In article <qIvp4DLA9...@eisner.encompasserve.org>, bri...@encompasserve.org writes: > The vector sum of two velocities, v1 and v2 in a particular > reference frame is itself a vector. It is not, quite, a velocity, > but it is expresed in units of velocity. If the individual > vectors have values whose magnitudes are strictly less than c > then the vector sum will have a magnitude that is strictly > less than 2c.
> As I said, this sum is not the velocity of any particular object > in any particular reference frame. Instead, it is the time rate of > change in the (vector) separation between the two objects whose > velocities are v1 and v2 as viewed in the reference frame within > which those objects have those velocities.
Damn. I accuse Uncle Al of a sign error and I make the exact same sign error myself.
Take the _difference_ of those velocties, not their sum if you want the time rate of change in their vector separation.
>>>>In Special Relativity Theory the basis of "Twin Paradox" is that >>>>"moving clocks run slow". What is not clear is that, when a 'clock >>>>runs slow' whether its frequency continuously decreases or not. Can >>>>anyone clarify this point?
>>>Nothing runs "slow" in any refernce frame. When otherwise identical >>>clocks - one of which sustained a velocity relative to the other - are >>>brought together to compare, one is seen to have less elapsed time >>>than its twin due to its hyperbolic rotation through 4-space. The >>>skewing factor is sqrt[1-(v^2/c^2)]. >>>No clock need be accelerated for the Twin Paradox to occur.
>>>Given any achievable velocities V1 and V2 and any finite lightspeed, >>>the sum of the velocities as viewed by any inertial observer cannot >>>exceed
>>>(V1 + V2)/[1 + (V1)(V2)/c^2]
>>>This is transformation of velocities parallel to the direction of >>>motion. For velocities at an arbitrary angle theta,
>>>Makes no difference who does the looking. Any inertial observer has a >>>valid reference frame. Disparities are only noted upon comparison of >>>reference frames. Spacetime is four-dimensional; travel through >>>spacetime is a hyperbolic rotation of all four coordinates. However, >>>the units of time are seconds not meters. ct is a nice length, but >>>the this fundamental unit of length is a very long one.
>>>At nominal velocities you don't travel much along ct compared to >>>x,y,x. Galilean transforms and Newtonian physics are good enough >>>approximations. At relativistic speeds you propagate along ct >>>comparable to a material dimension. You need Lorentzian transforms >>>and relativity to explain initially synchronized clocks separated and >>>then brought together for comparison thereafter.
>>>Acceleration of one observer has nothing to do with it, BTW.
>>> 1) Acceleration is an absolute measurement. There is no doubt who >>>is accelerated. >>> 2) Acceleration is irrelevant.
>>>We have three identical clocks that are off (a state of not running) >>>and zeroed. Each clock has a very short toggle jiggger switch
>>An infinitesimal length, if there is to be no acceleration of any part >>of the clocks, unless acceleration of parts of the clocks does not >>matter. Since, to move a jigger, one must accelerate it and possibly >>the whole clock, does that not count as an acceleration of a clock? >>Larry
> [snip]
> You are so are so ignorantly hopelessly fill of shit. You have no > idea what is going on. Replace the jiggers with complimentary > fiberoptic emitters and pinhole photodiode detectors. Have the ships > skim within 1 millimeter of each other to transfer synchronization. > Run your spew to bull bore. Show how:
> "Elapsed time #2=#3, but elapsed time #2+#3 does not equal #1, the > local stationary reference frame summation. The sum of #2+#3 elasped > time is only about 4.5% that than of #1's accumulated elapsed time"
> does not obtain. Now assume the experiment is 3 years elapsed time in > the stationary frame and show it again. Show us how three teeny dinks > make up for over 1045 days missing between the sum of the moving > clocks' elapsed time and the stationary clock's elasped time. Now do > it for 10 years, 100 years. How good is your spew now?
Sorry Al, I didn't mean to cause you to have a brain fart. Larry
: George Greene wrote: : > : > Uncle Al <Uncle...@hate.spam.net> writes: : > : Nothing runs "slow" in any reference frame. : > : > This begs the question of how you are supposed to : > be able to measure what a clock says "now" when it : > is somewhere else. :
: Did you read it? Did you really?
