Re: Types of SR measurements.

On Aug 10, 4:04 pm, "Gerald L. O'Barr" <glob...@xxxxxxxxx> wrote:
Subject: Re: Types of SR measurements.

PD <TheDraperFam...@xxxxxxxxx> wrote:
Gerald L. O'Barr" <globarr...@xxxxxxxxx> wrote:
. . . .

<deletes by O'Barr>





O'Barr wrote:
3) Any frame has the power and the right to
measure or determine
the relative velocity that might be existing
between any two objects that exist within
its space. . . .
PD wrote:
Yes, you certainly can. And the value that you
get by vector combination prescription that you
espouse will be different for every frame that
measures it.
O'Barr wrote:
So yes! You agree that we can measure these
velocities.
PD wrote:
I never disputed that. I told you that the result of
a vector combination of two measurements was not a
measurement itself. You can multiply the pressure of
a gas by its entropy, too, but that does not
correspond to a measurement or a measurable
quantity.
O'Barr wrote:
So I have been right all along. Thank
you all for now saying so. We can measure these
things. It does not matter that it is different
in each frame. What matters is that it is a
correct SR measurement in the frame in which it is
measured. It must be seen as a correct SR
measurement.
PD wrote:
That's fine. No "SR expert" will tell you that the
result of that operation would result in the same
value, independent of frame.
O'Barr wrote:
And the
relative velocity of light in all reference frames
are seen to be different than c by all independent
SR observers!
PD wrote:
That's exactly what an "SR expert" would tell you.
O'Barr wrote:
QED!
PD wrote:
This is not what Newton believed, but it is
certainly what is true in experiment, and it is
what SR says is the case.
O'Barr wrote:
Again you are right, this is not what Newton
believed, but it is what Lorentz believed,
PD wrote:
And Einstein as well.
O'Barr wrote:
and it is what
SR math clearly shows and requires and supports.
SR math has to show what LET shows, since it is
the same math. Thanks again for agreeing.
PD wrote:
Now, you may feel that this number "relative
velocity as determined by vector difference"
SHOULD be the same from frame to frame, and you
may additionally feel that there SHOULD be one
"real" value for that number.
O'Barr wrote:
Don't be silly. I believe in LET. And in LET,
every frame has rulers of different lengths, and
clocks with different rates. How could the same
fact
be measured to be the same? Unless it was c, that
is. So no, I do not believe any silly thing like
you are saying. I believe what SR math gives us,
exactly. No more or no less. And because I
believe
this, I find it silly of you SR experts not to
agree with me, when I am using your own math.
Don't you people know your own theory?
PD wrote:
No "SR expert" will tell you that closing speed or
departing speed is measured to be the same value in
all frames.

O'Barr comments:
And no one was saying it was the same value. What
has to be said and learned is that it is a valid SR
measurement. It is in every way a correct SR
measurement. And it is SR that says that it is
different for every observer. Thus SR is saying that
the real relative speed of light going past any one
specified frame is actually unknown. It all depends
on who measures it.

SR says two things very clearly. It says that the relative velocity as
written as the vector combination of two velocities will result in a
frame-dependent value. It also says that the speed of light as
*measured* in any frame will always result in the same value: c. Now
you may want to conflate those two statements, but they are quite
distinct and unambiguous. It doesn't matter at all that you don't want
them to be distinct, and that you'd prefer SR to appear ambiguous.


PD wrote:
However, I don't see any physical reason why you
would think it SHOULD be that way. You'll note
that Newtonian mechanics does NOT say that there
is
a "true" or "real" value of an object's linear
momentum or kinetic energy -- those values
completely and utterly dependent on the choice of
reference frame, and Newton and Galileo
both knew it. I don't know why you would think
that
relative velocity as determined by vector
difference is different in that regard.
O'Barr wrote:
Boy are you now confused. It was you and
Jenkyl who were demanding that only one specific
frame could be used, not me.
PD wrote:
No, we didn't. We made a very careful distinction
between what can be *measured* (a relative speed)
and what can be *calculated via a vector operation*
(a closing or departing speed). Performing a vector
operation will produce a number that is frame
dependent, as you and I agree. Making a
*measurement* of the speed of light in a particular
frame will result in a number that happens to be the
same in any frame.

O'Barr comments:
Well, anyone can go back and see exactly what each
one of us actually said. And I am glad that I think
we have reached a limited degree of understanding.
The question has never been on whether any
measurement was frame independent or not. The
question was only this, what do we really know! What
does SR really tell us as to the relative speed of
light going past any one specific frame? That is the
question.

I've already answered that above.

And the answer to this question is exactly as
follows: SR math does not allow us to really know
the actual velocity of light past any one frame. The
actual measurement of this relative velocity varies
with the observer.

That is incorrect, the result of conflating the two statements above.

The best guess is that it is not
c.

And that is CERTAINLY not a good conclusion.
You have made two successive assumptions
- that vector combination of two velocities and a measurement of a
velocity should be taken to be the same thing
- that majority rules apply in being able to say what is "real"
Neither of these are good arguments.

That is what the science of SR demands us to say.
SR does allow us to say that the measurement of this
velocity in one frame, and in one frame only, will be
c. But of the millions and millions of other frames,
it will not be confirmed. In fact, all these other
frames will explain that the odd value of c was only
due to the way the tools were changed in that one
specific frame. All these other frames will all say
that the relative velocity of light in this one frame
was not c, even if it were measured to be c.
This is what SR science says, this is what SR math
says, this is what SR measurements say. And I stand
by what I know. And I would suggest to you that you
come to understand these things. They are important.
We do have a mess on our hands, in working with SR
experts. And these errors are going to be corrected.
SR is a weak theory. And any true physicist would
understand these weaknesses, and would be more than
willing to consider them.

Thanks for reading.
Gerald L. O'Barr <globarr...@xxxxxxxxx>-- Hide quoted text -

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