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PostPosted: Sat Feb 11, 2012 6:00 pm 
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happyjack27 wrote:
tomclarke wrote:
happyjack wrote:
utterly pointless. you still don't frickin' get it. you can put whatever you want in there.

if

t(a in b over journey) = t(a in b) _S! + t(a in b)S2 + t(a change from S1 to S2)

then also

t(b in a over journey) = t(b in a) _S! + t(b in a)S2 + t(b change from S2 to S1)

duh.


I think we are finally getting somewhere.

There is no change in the A frame, since A stays in one inertial frame. There is a change in the B frame, from S1 to S2.

Hence the two equations are not the same, viewed from B, which changes frame, or A, which does not.

I have been saying this for some time, but perhaps this will help you more than previous posts.

Note that the time shift element is nothing to do with relative velocity changing. When calculated in B's frames it is independent of the velocity of A, and depends only on the change in velocity (and therefore frame) of B and the distance between B and A in the S1 (or S2) frame. Thus it is not symmetrical between A - which never changes frame, and B, which changes from S1 to S2.


Time shift is a correction needed in a relativistic world when an observer's frame changes. It affects all his calculated times of distant clocks. These times must be calculated because direct comparison is impossible. The change in (calculated) time of a distant clock seems a bit weird but not when you consider that in relativistic space there is no such thing as absolute "now". The set of spacetime events corresponding to "now" depends on the frame in which "now" is measured.

Thus the distant clocks do not change time, rather the distant clock time considered the same as the local time varies when the local frame changes.


we are not changing frames we are comparing them. if you want to introduce a frame change then you need to also introduce a frame change in the other side, otherwise you're talking about two different trajectories. - comparing apples to oranges.

i see now you are assuming the conclusion. you are comparing apples to oranges and wo and behold they don't equate. i am comparing apples to apples. have you not figured that out yet?


Well I am discussing what has been the topic of this thread, the classic twins paradox in which one twin stays on earth and the otehr goes to alpha centauri and comes back. In fact I stated that quite recently. So if you are talking about something else: e.g. both twins go in different rockets somehere, and then come back, we are talking at cross puposes and indeed the problem is not so interesting!

Anyway, I guess from your reply there is now no argument?


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PostPosted: Sat Feb 11, 2012 7:46 pm 
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Quote:
is anyone sure this isn't some maths quirk, quantisation issue, overflow or something like that?


That's a part of what the last 30 or so pages of this thread has been about.

As I understand it, there are two types of time dilation: dilation caused by traveling across spacetime curved by gravity, and dilation caused simply by changing relative frames.

The mainstream view of physicists is exactly what Tomclarke has described in detail - that the shift in velocity/frame of the one twin changes the amount of proper elapsed time s/he will experience as compared to the one who doesn't shift frames/velocities. So long as they are just traveling apart, the calculated changes in the other's clock are symmetrical and it just "appears" that the other is younger, but when the one going to Alpha Centauri turns around and comes back, s/he is actually younger.

Johan and Happyjack think this is a quirk of how most physicists have done the math and that it wouldn't actually happen this way - they think that both twins see each other's paths as symmetrical the whole way, and their clocks come back into agreement as they get closer to each other again.

As I understand it, Johan agrees that if one twin travels across space that is curved significantly differently than the space the other one is in (due to gravity) that they will then experience different elapsed time.

Someone please correct me if I'm wrong.


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PostPosted: Sat Feb 11, 2012 7:52 pm 
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It is the gravity well rub. That is Johan's point.

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What I want to do is to look up C. . . . I call him the Forgotten Man. (Sumner)


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PostPosted: Sat Feb 11, 2012 8:38 pm 
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CaptainBeowulf wrote:
Quote:
is anyone sure this isn't some maths quirk, quantisation issue, overflow or something like that?


That's a part of what the last 30 or so pages of this thread has been about.

As I understand it, there are two types of time dilation: dilation caused by traveling across spacetime curved by gravity, and dilation caused simply by changing relative frames.

The mainstream view of physicists is exactly what Tomclarke has described in detail - that the shift in velocity/frame of the one twin changes the amount of proper elapsed time s/he will experience as compared to the one who doesn't shift frames/velocities. So long as they are just traveling apart, the calculated changes in the other's clock are symmetrical and it just "appears" that the other is younger, but when the one going to Alpha Centauri turns around and comes back, s/he is actually younger.

Johan and Happyjack think this is a quirk of how most physicists have done the math and that it wouldn't actually happen this way - they think that both twins see each other's paths as symmetrical the whole way, and their clocks come back into agreement as they get closer to each other again.