This was at the beginning. I hadn't YET gotten to the point later about turning the clocks off.
: You have the clock off. You have : the clock on. You have the clock off. When the clock is off the : accumulated time doesn't change. Take the battery out of your analog : watch. The hands don't move. Put the watch in a deep gravitational : well, send it out to Alpha Centuri and back, put it in a Egyptian : pyramid for 5000 years. Has the indicated time changed? Write a : number on a piece of paper. Put the inscribed paper in a Beckman : Ultra-Max centrifuge at ONE MILLION GEES for year. Retrieve the : paper. HAS THE NUMBER CHANGED?
None of this is under debate. The issue isn't whether the number has changed. OF COURSE the number hasn't changed. The issue is, WHY is there a disparity?
: > : When otherwise identical : > : clocks - one of which sustained a velocity relative to the other - are : > : brought together to compare, one is seen to have less elapsed time : > : than its twin due to its hyperbolic rotation through 4-space. The : > : skewing factor is sqrt[1-(v^2/c^2)].
: > You can't assert this symmetrically. : > It cannot be the case BOTH that clock a has less time elapsed : > than clock b AND that clock b has less time elapsed than clock a.
HAS THE NUMBER CHANGED??
: It's called "The Twin Paradox." This is an especially fine rendering : of it. THAT IS WHY IT IS A PARADOX. Acceleration has been removed : and velocity is relative, yet the clocks do not agree. Go ahead, : resolve it.
The issue is not whether the clocks agree. THAT is NOT a paradox. The issue is if one clock reads less than the other, AND the other clock reads less than the one. What are the numbers on the two pieces of paper? Can you envision two pieces of paper where the number on one is less than the number on the other, AND the number on the other is less than the number on the one??
: > : No clock need be accelerated for the Twin Paradox to occur. : > : > Please. The clocks have to be acclerated just to get back : > to the same place, in order for the comparison to occur.
: You stupid bastard. The crew WRITES DOWN the elapsed time. You may : now burn the clock or go at it with sledgehammers for all I care.
Then the clocks will never be compared.
: The figures for elapsed time were never accumulated including an : acceleration.
Numbers are not part of any frame.
: > : Makes no difference who does the looking. Any inertial observer has a : > : valid reference frame. Disparities are only noted upon comparison of : > : reference frames. : > : > What does it even mean to compare two whole frames, as opposed : > to just two clocks? : : You stupid bastard. Words fail me. THE CLOCKS ARE THE FRAMES.
Then if you destroy them, and just remember what reading you wrote down from them, you destroy the frames.
...
: No clock ever accelerates while it is on. Acceleration while it is : off is irrelevant.
You just plain CAN'T PROVE that. Your calling me a stupid bastard isn't a proof.
: You stupid bastard. THE ELAPSED TIME NUMBERS WERE WRITTEN DOWN. Will : the written numbers change no matter how you spew and fart?
The question is not whether they will change. The question is whether they will both be less than each other. The answer is of course that they will not. -- --- "It's difficult ... you need to be united to have any strength, but internal issues have to be addressed." --- E. Ray Lewis, on liberalism in America
>Uncle Al <Uncle...@hate.spam.net> wrote: >> No clock need be accelerated for the Twin Paradox to occur.
>I doubt this. I've seen you make this claim before. Let's take a >closer look ... >Oh ... you cheated! You used _three_ clocks. Well, this seems like a >pretty Rube Goldberg "twin paradox", but I guess. The out and back >clock could be replaced with two clocks running hot, straight and >normal, which pass off a token in a kind of relay race. I agree then >that the elapsed proper time on this clock pair would be less than on >a single inertial clock which they crossed at event A and event B, >although it could be argued that the two clocks doing the relay race >were the moral equivalent of one clock doing a sharp acceleration.
Yes, but the difference is that in the three-clock case, no clock is physically accelerated. That should put an end to the idea that time dilation is something physical that happens to clocks when they accelerate.
