Thread: Is time universal? NO (and its proof)

  1. #821
    Registered Senior Member MacM's Avatar
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    Pete,

    Typo.
    Your meter markers are an Earth-frame ruler.
    The spaceship clock is a spaceship-frame clock.
    Fair enough.

    If you want to calculate velocity, you need to use clocks and rulers from the same frame... as you agreed.
    Still agree and assert that you have changed measurement standards (rulers) when you cross over frames and use a dilated clock in d = vt.

    Typo, I think. SRT suggests that length is frame dependent. This follows directly from the postulate of the invariance of c, as shown.
    Agreed. It is merely "suggested" by the assumption about the invariance. But other consequences suggest more pointedly that that assumption must be flawed. i.e. - Reciprocity.

    It is not necessary to make that assumption, Mac.
    And in fact, if c is frame-invariant, then length must vary between frames, as shown. Or as will be shown, if you bother trying the exercise.
    Nor is it "necessary" to conclude the invariance is due to a given photon having this magical power.

    It is more rational to assume a different physics not detected such as RCM or Emission Extinction Shift or my view of a quantum energy based photon where every frame will see a different photon based on the observers relative velocity (energy) to the source where the source is exciting a multi-energetic spectrum of energies in some carrier medium (which may also account for particle entanglement)..

    What particular "basic physics" principles do you invoke?
    What basic physics principles to you invoke to account for the invariance?

    Or are you simply asserting that length is frame invariant?
    I assert that the assumption of invariant velocity between frames when velocity is based on v = d/t and using a different "t' standard but treating t as = t' is false.

    I assert that the dilated t' is a change in measurement standard (rulers) and that acknowledging that mathematically shows physical distance in a universal sense has not occured.

  2. #822
    Registered Senior Member MacM's Avatar
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    Quote Originally Posted by Pete
    Look closer, Mac. Pick any Train clock and any embankment clock. Compare the time that elapses on each clock over any duration. Do this in each frame, and tell us what you find.
    I don't need to look closer. I merely wanted to note the respective clocks being compared. It is obvious that all clocks in each frame undergo the same accumulative time change.

    Mac, you're trying to impose absolute simultaneity again. If the test ends when clock Te meets clock Ee, the time shown on the other clocks simultaneously with this event is frame-dependent according to SRT.

    Come on, this is basic stuff.
    This is where you error. Time of start is when both frames see Ta & Ea point at 12:00 O'clock. (You can pick any number of such start comparisons but they are all linked to this condition.)

    The test ends when Ee & Te reads 12:00 O'clock in both frames. (again you can pick any number of simular comparisons but all are linked to this condition.

    Having said that and acknowledging that the test is broken down into 12 equal steps in both frames and assuming that the dial is a minute hand of a clock, it can be seen that the test is 1 hour duration in both frames.

    Your simultaneity arguement is a failure and serves only to confuse and cloud the issue. The test time is one hour in both frames. Therefore what you have can only be perception due to illusions of motion and not physical time dilation with reciprocity which can or will be displayed on any clock.

    i.e. - It is not actual time dilation and is nothing more than an assertion made by SRT but is unsupported by physics.

    It is this absence of actual recorded time dilation and common sense which stipulate that the assumption about invariance of SOL is flawed. It mandates a different view.
    Last edited by MacM; 01-25-06 at 01:41 AM.

  3. #823
    Quote Originally Posted by MacM
    Still agree and assert that you have changed measurement standards (rulers) when you cross over frames and use a dilated clock in d = vt.
    So you agree that to measure velocity in the space ship frame, we need to use clocks at rest in the spaceship frame and rulers at rest in the spaceship frame?
    Or do you still want to use the clock in the spaceship frame and the ruler in the Earth frame?



    Quote Originally Posted by MacM
    Agreed.
    So you do agree that if c is frame invariant, then lengths are contracted in moving frames? I'm surprised, but impressed.

