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From: Paul Stowe on 28 Feb 2010 14:19
On Feb 28, 8:33 am, Bruce Richmond <bsr3...(a)my-deja.com> wrote:
> On Feb 28, 1:54 am, Ste <ste_ro...(a)hotmail.com> wrote:
>
>
>
>
>
> > On 27 Feb, 15:54, PD <thedraperfam...(a)gmail.com> wrote:
>
> > > On Feb 26, 6:54 pm, Ste <ste_ro...(a)hotmail.com> wrote:
>
> > > > On 26 Feb, 17:34, PD <thedraperfam...(a)gmail.com> wrote:
>
> > > > > On Feb 25, 9:05 pm, Ste <ste_ro...(a)hotmail.com> wrote:
>
> > > > > > I also doubt one exists at the moment, but I see that as a problem.
> > > > > > It's utterly irreconcilable, within any conceptual framework that I
> > > > > > know of, to have situations where, for example, a large ladder can end
> > > > > > up in a smaller barn according to an observer stationary in the barn,
> > > > > > but not according to an observer riding the ladder.
>
> > > > > Why? And here we can systematically trace back to the assumptions you
> > > > > are making and then question them. In this case, you have a firm
> > > > > belief that length is definable in such a way that it is intrinsic to
> > > > > the object and frame-independent, and that physical "fitting" is a
> > > > > function of the *intrinsic* lengths of two objects (or an object and a
> > > > > container).
>
> > > > My only contention is that it is *not realistic* to say that from the
> > > > barn frame frame the ladder contracts and fits inside, while saying
> > > > that from the ladder frame it is the barn that contracts and the doors
> > > > actually never shut simultaneously. It is simply not realistic.
>
> > > I don't know what basis you have for judging whether something is
> > > "realistic".
>
> > I must admit I can't quite put my finger on it myself.
>
> > > I'm guessing that it means that it is consistent with
> > > your intuition, and that your intuition tells you that something
> > > cannot fit in one frame and not fit in another, or that two events are
> > > simultaneous in one frame and not simultaneous in another. If this is
> > > accurate, then I would ask on what basis you trust your intuition. Or,
> > > even more aptly, why do you trust your intuition so much that you rule
> > > out other possibilities as real if they conflict with your intuition?
>
> > Because on the one hand my physical (i.e. practical-mechanical)
> > intuitions are well-developed and highly consistent with my experience
> > of reality, and secondly it is not readily apparent that SR is
> > inconsistent with these intuitions. In the face of people who suggest
> > the two are inconsistent, obviously I've got to first consider whether
> > there's a language difference between me and the opponent (i.e. no
> > common apprehension of verbal meaning), and secondly whether the
> > opponent is confused or simply wrong (i.e. no common apprehension of
> > the evidence).
>
> > The ultimate resolution of this question seems to be confounded
> > firstly by the degree to which there is no shared language, secondly
> > the degree to which opponents seem to be unclear about the conceptual/
> > qualitative basis of SR, and thirdly the preconceptions and
> > psychological style of many posters.
>
> > > > If
> > > > such a thing appears to happen, then it is obviously an artefact of
> > > > subjective observation.
>
> > > I disagree. In science, if there is a conflict between experimental
> > > observation and intuition, then it is *intuition* that becomes
> > > suspect, not the experimental result, especially if the latter is
> > > confirmed independently and by complementary means.
>
> > I'm afraid there is no room for a discrepancy between intuition and
> > observation. Intuition is supposed to account for observation, and
> > there is no question of observation taking a back seat to intuition.
> > So that in that way we agree.
>
> > But this is not the same as crude observationalism.
>
> > > > > > > Your disbelief of SR stems from the fact that you don't understand it.
>
> > > > > > My disbelief, really, stems from the blatant lack of conceptual
> > > > > > understanding of the theory. I mean, as I repeatedly point out, I
> > > > > > don't know a single equation of relativity, and yet I can root out the
> > > > > > conceptual contradictions immediately when people here have a crack at
> > > > > > making meaningful qualitative statements in SR. The classic example,
> > > > > > of course, was Paul's contention that "what is simultaneous in one
> > > > > > frame can never be simultaneous in another", which of course isn't
> > > > > > true according to SR.
>
> > > > > I'm sorry? It is very much true in SR that two spatially separated
> > > > > events that are simultaneous in one frame are not simultaneous in
> > > > > another frame moving relative to the first.
>
> > > > But I contradicted that when I pointed out that two observers can be
> > > > moving relative to each other, and yet undoubtedly events can be
