Re: GR ?


"Tom Roberts" <tjroberts@xxxxxxxxxx> wrote in message
news:SpBEe.3241$fx4.3153@xxxxxxxxxxxxxxxxxxxxxxxxxxxxx
| Significant Zero wrote:
| > "Tom Roberts" <tjroberts@xxxxxxxxxx> wrote in message
| > news:ImDDe.1901$fx4.1574@xxxxxxxxxxxxxxxxxxxxxxxxxxxxx
| > | 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.
|
| Right. Ditto for "time dilation" and "length contraction" in SR --
| neither clock nor ruler "changes in physical reality", only the
| relationship between moving clock and stationary clocks, or between
| moving ruler and stationary ruler.
|
| A rotation is a rotation -- in Euclidean space or in
| spacetime. Rotations affect projections of objects onto axes,
| but THEY DO NOT AFFECT THE OBJECTS THEMSELVES. A relative
| velocity is merely a rotation in the x-t plane. <shrug>

That seems fairly clear to mean that in your view time dilation and length
contraction are products of remote observation, measurement and perspective
and have no basis in physical reality in the same way that Picassos pictures
have no basis in physical reality other than from an interpretation of a
reality in his head. This doesn't seem good grounds for presenting something
as a useful scientific interpretation. I was expecting something on the
order of a blue print of reality at the very least and you seem to be
offering a Einstein\Tom R. picture in the same type of gallery as a Picasso.
Why would I want a methodology and set of measurements that don't reflect as
accurately as possible the physical reality of something ? If I want a
distorted view I would paint it myself or go and look at a Picassos or
similar.

|
|
| > | 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.
|
| No. You need a MODEL of the world to describe this. The only "physical
| facts" are whether or not it fits each time you apply ladder to doorway.
| Both geometrical projection and rotation are such models (well, parts of
| such models).
|
| Just think of each application of ladder to doorway as a MEASUREMENT (of
| ladder's length projected onto the doorway's width), and you'll see the
| relationship between this and "length contraction" and "time dilation"
| in SR. It's just that the ladder/doorway is quite familiar to you, but
| the SR effects aren't -- to understand SR you need to change that
| familiarity....

The ladder and doorway are fine by me untill a better example is presented
as presumably as the are physical reality, or examples of you should be able
to deal with them present in a SR\GR context and be able to state a result
so I have put your example in a SR\GR context to just confirme my
understanding of your position.
Ladder L to L 10ft long moving down page ar near c.
Doorway D to D 3ft moving across page at near c

L



L
\/

D
>
D

Will length contraction allow the ladder to pass through the door way
without them contacting each other if the relative intersecting positions of
the ladder and door were appropriate?


|
|
| > | 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 [...]
|
| Right. It is a MODEL of myriad physical facts. Just like the rotation
| used for ladder and doorway.
|
|
| > You appear to be mixing physical facts with observational and or
| > mathematical ones and then forgetting which is which.
|
| Not me. You. Rotation of ladder into doorway is no more "physical fact"
| than "time dilation" or "length contraction".

A rough drawing of physical facts

D
L L
D

Time 5pm my garage {:-)
Ladder fits.

L
D

D
L

Time 5:10pm my garage {:-)
Ladder dont fit

Now do me as clear a one for time dilation and length contraction please.

|
|
| > | > | > 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 ?
|
| You keep insisting that this is a "difference" in the clock's tick
| rates. But in fact you have no basis for that particular prejudice --
| all the actual MEASUREMENTS show is a difference in MEASUREMENTS. And
| that could be due to EITHER a change in clocks' tick rates or in the
| signals used for the measurements.

!00% agree but which view are *you* taking and believe to be the facts ?
My view is still relatively immature and needs to be banged against others
views to knock the wood worm out so please state *your* view.{:-)


|
| In GR this is modeled NOT as a "change in tick rates", and not in a
| change of the local speed of the light signals used in the measurement,
| but rather as a curvature of spacetime.

You now seem to be claiming that "curvature of space-time" is a real
physical reality that produces an effect on real physical reality or even is
the real physical reality. I understand "curvature of space-time" as a real
physical reality to mean a relative change in space and time from one place
to another which you have denied, if this is not accurate please correct it.

| Only this last approach is
| general enough to account not only for this, but also "time dilation"
| and "length contraction" due to relative velocity, and fictitious forces
| like "centrifugal force" and "Coriolis force" and "gravitational force".
| That is, _ONE_ assumption explains many seemingly-unreleated phenomena,
| and that assumption is simply that the geometry of spacetime is
| Lorentzian (which implies it is locally Minkowskian).
|
|
| > | 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.
|
| No. You are reading more into the MEASURMENTS than is there -- you are
| imposing your personal prejudice onto the data. DON'T DO THAT!!!

I far as I am aware I don't have a personal prejudice, the muon and clock
data seemed to support the actual physical reality of time and length
variance so I was just working from the data as presented. If you are
categorically stating that time and distance are invariant except
*apparently* when measurements are not corrected for observational
distortions then I need to look and rethink my position.

|
| In fact, the MEASUREMENTS are exceedingly accurately predicted by GR,
| and in GR the intrinsic rate of clocks does NOT depend on either gravity
| or any velocity. All your statements clearly show that in order to
| understand this you need to STUDY.

This seems a clear statement that the twins scenario is a none factual red
herring.

|
|
| > | The word "moving" does not apply to "time".
| >
| > I disagree, process is moving both in space and time.
|
| "moving" means a change of spatial position over time. That CLEARLY
| cannot be applied to time itself. <shrug>

Your definition of moving is CLEARLY different to mine and the dictionary
<shrug> {:-)
Try reading it.

|
|
| > | 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.
|
| That is measuring elapsed time, not "motion of time".

Time is elapsed with a natural clock.

|
|
| > | 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.
|
| Huh?? Lagrangians involving fields are the basis of ALL modern
| fundamental theories of physics. As I said, you need to STUDY.

T = kinetic energy of system. Whats the kinetic energy of a field and how do
I calculate it ?

|
| > | 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.
|
| But not good enough -- they do not COVER the sphere S^2. Specifically:
| there are coordinate singularities at the north and south poles. I
| repeat: you need to STUDY.

I see that as a bit of a red herring as my ref. on spherical geometry seems
happy to use latitude and longitude or simlair systems for dealing with
spheres <shrug> {:-) and I am studying and you have no need to shout as it
projects in a similair way to if I write, go for a CRAP Tom.

--
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?



.

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