    But other consequences suggest more pointedly that that assumption must be flawed. i.e. - Reciprocity.
    I sense we're returning to your persistent notion that relativity predicts that two clocks taken apart and brought together again will show less time than each other.

    We have discussed this before... over and over and over. In each case, you get caught assuming that simultaneity is absolute. But in fact, if c is frame invariant, then simultaneity cannot be absolute.

    Nor is it "necessary" to conclude the invariance is due to a given photon having this magical power.

    It is more rational to assume a different physics not detected such as RCM or Emission Extinction Shift or my view of a quantum energy based photon where every frame will see a different photon based on the observers relative velocity (energy) to the source where the source is exciting a multi-energetic spectrum of energies in some carrier medium (which may also account for particle entanglement)..

    You're welcome to your opinion, of course.

    Quote Originally Posted by MacM
    Because basic physics shows there is no differance in spatial seperation of the meter markers.
    Quote Originally Posted by Pete
    What particular "basic physics" principles do you invoke?
    What basic physics principles to you invoke to account for the invariance?
    It seems your claim was unfounded, hmmm?
    It would indeed be interesting to account for the invariance, but as far as I know it's just the nature of the Universe. If it turns out that c is not frame invariant, then I'll be excited... but since all experimentation to date is consistent with c being frame invariant, why should we not accept the idea and its consequences? Is the notion of non-absoluteness of time and space really that disturbing to you?

  4. #824
    Quote Originally Posted by MacM
    Nice work granted. However, it must be noted that it is based on the assumption of recipocal time dilation and spatial length contraction (Reciprocity).

    Which simply has not ONCE been demonstrated. I have never argued that SRT didn't advocate such results. I have argued such results have not been demonstrated and are nonsensical.
    You are welcome to your opinion, of course. I merely note that all experiments to date are exactly consistent with the idea.

    We should also note that the respective clocks claimed to have accumulated 1/2 the amount of time are Ta & Ed in the Embankment Frame and it is Td & Ea in the Train Frame.

    This is not Clock A slower than clock B and clock B slower than clock A.
    So compare Ta and Ed in the train frame, and Td and Ea in the embankment frame. In the train frame, Ed ticks half an hour in the time it takes Ta to tick an hour. In the embankment frame, Td ticks half an hour in the time it takes Ta to tick an hour.
    What do you know? Clock A ticks slower than Clock B, and Clock B ticks slower than Clock A!

    Quote Originally Posted by MacM
    Further if you look at the 12:00 O'clock position of Ta in the Embankment Frame at the start and its 6:00 O'clock position at the end of the test.

    That is in complete disagreement with the Train Frame where Ta starts at 12:00 O'clock and ends at 12:00 O'clock in the same physical test period.
    You're assuming absolute simultaneity again.
    The clocks shown are snapshots of the clock locations and times as they pass each other. But the clocks continue to tick and move before and after the test.

    Each set of snapshots begins when clock Ta meets clock Ea, and shows the other clocks as they are simultaneously with this event.

    If simultaneity is relative (as required by the invariance of c), then naturally the snapshots don't begin at the same time for any other clock.

    If you think this leads to impossible conclusions, please give details. Repeated assertions of "nonsense" are inadequate on their own. Show us how it would lead to a physical contradiction... a trigger firing in one frame but not another, for example.

  5. #825
    Registered Senior Member MacM's Avatar
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    Quote Originally Posted by Pete
    So you agree that to measure velocity in the space ship frame, we need to use clocks at rest in the spaceship frame and rulers at rest in the spaceship frame?
    Correct.

    Or do you still want to use the clock in the spaceship frame and the ruler in the Earth frame?
    I have NEVER made any such statement. I have said and do say the "Rulers" are the same in both frames. As a minimum there is no basis to assume otherwise or to ignore the dilated condition of the clock being used to measure d = vt. Ignoring the emperical known condition of the moving clock is assinine and the consequences of such an assumption is unacceptable.

