DaleSpam said:
If length is invariant then the moving meter markers are just as good as the stationary ones. I'm not the one making the rules of your transform. I am just deriving the consequences. So which is it? Are the moving markers the same or not?-Dale
I predict you will not trap an experienced duck and weaver with logic. (MacM gave 15 different duck and weaves before quitting in the thread "Is time universal ... ." Eventually he will just start a new thread, as this one.)
All that MacM disputes (SRT etc.) follows logically from one simple starting point:
(0)
Physic is the same in all inertial frames.
{I am not sure the adjective "inertial" is required. MacM has admitted that he believes an absolute rest frame exists, but also that this can not be demonstrated, so MacM posts consistently, according to his faith, not science. }
Hence, from (0) above:
(1) Maxwell's equations describe all EM waves, light included,
for all frames.
(2) Vacuum magnetic permeability and dielectric constant are same,
for all frames.
{SOL (and all EM waves) can be calculated from these two lab measurements - Maxwell did predict vacuum SOL, radio waves, etc. this way.}
(3) Speed of light in vacuum is same,
for all frames.
(4) Time dilation and length contraction of clocks and objects in the moving frame, as given by SRT equations, are required to make SOL constant, when time and distances in frame moving wrt yours are measured (observed, without or correcting for perception effects) with your clocks and rulers.,
for all frames.
{Pete has recently presented a nice proof of this but, as is his style, left it to the reader to work out the details, at least for the present.}
Even if SRT were false:
Events simultaneous in one frame are not simultaneous in any other moving with respect to it.
This is proven, (but of course denied by MacM, who believes in universal time, and one absolute frame in which “velocity history” must be measured.) by the “thought experiment” of the "Is time universal ..." thread.
This “thought experiment” assumed only.
Assumption:
Experiment assumes that the speed of light in any one frame is not dependent upon the direction in which the light is traveling.
For example, the conclusions of the experiment (that simultaneous events in one frame are not simultaneous in another moving wrt to the first) still follows if the speed of light in the embankment frame is only 10^4m/s and in the frame of the train is 3x10^8m/s. (I.e. SRT is NOT assumed.)
This “thought experiment” postulated two things.
Postulates:
(1)Very brief light flash occurs when its source is midway between two photo triggers of firecrackers mounted on side of moving train, one near front and one near rear of train. (Perhaps, a flash bulb is mounted on side of train at mid point, or from mid point of train, a copper arm extends to complete electrical circuit for flash bulb mounted on post in the ground.)
(2) To avoid disputable corrections for any propagation delays, there are adjacent to firecrackers, in both train and ground frame, clocks that stop and record the time the explosions.
From this assumption alone the experiment’s results are:
(a) Both stopped clocks on the train show the same time ==> Simultaneous Explosions.
(b) Ground clock at rear explosion shows earlier time for that explosion than recorded by clock at the front explosion location. ==> Not Simultaneous Explosions.
(During the interval while light is approaching the photo triggers, the rear of the train moves closer to the flash origin, an invariant point in space, and the front of train moves further away from this point.)
MacM does not agreed that simultaneous events in one frame are not simultaneous in another* but no longer has anything to say as to why. (His 15 prior duck and weaves, spoke of length contraction, lack of "same photons," time dilation, velocity history, and many more things that have nothing to do with the experiment or its assumption.)
I predict that when he can no longer, as James recently put it "muddy the waters," in reply to logic of Dalespan and others, he will just start a new thread. (BTW James R. preceded me in noting Mack's extraordinary ability to "duck and weave.")
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*This is why, for example, MacM's “Reciprocity shows that SRT is nonsense.” is itself nonsense.
In his “reciprocity argument,” MacM speaks of “accumulated time” but fails to realize that even if the accumulation periods begin when the passing clocks are adjacent. They will be far apart when the “stop accumulation” event occurs. That is, each of the observer's two clocks, moving wrt each other, will stop accumulating time (say after 10^6 ticks of identical clocks) but for each observer, the other did not stop accumulating time simultaneously with the stopping of his clock. For both, the other let his clock run too long before stopping it to be simultaneous with his stopping his. I.e. Simultaneously (for A) with stopping of A’s clock, B’s clock had accumulated less than 10^6 ticks or “was running slow.”
If one understands that "simultaneous" for A is not "simultaneous" for B and conversely, it is MacM's "reciprocity" objection, which is clearly nonsense, not SRT.
MacM thinks “simultaneity” has nothing to due with time accumulation measurements. He thinks that both can simultaneous stop and if they do so that both show 10^6 ticks accumulated. He thinks SRT is nonsense, despite its many experimental confirmations or the above logic which shows:
Events simultaneous in one frame, such as the same firecracker explosion measured by a local clock used as the “stop event,” are not simultaneous in another frame.
In the train example above, zero time is accumulated in the train frame between the two explosions but some quantity of time is accumulated in the ground frame as the “rear explosion” precedes the one at the front of train.
Only an expert “duck and weaver", self confident in his faith in the universality of time and absolute space, can avoid this conclusion and “muddy the waters” to divert the attention of readers from the obvious consequences of the single, non-SRT assumption, above.
PS In this thread, MacM appears to be developing a duck and weave which focuses on his idea that clocks are slow only because of their acceleration in F = ma, which caused them to be moving (presumably wrt his unstated rest frame). This is a modification of his old "velocity history" argument, but it avoids making obvious his faith in an absolute rest frame.
Fortunately nature provides daily billions of examples of secondary muons which were never accelerated. These muons reach the surface of the Earth only because their "clocks" are running extremely slow. Otherwise they would decay not far from where they were created, high in the atmosphere.
{The muons were not part of the oxygen or nitrogen atoms that were struck by the primary cosmic ray. They are "born," like photons, with their velocity, not accelerated.}
