The one-way speed of light is not c if the distance of separation between
the two synchronized (using slow transport of the clocks in the opposite
directions) clocks is measured using a physical ruler instead of using a
light second to measure length. Why? Using light-second to measure length is
the same as defining the speed of light equal to c as follows:
The definition for a meter=1/299,792,458 light-second
Therefore 1 light-second=299,792,458m
Therefore the speed of light is by definition =1 light-second/1 second
=
299,792,458m/1 second

Ken Seto

In sci.physics, kenseto

wrote
on Wed, 01 Jun 2005 14:36:08 GMT
:
The one-way speed of light is not c if the distance of separation between
the two synchronized (using slow transport of the clocks in the opposite
directions) clocks is measured using a physical ruler instead of using a
light second to measure length. Why? Using light-second to measure length is
the same as defining the speed of light equal to c as follows:
The definition for a meter=1/299,792,458 light-second
Therefore 1 light-second=299,792,458m
Therefore the speed of light is by definition =1 light-second/1 second
=
299,792,458m/1 second

Ken Seto


And the reason for this is because...?

--
#191,
It's still legal to go .sigless.

"The Ghost In The Machine" wrote in message ...
In sci.physics, kenseto

wrote
on Wed, 01 Jun 2005 14:36:08 GMT
:
The one-way speed of light is not c if the distance of separation between
the two synchronized (using slow transport of the clocks in the opposite
directions) clocks is measured using a physical ruler instead of using a
light second to measure length. Why? Using light-second to measure length is
the same as defining the speed of light equal to c as follows:
The definition for a meter=1/299,792,458 light-second
Therefore 1 light-second=299,792,458m
Therefore the speed of light is by definition =1 light-second/1 second
=
299,792,458m/1 second

Ken Seto


And the reason for this is because...?

.... he just gave the reason in the World famous Seto-Why-Clause:

| "Why? Using light-second to measure length is
| the same as defining the speed of light equal to c as follows:
| The definition for a meter=1/299,792,458 light-second
| Therefore 1 light-second=299,792,458m
| Therefore the speed of light is by definition =1 light-second/1 second
| = 299,792,458m/1 second"

Dirk Vdm

kenseto wrote:
The one-way speed of light is not c if the distance of separation between
the two synchronized (using slow transport of the clocks in the opposite
directions) clocks is measured using a physical ruler instead of using a
light second to measure length. Why? Using light-second to measure length is
the same as defining the speed of light equal to c as follows:
The definition for a meter=1/299,792,458 light-second
Therefore 1 light-second=299,792,458m
Therefore the speed of light is by definition =1 light-second/1 second
=
299,792,458m/1 second

Ken Seto



In a way Seto reminds me of Shead--inability to learn
and being hung up on units. Poor sod.

The speed of light is so well tested that it has become
a *defined* constant of nature! It's that same for all
observers. GPS sends signals one way. GPS offers an
accessible laboratory for confirmation of many SR and GTR
predictions.

There has never been an observation (to date) that has
contradicted a prediction of SR and GTR.

Indeed. See the really excellent summary of SR tests in:

http://math.ucr.edu/home/baez/physic...source%20tests

Here's a small subsection:

Experiments Using Terrestrial Sources

Beckmann and Mandies, Radio. Sci. 69D (1965), p623.
A moving mirror experiment.
Alvaeger F.J.M. Farley, J. Kjellman and I Wallin, Physics Letters 12,
260 (1964).
Measured the speed of gamma rays from the decay of fast pi0 (~0.99975
c) to be c with a resolution of 400 parts per million.
Sadeh, Phys. Rev. Lett. 10 no. 7 (1963), p271.
Measured the speed of the gammas emitted from e+e- annihilation (with
center-of-mass v/c ~ 0.5) to be c within 10%.
Babcock and Bergmann, Journal Opt. Soc. Amer. Vol. 54, pg 147 (1964).
-
Filipas and Fox, Phys. Rev. 135 no. 4B (1964), p B1071.
Measured the speed of gamma rays from the decay of fast pi0 (~0.2 c)
in an experiment specifically designed to avoid extinction effects.
Their results are in complete disagreement with the assumption c + v,
and are consistent with SR.

Because of the high energies of the gammas in Alvaeger, extinction is
not a problem for it; Filipas and Fox specifically designed their
experiment to avoid extinction."


COMMENT:

We've had some people arguing that one way speed of light velocities
from stars are dithered by the extinction and re-radiation effects of
passage through atmospheres. This turns out to be an OLD argument that
goes all the way back to Ritz in about 1913. Experiments in the 1960's
disproved it finally by using gamma rays, which are not absorbed
re-radiated, and thus retain their initial speed, whatever that is. And
that turns out to be c, even if the gammas come from very fast objects.
Conclusion: Einstein was right.

SBH

"Sbharris[atsign]ix.netcom.com" wrote in message
ups.com...