    So you do agree that if c is frame invariant, then lengths are contracted in moving frames? I'm surprised, but impressed.
    I have NEVER argued otherwise. But "IF" is a very large word. It seems you are only now beginning to understand that my view is NOT one of ignorance about relativity but one of rejecting the relavistic view of the data.

    My doing so is not a stand alone view there are numerous Phd physicists that do also. I grant without arguement that there are more that are reluctant to either consider alternatives or openly challenge relativity.

    I sense we're returning to your persistent notion that relativity predicts that two clocks taken apart and brought together again will show less time than each other.
    That is correct and I stand by that interpretation. You and others only confuse yourselves on this issue by trying to argue simultaneity shifts and that is not at issue if you look deep enough at the question.

    We have discussed this before... over and over and over. In each case, you get caught assuming that simultaneity is absolute. But in fact, if c is frame invariant, then simultaneity cannot be absolute.
    Correct but "IF" is a much larger word than just its two characters. There is really no logical basis to assume the measured invariance is actually invariance of the same photon.

    You're welcome to your opinion, of course.
    Thanks, that would be nice for a change.

    It seems your claim was unfounded, hmmm?
    This comment is unresponsive and false.

    It would indeed be interesting to account for the invariance, but as far as I know it's just the nature of the Universe.
    Cop out.

    If it turns out that c is not frame invariant, then I'll be excited... but since all experimentation to date is consistent with c being frame invariant, why should we not accept the idea and its consequences? Is the notion of non-absoluteness of time and space really that disturbing to you?
    Not disturbing at all. Disappointing that we cannot move forward with greater indepth consideration of actual physics and forget all the assinine voodo.

  6. #826
    MacM,

    I frankly don't care about your wacky redefinition of time, distance and velocity. If you want to deny that d = vt (which is true pr. definition), then you damn sure are going to come up with something other than "because I say so".

    Furthermore, your insistence at using dilated time instead of measured time (which is as clear cut a case of frame mixing as I've seen) has the obvious fault that you don't know which frame is the "real" rest frame.

    Here's a scenario for you.

    An observer in a spaceship, A, with its engine turned off is passed by another spaceship, B, also with its engine turned off. A measures the speed of B by, say, measuring the time, t, it takes for the tip of B's rocket to pass from the tip to the tail of A's rocket. A knows the length of his rocket to be l meters, and by definition B's speed with respect to A is v = l/t.

    1. Is this a valid way for A to measure B's speed wrt. A?

    With the speed in hand, A measures the length of B's rocket by measuring the time it takes for B's rocket to pass by a given point on A's rocket (say, the tip). This takes time t'. So the length, l', of B's rocket is l' = v*t'.

    2. Is this a valid way for A to measure B's rocket's length?

  7. #827
    Quote Originally Posted by MacM
    Quote Originally Posted by funkstar
    Now, will you acknowlegde that relativity theory does not predict that two clocks taken apart and brought together again will have to show less time than each other, or will you not?
    I dispute your assertion. As the extract posted above shows reciprocity infact requires precisely what I have merely quoted.
    Wool.

    Do you believe that mutual time dilation can ever lead to a prediction that two clocks A and B, brought apart and brought together again, will have to show mutually less accumulated time, i.e. A reads less than B and B reads less than A; yes or no?

  8. #828
    Quote Originally Posted by MacM
    We should also note that the respective clocks claimed to have accumulated 1/2 the amount of time are Ta & Ed in the Embankment Frame and it is Td & Ea in the Train Frame.
    *fault buzzer*

    All the clocks of the embankment frame accumulate exactly half the amount of time as the train clocks during the experiment as viewed from the train frame, and vice versa. You need better glasses, obviously. You didn't think that just because the time dilation ratio is independent of the clock position, that the actual times on the clocks would be so, too? Or have you forgotten that the transformed time coordinate is dependent on the original space coordinate as well as the original time coordinate?
    This is not Clock A slower than clock B and clock B slower than clock A.
    Of course it is. From the embankment frame every clock in the train frame is ticking slower than every embankment clock, and vice versa.

