Re: Is the speed of light really constant ?

From: Pax (pax1_at_whitesweb.com)
Date: 10/14/04 

Date: Thu, 14 Oct 2004 07:12:40 GMT

"Eric Baird" <eric_baird@compuserve.com> wrote in message
news:mf56m0prqm2lm47n4sft8u7k9b23d5hdj5@4ax.com...
On Tue, 28 Sep 2004 14:24:33 GMT, "Pax" <pax1@whitesweb.com> wrote:

>"Eric Baird" <eric_baird@compuserve.com> wrote in message

>> On Sat, 18 Sep 2004 15:18:23 -0400, "robert j. kolker" wrote:
>>
>> >joseph levy wrote:

>> >> We now know that the speed of light is not really constant.

>> > Can you show circumstances where light in a vacuum travels at various
speeds? Please supply references to experiments which show this.

>> Shapiro effect.

<snip>

>> ------------
>>
>> And anyway, is c really /known/ to be constant inside a running particle
accelerator?
>> Has anyone ever checked?
>>
>> If a particle-physics experiment comes out how we like, we can say, yes,
there's a very high vacuum inside, so obviously SR applies to the case of a
particle beam.
>> But if we measure the velocity of light in that particle beam and find
that it is altered by the particles' motion, we have a fallback position of
being able to say that of course the experiment doesn't have to conform to
SR, because a high-speed particle beam is a relativistic particulate medium,
pretty much by definition, and is NOT a vacuum.
>>
>> Maybe this is why nobody here seems to have ever heard of anyone
repeating Fizeau's experiment with a highly relativistic particle beam. If
the experiment showed a variation in c due to the moving matter in the
lightbeam's path (a not-unexpected outcome, when you think about it), then
some p-p experimenters might be highly pissed off that one of their number
was apparently trying to generate evidence that SR might not be valid in
/their/ SR-based experiments.
>>
>> If they felt that someone was trying to undermine and discredit their
back-catalogues of "good" experimental results, that person might have to
start eating at their own table in the staff canteen.

>> >> It is erroneously found to be constant because of three kinds of
systematic measurement distortions entailed by length contraction, clock
retardation, and arbitrary clock synchronization.

>> > Utter nonsense

> > http://www.bnl.gov/RHIC/fascinating.htm
> > RHIC's beam travels at 99.995% the speed of light (186,000 miles per
second, or 300,000,000 meters per second).
> >
> > http://www.bnl.gov/RHIC/heavy_ion.htm
> > RHIC collides two beams of gold ions head-on when they're traveling at
nearly the speed of light (what Einstein called relativistic speeds).

> That looks fun!

> > The beams travel in opposite directions around RHIC's 2.4-mile, two-lane
"racetrack." [...] Traveling at 99.95% the speed of light, the ions appear
flat, instead of spherical, due to the relativistic effects which occur at
such speeds.

> Well, that's beginning to get a bit interpretational, given that its a bit
difficult to take a conventional photograph of an ultrarelativistic ion!

They get the big bucks for being interpretational... well, at least the big
recognition that goes with working at RHIC... interpreting, etc. misc. phys.
stff. wth. hvy. prtcls. clldng. Name tags, probably smocks, clipboards, and
keys to special "Employees Only" places too. One of them probably draws...
comp. grphs., of course.

> It's also a /leeetle/ bit misleading, since under most theories, the
apparent geometrical distortion of the ion is angle-dependent, and that
includes SR -- a receding ion should normally appear compacted, but an
approaching one should normally appear elongated, and at other angles, the
degree of apparent change in dimensions is somewhere between those two
extremes.
>
> The strength of the supposed compaction component also depends on the
theory that we apply, and the choice of "other" theory that we are using for
our reference predictions of how strong the purely propagation-based effects
ought to be.
>
> So, SR predicts that the ions ought to look "flatter" (by a Lorentz term)
than the predictions that we'd make by assuming a flat absolute aether
stationary in the lab frame ...
> ... but old-fashioned emission theory predicts that the ions should in
turn appear even flatter than SR says, by an /additional/ Lorentz effect.

Okay. They were warping round. Not round anymore is not round anymore. Looks
good though. Really flat. Relatively speaking. Relative to the caption.
Everybody expects pictures relative to the text, otherwise they think the
text is too technical and won't read it. That could lose a potential
contributor, with a relative drop in funding.