>Still, your prevarication has the valuable property of showing that it >is not any intrinsic effect of acceleration on the clock which results >in the "paradox", but only on the trajectory.
Exactly. In Special Relativity, time dilation is a feature of spacetime, not a feature of clocks.
>Indeed, how could it be otherwise? SR >knows nothing of acceleration, contains no terms in acceleration, and >hence any effects of acceleration in SR must merely be an integrated >compounding of many small increments of constant velocity. To deal >with the effects of acceleration per se on matter we need GR.
No, that's not right. In flat spacetime (regardless of whether anything is accelerating) GR reduces to SR. GR tells you nothing about the effects of acceleration on clocks that isn't already present in SR.
>Amazing how many iteration the understanding goes through. From the >false claim sometimes seen "We need GR to handle acceleration", >meaning apparently that we must invoke the GR deity whenever the >sacred word "acceleration" appears, to the antithesis that we can in >fact handle a lot about acceleration in a pure SR environment, in >effect by integration over many contiguous inertial frames, yadda, >yadda, to the final triumphant (?) synthesis: we can handle a lot >about acceleration in SR but for a _complete_ account of a process >involving the acceleration of material bodies even in flat space, I >think we must after all invoke GR.
You need one more iteration. If space is flat, there is no need for GR, and, in fact, GR gives you nothing more than SR in that case.
>Actually, I'm not 100% sure of the last claim: Is there any "purely >GR-ish" effect related to the acceleration of material bodies in flat >space, or are all physical effects obtained by combining the >predictions of SR with any direct effects of the forces involved on >the body?
No. There is no purely GR-ish effect in flat spacetime.
Maybe it would help to show you a series of steps in going from SR to GR:
1. SR in which only inertial coordinates are used and the only problems considered are those that don't involve acceleration. 2. Generalize to allow accelerations (but stick to using inertial coordinate systems). 3. Generalize to arbitrary coordinates (but still letting spacetime be flat). 4. Generalize to fixed curved spacetime. 5. Allow matter and energy to affect spacetime curvature.
Exactly where in the progression from 1-5 the theory becomes GR is a matter of terminology. But I don't think any physicist would say that the transition from 1 ==> 2 involves GR. Einstein developed SR specifically for electrodynamics, in which charges are being accelerated by electromagnetic forces. It would be pretty much a failure if SR didn't handle accelerations.
The only thing that makes handling accelerations difficult is that you have to actually worry about what the laws of physics are governing accelerations. If you leave out accelerations, then you can forget actual physical properties of matter, and just work with idealized clocks and rulers.
Going from 2 ==> 3 is purely mathematical. If you know how to do SR using inertial coordinates, then you can figure out how to do SR using noninertial coordinates. It's just a matter of performing a coordinate change, which is pure math.
Going from 3 ==> 4 involves a tiny amount of additional physics: you need to make assumptions about how curvature affects things. The minimal assumption is that given by the "equivalence principle": you assume that SR holds approximately in any small region of spacetime. This allows you to adopt the math developed in stage 3 for use in stage 4.
Going from 1 ==> 4 was pretty straight-forward once he had the basic idea that gravity is spacetime curvature. All the paradoxes and thought experiments of relativity involving accelerating clocks and rockets and so forth are all covered by 4.
Going from 4 ==> 5 is really hard, and that's the part that took Einstein several years to do. But this final step, to true GR, is irrelevant for most layman discussions of relativity.
The biggest misconception about the relationship between SR and GR is the idea that GR tells us how to handle accelerations in SR. That's exactly backwards. GR instead assumes that accelerations in small regions of spacetime work out the same way they do in SR. So the import of the equivalence principle is that it allows us to do gravitational problems using SR, not that it allows us to do acceleration problems using GR.
>I guess the last question could be summed up by experiment: put any >kind of clock we like in an ultracentrifuge. Spin liberally. Once we >have accounted for (1) the relativistic effects of |u| (magnitude of >speed at the end of the arm) (2) any direct effects of the stress >field on the clock, is there (3) some residue left over for GR, an >"intrinsic effect of acceleration".