    You really didn't look at the diagram, did you?
    Further if you look at the 12:00 O'clock position of Ta in the Embankment Frame at the start and its 6:00 O'clock position at the end of the test.

    That is in complete disagreement with the Train Frame where Ta starts at 12:00 O'clock and ends at 12:00 O'clock in the same physical test period.


    You now have specific physical clocks recording two distinctly different accumulated times in the same test period.
    Simultaneity is relative.
    WHICH DO YOU WANT TO CLAIM THE CLOCK WILL DISPLAY AT THE END OF THE TEST? IT CANNOT AND WILL NOT DISPLAY BOTH WILL IT.
    Depends, doesn't it. On what, you say? Well, on the frame, of course. Because, as the diagram illustrates, the two frames do not agree on when the experiment ends. For instance, the train frame says that when the experiment ends then all the train clocks read the same thing, but the embankment clocks are all over the place. The embankment frame, of course, disagrees.

    So, when you want to specify the time at which the experiment ends, you need to specify a frame, too.
    The later is physically impossible. Thanks for making this even more clear to readers.
    MacM is physically impossible. I said it, so it must be true.

    Oh, hang on. Nature doesn't bend to my whim. Hmm. Somebody here could learn from that.

  9. #829
    Quote Originally Posted by 2inquisitive
    I'm not trying to disagree with you personally, DaleSpam, just pointing out what seems to me to be philosophical errors in STR gedankins.
    I have never felt any personal attacks in any of your comments. I actually quite enjoy your posts. You are one of the few with whom it is possible to actually have a conversation that progresses instead of getting stalled repeating the same thing over and over.

    Quote Originally Posted by 2inquisitive
    If the photon is emitted at 90 degrees perpendicular to the direction of things passing by the observer in his 'rest' frame, how can it be emitted at a different angle in the distant observer frame unless the photon is 'carried along' by the frame, i.e. not independent of the motion of the frame?
    That is a good question. After all, the laser is "aimed" at 90º, not an angle of arctan(4/3). Unfortunately, I don't have a good answer to this question except to point out that this is not unique to the Lorentz transform, it applies just as much to the Galilean transform. In other words, let's forget for a moment the invariance of c, time dilation, length contraction, etc., and try to explain the operation of a light clock using the Galilean transform. I will refer back to my previous perpendicular example:


    So the light clock is 4 sc (lightseconds) long. In it's proper frame the light has a path length of 8 sc so it ticks once every 8 s. In our frame it is moving at .6 c, so the total path length of the light is 10 sc. Since we are not using any of the SRT concepts the speed of the photons is 10 sc / 8 s = 1.25 c in our frame, and their clock doesn't run slow, their lengths are not contracted, etc. This is the Galilean or non-relativistic view.

    However, the light must still be emitted at 90º in the clock's proper frame and arctan(4/3) in our frame. So, the angle thing is just a function of a frame change, regardless of what method you pick. So this isn't really a SRT problem. I think the only way to not have that angle effect is to conclude that there is some absolute prefered reference frame and that physics only works correctly there.

    -Dale

  10. #830
    Quote Originally Posted by MacM
    WHAT? Not hardly. Others stopped posting since they had no valid rebuttal to the issue of different photons in different frames view where the explosion would hence become simultaneous in all frames but not the view of light activation of the detonators.
    MacM, you are a champion at ignoring facts. Looking back at just the conversation between you and me on the photons/Mustangs I count about 18 posts on this topic, with mine being the most recent. I didn't know that this was related to the doomsday device, but the different photons idea was dropped by you, not others.

    And you still haven't shown how your idea precludes relativity which is based entirely on the motion of light not its identity.