"Show them something! Don't make them read it and try to picture it for
themselves! This is the PUBLIC you're talking to, everybody knows the public
is too stupid to actually think! It's only by the grace of God they ever
found our website in the first place!"

> So
> [1] It'd probably be easier to verify SR's supposed "flattening" effect if
SR was wrong and NM was right, because the "stronger" NM version of the
effect should be easier to spot, and
>
> [2] If we took NM as our reference theory instead of a "simple" aether
model, we could point to the same physical SR predictions and say that these
represented the ion looking as if is was Lorentz-/elongated/under SR,
compared to our NM-based expectations.

Man! This is a *point* with you, isn't it?! You need to get out more. Unless
you already are out because someone who was in with you threw you there.
Laptop? Ethernet card? Won't work. No ether.

Perhaps if you wrote them an email suggesting they fire the artist
immediately? ...or they immediately remove the offending graphics *and* fire
the artist immediately? ...or they keep the artist and his lousy graphics
but send you a compensatory sum to compensate for the uncompensatable
magnitude of your permanent disgust relative to their graphics with its
relative drop in the future quality of the rest of your life?
...f..r..o..m... which you were suffering even as you wrote your post in
reply to me! Of course! You poor thing! I can testify in your behalf. I want
half. I'll get a POBox. Can I testify by email?

> A lot of what we see depends on what we expect to see.

Yup. Also on what we are capable of seeing. Maybe more.

> > Taking the above into account, what is the approaching velocity of one
ion as that velocity would be clocked by the other oncoming ion with which
it collides?

> Multiple possible answers, depending on the theory being used:
>
> If the ions are carrying teeny radar speed-guns, then the speed "clocked"
by those devices will depend on the Doppler formula that has been programmed
into them, to map between the observed blueshifted frequency and an approach
velocity that is /thought/ to produce that frequency.

Why do I have a growing urge to defrag you?

> So if the radar guns have been programmed according to SR, any degree of
blueshift from unity to infinity will result in the speedgun's display
showing a value between zero and c.

Not according to SR, according to their interpretation of SR. Einstein began
with the assumption that even if he was riding a light beam light would
still be coming at him at c. Relative. The local frame is the normal frame,
all other frames are warped.

> If the radar gun has been programmed to use with a different Doppler law
(eg the Newtonian emission theory one), then the device will dutifully
report a velocity values that can be greater than c, from the same raw data
(although in this case, if we also want local lightspeed constancy, we'd
probably have to invoke some sort of local light-dragging effect to explain
how the approaching ion doesn't outrun its own light).

I like playing with that thought experiment. Interesting you mentioned it.
Only if the radar gun uses something besides light to do its radaring with.
Even in the cesium experiment they had to wait until the light exited the
chamber and normalized to measure its velocity.

> Luckily for this second explanation, it would seem that clusters of
particles /do/ cause an offset in the speed of light (Fizeau), so ... who
knows ... the non-SR explanation might still turn out to be correct.
>
> OTOH, the ions might choose to ignore these interpretative methods and
stick to raw observation -- how fast they /see/ each other to be crossing
the intervening distance.

ahHAH!! (I venture tentatively.)

> Unfortunately, its still difficult to distinguish between the two earlier
explanations, SR says that a particle approaching at c is /seen/ to be
closing the gap between it and the observer infinitely fast, so for any
"apparent speed" from zero to infinity, SR can claim that the result
demonstrates that the particle is "really" approaching subluminally.
>
> Whether it /is/ or not is, of course, a slightly more tricky issue.

Retracting ahHAH!

You are so up to your ears... I love it. :) :) :) :) What you type is
similar to the noise in my head. "If...", "or...", "and...", "but..." "This
leads to that if it's qualified by this, otherwise it leads there, which
winds up leading here, which points to there under certain conditions, which
wind up being not the case except in a specific instance, which takes me
to... nowhere... again... I did something wrong." "Advil! Now!"

> > If two automobiles, each traveling at a velocity of 70mph in opposite
directions on the highway, approach each other, what is the approaching
velocity of one oncoming vehicle as that velocity would be clocked by the
other?

> Again, it depends on the methods used by the automobiles to convert their
literal observations of each other's "apparent speeds" and apparent
frequency shifts back into nominal velocity values.