> > > > simultaneous for both.
>
> > > Not spatially separated ones, no.
>
> > I'm confused, because I thought we previously agreed that two
> > observers travelling along the same axis, maintaining equidistance
> > from both events at all times, would both report each event as
> > simultaneous with the other event. And moreover, if they not only both
> > maintained equidistance from both events, but if they maintained a
> > separation which was equal for both observers (which, if both
> > observers are moving relative to each other, requires either a
> > collision course between observers, or travel in diametrically
> > opposite directions), then there is no question that the signals are
> > received simultaneously.
>
> > Illustration:
>
> >   E1
>
> > --------
>
> >   E2
>
> > The line represents the line between events E1 and E2, along which the
> > observers may move while always reporting both events to be
> > simultaneous.
>
> You are correct about E1 and E2 being simultaneous to all observers on
> the line despite their motion relative to other observers on the
> line.  The statement about spatially seperated events is about
> seperation along the axis of travel.  In the train experient A and B
> are on the tracks, which we call the x axis.  You have E1 and E2 off
> to the sides of the tracks on the y axis, which isn't normally
> considered in the train experiment.
>
> See if this makes sense to you.  We were given the definition of
> simultaneous, that if an observer at the midpoint between two strikes
> sees the flashes at the same instant the strikes were simultaneous.
> We have four events given to us.
>
> 1. A strike hits A and A' when they are together.
> 2. A strike hits B and B' when they are together.
> 3. M and M' pass each other before observing either strike.
> 4. M observes the strikes at A and B at the same instant.
>
> It is not given that the strikes were simultaneous.  It is up to M and
> M' to figure that out on their own, based on measurements made in
> their own coordinate system.
>
> M knows that A and B are the same distance from him.  Since both
> flashes traveled at the same speed, the same time elapsed as they were
> traveling to him.  And since the flashes arrived at the same instant,
> the strikes must have happen at the same instant *as measured on
> clocks in his coordinate system*.
>
> Now let's look at things after the strikes but before the flashes have
> arrived.
>
> A   A'      F1      M   M'  F2          B   B'
>
> A and A' were together when F1 was emitted.  B and B' were together
> when F2 was emitted.  There is one and only one wave front moving
> outward frome each strike.  It was given that both flashes will reach
> M at the same instant.  From the diagram you can see that at the
> instant M sees the two flashes F2 has already been observed passing
> M', while F1 has not yet reached M'.  So the flashes do not reach M'
> at the same instant.
>
> M' knows that A' and B' are the same distance from him.  Since both
> flashes traveled at the same speed, the same time elapsed as they were
> traveling to him.  And since the flashes arrived at different times,
> the strikes must have happen at different times *as measured on clocks
> in his coordinate system*.
>
> From the tracks it looks like the clocks on the train were set out of
> sync to force the transit time of the flashes to be the same, but on
> the train they were just following the clock sync procedure.  The
> important thing is that according to the clocks on the train the
> flashes happen at different times.  In the train frame M just happen
> to be at the right spot for the two flashes that happen at different
> times to reach him at the same instant.
>
> Hope this helps.  Some here don't seem to understand that it's not the
> math that is difficult to grasp, it is what the math is modeling that
> isn't clear.  For me it was easier to see this in terms of LET.
> Neither frame is at rest wrt the ether, but both must sync their
> clocks in such a way that the same flash is measured to travel at c in
> their own frame.  I figured out how to do that using LET, and since SR
> and LET use the same math, it must work for SR.
>
> Given that math you can then see that things are symetric.  If you
> pick a third frame to view things from, such that the first two are
> moving in opposit directions at the same speed, then the first two
> will be equally contracted and their clocks will tick at the same
> rate.
>
> Try drawing some space,time diagrams.  That is using the x and t
> axis.  It's not hard to do and it shows the geometry you keep hearing
> about.  Again, knowing how to draw the lines doesn't explain what is
> happening, but it does make it easier to see relationships between
> frames after you figure out what's going on.
>
> Bruce
>
> - Hide quoted text -
>
>
>
>
>
> > - Show quoted text -- Hide quoted text -
>
> > - Show quoted text -