    -Dale

  11. #831
    Please use Sugar Cane Alcohol Billy T's Avatar
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    Quote Originally Posted by DaleSpam
    ...the laser is "aimed" at 90º, not an angle of arctan(4/3). Unfortunately, I don't have a good answer to this question except to point out that this is not unique to the Lorentz transform, it applies just as much to the Galilean transform...
    Perhaps it will help 2inqusitive to imaging that in the moving frame there are several thin pieces of paper in the perpinducular path the photons use to go to the mirror. Also imagine that the LASER is intense but very short duration, so that it is meaningful to speak of the current location of the burst of optical energy and this burst burns holes in this straight line of papers. The returning light after mirror reflection passes back thru these same holes. (and this "return thru holes" is true also for the distant observer, not moving with the LASER or the line of papers.)

    The distant observer makes an xy plot (using his coordinate frame of course and x=t= time, like Dales plots.) of where the paper hole was when it was made by the LASER's light burst going to the mirror, and also where each of the holes was as the reflected beam came back thru each of these holes.

    To 2inqusitive:

    What is the shape of the distant observer's plotted points? Can you not see that they all are on a V shaped trajectory? I.e. For him, even though the LASER was aimed perpendicular to the mirror, the path of the light does not strike the mirror perpendicularly and it also reflects at angle, not 90 degrees.

    Hope this helps.

    BTW, I agree with Dale, you are willing to learn and unlike some, not so sure that your are correct and that 99+% of all physics PH.D. are wrong to believe SRt. etc. (But SRT is confirmed by 1000s of experiments, not by votes of Ph.D. physicists.)
    Last edited by Billy T; 01-25-06 at 06:09 PM.

  12. #832
    Registered Senior Member MacM's Avatar
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    Quote Originally Posted by funkstar
    MacM,

    I frankly don't care about your wacky redefinition of time, distance and velocity.
    And I care even less about your distortion of what I have said.

    If you want to deny that d = vt (which is true pr. definition), then you damn sure are going to come up with something other than "because I say so".
    Since you do seem to be a bit of a slow learner I will try 1 last time to walk you through the door. I have never claimed d = vt is invalid.

    Furthermore, your insistence at using dilated time instead of measured time (which is as clear cut a case of frame mixing as I've seen) has the obvious fault that you don't know which frame is the "real" rest frame.
    Here is where you are getting lost. I am not using dilated time. You think that because you are not listening and you are making to many assumptions about me personally. I don't know your education or experience but I can assure you I can converse rationally along side you in most topics.

    Frankly I can more likely teach you some things if you were not so hard headed and egotistical.

    Here's a scenario for you.

    An observer in a spaceship, A, with its engine turned off is passed by another spaceship, B, also with its engine turned off. A measures the speed of B by, say, measuring the time, t, it takes for the tip of B's rocket to pass from the tip to the tail of A's rocket. A knows the length of his rocket to be l meters, and by definition B's speed with respect to A is v = l/t.

    1. Is this a valid way for A to measure B's speed wrt. A?

    With the speed in hand, A measures the length of B's rocket by measuring the time it takes for B's rocket to pass by a given point on A's rocket (say, the tip). This takes time t'. So the length, l', of B's rocket is l' = v*t'.

    2. Is this a valid way for A to measure B's rocket's length?
    We don't need new scenario's. YOU need to address my scenario. You need to understand that I only point out the dilated clock in the moving frame because it is a known and emperically demonstrated physical fact.

    After recognizing that fact and that the trip time differential of the moving frame is completely accounted for by the fact of the dilated clock and there is and can be no contracted space, I then compute "v" based on the local proper time of the moving frame and the fixed distance of space.

    That shows that the correct consequence of time dilation is velocity that is frame dependant, not distance that is frame dependant. This all comes naturally by the acknowledgement of known physical measurement standards between frames.