We've had some people arguing that one way speed of light velocities
from stars are dithered by the extinction and re-radiation effects of
passage through atmospheres. This turns out to be an OLD argument that
goes all the way back to Ritz in about 1913. Experiments in the 1960's
disproved it finally by using gamma rays, which are not absorbed
re-radiated, and thus retain their initial speed, whatever that is. And
that turns out to be c, even if the gammas come from very fast objects.
Conclusion: Einstein was right.

Not that I am supporting Ken Seto in any way, but you need
to be a little careful here.

You cannot measure the one way speed of light without
making assumptions about clock synchronisation.
Einstein's second postulate remains exactly that - a
postulate. A good one in my opinion but nevertheless a
postulate.

Martin Hogbin

Martin Hogbin wrote:
"Sbharris[atsign]ix.netcom.com" wrote in message
ups.com...

We've had some people arguing that one way speed of light velocities
from stars are dithered by the extinction and re-radiation effects of
passage through atmospheres. This turns out to be an OLD argument that
goes all the way back to Ritz in about 1913. Experiments in the 1960's
disproved it finally by using gamma rays, which are not absorbed
re-radiated, and thus retain their initial speed, whatever that is. And
that turns out to be c, even if the gammas come from very fast objects.
Conclusion: Einstein was right.

Not that I am supporting Ken Seto in any way, but you need
to be a little careful here.

You cannot measure the one way speed of light without
making assumptions about clock synchronisation.
Einstein's second postulate remains exactly that - a
postulate. A good one in my opinion but nevertheless a
postulate.

Although it is clearly impossible to measure OWLS without
making assumptions about clock synchronization, I believe
it to be possible to make measurements of delta-OWLS (i.e.
OWLS anisotropy) that are free of such assumptions.

On April 8, I started a thread on this topic:
http://groups-beta.google.com/group/...4d4ebd8ed246d4

While I believe that the experimental setup of Gagnon et al.
(1988) provides a true test of delta-OWLS without requiring
assumptions about clock synchronization, please note that both
Tom Roberts and Bill Hobba disagree with me, and believe
Gagnon et al.'s experiment to have hidden clock synchronization
assumptions. I never found their arguments convincing, and I
would appreciate your comments.

I have reinstated the temporary link that I posted on April 8.
http://imaginary_nematode.home.comca...LightSpeed.htm
This link will provide access to a scanned PDF of Gagnon
et al. (1988)

I will leave this link up for one week (until June 8) after
which I will take it down. This is, after all, copyrighted
material, and I don't want to violate Fair Use.

Thanks for your comments,
Jerry

You cannot measure the one way speed of light without
making assumptions about clock synchronisation.

Such as? I see no reason why the one-way speed of light can't be
measured in principle with only ONE clock, and signals coming back from
two gates (triggered by two gamma photons from an annihilation, say).
Are you talking about gate synchronization?

You can pre-synchronize gamma-photon detector gates separated by a
distance, with a non-moving source of simultaneous photon emission (a
positron source) midway between them. Or you can synch them when at the
same spot, then separate them. Keeping the same wires . This
involves mighty few assumptions.

SBH

Sbharris[atsign]ix.netcom.com wrote:
You cannot measure the one way speed of light without
making assumptions about clock synchronisation.

Such as? I see no reason why the one-way speed of light can't be
measured in principle with only ONE clock, and signals coming back from
two gates (triggered by two gamma photons from an annihilation, say).
Are you talking about gate synchronization?

You can pre-synchronize gamma-photon detector gates separated by a
distance, with a non-moving source of simultaneous photon emission (a
positron source) midway between them. Or you can synch them when at the
same spot, then separate them. Keeping the same wires . This
involves mighty few assumptions.

But it *does* require you to assume that speed of
propagation in the wires is independent of direction.
Thus essentially begging the question, eh?

Sbharris[atsign]ix.netcom.com wrote:
You cannot measure the one way speed of light without
making assumptions about clock synchronisation.

Such as? I see no reason why the one-way speed of light can't be
measured in principle with only ONE clock, and signals coming back from
two gates (triggered by two gamma photons from an annihilation, say).
Are you talking about gate synchronization?

You can pre-synchronize gamma-photon detector gates separated by a
distance, with a non-moving source of simultaneous photon emission (a
positron source) midway between them. Or you can synch them when at the
same spot, then separate them. Keeping the same wires . This
involves mighty few assumptions.

It is theoretically possible that the universe is involved in a
conspiracy.
:-)

If you synchronize your gamma-photon detector gates, then separate
them, the signal speed in the return path through your cables could
vary in exactly such a way as to cancel out your ability to detect
OWLS anisotropy.

Yes, quite a bizarre coincidence. But "Test theories" have been
developed in which this is exactly the case.
http://math.ucr.edu/home/baez/physic...periments.html

"Test theories" are an experimental tool, not intended to be
considered serious alternatives to SR. Rather, they offer a
descriptive framework for quantifying any deviations from
theory that might be observed.

Jerry