Re: GR ?


"Tom Roberts" <tjroberts@xxxxxxxxxx> wrote in message
news:ImDDe.1901$fx4.1574@xxxxxxxxxxxxxxxxxxxxxxxxxxxxx
| Significant Zero wrote:
| > "Tom Roberts" <tjroberts@xxxxxxxxxx> wrote in message
| > news:lOYCe.673$lX2.670@xxxxxxxxxxxxxxxxxxxxxxxxxxxxx
| > [...]
| > This seems to be saying that length contraction and time dilation are
just
| > observational distortions in the same way that railway lines get
apparenly
| > nearer as they extend to the horizon.
|
| Sort of -- both are effects of perspective, but different effects.
|
|
| > Is this the way you explain to
| > yourself the experimental variation in muon decay and contraction in the
| > direction of motion ?
|
| It is the way SR explains them. Just like rotations in 3D -- what
| "explanation" do you use for the fact that a 10-foot-long ladder will
| fit through a 3-foot-wide door in one orientation but not in another?

Nice example but neither the doorway or the ladder change in physical
reality only the relationship between the ladder and door. The pov can
change as much as it likes it still will not enable the ladder to fit
through the door in the inappropriate orientation. The physical fact of the
ladder and door are not changed by observation or measurement and any
measurement that fails to correct for factors it is aware are imbedded in
its methodology needs a poke in the eye with a sharp stick.
BTW try a piano as they take no notice of observational distortion or
perspective but are effected by gravity and velocity.{:-)

| I say it is because the PROJECTION of the ladder's length onto the axis
of
| the door's width depends on their relative orientations.

Yes as a physical fact.

| Similarly in
| SR, the PROJECTION of a rod's length, and the PROJECTION of a clock's
| tick-interval, depend on their orientation relative to the measuring
| apparatus. This is, of course, orientation in spaceTIME.

This is not a physical fact its a observational or mathematically engineered
one and has no comparison or effect on the ladder or the doorway or rod and
clock.
You appear to be mixing physical facts with observational and or
mathematical ones and then forgetting which is which.

|
| On a Euclidean plane, the x' axis of Cartesian coordinates
| rotated relative to x-y coordinates has a nonzero dy/dx.
| In 2-d spacetime the x' axis of Minkowskian coordinates
| rotated relative to x-t coordinates has nonzero dx/dt --
| that is clearly a relative velocity. The rotation is of
| course hyperbolic, not circular as in the Euclidean case.
|
|
| > | > i.e A cubic meter of the vacuum state between galaxies
| > | > has different characteristics to a cubic meter just outside an event
| > | > horizon[...]
| >
| > This may be difficult to explain but perhaps you will agree that a clock
in
| > the in the two vacuum cases above will tick at different rates,
|
| No, I don't agree to that highly-ambiguous statement.

Well I did not think it was particularly ambiguous as if you don't agree to
that then you must not agree that clocks generally run slower on earth than
in space and you must now have switched to the view that GR is invalid ?

| Before you can say
| anything about this you have to define how the rates of the two clocks
| are compared. Once you realize that, you will realize that you cannot
| possibly separate "difference in tick rate" from "effects on the signals
| used to compare them".
|
| In GR this is modeled as geometry in spacetime. To do that the intrinsic
| rate of a clock cannot depend on its environment.

All the proof seems to contradict you as the intrinsic rate of clocks
appears the be dependent on Gravityand and velocity.

| For instance if you
| define "comparison of tick rates" by placing a standard clock next to
| each clock to be compared and then comparing those clocks to the
| standard clocks, you will immediately see that their tick rates are the
| same.

Yes, because they are now in the same environment.

|
|
| > so time
| > according to the clocks is moving at a different rate ?
|
| The word "moving" does not apply to "time".

I disagree, process is moving both in space and time.

|
| A simple way to avoid such nonsense is to remember that in physics
| anything worth discussing must be MEASURABLE. How could one possibly
| measure "motion of time"???