    Since the trip time is accounted for by the dilated tick rate of the clock and length contraction is prohibited it becomes mandatory that "v" is what changes in the moving frame.

    If you are to inept to understand that then what can I say. I will merely sumarize the situation. You specifiy which aspect is incorrect physically - not according to some theory that ignores measurement standard variations between frames.

    1 - The trip time of the moving observer is accounted for by the dilated tick rate of his clock.

    2 - #1 leaves no physical room or basis for claiming spatial length contraction, it becomes frame invariant.

    3 - Using the local proper time and the invariant spatial dimension it is "v" that becomes frame dependant and not "d".
    Last edited by MacM; 01-25-06 at 07:46 PM.

  13. #833
    Bloodthirsty Barbarian
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    Quote Originally Posted by MacM
    1 - The trip time of the moving observer is accounted for by the dilated tick rate of his clock.

    2 - #1 leaves no physical room or basis for claiming spatial length contraction, it becomes frame invariant.

    3 - Using the local proper time and the invariant spatial dimension it is "v" that becomes frame dependant and not "d".
    But the time dilation in #1 depends on the velocity, no? Which velocity is it, since the two frames don't agree, and why?

  14. #834
    Registered Senior Member phoenix2634's Avatar
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    MacM,
    Not really sure I want to ask, but what the hell...

    Couldn't you also calculate that the spaceships velocity is still .866c? What I mean is since your using the spaceships clock which is running twice as slow as the Earth clock, you could calculate that the c = 600,000km/s. Since the ratio of the clocks rate is 2:1? And since the ships captain notices the ship passing 519,600km/s...This probably makes a little more sense physically...given your current argument...eliminates length contraction, still accounts for time dialtion, eliminates the illusion of the ship traveling 1.732c, still maintains a constant speed of light (which would have to numerically vary based upon the rate of a clock...you don't have to go anywhere to illustrate this point...take a metronome crank it up to 120 beats/minute counting each beat as one second the speed of light should be 150,000km/s

    I don't know I am probably just thinking crazy thoughts right now...but it is something I wanted to ask...

  15. #835
    Quote Originally Posted by MacM
    Quote Originally Posted by Pete
    So you agree that to measure velocity in the space ship frame, we need to use clocks at rest in the spaceship frame and rulers at rest in the spaceship frame?
    Correct.
    And yet in your scenario, you are clearly using a ruler at rest in the Earth frame to calculate velocity in the spaceship frame.

    You explicitly use the meter markers (at rest in the Earth frame) to measure velocity in the spaceship frame. In direct denial of the agreed rule that clocks and rulers must be in the same frame to measure velocity.

    Why agree to the rule if you then assume that any ruler will do?
    And why assume that any ruler will do if you don't need to?
    Why not use a ruler that is at rest in the spaceship frame (like you agreed we must), instead of assuming that the one in the Earth frame will do?

    We don't have to assume that the rulers are different. We don't have to assume that they are the same. All we need to do is to use a ruler at rest in the frame we're measuring velocity in, then we know we're safe.

    That is correct and I stand by that interpretation.
    I see we need to return to this issue yet again. Don'y forget to review our recent discussion about simultaneity in this thread first. I think you need to honestly work at understanding what simultaneity in relativity means to clear up your misconceptions (like when you said "If I am setting at the back of the train the aft explosion occurs first and vice versa if I am setting at the front of the train.") before you tackle that problem again.

    There is really no logical basis to assume the measured invariance is actually invariance of the same photon.
    Invariance is about more than photons. If it were only about photons, then why can't any massive particles be accelerated past c? Why do relativity-based calculations of the equations of state for stars give accurate predictions?

    Postulating some magical nature of photons to account for the apparent invariance of speed seems like voodoo to me, and it fails to account for other predictions of relativity.

    But like I said... you're welcome to hold whatever faith-based opinion you like. It's the bad logic and misstatement of facts that I'll pull you up on.
    Last edited by Pete; 01-25-06 at 10:36 PM.