INDEED! Very good explanation, especially the comment about there is
only one wavefront per flash. How one perceives the order is due to
propagation transit times (including so-called time dilation and the
physical differential contraction along the axis of motion). The
ordering of observations in a universe with a finite upper limit on
the speed at which information can be propagated will invariably lead
to variations in the order of observations. Couple this with the fact
that clock synchronization inherently includes any systemic velocity
effects leads to relative simultaneity perception. Again this is
neither mysterious or 'special'.

Paul Stowe
From: Paul Stowe on 28 Feb 2010 17:59
On Feb 25, 11:21 pm, Ste <ste_ro...(a)hotmail.com> wrote:
> On 26 Feb, 06:37, "Peter Webb" <webbfam...(a)DIESPAMDIEoptusnet.com.au>
> wrote:
>
> > Some more work has been done on the concept. About a 150 years worth. Its
> > exactly how radio and TV transmitters work. You do concede that they do
> > work, right? And that radio is a form of light? And radio waves can be made
> > by simply oscillating electric and magnetic fields?
>
> > Just because you *nothing* about Maxwells eqns doesn't mean they need more
> > work. It means you need to do more work, to bring your knowledge of physics
> > up to where it was in the mid 19th Century.
>
> I think you misunderstand. I concede that light comprises some kind of
> oscillation, and that many of its manifestations are well-understood,
> but it seems to me (from what I've read) that it's conceptual basis is
> a bit suspect.

Hi,

I'll try this again. SR like the equivalent theories of Lorentz &
Poincare that preceded it does represent actual reality. The short
answer to the thread's question is, light speed is the result of the
density and compressibility of the substance of space. You can call
that substance quantum foam, zero point field, dark stuff,
quintessence, or whatever but it is independent of any movement of
emitters/receivers. It is 'measured' as the same value in all
'inertial' reference frames solely because matter isn't rigid and
consists of perturbative fields with remain internally consistent when
moving. These fields 'resist' changes in motion because such changes
result in reconfiguration of said fields. This is the likely root of
the property we call inertia. The Lorentz contraction is the result.
Because of the contraction all round trip paths remain equal under all
states of uniform motion. Therefore a moving system and the paths
light signals must travel is illustrated below.

Definition of terms used

P -> Path of light
L -> Measured (Local) Length
x -> velociy Displacement
c -> Light Speed
c'-> Local Light Speed
v -> velocity
b -> Lorentz Beta Factor
g -> Einstein's Gamma Factor (inverse Beta)


= y axis
/^ |
/ | |
/ | |
(P) c c' (L) |
/ | |
/ (x) | |
---v---> -----------+----------- = x axis

c^2 = c'^2 + v^2 => c'^2 - v^2 = c'^2

Therefore,

c' = c[Sqrt(1 - {v/c}^2)]

Divide both sides by c,

c'/c = Sqrt(1 - {v/c}^2) = b = 1/g

Thus the ratio c'/c is the Lorentz beta factor (b) and, in SR, the
inverse gamma factor (g). It relates the (L)ocal component of speed c
(c') to the total propagation speed c, if, and only if, speed c is
some finite value independent of any speed v.

