration. > > > >> > > The problem is your use of the term "total acceleration". If by > > >> > > total > > >> > > acceleration, you mean integral(a dt), then yes, you are correct.. > > >> > > However, there is already a word for integral(a dt) -- it's called > > >> > > "the change in velocity". The term "total acceleration" isn't > > >> > > actually defined. Acceleration is defined, velocity is defined, > > >> > > deltav is defined. But "total acceleration is not". > > > >> > Essentially, I'm defining "total acceleration" as something akin to > > >> > total force, so that even though the force may be small, if it > > >> > continues for a long time then the total force will be the same as if > > >> > a large force was applied for a short period of time. In this way, if > > >> > the application of force is what is causing either part or the whole > > >> > of the time dilation effect, then it is the final speed that counts, > > >> > not how quickly the object reached that speed. > > > >> Indeed. This should tell you that it is not the details of the > > >> acceleration that matter. > > >> The overly simplistic statement would be, "Yes, you see that is why > > >> SR's effects are based on speed, not on acceleration." > > > >> In fact, there is a speed time dilation effect on GPS satellites, > > >> which are going around in a circular path at constant speed, relative > > >> to earth clocks, and accounting for this is crucial to their proper > > >> operation. This is the same speed dilation effect, though different > > >> size, as seen in muons in a circulating ring. (Since, by the way, the > > >> GPS satellites are certainly not inside a magnetic ring but still > > >> experience time dilation properly calculated by SR, this is another > > >> good way to be sure that the magnetic ring is not what's responsible > > >> for the time dilation of the muons.) > > > >> Regarding something I alluded to earlier, though, what really matters > > >> is how straight the path through spacetime is. We're used to thinking > > >> that the shortest path through space is the straight one (and that's > > >> right), but the straightest path through spacetime yields the LONGEST > > >> duration. Any change in motion (such as an acceleration) introduces a > > >> kink in this path (something that can be illustrated visually very > > >> easily) and so lowers the duration. Why this is, has to do with the > > >> structure of spacetime and we could discuss that. But this is perhaps > > >> the most intuitive way (once these concepts are explained) to > > >> understand why the traveling twin returns younger. > > > >> > > Also, you could just be dealing with a system where the velocity > > >> > > started out high and you never measured any acceleration. > > > >> > Indeed. > > > > ---------------------- > > > (:-) > > > to mix **biologic process** with > > > inorganic physics > > > is ridiculous!!! > > > He didn't .. there was no biologic process mentioned in the above. > > > > (i said it in a big understatement ...(:-) > > > Y.Porat > > > ----------------------- > > here is a quote from PD > quote > > 'and so lowers the duration. Why this is, has to do with the > structure of spacetime and we could discuss that. But this is perhaps > the most intuitive way (once these concepts are explained) to > understand why the traveling twin returns younger. > end of quote > ------------- > so the tarveling twin returns younger ???!!! Yes. ALL clocks behave this way, including the chemical clocks that drive biological processes. > 2 > if you dont rmind > EM radiation HAS MASS! > > therefore it i influenced by gravity > SIMILAR BUT NOT EXACTLY AS ANY OTHER MASS!! > no curvature and no shmervature of space > > but that is again not for born parrots > BYE > Y.P > ------------------------------ |