  16. #836
    Registered Senior Member MacM's Avatar
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    Quote Originally Posted by quadraphonics
    But the time dilation in #1 depends on the velocity, no? Which velocity is it, since the two frames don't agree, and why?
    Good question. I certainly don't have all the answers. However, the time dilation seems based on actual motion assuming an accelerated condition. That would be the velocity as stipulated by the rest observer (in this scenario).

    There seems to be no emperical evidence of any time dilation due to mere relative velocity or in this case of the apparent velocity of the non-accelerated frame.

    I am merely making note of a most unusual situation.

  17. #837
    Registered Senior Member MacM's Avatar
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    Quote Originally Posted by phoenix2634
    MacM,
    Not really sure I want to ask, but what the hell...

    Couldn't you also calculate that the spaceships velocity is still .866c? What I mean is since your using the spaceships clock which is running twice as slow as the Earth clock, you could calculate that the c = 600,000km/s. Since the ratio of the clocks rate is 2:1? And since the ships captain notices the ship passing 519,600km/s...This probably makes a little more sense physically...given your current argument...eliminates length contraction, still accounts for time dialtion, eliminates the illusion of the ship traveling 1.732c, still maintains a constant speed of light (which would have to numerically vary based upon the rate of a clock...you don't have to go anywhere to illustrate this point...take a metronome crank it up to 120 beats/minute counting each beat as one second the speed of light should be 150,000km/s

    I don't know I am probably just thinking crazy thoughts right now...but it is something I wanted to ask...
    As I said to Quad... above, I don't hve all the answers but I don't see how one can calculate anyother value than 1.732c as viewd from the moving frame.

  18. #838
    Registered Senior Member MacM's Avatar
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    Quote Originally Posted by Pete
    And yet in your scenario, you are clearly using a ruler at rest in the Earth frame to calculate velocity in the spaceship frame.

    You explicitly use the meter markers (at rest in the Earth frame) to measure velocity in the spaceship frame. In direct denial of the agreed rule that clocks and rulers must be in the same frame to measure velocity.

    Why agree to the rule if you then assume that any ruler will do?
    And why assume that any ruler will do if you don't need to?
    Why not use a ruler that is at rest in the spaceship frame (like you agreed we must), instead of assuming that the one in the Earth frame will do?

    We don't have to assume that the rulers are different. We don't have to assume that they are the same. All we need to do is to use a ruler at rest in the frame we're measuring velocity in, then we know we're safe.
    How do you dismiss the fact that I have shown that the ruler (distance) is invariable and is the same in both frames.

    I AM USING THE MOVING FRAME RULER. IT JUST HAPPENS TO BE THE SAME SIZE AS THE REST RULER BECAUSE IT COULD NOT AND DID NOT CHANGE AS ADVOCATED BY SRT.

    The change in rulers advocated by SRT is based on changing measurement standards in the form of the tick rate of the clock. Hence the physical spacing of the meter markers did not and cannot change.

    Draw yourself a horizontal line on a piece of paper. Now above the line divide the line by 100 evenly spaced marks. Call those marks clock ticks in the rest frame.

    Now below the line draw the tick marks of the comparative moving clock which has a gamma = 2.000. That is one tick mark for every two tick marks above the line.

    You now have 100 marks above the line and 50 marks below the line. Notice you have recorded 1/2 the accumulated time in the moving frame but the physical length of the line has not changed.

    I see we need to return to this issue yet again. Don'y forget to review our recent discussion about simultaneity in this thread first. I think you need to honestly work at understanding what simultaneity in relativity means to clear up your misconceptions (like when you said "If I am setting at the back of the train the aft explosion occurs first and vice versa if I am setting at the front of the train.") before you tackle that problem again.
    We have covered this issue. I was expressing my concerns about Billy T's statment that all train observers "Saw" the explosion at the same time. They don't due to signal proagation delay.