If your centrifuge is floating in flat spacetime, then GR doesn't predict any effect that is not accounted for by SR. Both GR and SR predict the same thing:
Elapsed time on clock = Integral of square-root(1-(v/c)^2) dt
> >Oh ... you cheated! You used _three_ clocks. Well, this seems like a > >pretty Rube Goldberg "twin paradox", but I guess. The out and back > >clock could be replaced with two clocks running hot, straight and > >normal, which pass off a token in a kind of relay race. I agree then > >that the elapsed proper time on this clock pair would be less than on > >a single inertial clock which they crossed at event A and event B, > >although it could be argued that the two clocks doing the relay race > >were the moral equivalent of one clock doing a sharp acceleration.
> Yes, but the difference is that in the three-clock case, no > clock is physically accelerated. That should put an end to > the idea that time dilation is something physical > that happens to clocks when they accelerate.
Well, it doesn't. Since the whole premise of *Relativity* has nothing really to do with either space contraction or time dilatiion.
As Einstien wrote in *his* version of Relativity, it goes:
*Space-time* is not something that happens to moron scientists when they are resting.
: news:xeslm4niu65.fsf@eagle.cs.unc.edu... : > Uncle Al <Uncle...@hate.spam.net> writes: : > : Nothing runs "slow" in any reference frame. ... : > : When otherwise identical : > : clocks - one of which sustained a velocity relative to the other - are : > : brought together to compare, one is seen to have less elapsed time : > : than its twin due to its hyperbolic rotation through 4-space. The : > : skewing factor is sqrt[1-(v^2/c^2)].
I retorted: : > You can't assert this symmetrically. : > It cannot be the case BOTH that clock a has less time elapsed : > than clock b AND that clock b has less time elapsed than clock a.
It IS SO, TOO, dammit. Where is Uncle Al berating people for being ignorant about physics when you NEED him?
: Draw a world line for a stationary : clock. Draw a world line for a moving clock
SHUT UP! There is NO SUCH THING as "a stationary clock" or "a moving clock"! ALL INERTIAL FRAMES ARE EQUIVALENT! The assumption here is that all 3 clocks are moving at CONSTANT velocities relative to each other and are NOT being accelerated.
: which starts out and ends up : where the stationary clock is.
In its own frame, each of the 3 clocks is stationary and the other 2 are moving at constant velocities. No one of the 3 clocks is any more stationary than the others.
: > : No clock need be accelerated for the Twin Paradox to occur. : > : > Please. The clocks have to be acclerated just to get back : > to the same place, in order for the comparison to occur. : : No. Use your loaf. This has been explained countless times in the ng.
I don't read sci.physics. Please note which ng this thread is now continuing in.
: > What does it even mean to compare two whole frames, as opposed : > to just two clocks? : : Oh dear.
That is neither an explanation nor a refutation.
: > : Acceleration of one observer has nothing to do with it, BTW. : > : : > : 1) Acceleration is an absolute measurement. There is no doubt : who : > : is accelerated. : > : 2) Acceleration is irrelevant. : > : > It's not irrelevant to your thought-experiment below. : : It is irrelevant. You have not shown anywhere below where the : acceleration of anything affected anything.
The burden of proof is NOT ON me. I don't HAVE to show anything. YOU have to show that DESPITE the fact that people have been alleging that "moving clocks run slow" in relativity TEXTBOOKS for DECADES, *that* is not acutally true. YOU have to show that a generation of respected authors in YOUR field have been WRONG.
More to the point, given that the result is paradoxical, that IS showing something. Your primary mission is to explain away the paradox.
-- --- "It's difficult ... you need to be united to have any strength, but internal issues have to be addressed." --- E. Ray Lewis, on liberalism in America
> >> No clock need be accelerated for the Twin Paradox to occur.
> >I doubt this. I've seen you make this claim before. Let's take a > >closer look ...
