Re: one way light speed


mluttgens@xxxxxxxxxx wrote:
Tom Roberts wrote:
nobody1357@xxxxxxxxxxxxx wrote:
I have been told a few times that all measurements of light speed are
two way and I can't think of an experiment setup which can show a
different result if one way speed differed in two directions.

Take two clocks separated by some distance, with a light source and
detector at each such that the clocks can record the time of emission
and arrival of light pulses. Watch the variation in the time difference
for successive pulses sent between them as the apparatus rotates. If the
one-way speed of light varies for different orientations, the time
difference for propagating light pulses will likewise vary.

This has been done: see the FAQ for references to Cialdea, to Krisher et
al, and to Torr and Kolen, plus the other experiments listed under
"one-way tests of light-speed isotropy".

Exercise: there is a hidden assumption in claiming this
experiment measures one-way light speed anisotropy. Explain
what it is. Discuss implications.


So, if
one way speed can never be measured, doesn't this mean it has no effect
on laws of nature and in a sense it doesn't exist like aether?

It can be measured. But _interpreting_ the measurement is complicated by
the fact that the two clocks must be synchronized; _any_ method can be
use to synchronize them, and the results depend directly on the method used.

This is merely one more instance of why in modern science we don't do
experiments to "measure things", we use them to TEST THEORIES. In
testing a theory applied to a one-way measurement, the method of clock
synchronization must be included in the analysis, and for all viable
physical theories it will cancel out (an arbitrary human choice like
clock synchronization cannot affect any physical phenomena).


Suppose
I'm saying that speed of light is infinite in this direction and c/2 in
the opposite direction, what can disprove this claim?

The above experiment could do so. Note that what you claim is not
enough, and you must describe how the one-way speed of light varies with
orientation. The fact that rotations come back to the same orientation
after an angle of 2pi puts rather strong constraints on how it can vary
with orientation. Indeed, for the outrageously large variation you
suppose even a second-order experiment like the MMX could refute it
(because you cannot make the anisotropy vary with orientation in such a
way that the MMX would not detect it in some orientations).

You will probably claim that the authors of the following paper are
crackpots!

Search for anisotropic light propagation as a function of laser
beam alignment relative to the Earth's velocity vector
astro-ph/0608223

"The results obtained with both methods show that the course of
the light rays are affected by the motion of the Earth, and
a predominant quantity of first order with a $\Delta c/c=-\beta
(1+2a)\cos \theta$ signature with $a=-0.4106\pm 0.0225$ describes
well the experimental results. This result differs in a amount
of 18% from the Special Relativity Theory prediction and that
supplies the value of $a=-1/2$ (isotropy)."

Marcel Luttgens



Ah, the wonderful Navia et Co papers!
I love the appendix where they rehash the nonsense about being able to
detect one way light speed anisotropy in gaseous medium with n slightly
greater than 1 (same erroneous claim as Cahill). So, Navia's theory is
pure bunk.

Most probably their experimental data is bunk as well. Tom will let us
know.

.

Relevant Pages

  • Re: one way light speed
    ... detector at each such that the clocks can record the time of emission ... But _interpreting_ the measurement is complicated by ... The fact that rotations come back to the same orientation ... a particle would be different in two directions. ...
    (sci.physics.relativity)
  • Re: one way light speed
    ... detector at each such that the clocks can record the time of emission ... But _interpreting_ the measurement is complicated by ... The fact that rotations come back to the same orientation ... a particle would be different in two directions. ...
    (sci.physics.relativity)
  • Re: one way light speed
    ... detector at each such that the clocks can record the time of emission ... But _interpreting_ the measurement is complicated by ... The fact that rotations come back to the same orientation ... a particle would be different in two directions. ...
    (sci.physics.relativity)
  • Re: one way light speed
    ... Take two clocks separated by some distance, with a light source and detector at each such that the clocks can record the time of emission and arrival of light pulses. ... In testing a theory applied to a one-way measurement, the method of clock synchronization must be included in the analysis, and for all viable physical theories it will cancel out. ... The fact that rotations come back to the same orientation after an angle of 2pi puts rather strong constraints on how it can vary with orientation. ... a particle would be different in two directions. ...
    (sci.physics.relativity)
  • Re: Experimental disproof of the theory of Relativity
    ... See the original measurement of the speed of light using Jupiter's moons. ... > This has nothing whatsoever to do with e-synching. ... "If one uses light to synchronize clocks then it is ... Adjusting the clocks is what is called synchronization. ...
    (sci.physics.relativity)