    That issue has absolutely nothing to do with this situation.

    Invariance is about more than photons. If it were only about photons, then why can't any massive particles be accelerated past c?
    You are ignoring the fact which I have pointed out before that you are trying to accelerate particles using EM which is propagating at v = c relative to the lab frame.

    It would be amazing indeed if a car could push another car faster than the pushing car could go. The v = c limit is on the transfer of energy between objects and not on objects perse.

    Why do relativity-based calculations of the equations of state for stars give accurate predictions?
    This is completely irrelevant.

    Postulating some magical nature of photons to account for the apparent invariance of speed seems like voodoo to me, and it fails to account for other predictions of relativity.
    The voodoo is to grant a specific photon the ability to exist at v = c to every observer in the universe, all of which are moving relative to each other.

    But like I said... you're welcome to hold whatever faith-based opinion you like. It's the bad logic and misstatement of facts that I'll pull you up on.
    You are welcome to do that. Indeed please do that for the physical circumstance I have outlined in this scenario.

    Do you deny that the accumulated trip time of the moving clock is accounted for by the stipulated and physical time dilation (tick rate) of the clock?

  19. #839
    Quote Originally Posted by MacM
    How do you dismiss the fact that I have shown that the ruler (distance) is invariable and is the same in both frames.
    You asserted it plenty of times... but that doesn't make it a fact.

    I AM USING THE MOVING FRAME RULER.
    Are you using the meter markers to calculate velocity?
    Are the meter markers stationary in the Earth frame?

    Assuming that a ruler is eqiuvalent to a spacehsip frame ruler is not the same as using a spaceship frame ruler.

    The change in rulers advocated by SRT is based on changing measurement standards in the form of the tick rate of the clock. Hence the physical spacing of the meter markers did not and cannot change.
    Mac, you agreed that length contraction is required by the postulate of the invariance of c. It's not based on time dilation... it's follows from invariance of c.

    If you want to argue against the invariance of c, fine, do so... there's no need to pretend that length contraction has any other source.

  20. #840
    Quote Originally Posted by MacM
    We have covered this issue. I was expressing my concerns about Billy T's statement that all train observers "Saw" the explosion at the same time. They don't due to signal proagation delay.

    That issue has absolutely nothing to do with this situation.
    Your confusion over what relativity does and doesn't say about simultaneity has everything to do with your notion that relativity predicts that two clocks taken apart and brought together again will show less time than each other.

    You are ignoring the fact which I have pointed out before that you are trying to accelerate particles using EM which is propagating at v = c relative to the lab frame. It would be amazing indeed if a car could push another car faster than the pushing car could go. The v = c limit is on the transfer of energy between objects and not on objects perse.
    The particles are accelerated through fields which are in place long before the particle get there.

    You may consider it amazing that a car can push against a road surface that is obviously moving slower than the car, but I don't.

    This is completely irrelevant.
    It's a physical case in which the theory of relativity gives predictions which accurately match observations. Do you think obsevational evidence is irrelevant?

    The voodoo is to grant a specific photon the ability to exist at v = c to every observer in the universe, all of which are moving relative to each other.
    Again, you're limiting invariance to photons. The nature of spacetime apparently enforces all causal communication to a limit of c.

    And I notice you haven't addressed the voodoo-like nature of magical disappearing photons, only visible if you're moving the right way.

    You are welcome to do that. Indeed please do that for the physical circumstance I have outlined in this scenario.
    Done. Repeatedly. You are arbitrarily assuming that length is absolute. You are using the meter markers (stationary in the Earth frame) to measure velocity in the spaceship frame.

    Do you deny that the accumulated trip time of the moving clock is accounted for by the stipulated and physical time dilation (tick rate) of the clock?
    No.
    Last edited by Pete; 01-26-06 at 06:36 AM.

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