Does time dilation contradict the constancy of light speed?
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27-11-2013, 07:42 AM
RE: Does time dilation contradict the constancy of light speed?
I'm not a physicist and don't know the maths of this subject, but I'll give it a crack. Yes, length changes with velocity as time changes with velocity. The observer at A would see the length of the B observer contract, and B would see the distance between A and C contract. Length, mass, and time all distort while the speed of light in all reference frames remains the same. The thinking is that effectively objects travelling at different velocities kind of "rotate" into the time dimension... so our three-dimensional perception of them is incomplete and distorted in much the same was as any two-dimensional representation of the earth is necessarily distorted in some way. The "shape" of the vacuum of space is not exactly three dimensional.

Looking at your second case we have fixed points A and C that are in the same inertial frame. The "A" observer remains fixed with respect to its frame, as does the "C" observer. B is travelling in a different reference frame travelling at 0.5c with respect to the "A/C" reference frame. As in Ozomorid's twin paradox video the "x" dimension and time are both distorted. There is no acceleration in this case so the distortion is symmetrical. The "A/C" frame seems distorted to B, and the B frame seems distorted to A and C.

I'm cribbing from wikipedia here as I go[1].

According to A and C, B starts 1 light year from A and travels at 0.5c for two years to reach A at the 2 year mark. C observes the light arriving at the same time A observes B arriving.

B's time dimension and x dimension are distorted as follows:
t' = gamma * (t - vx / c^2)
x' = gamma * (x - vt)
where gamma = 1/sqrt(1-(v/c)^2).
At 0.5c with c = 1ly/year,
gamma is 1/sqrt(1-(v/c)^2) = 1/sqrt(1-(0.5)^2) = 1/sqrt(0.75) ~= 1.1547
t' = 1.1547 * (t - 0.5x)
x' = 1.1547 * (x - 0.5t)

At t=0y, x=1ly in the AC frame. I'm arbitrarily choosing 5 significant figures since we are dealing with exact quantities:
t' = 1.1547 * (0 - 0.5*1) = -0.57735y
x' = 1.1547 * (1 - 0.5*0) = 1.1547ly
At t=2y, x=0ly in the AC frame:
t' = 1.1547 * (2 - 0.5*0) = 2.3094y
x' = 1.1547 * (0 - 0.5*2) = -1.1547ly
ie. A thinks B is travelling at 0.5c for a distance of 1ly over a period of 2 years, but B thinks they are travelling at a speed of 0.8c for a distance of 2.3ly over a period of 2.9 years. I think. I could very easily be wrong in these calculations. I have the barest understanding of the maths and could stand to be corrected Wink

By my calculation the the event of C receiving the light pulse occurs at t' = 1.1547y and x'=1.1547ly. So both the AC frame and the B frame both see the light having travelled at light speed but each think the light has travelled for a different distance and time. The ordering of events is also different. In the B frame the C light pulse observation occurred 1.7320 years after B began its journey and 1.1547 years before B arrived at point A.

[1] http://en.wikipedia.org/wiki/Lorentz_tra...figuration

Give me your argument in the form of a published paper, and then we can start to talk.
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27-11-2013, 08:38 AM
RE: Does time dilation contradict the constancy of light speed?
(26-11-2013 04:57 AM)Hafnof Wrote:  



View in playlist: http://www.youtube.com/watch?v=kN_d7eknf...7E&index=5

If you need to understand anything in relativity or quantum physics, viascience (ozmoroid[1]) is your go to guy.

[1] http://www.youtube.com/user/ozmoroid

If I just watch it one more time I'll make sense of it. Consider

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27-11-2013, 09:12 AM
RE: Does time dilation contradict the constancy of light speed?
(27-11-2013 07:42 AM)Hafnof Wrote:  I'm not a physicist and don't know the maths of this subject, but I'll give it a crack. Yes, length changes with velocity as time changes with velocity. The observer at A would see the length of the B observer contract, and B would see the distance between A and C contract. Length, mass, and time all distort while the speed of light in all reference frames remains the same. The thinking is that effectively objects travelling at different velocities kind of "rotate" into the time dimension... so our three-dimensional perception of them is incomplete and distorted in much the same was as any two-dimensional representation of the earth is necessarily distorted in some way. The "shape" of the vacuum of space is not exactly three dimensional.