P = ct
L = c't = ct/g
x = vt

Thus,

P = Lg = L/b
L = Pb = P/g

and,

t = P/c = Lg/c = L/c' = x/v

Finally,

dP/dt = c
dL/dt = c'

and therefore as long as for any round trip path the physical length
(L) is invariant, for 0 < v < c the actual path (P) light takes must
result in invariant speed measurements. Now why is that? Let's aay
we don't know know the system is moving along the x axis at v. We do
know that we define speed as dx/dt and assume light speed c is not
altered by v, so what is the speed of a light pulse across distance
L? Well, because we are actually traveling at v while we have
'assumed' instead v = 0 the actual path the light takes is P, not L.
Thus what we 'think' is simply dL/dt is, in actuality, dP/dt. Clearly
dP/dt = c and the path of our light ray is, in fact Lg, with a transit
time of Lg/c. Thus what we has defined as dL/dt is, in actuality Lg/
(Lg/c) which, by mathematical definition, will always return a value
of c.

So, while it looked like light traveled path L it actually takes path
P -> Lg and the time it took to transit is not L/c it was actually Lg/
c. So, if any system is moving at some dv relative to our reference
and we assume that, for them, L is the same as ours, then 'relative'
to us there must exist a g' (1/Sqrt(1 - {dv/c}^2)) and again, relative
to us, an increase in transit time and increase in travel length of
Lg' - L and the increase in travel time Lg'/c - L/c. Further, knowing
that for them, they can assume their v = 0 and will also measure speed
c as P/P/c or the same as ours, these actual physical differences of
g' must be assigned to distortions in length and time between the two
systems. In reality however, it should be rather obvious by now that
the actual speed of transit is L/Lg/c = c'.

Given the above derivation actual differental velocities would result
in measurements which uniquely fit this specific mathematical form and
the necessity of this form constitute proof that, while measurements
in any frame returns an invariant value for light speed c, the reason
isn't that the value hasn't physically changed. On the other hand,
since only differental speeds are necessary to properly account for
perspective changes, using the invariant measured value of c as a base
for any local base is both mathematically sound, and in the absence of
a common backdrop, logical. However, not so much for understanding if
you do not know, or realize the reasons behind it. As illustrated
above the physics behind it is that, in fact, the local speed of light
in any moving system is actually slows to c' (c/g = cb) which results
in longer transit times of L. Without a universal framework however
one can readily assign this slowing in speed to distortion of length
and time. This universal rest frame problem has, up until recently,
been ambigious. Luckily we discovered that the universe illuminates
it for us, its called the Cosmic background radiation. For it there
exists one, and only one frame of reference where this radiation is
isotropic. Thus any motion in respect to it is both detectable and
quantifiable, as an anisotropic dipole Doppler shift, all one has to
do is look at this background to and make the measurement. With this
backdrop we can now sort all of this out and see the system Lorentz
proposed in his 1904 paper along with all of the associated elements,
local times, proper times, as as local light speed c' and proper light
speed c.

Regards,

Paul Stowe
From: spudnik on 28 Feb 2010 18:26
I'd pen-intimately agree about Newton's dog-gone calculus;
the original motivating problem was the brachistochrone
of Bernoulli and Liebniz and Huyghens, apparently also solved
by Sir Mintminder.

remeber, that the speeed of light will be affected
by the slowdown of your time-base (more or less frozen,
"at" lightspeed, so....).

>   In the next sentence, answer the first two questions  and then
> answer, if you can, the third and most significant one.
>   In his equation tau = a(t - vx'/{c^2 - v^2}),
> where did the "a" come from and what does it signify; and IF it IS "a
> function phi{v) at present unknown" WHAT is its value if, as he later
> said, "phi(v) = 1"?