As I understand it, Johan agrees that if one twin travels across space that is curved significantly differently than the space the other one is in (due to gravity) that they will then experience different elapsed time.

Someone please correct me if I'm wrong.


I think this is probably fair.

Two comments:

The GR issue is a distraction. GR effects also exist and are significant, but they can be precisely calculated and isolated from SR effects. So the experimental data (which accounts for GR) is no less able to verify SR than if GR effects did not exist. In general GR and SR effects vary differently so you will not get one mistaken for the other.

Johan and (possibly) HappyJack do not have a consistent theoretical position. The time shift correction is necessary for math consistency in SR as much as the time contraction. There is no math that supports calculating remote times the same for all frames (if you suppose this you can quite easily derive a contradiction).

And the experimental evidence overwhelmingly contradicts such an alternate view, so it is not like QM interpretations where the differences are subtle and not decided by experiment.


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PostPosted: Sun May 06, 2012 5:13 am 
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Johan, you are not alone in your frustration.

Commercializing the First Room-Temperature Superconductor: A Bleak Outlook


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PostPosted: Wed Sep 12, 2012 10:54 pm 
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This popped up on NBF today from Arxiv, and guess who the third reference is.

Can doping graphite trigger room temperature superconductivity? Evidence for granular high-temperature superconductivity in water-treated graphite powder

T. Scheike, W. Böhlmann, P. Esquinazi, J. Barzola-Quiquia, A. Ballestar, A. Setzer
(Submitted on 10 Sep 2012)
Trying to dope graphite flakes we found that the magnetization of pure, several tens of micrometers grain size graphite powder and after a simple treatment with pure water shows clear and reproducible granular superconducting behavior with a critical temperature above 300K. The observed magnetic characteristics as a function of temperature, magnetic field and time, provide evidence for weakly coupled grains through Josephson interaction, revealing the existence of superconducting vortices.

http://arxiv.org/abs/1209.1938


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PostPosted: Thu Sep 13, 2012 5:05 am 
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Nice.

<munches more popcorn,...wonders what Johan will say...>

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The development of atomic power, though it could confer unimaginable blessings on mankind, is something that is dreaded by the owners of coal mines and oil wells. (Hazlitt)
What I want to do is to look up C. . . . I call him the Forgotten Man. (Sumner)


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PostPosted: Mon Oct 22, 2012 5:01 am 
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Atomic nuclei intimately entangled by a quantum measurement
Diamond again.

See the comments for a post by Johan and an interesting paper from Vienna.


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PostPosted: Sun Feb 24, 2013 5:48 am 
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Sabotaging the next Industrial Revolution


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PostPosted: Sun Feb 24, 2013 1:35 pm 
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DeltaV wrote:



Good to see Johan still having at it. I wonder how his work is going of late. The book seemed to do well enough.

_________________
The development of atomic power, though it could confer unimaginable blessings on mankind, is something that is dreaded by the owners of coal mines and oil wells. (Hazlitt)
What I want to do is to look up C. . . . I call him the Forgotten Man. (Sumner)


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PostPosted: Sat Mar 09, 2013 5:03 pm 
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Johan gets slammed by his first Amazon reviewer. No specific math/physics criticisms are given, just a generic dislike.
http://www.amazon.com/The-Physics-Delus ... ewpoints=1


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PostPosted: Sat Mar 09, 2013 8:14 pm 
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Since the review was pretty useless, I made that statement on the Amazon site. So far, I am it for reviews of the reviewer. Where is yours?


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PostPosted: Sun Mar 10, 2013 3:17 pm 
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Yeah I pushed "no" on the comment feedback. No math or sound reasoning to contradict Johan.


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PostPosted: Sun Mar 10, 2013 5:08 pm 
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I pushed No.

Then they wanted my email. No go.


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PostPosted: Mon Mar 11, 2013 11:44 pm 
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Apparently the reviewer is a spammer. He flames stuff without reading it. At least according to the author of another book this guy "reviewed" and torched. The author's argument is that he could not have reviewed it because he posted the review before any were purchased.
You can say anything you want at Alice's Internet Cafe...just around back by the railroad track, Alice's Internet Cafe. Hmmm. Or should it be Alice's Wi-fi Enabled Restaurant? Might flow better.

_________________
The development of atomic power, though it could confer unimaginable blessings on mankind, is something that is dreaded by the owners of coal mines and oil wells. (Hazlitt)
What I want to do is to look up C. . . . I call him the Forgotten Man. (Sumner)


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