Looking at your second case we have fixed points A and C that are in the same inertial frame. The "A" observer remains fixed with respect to its frame, as does the "C" observer. B is travelling in a different reference frame travelling at 0.5c with respect to the "A/C" reference frame. As in Ozomorid's twin paradox video the "x" dimension and time are both distorted. There is no acceleration in this case so the distortion is symmetrical. The "A/C" frame seems distorted to B, and the B frame seems distorted to A and C.

I'm cribbing from wikipedia here as I go[1].

According to A and C, B starts 1 light year from A and travels at 0.5c for two years to reach A at the 2 year mark. C observes the light arriving at the same time A observes B arriving.

B's time dimension and x dimension are distorted as follows:
t' = gamma * (t - vx / c^2)
x' = gamma * (x - vt)
where gamma = 1/sqrt(1-(v/c)^2).
At 0.5c with c = 1ly/year,
gamma is 1/sqrt(1-(v/c)^2) = 1/sqrt(1-(0.5)^2) = 1/sqrt(0.75) ~= 1.1547
t' = 1.1547 * (t - 0.5x)
x' = 1.1547 * (x - 0.5t)

At t=0y, x=1ly in the AC frame. I'm arbitrarily choosing 5 significant figures since we are dealing with exact quantities:
t' = 1.1547 * (0 - 0.5*1) = -0.57735y
x' = 1.1547 * (1 - 0.5*0) = 1.1547ly
At t=2y, x=0ly in the AC frame:
t' = 1.1547 * (2 - 0.5*0) = 2.3094y
x' = 1.1547 * (0 - 0.5*2) = -1.1547ly
ie. A thinks B is travelling at 0.5c for a distance of 1ly over a period of 2 years, but B thinks they are travelling at a speed of 0.8c for a distance of 2.3ly over a period of 2.9 years. I think. I could very easily be wrong in these calculations. I have the barest understanding of the maths and could stand to be corrected Wink

By my calculation the the event of C receiving the light pulse occurs at t' = 1.1547y and x'=1.1547ly. So both the AC frame and the B frame both see the light having travelled at light speed but each think the light has travelled for a different distance and time. The ordering of events is also different. In the B frame the C light pulse observation occurred 1.7320 years after B began its journey and 1.1547 years before B arrived at point A.

[1] http://en.wikipedia.org/wiki/Lorentz_tra...figuration

Thanks, whether its right or not, it explains enough to realize I wasnt thinking relatively enough.. hehe

I think i will go and have a lie down.. my head seems to be hurting somewhat Wink
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27-11-2013, 09:24 AM
RE: Does time dilation contradict the constancy of light speed?
(27-11-2013 09:12 AM)PursuingTruth Wrote:  I think i will go and have a lie down.. my head seems to be hurting somewhat Wink

You and me both, brother Ohmy

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(06-02-2014 03:47 PM)Momsurroundedbyboys Wrote:  And I'm giving myself a conclusion again from all the facepalming.
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27-11-2013, 02:26 PM
RE: Does time dilation contradict the constancy of light speed?
this video will help clear things up




KingsChosen is a lying douchebag
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27-11-2013, 10:23 PM
RE: Does time dilation contradict the constancy of light speed?
Yes it does.
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27-11-2013, 11:38 PM
RE: Does time dilation contradict the constancy of light speed?
O, FFS, just when I get a grip on time dialation, now I have to comprehend and factor in gravitys-effect-on-time-confirmed

Theism is to believe what other people claim, Atheism is to ask "why should I".
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08-12-2013, 05:59 AM
RE: Does time dilation contradict the constancy of light speed?
It's general relativity that deals with gravity and its warping effect on space time. It took Einstein about 11 years to develop general relativity from special relativity (that's the length of time between him publishing the relevant seminal papers) so don't expect the maths to be particularly comprehensible Wink

Give me your argument in the form of a published paper, and then we can start to talk.
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08-12-2013, 01:38 PM
RE: Does time dilation contradict the constancy of light speed?
Velocity of light will remain the same because while B is observing less time he is also observing less distance.
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