You're not an "Is the glass half full/half empty?" guy, are you? You're an
"Is there even a glass?" guy. There really is a real answer to that one.
Honest. Remember back when 2+2=4 and not some arbitrary number according to
certain specific prequalifications as determined by the theory under
utilization within the realm of a specific set of limited circumstances?

> Under SR, every possible apparent frequency shift or "apparent" speed will
always map to a "subluminal" nominal velocity, so even if SR was wrong about
lightspeeds, we couldn't disprove it by finding a single isolated "illegal"
apparent approach speed or blueshift.

We don't need to disprove SR, all we need to do is disprove the interpreters
of SR. That's different. SR says c is *constant* relative to *all* inertial
frames, no matter their actual velocities. In SR and in GR, everything is
*relative*, hence the tag "Relativity". Cliff Notes sort of thing, gives it
all away immediately. Every local frame is considered to be stationary from
the vantagepoint of the inhabitants of that frame, and all the laws of
nature continue to work normally inside that frame... just as they do inside
all inertial frames. The scenery can get a bit weird though.

But I was speaking of a very unique opportunity as presented by a collider,
the opportunity to view two nonlocal inertial frames each moving at all but
c toward each other within the confines of an inertial frame that
incorporated both of those other inertial frames. Sheesh! Now you've got me
doing it.

> Where we /could/ make an objective assessment of which Doppler
relationships are right and which are wrong, is by simultaneously measuring
the forward and rearward redshifts and blueshifts on an object moving along
a straight line with constant velocity, and comparing the redshifted,
blueshifted and unshifted frequencies or wavelengths to get a three-way
"fingerprint" set of ratios that would rule out one or other Doppler
relationship (or both!), without actually specifying what the "true"
velocity really is.
> Then, once we've really found a Doppler law that is the best fit to
reality, we could use that to back-calculate velocity values in other
experiments, and would be able to claim that these velocity values weren't
theory-specific.

uh... why won't actual reality suffice? Reality fits reality fairly well...
locally anyway. If RHIC winds up being a real-world version of "The
Emporer's New Clothes" I'm going to be very bummed.

> It's a good method, and it's already used to compare the "relativistic
Doppler" predictions used by SR with those associated with there being a
simple fixed speed of light in the lab frame, and to show, IMO fairly
conclusively, that the SR predictions are the better of the two.
> What they don't ever seem to do, though, is use the method to compare the
SR shift law predictions with the NM shift law predictions, apparently
because it's assumed that we already "know" that the NM version has to be
wrong, because we "know" that lightspeed is always fixed wrt the observer.

We observe one coming from the right, we observe once coming from the
left... fast little suckers. Whoa! Almost head-on! Mosquito plasma achieved!
Guts and gluons everywhere. No glueballs yet though... but we can hope,
can't we?

> Whether we "know" this idea of complete c-constancy also applies in the
context of making observations of ultrarelativistic clumps of gold ions cle
beam, when one might expect the clump to act as an ultrarelativistic
particulate medium and drag lightspeeds (Fizeau), is, again, a more tricky
issue.

It has come to my attention that with you *everything* is a tricky issue.
Think on. :)

> > Be well - Pax

> Likewise
> =Erk= (Eric Baird)

Thanks. :)

>: A young Swedish science student wins a visit to the Geneva complex as a
prize, and is supposed to write up his visit for a school science project.
>: Amazed by the incredible engineering, he points at a particularly
spectacular chunk of macroengineering and asks a nearby technician, "What IS
that?"
>: The technician looks up, says "Two billion Euros", and goes back to his
work.
>:
>: The student says, "No, what I mean, is, what is it FOR?"
>: "Two billion Euros.", says the technician, curtly, and goes back to his
screens.
>:
>: The student tries again. "Sorry, you must have misunderstood me. Perhaps
my English is not good. What I meant was, what is it's reason for existence?
What does this machine provide, that the researchers needed? What did it
give them that they did not have before?"
>: The technician replies. "Two billion Euros."

 :) :) :) :) :)

Be well - Pax

.~*~._.~*~._.~*~._.~*~._.~*~._.~*~._.~*~._.~*~._.~*~.

May people say of you:
"The world is a better place because you are in it."

>From Andromeda:
"Dillon Hunt, there are three kinds of people in this
universe, those who can count, and those who can't."

We sit inside the impossible and say the impossible
is impossible.

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