With a clock.

|
|
| > If so then if c is
| > measured locally constant in these two environments but the clocks are
| > running at different rates then actual length must have changed to
| > accommodate the actual but locally unobservable change in c ?
|
| See above. You confuse yourself by attempting to use incomplete sound
| bites to describe things instead of complete and detailed descriptions.
|
| Most people, especially around here, do not realize how important
| precision in thought and word is. Modern physics is quite subtle, and
| precision is ABSOLUTELY ESSENTIAL. My insistence on such precision is
| not "nit picking", but is ESSENTIAL to understanding the concepts.

That's fine but I would like to nit pick some of your statements definitions
and contradictions starting with your apparent contradictions with regard to
physical reality, observational reality, personal conceptual reality and
common conceptual reality.

|
|
| > | Certainly the Lagrangian of a system does not, in general, by itself
| > | define energy. But if it is invariant over time translations then it
| > | does (via Noether's theorem). And if it is not so invariant, energy is
| > | not so useful....
| >
| > That makes no sense to me as energy is a dynamic and the only relatively
| > static and invariant over time, form of energy that I can think of at
the
| > moment is a partical. Which implies that Lagrangian are not applicable
to
| > energy of fields.
|
| You clearly do not understand Lagrangians. Study them. Don't merely
| fling words around without understanding.
|

I might if I was convinced they applied to fields.


|
| > | The metric _IS_ the geometry.
| >
| > I tend to think as the metric as being [...]
|
| You clearly do not understand differential geometry. Study it. Don't
| merely fling words around without understanding.

Thanks you can snip you own statments and views as well.

|
|
| > | And in general it is not possible to
| > | "refer" a curved Lorentzian manifold to a "flat Euclidean geometry".
| >
| > I don't see the difficulty in overlaying one metric space with another
and
| > translating between them other than the complexity.
|
| You clearly do not understand differential geometry. Study it. Don't
| merely fling words around without understanding.
|
| Specifically: the topology of a curved manifold can be, and usually is,
| incompatible with the topology of a flat Euclidean manifold. So such
| "referal" or "translating" is simply not possible.
|
| Why do you think that it is impossible to cover the surface
| of a sphere with a single coordinate system? That is
| directly related to the impossibility I discuss here.
|

Latitude and longitude seem a fairly good system.

|
| > In fact curvature is a
| > Euclidean statement [...]
|
| Not true. You clearly do not understand differential geometry. Study it.
| Don't merely fling words around without understanding.

Perhaps you are pompously flinging concepts and words around without
understanding them.
--
Significant Zero E-field = Electric field, M-field =Magnetic field, two
unbound field effects
http://home.freeuk.com/paulps/
Maybe updates. (1-(1/(1/3))^2)/(1 + (1/(1/3))^2) = - 0.08 = FTL ? -p<+p or
(m*-v)<(m*+v) or (m*-c^2)<(m*+c^2) =g?
..
|
|
| Tom Roberts tjroberts@xxxxxxxxxx


.

Relevant Pages

  • Re: GR ?
    ... >>> reality only the relationship between the ladder and door. ... >> And so does SR - which is why proper time is the only invariant time. ... The theory says the flying clocks ... >>> Yes as a physical fact. ...
    (sci.physics.relativity)
  • Re: Ton of Bricks Paradox/Contradiction?
    ... that the 'clocks remain synchronized' to clocks that are no longer in their ... extrapolation from the original synchronisation process ... Your argument against Special Relativity doesn't ... These are all I need to show that length contraction ...
    (sci.physics.relativity)
  • Re: The concept of time contractrion in special relativity
    ... |>>> time contraction by using the standard light clock setup? ... "Somewhere in the orbit, the clocks on ship B must run faster than ... | No, the ones that avoid the revolving clocks problem (certainly, not all ...
    (sci.physics.relativity)
  • Re: The concept of time contractrion in special relativity
    ... >> time contraction by using the standard light clock setup? ... the clocks on ship B must run faster ...
    (sci.physics.relativity)
  • Re: PD does not understand SR
    ... Doppler shift physically slows clocks! ... Why bring up the Doppler shift? ... without also showing a physical contraction of the ruler, ... Since clocks are analogous to people when it comes to time ...
    (sci.physics.relativity)