> >Oh ... you cheated! You used _three_ clocks. Well, this seems like a > >pretty Rube Goldberg "twin paradox", but I guess. The out and back > >clock could be replaced with two clocks running hot, straight and > >normal, which pass off a token in a kind of relay race. I agree then > >that the elapsed proper time on this clock pair would be less than on > >a single inertial clock which they crossed at event A and event B, > >although it could be argued that the two clocks doing the relay race > >were the moral equivalent of one clock doing a sharp acceleration.
> Yes, but the difference is that in the three-clock case, no > clock is physically accelerated. That should put an end to > the idea that time dilation is something physical > that happens to clocks when they accelerate.
Good Lord! Somebody else knows which tin has the Shinola.
[snip]
> >I guess the last question could be summed up by experiment: put any > >kind of clock we like in an ultracentrifuge. Spin liberally. Once we > >have accounted for (1) the relativistic effects of |u| (magnitude of > >speed at the end of the arm) (2) any direct effects of the stress > >field on the clock, is there (3) some residue left over for GR, an > >"intrinsic effect of acceleration".
> If your centrifuge is floating in flat spacetime, then GR doesn't > predict any effect that is not accounted for by SR. Both GR and > SR predict the same thing:
> Elapsed time on clock = > Integral of square-root(1-(v/c)^2) dt
Straightforward but insensitive experiment: Generate some suitably short half-life unambiguously countable (via 4(pi)steradian two-photon coincidence) radioisotope like 0-15 (2.03 min), N-13 (9.97 min), C-11 (20.3 min), or F-18 (109.8 min). Apportion the solution into two batches, one to sit on the bench and the other to whiz around in a Beckman-Coulter Optima MAX ultracentrifuge at one million gees for an hour or two. Run that puppy.
Will you see the effect of only velocity (SR) slowing time for the centrifuged sample, or will the pseudogravitational field (GR) add in? We expect only SR.
Simple experiment: Do an external Mossbauer resonance experiment with a sample in the running centrifuge rotor inside rim (correcting for transverse Doppler shift) vs. an identical piece sitting atop the hub (same angular velocity). Emitter and detector on opposite sides of the rotor is even nicer - same pseudogravitation, double the velocity difference - or are they moving at all vs. one another? "8^>)
-- Uncle Al http://www.mazepath.com/uncleal/ (Toxic URL! Unsafe for children and most mammals) "Quis custodiet ipsos custodes?" The Net!
: Blow the clock out the plasma warp drive. : Come back home. The clock NEVER accelerates.
Getting blown out of a plasma warp drive will usually cause your velocity to change.
-- --- "It's difficult ... you need to be united to have any strength, but internal issues have to be addressed." --- E. Ray Lewis, on liberalism in America
>Daryl McCullough wrote: >> Yes, but the difference is that in the three-clock case, no >> clock is physically accelerated. That should put an end to >> the idea that time dilation is something physical >> that happens to clocks when they accelerate.
>Good Lord! Somebody else knows which tin has the Shinola.
I have no idea what that means, but since I think I was agreeing with you, I'll take that as a compliment.
: > > Uncle Al <Uncle...@hate.spam.net> writes: : > > : Nothing runs "slow" in any reference frame.
As far as I'm concerned, the 3-clock experiment you posited CONFIRMS that moving clocks run slow; it does not refute it. When you bring your two pieces of paper announcing what times the moving clocks ran to, back to the place where "our" clock (clock 1) has ITS time, both of the numbers on those pieces of paper are a lot lower than the time on our clock -- or than half the time on our clock-- which IS what they WOULD say if those clocks were NOT running slow. -- --- "It's difficult ... you need to be united to have any strength, but internal issues have to be addressed." --- E. Ray Lewis, on liberalism in America
> > Fast mesons live longer than stationary muons. What goes tick tock in a > > meson?
> <Spaceman> > "Fast mesons" are a mass in motion and you > don't even see it. Motion = ticker. > Clock worship god sinking. Blub blub. > Research all clocks. > -2*-2 = -4 > Pressure of uncharged electrons as > big as basketballs. > LOL. > Yeeha! > </Spaceman>
What's the bet Spaceman does not thank you for saving him some typing?
