On Jan 2, 1:05*pm, PD wrote:
On Jan 2, 11:13*am, kenseto wrote:





On Jan 2, 10:48*am, PD wrote:

See? You say it only applies to sources at rest with respect to the
grating and then say it is universal. Poor use of the word universal.

But the sodium atoms are not at rest wrt the grating when they are
heated. The result is that they reach a average velocity of V_t wrt
the grating and 588.995 nm is the wavelength of the center line of V_t
in every frame. Therefore this special wavelength is the universal
wavelength for that special line of sodium.

Those atoms that are not at rest wrt the grating do not exhibit light
with a wavelength at 588.995 nm. You and I have both said that.

When the sodium is heated no atom is at rest wrt the grating.

Well, actually, that's not true either. Even in a hot gas, some atoms
are not moving relative to the grating. The atoms in a gas at a
particular temperature have a *distribution* of velocities relative to
the grating. That *distribution* is centered around 0 and there very
definitely are atoms in that distribution that are sitting at 0. You
know what a distribution is?

No...every heated sodium atom is in a state of relative motion wrt the
whole of the grating.

Sorry, but you obviously don't know what a thermal distribution looks
like.

However, this is irrelevant. What is relevant is
that there is a distinct line that has a universal wavelength of
588.995 nm

No, it doesn't. Why are you repeating the same incorrect statement?
Where did you read such nonsense?

So where is the wavelength of 588.995 nm for sodium come from? BTW you
claimed that this wavelength is the result of those sodium atoms at
rest wrt the grating. The sodium also have another wavelength 590.58nm
is this wavelength aslo come from those sodium atoms at rest wrt the
grating?





and this line is caused by those sodium atoms that has a
relative velocity of V_t wrt the grating.

This
is why there isn't a line specifically at 588.995 nm, but instead a
*range* of wavelengths *centered* on 588.995 nm. There is no
*definition* of sodium light being at 588.995 nm; I don't know where you got the impression or read any differently.

This is irrelevant. We known that when the sodium is heated in the
frame of the grating there is a line in the spectrum that has a
universal wavelength of 588.995 nm.

No, you don't know that at all. Where on earth did you get the idea
that there is a line in the spectrum that has a universal wavelength
of 588.995 nm?

Because the grating measures it to be so?

No, it doesn't. Where on earth did you get the idea that it does that?

So the grating doesn't measure sodium to have a wavelength of 588.995
nm? Then why did you agree previously that every observer measures his
sodium source to have a wavelength of 589 nm????





It isn't bad science if that's what's actually observed.

Sure it is bad science....what is actually observed is a new light
source in the frame of the grating and thus the grating defines a new
wavelength for it.

You are
saying that the universe cannot possibly behave that way, and that you
would prefer it if it behaved a way that makes more sense to you. That
is not good science.

No....you made the wrong assumption and continued to assert that your
assumption is correct.

I'm not making any assumption. I'm taking the wavelength to be what
it's measured to be, which is NOT 589 nm.

It was you who first told me that the wavelength of sodium have a
wavelength of 589 nm.

You instead say that, even
though the wavelength is not measured to be 589 nm, it is nonetheless
589 nm, because you would prefer to assume that than to assume that
the speed of light is invariant. Thus you are changing a wavelength
from what is measured to a value other than that. That's bad, bad
science.

The incoming sodium light becomes a different light source so the
grating defines a new wavelength for it.



It is ALWAYS a bad idea to prefer something that is in conflict with
measurement.

But my assumption is based on valid reasoning and your assumption is
based on the bogus idea that light changes speed during transit from
the source to the observer.

Sorry, Ken, valid reasoning does not trump measurement in science.
Never has, never will. If you have valid reasoning that says something
other than what measurement says, then your valid reasoning is simply
wrong nevertheless.

Wavelength doen't change during transit. Light speed change due to
motion of the observer wrt the incoming light rays.


Valid reasoning does not make good science. Valid reasoning and 75
cents will buy you a cup of coffee. Valid reasoning that also happens
to agree with measurement, on the other hand, is extremely valuable.
Changing measured values to conform with what you think is valid
reasoning is not only worthless, but it is scientific fraud.

I did not change any measured value. The grating defines a different
wavelength for different light ray passing through it. The incoming
sodium light is a different light ray in so far as the grating is
concerned.




No, that observer does measure the light speed to be c relative to the
source. But that isn't what the other observer sees.

So what is the observer at the source frame measures the speed of his
light source to be?

On average, zero. Why?

??????are you saying that he doen't maeasure his own light to have a
speed of c????



You are
suggesting the speed changes because you're comparing it in two
different reference frames.

In SR the speed of light is a universal constant c. So what is wrong
by saying that the speed of light is c in the source frame and it is
also c in the observer's frame?????


There's nothing wrong with that. The problem is you then conclude that
the speed had to change in between.

But the source and the observer are in a relative motion. That means
that the incoming light must change speed during transit to eliminate
the effect of relative motion so that it can be detected as arriving
at the observer at the same speed of c as measured by the source
observer.

By the way, light "in the source frame" doesn't talk just about the
light in the vicinity of the source, and light "in the observer frame"
doesn't talk just about the light in the vicinity of the observer.
It's not like light is traveling from one reference frame to another
reference frame. The same light is in *BOTH reference frames for the
ENTIRE trip. You seem to have a difficult time understanding what a
reference frame is.



You are thinking that if the speed of
light leaving the source is c, as seen by the observer at the source,
then it can't be c as viewed by an observer moving at relative speed u
wrt to the source.

That would be a valid reasoning but SR said that the observer also
measures the incoming light from the source to be c. So the only way
this can happen is that the speed of light changes during transit to
eliminate the effect of relative motion between the source and the
observer.

What "effect of relative motion"?

The effect is:
The transit time for a light ray to reach a moving object moving
toward you is shorter because the effect of relative motion between
you and the object is added to the speed of light.



If it is c as viewed by an observer moving at
relative speed u wrt to the source, then the speed of light must have
changed, according to you. Perhaps you think that the speed of light
as viewed by the second observer should be c+u or c-u.

NO....I don't think that at all.

Then what's the "effect of relative motion" that you think needs to be
eliminated by a change in the speed of light?

I think that the speed of light is a
constant math ratio in all frames as follows:
Light path length of ruler (299,792,458 meters long physically)/the
absolute time content for a clock second co-moving with the ruler.

That would be a mistake. Velocities don't combine by simple addition
or subtraction. Why do you think that they do?

Yes light velocities don't combine by simple addition or substraction
because light is being transmitted by the E-Matrix at a max. constant
speed of c.

They don't combine by simple addition or subtraction anyway, even
without the E-matrix.


Without the E-Matrix simple addition and subtraction of speed will
work fine. With the E-Matrix the max speed is the speed of
transmission by the E-Matrix.

Ken Seto