View Poll Results: Does the noncontextual description x(t) takes 'c=v_max' into account ?  
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Descriptions in physics 
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#1
Nov2105, 11:50 PM

P: 309

Let suppose we have a frame of reference, in which a particle is decribed by [tex] \vec{x}(t) [/tex]...I don't give, on purpose, the context, if it is a classical framework, or a relativistic one...(Like somebody new, that does not even know what those word mean)...The question is : does this trajectory, which is, after some discussion with the nonknower, as seen (or oberseved or measured ??..not measured, because this would mean a radar like method...at least I suppose) by an observer at the origin, hence at x=0. So the question is : does this take into account the delay imposed by the speed of light limit, after another discussion with the same person who has to give an answer to the question ?
Do you think it takes the delay into account ? 


#2
Nov2205, 01:01 AM

Emeritus
Sci Advisor
PF Gold
P: 6,236

As in nonrelativistic physics, the lightcone is flat, it coincides with the spacelike foliation, so both notions are identical. But in relativistic physics, clearly the cone is not flat. 


#3
Nov2205, 03:05 AM

P: 309

So do you think that the following transformation [tex] x_o(t_o)=x(t_ox_o(t_o))[/tex] could eventually be a transformation of a "time foliation" (in which I don't really understand that global time valid on the whole space)...to a sort of "observed trajectory" (the observer reamains at O)...or is there another formula, because i get trapped in kind of circular reasoning...: the third time argument should be t ot[tex] t_o[/tex] ?



#4
Nov2305, 06:47 AM

Emeritus
Sci Advisor
PF Gold
P: 6,236

Descriptions in physics
x+ = x + t x = x  t y = y z = z I'm forgetting right now the name of this coordinate system... it has a specific name... 


#5
Nov2305, 12:21 PM

P: 309

Thanks, I suppose it is linked to the oldfashioned : retarded or advanced terms...which correspond two the two x+, x (with c=1 of course) (depending on your consider observer>observed, or observed>observer transformation i suppose : if you observe x at t, it was at tx (it is not there at 't'), whereas if it is at x in t, it will be observed at t+x...but do you know for the formula above, because it is not only an event coordinate transformation, it involves the whole trajectory (hence a dependence between x and t, or other way expressed : x+ and x)...? (it seems to be an implicit notion..)



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