> > : Blow the clock out the plasma warp drive. > > : Come back home. The clock NEVER accelerates.
> > Getting blown out of a plasma warp drive will > > usually cause your velocity to change.
> It won't be a clock any more and nobody will look at it anyway. You > really are thick.
That only happens in Gandankerville though, where light is actually used by morons as a speed limit. But, since it's irrelevant to technology, just like Relativity is, the spontaneously religous are always told that school bells, church bells, and Born Again Geometric Revivalist Ho Downs don't count as clocks.
> > > In Special Relativity Theory the basis of "Twin Paradox" is that > > > "moving clocks run slow". What is not clear is that, when a 'clock > > > runs slow' whether its frequency continuously decreases or not. Can > > > anyone clarify this point?
> > Nothing runs "slow" in any refernce frame. When otherwise identical > > clocks - one of which sustained a velocity relative to the other - are > > brought together to compare, one is seen to have less elapsed time > > than its twin due to its hyperbolic rotation through 4-space. The > > skewing factor is sqrt[1-(v^2/c^2)]. > > No clock need be accelerated for the Twin Paradox to occur.
> > Given any achievable velocities V1 and V2 and any finite lightspeed, > > the sum of the velocities as viewed by any inertial observer cannot > > exceed
> > (V1 + V2)/[1 + (V1)(V2)/c^2]
> > This is transformation of velocities parallel to the direction of > > motion. For velocities at an arbitrary angle theta,
> > Makes no difference who does the looking. Any inertial observer has a > > valid reference frame. Disparities are only noted upon comparison of > > reference frames. Spacetime is four-dimensional; travel through > > spacetime is a hyperbolic rotation of all four coordinates. However, > > the units of time are seconds not meters. ct is a nice length, but > > the this fundamental unit of length is a very long one.
> > At nominal velocities you don't travel much along ct compared to > > x,y,x. Galilean transforms and Newtonian physics are good enough > > approximations. At relativistic speeds you propagate along ct > > comparable to a material dimension. You need Lorentzian transforms > > and relativity to explain initially synchronized clocks separated and > > then brought together for comparison thereafter.
> > Acceleration of one observer has nothing to do with it, BTW.
> > 1) Acceleration is an absolute measurement. There is no doubt who > > is accelerated. > > 2) Acceleration is irrelevant.
> > We have three identical clocks that are off (a state of not running) > > and zeroed. Each clock has a very short toggle jiggger switch > > sticking out. We load them in individual spaceships and set up the > > experiment.
> > CLOCK 1: That's our clock. It sits stationary in our inertial > > reference frame with a little jigger sticking out. Touch the jigger > > and the "off" state becomes "on" or the "on" state becomes "off." > > Clock 1 is "off."
> > CLOCK 2: In a spaceship traveling at 0.999c relative to our > > inertial frame of reference. Clock 2 is "off." It skims past Clock > > 1, the jiggers touch, both Clocks 1 and 2 are now "on" and > > synchronized.
> > CLOCK 3: In a spaceship traveling at 0.999c relative to our > > inertial frame of reference, but 180 degrees counter in direction to > > Clock 2. Clock 3 is "off." Some arbitrary time after Clocks 1 and 2 > > synchronize and turn "on" by touching, Clocks 2 and 3 brush past each > > other, touching jiggers. Clock 2 is now "off," Clock 3 is now "on."
> > CLOCK 1: That's our clock. It sits stationary in our inertial > > reference frame with a little jigger sticking out. Clock 3 rushes > > past, jiggers touch. Clocks 3 and 1 are now off. All clocks are > > off. No clock has accelerated while "on."
> > BOTTOM LINE: Get all three clocks together and compare elapsed > > times. Elapsed time #2=#3, but elapsed time #2+#3 does not equal #1, > > the local stationary reference frame summation. The sum of #2+#3 > > elasped time is only about 4.5% that than of #1's accumulated elapsed > > time. You now have the Twin Paradox without any running clock having > > been accelerated.
> When you can define time, then maybe your input will be interesting. > Clocks do not measure the passage of time, they 'register' an internal > velocity (of some mass or system of mass) times it's displacement,
Oops! Make that inverse of velocity times displacement.
