Natural Science Forum / Physics / Relativity / April 2005

Well, now we are finally getting somewhere; however,
your (2) is ambiguous, and that is a big problem since
(2) is 50% of your given answer.

If (2) means "light's round-trip speed per one clock,"
then we can all agree that this speed is observer
independent, but if (2) means "light's one-way speed
per two clocks," then, 'Houston, we have a problem'
because this involves the infamous clock synchronization.

Since your (1) pertained to a definition of synchronization,
it could be assumed that your (2) pertained only to light's
one-way speed per two clocks, but you didn't pin this down.
I will go ahead with (2) = one-way speed.

You claimed that we do not know why we experience (2), but
at the same time you said that it was due to a definition;
can you see that this is self-contradictory?

Here is why we experience (2):
If clocks are forced by definition to obtain one-way light
speed invariance, then clocks will obtain one-way light
speed invariance, but such circularity is not physics.

Let me put this in simple, direct terms, as follows:

Clocks C1r and C2r are x distance apart on a railway track.

Clocks C1t and C2t are at the ends of a train that is x long.

When both C1 clocks are coincident in passing, and both read
zero, a light signal is sent out from them toward the C2 clocks,
which are to be started by the signal.

Train
C1t[0]----------X--------[-]C2t -->
----~~~>light signal
C1r[0]----------X--------[-]C2r
Rail
Since the train moves on, the signal reaches C2r before it
reaches C2t, as shown:

Train
--------t[x/c]----------X--------[-]C2t -->
-------------------------->light signal
C1r[x/c]----------X-------[x/c]C2r
Rail

At this point, Einstein's definition of clock synchronization
says to place the pre-chosen time x/c on clock C2r, as shown.

This may or may not be the correct time because the Earth and
the rails may be moving toward or away from the signal, but we
will give Einstein a break by assuming that this time is OK for
the signal's journey.

But we CANNOT allow Einstein to place this SAME time x/c on
the train clock C2t because it is perfectly clear that this
clock was NOT hit by the signal when C2r was hit.

Here is Einstein's definition applied to the train clocks:

Train
-------------------t[x/c+]----------X--------[x/c]C2t -->
---------------------------------------------->signal
C1r[x/c+]----------X-------[x/c+]C2r
Rail

The above little picture shows that the train clocks
are not synchronous under Einstein's definition.

It also shows that the clocks of all other frames will also
not be synchronous under Einstein's definition.

It further shows that these other frames' clocks will be
DIFFERENTLY asynchronous because all of the other frames
will move differently.

Moreover, the picture tell us that only ONE frame's clocks
will be synchronous under Einstein's definition. (As noted
above, we assumed that this was the rail frame in this case.)

What can now be said about Einstein's definition?

[1] It has no basis because nothing in nature says
   one-way light-speed invariance. (Einstein's "invariance"
   was given only by definition, not by experiment.)

[2] It produces asynchronous clocks in general.

[3] Asynchronous clocks cannot make correct measurements.

[4] Therefore, all 2-clock measurements in special relativity
   are incorrect, including the "measurement" of light's
   one-way, two-clock speed.

[5] Simultaneity is not really relative because it is caused
   by the asynchronicity of Einstein's clocks, as follows:

[3]-----Frame A------[3]
E1                   E2
[4]-----Frame B------[5]

Frame A finds the events to be simultaneous, but Frame B
does not find them to be simultaneous. Notice that this
cannot be blamed on the events themselves because events
are observer-independent. It is clear from the picture that
the cause of Einstein's relative simultaneity is simply the
use of his asynchronous clocks (in all frames but one).

Having seen invariance in the round-trip, one-clock case,
Einstein falsely extrapolated this to the one-way case, where,
as we have seen, invariance cannot occur experimentally (as
in the round-trip case), but must be given via definition.
a definition which makes clocks **asynchronous** and therefore
incorrectly related.

We do not need special relativity and its asynchronous clocks.

We need synchronous clocks.

Given synchronous clocks, we could correctly measure light's
one-way speed.

Since this speed would vary with frame velocity, we could us
it to calculate our speed through space.

End of story.