--les OEuvres!
http://wlym.com

--Weber's electron!
http://www.21stcenturysciencetech.com/edit.html

--Moon's atom!
http://www.21stcenturysciencetech.com/articles/Fall02/Moon.html

--Stop Cheeny, Rice, Waxman and the ICC's 3rd British invasion!
http://www.larouchepub.com/pr/2010/100204rice-ists_sudan.html
From: Ste on 28 Feb 2010 23:40
On 28 Feb, 06:25, "Peter Webb" <webbfam...(a)DIESPAMDIEoptusnet.com.au>
wrote:
> "Ste" <ste_ro...(a)hotmail.com> wrote in message
>
> > How on Earth have you drawn that conclusion? On the contrary, I hold
> > that it *is* a problem that there is no apparent physical explanation
> > for gravity (in terms of what it is, how it is mediated, how it
> > relates to other forces, etc).
>
> I am demonstrating that you are inconsistent in your requirement that
> explanations be physical.
>
> You claimed that you had a physical model "in your head" of how the solar
> system rotates - involving orbits, masses and "gravity". But your model has
> no physical explanation for gravity. It is no more a physical description of
> the solar system than Minkowski is of SR - both models contain things which
> have no physical explanation (according to you, anyway). Yet you accept
> these in your model of the solar system (as did Newton in his model), but
> reject them for SR.

I certainly accept that, in the model I have of gravity, gravity is
simply assumed to be a fundamental manifestation of reality. And the
obvious truth of its existence and apparent simplicity does not make
that hard to believe. However, I fully accept that there is a question
as to what gravity actually is, but when that question is answered my
physical conception of the solar system will not really need to be
retailored.

As to the question of what defines a "physical model", as I've said,
even I concede that it's very difficult to conceive of any particular
explicit specification, even though I (and apparently many others) can
identify intuitively what does and does not meet this specification.

As I said, in the case of Minkowski, it clearly fails the test of
having any meaningful physical form. The defining elements of
Minkowski spacetime are all mathematical. It clearly requires
interpretation to give it any meaning that would be amenable to our
senses, and yet this interpretation layer seems to be implicit and
adhoc. The prime example was the "rotating into time" explanation for
length contraction.
From: Ste on 1 Mar 2010 00:08
On 28 Feb, 07:07, "Peter Webb" <webbfam...(a)DIESPAMDIEoptusnet.com.au>
wrote:
> "Ste" <ste_ro...(a)hotmail.com> wrote in message
>
> On 27 Feb, 15:44, PD <thedraperfam...(a)gmail.com> wrote:

> > > I think you're attributing an absurd definition to "science". Paul
> > > Draper probably had a more tenable argument when he said that string
> > > theorists are scientists doing science, but that they do not yet have
> > > a "scientific theory". But I know from talking to him that he
> > > attributes a very contorted meaning to the phrase "scientific theory",
> > > that would condemn a lot of scientific knowledge, both historical and
> > > current, as being "unscientific".
>
> > Examples, please.
>
> In physics I would raise the same old example: string theory . But
> there are certainly more. We have things like "dark matter". Or even
> Newton. Or Galileo. And more broadly, in biology we have evolution,
> and in economics, rational choice theory.
>
> __________________________________
> All of these things are falsifiable, or they are not scientific theories. I
> don't know much about string theory, but the rest are certainly falsifiable.
> Newton's theory was in fact falsified by observation. In another part of the
> thread, I gave you half a dozen ways evolution could have been falsified.

Not true.



> All managed to fail your previously stated requirement of a
> "scientific theory", which (amongst other things) is being falsifiable
> (in a practical rather than just notional sense), not ad-hoc, and
> predicting observations that are not already accounted for.
>
> _______________________________
> I didn't state any of these requirements other than it was falsifiable.

Well I was replying to Paul.



> All
> of those theories are, at least as I understand them, with the proviso I
> know zero about string theory and not a lot about some of the others. I have
> already demonstrated how many of them in fact could be falsified.

String theory is *not* falsifiable. Dark matter is resistent to
falsification, because it "does not interact except through gravity
and inertia". Both Newton and Galileo were falsified a number of times
by their contemporaries, and they were forced to revise (of course,
this was before Popper). We've dealt with evolution elsewhere.
Rational choice theory is either falsified when it makes express
claims as to what people want, or it becomes unfalsifiable when it
makes no express claim as to what people want.
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