> either linear or angular depending upon the type of clock, an internal > velocity that must change in order for the registered 'ticks' to get out > of sync with another clock. A change in velocity does not a change in > time equal. Now suppose I adopt the motion of an elastic ball between to > walls as my time-piece: > 1) How will this clock differ fundamentally from any other clock? > 2) Since when will an acceleration of the elastic ball constitute a > change in the rate that I am passing through time, rather than > constituting simply an increase in its intrinsic frequency wrt time?
: George Greene wrote: : > : > Uncle Al <Uncle...@hate.spam.net> writes: : > : > : Blow the clock out the plasma warp drive. : > : Come back home. The clock NEVER accelerates. : > : > Getting blown out of a plasma warp drive will : > usually cause your velocity to change. : : It won't be a clock any more
Then it won't be a frame any more either, according to your previous equation of a clock with a frame.
: and nobody will look at it anyway.
OK, fine, they only look at the little piece of paper or whatever emitted by the clock after it shuts off, telling how long it ran. That doesn't change anything. The number on that piece of paper is still smaller than (half of) the number on the piece of paper coming out of clock 1. In other words, that clock really DID run slow. -- --- "It's difficult ... you need to be united to have any strength, but internal issues have to be addressed." --- E. Ray Lewis, on liberalism in America
: >> Yes, but the difference is that in the three-clock case, no : >> clock is physically accelerated.
While it's running. Or even existing, if he wants to keep going that far.
: >> That should put an end to : >> the idea that time dilation is something physical : >> that happens to clocks when they accelerate.
Hardly. It was about FRAMES, NOT clocks. Which Uncle Al wilfully obscured first by claiming that clocks ARE frames and then insisting that clocks could be destroyed (frames can't).
His originally claim was that the usual maxim that "moving clocks run slow" was disprovable. This thought experiment doesn't disprove that; it proves it. Seconds are "longer" for the moving clock and the faster it is going the longer they are. In other words, the more they have been dilated. And they GOT dilated BY/DURING the acceleration. Which was happening to the FRAME (or the ship that the clock later got built on, right before it got turned on), NOT the clock.
-- --- "It's difficult ... you need to be united to have any strength, but internal issues have to be addressed." --- E. Ray Lewis, on liberalism in America
> > When you can define time, then maybe your input will be interesting. > > Clocks do not measure the passage of time, they 'register' an internal > > velocity (of some mass or system of mass) times it's displacement, > > either linear or angular depending upon the type of clock, an internal > > velocity that must change in order for the registered 'ticks' to get out > > of sync with another clock.
> Radioactivity, shithead. You look at the declining rate of decay and > that is your clock. Why don't you tell us where the "internal > velocity" is in radioactivity?
It's not too fucking complicated that even you can't understand Al, but only agglomerations of quanta produce radioactive decay. Which of the involved quanta has zero velocity shit for brains? Controlled fission, hmmm Al, how the hell did that happen I wonder, I mean, radioactive decay is independently spontaneous, uncaused, isn't it? Git.
> When you can define time, then maybe your input will be interesting. > Clocks do not measure the passage of time, they 'register' an internal > velocity (of some mass or system of mass) times it's displacement, > either linear or angular depending upon the type of clock, an internal > velocity that must change in order for the registered 'ticks' to get out > of sync with another clock.
Time o regarded as a coordinate dimension and required by relativity theory, along with three spatial dimensions, to specify completely the location of any event.
> > When you can define time, then maybe your input will be interesting. > > Clocks do not measure the passage of time, they 'register' an internal > > velocity (of some mass or system of mass) times it's displacement, > > either linear or angular depending upon the type of clock, an internal > > velocity that must change in order for the registered 'ticks' to get out > > of sync with another clock.
> Time > o regarded as a coordinate dimension and required by relativity > theory, along with three spatial dimensions, to > specify completely the location of any event.
As perceived: A motion through ordered changes in state of the universe.
As it enters physics: The logical displacement of the initial state of a closed system and the state of the same system through an arbitrary and homogenous sequence of changes. Those cyclic changes in a sub-system (also virtually closed) in particular being regarded as "regular", and arbitrarily designated as a standard unit of change. The homogenous sequence of ordered microscopic changes (events) in the universe constitute a universal time-line, "moved" through equally by all particles, since all particles simultaneously exist in every state subtending any "duration".
> > > When you can define time, then maybe your input will be interesting. > > > Clocks do not measure the passage of time, they 'register' an internal > > > velocity (of some mass or system of mass) times it's displacement, > > > either linear or angular depending upon the type of clock, an internal > > > velocity that must change in order for the registered 'ticks' to get out > > > of sync with another clock.
> > Time > > o regarded as a coordinate dimension and required by relativity > > theory, along with three spatial dimensions, to > > specify completely the location of any event.
> As perceived: A motion through ordered changes in state of the universe.
> As it enters physics: The logical displacement of the initial state of a > closed system and the state of the same system through an arbitrary and > homogenous sequence of changes. Those cyclic changes in a sub-system > (also virtually closed) in particular being regarded as "regular", and > arbitrarily designated as a standard unit of change. The homogenous > sequence of ordered microscopic changes (events) in the universe > constitute a universal time-line, "moved" through equally by all > particles, since all particles simultaneously exist in every state > subtending any "duration".
> In <3DB81FA6.ADDC5...@hate.spam.net> Uncle Al <Uncle...@hate.spam.net> writes:
> [Three-clock version of the twin paradox]
> Hey, that's good. Really good!
> Also, I salute your ability to draw out idiots with a substantive > post. Is this normal in sci.physics? I'm reading the thread from > sci.logic .
One might suspect that a superior mentality would draw out an angry otherwise disenfranchised mob. In sci.physics *any* working mentality generates shockwaves in kind. Cranks, crackpots, and psychotics are like eunuchs in a brothel. Their mouths hang open drooling spit and they loudly boast about their prowess, but there are no facts arising - and slapping on a testoterone patch is like administering medicine to the dead.
Physics is self-consistent. Physics contains no mistakes. However, physics is ripe for attack at its postulates (as was Euclid when elliptic and hyperbolic geometries appeared),
nullde...@aol.com (Edward Green) wrote in message <news:2a0cceff.0210250540.5b66532c@posting.google.com>... > Indeed, how could it be otherwise? SR > knows nothing of acceleration, contains no terms in acceleration, and > hence any effects of acceleration in SR must merely be an integrated > compounding of many small increments of constant velocity. To deal > with the effects of acceleration per se on matter we need GR.
False.
> Actually, I'm not 100% sure of the last claim: Is there any "purely > GR-ish" effect related to the acceleration of material bodies in flat > space, or are all physical effects obtained by combining the > predictions of SR with any direct effects of the forces involved on > the body?
> Some question just never go away. Damn.
They would go away, if only you were willing to take the time (and invest the effort) to read (and work your way) through MTW.
If you are comfortable with special relativity, go directly to chapter 6 ("accelerated observers"). Read the chapter and work out all the problems. There you have SR dealing with acceleration. No big deal.
"Franz Heymann" <Franz.Heym...@btopenworld.com> wrote in message <news:apbp93$j5u$2@knossos.btinternet.com>... > "V.Gopal" <vgopa...@rediffmail.com> wrote in message > news:38af3945.0210240748.1fc8e6cb@posting.google.com... > > In Special Relativity Theory the basis of "Twin Paradox" is that > > "moving clocks run slow". What is not clear is that, when a 'clock > > runs slow' whether its frequency continuously decreases or not. Can > > anyone clarify this point?
> If a clock's frequency continuously decreases, it needs winding up.
> Franz Heymann
It needs no winding up, let it stop. What I want to know is how do we express or convey continuously and uniformly decreasing rate of counting. Can we know when we reach zero if the rate of counting decreases uniformly and continuously? Here 'counting' does not divide time into equal intervals and in this case because there is no linear or angular displacement, time appears to 'shrink' continuously. How can we canvey rate of shrinkage of time?
|
