A short Relativistic Enigma

On May 6, 8:40 am, Tom Roberts wrote:
On 5/5/11 5/5/11 - 2:21 PM, Paul Cardinale wrote:

An interesting circumstance; the "straightedge" would look curved.

Yes. This is not at all unusual in GR, where spacelike geodesics are often not
spatial projections of the null geodesics that light follows.

Under gravitational influence, you cannot tell if your time is dilated
or not. To do so, you have to compare your time flow with someone in
great confidence not under any gravitational influence. shrug

Spatial curvature should exhibit similar manifestation. That means
you cannot tell if your straight-edge is curved or not. As far as you
are concerned, all straight-edges are straight in your own local
spacetime. Only by comparing with someone not under any gravitational
influence of what straight-edge would look like, you can conclude that
your straight-edge is curved. shrug

Spacetime curvature should be relative. Any conjecture tries to find
an absolute or a preferred state of curvature is just nonsense.
shrug

On May 6, 6:39*pm, Koobee Wublee wrote:
On May 6, 8:40 am, Tom Roberts wrote:

On 5/5/11 5/5/11 - 2:21 PM, Paul Cardinale wrote:
An interesting circumstance; the "straightedge" would look curved.

Yes. This is not at all unusual in GR, where spacelike geodesics are often not
spatial projections of the null geodesics that light follows.

Under gravitational influence, you cannot tell if your time is dilated
or not. *To do so, you have to compare your time flow with someone in
great confidence not under any gravitational influence. *shrug

Spatial curvature should exhibit similar manifestation. *That means
you cannot tell if your straight-edge is curved or not. *As far as you
are concerned, all straight-edges are straight in your own local
spacetime. *Only by comparing with someone not under any gravitational
influence of what straight-edge would look like, you can conclude that
your straight-edge is curved. *shrug

Spacetime curvature should be relative. *Any conjecture tries to find
an absolute or a preferred state of curvature is just nonsense.
shrug

I desagree with these statements;Using suitable caesium clock you can
make clear that a time dilation exists.You can measure it.
The principal assumption is that clock reacts as any piece of matter.
An atom is also a clock. We suppose that the clock reflects the "time"
and allows to measure the time dilation. Length dilation cannot be
measured inside the system (gravitational or moving )Time dilation can
be measured
Thank you for the comment
hippolyte Lapoyat

Fatty "hippolyte Lapoyat" wrote:...
KW Koobee Wublee wrote:
Tom Roberts wrote:

On 5/5/11 5/5/11 - 2:21 PM, Paul Cardinale wrote:
An interesting circumstance; the "straightedge" would look curved.

Roberts wrote:
Yes. This is not at all unusual in GR, where spacelike geodesics are
often not
spatial projections of the null geodesics that light follows.

KW wrote:
Under gravitational influence, you cannot tell if your time is dilated
or not. To do so, you have to compare your time flow with someone in
great confidence not under any gravitational influence. shrug

Spatial curvature should exhibit similar manifestation. That means
you cannot tell if your straight-edge is curved or not. As far as you
are concerned, all straight-edges are straight in your own local
spacetime. Only by comparing with someone not under any gravitational
influence of what straight-edge would look like, you can conclude that
your straight-edge is curved. shrug

Spacetime curvature should be relative. Any conjecture tries to find
an absolute or a preferred state of curvature is just nonsense.
shrug

Fatty wrote:
I desagree with these statements;Using suitable caesium clock you can
make clear that a time dilation exists.You can measure it.
The principal assumption is that clock reacts as any piece of matter.
An atom is also a clock. We suppose that the clock reflects the "time"
and allows to measure the time dilation. Length dilation cannot be
measured inside the system (gravitational or moving )Time dilation can
be measured
Thank you for the comment
hippolyte Lapoyat

hanson wrote:
Time, never mind time-dilation or clocks, is a
discombobulated, pharisaic and ill defined
concept. Google for --[ "timne definition"]---
& you get some 200'000 different assertions
and arguments.

So, which one of those takes is your definition
of time in which your clocks appear and when
moving, exhibit a "dilation"?

And then if so, is it real or does that "dilation"
appear as such only to an ad hoc introduced
"observer" by you, to whom you, yourself, can
and will dictate any outcome that pleases you?
ahahahaha... ahahahanson


--- Posted via news://freenews.netfront.net/ - Complaints to ---

the 'corpuscle' of light is an artifact
of geometric optics or "ray-tracing," and
didn't Newton wite a book on that?... then,
de Boglie and Dirac pictured a wave of light,
merely as "1+1 dimensional" phase-space, and
that is obviously just a one-dimensional cross-section
of a piece of wire, projected to an oscilloscope,
as in elecronics engineering.

the great thing about elecronics is that
it manifestly required the use of complex numbers,
in that cross-section, although it can be done
using quaternions, as with special rel.

Brian Quincy Hutchings" QncyMI at netscape.net
who was originally Lyndon LaRouche's roach, that
morphed into "Spudnick", son of "Mr. Potato head",
rasterspace", "tensegriboy" is now brain fossilized in
"1treePetrifiedForestLane"
& no longer able to realize what's going on and so
||Brian said|| "... do I have to kiss the dingleberries?"
because of this:


Fatty "hippolyte Lapoyat" wrote:...
KW Koobee Wublee wrote:
Tom Roberts wrote:

On 5/5/11 5/5/11 - 2:21 PM, Paul Cardinale wrote:
An interesting circumstance; the "straightedge" would look curved.

Roberts wrote:
Yes. This is not at all unusual in GR, where spacelike geodesics are
often not
spatial projections of the null geodesics that light follows.

KW wrote:
Under gravitational influence, you cannot tell if your time is dilated
or not. To do so, you have to compare your time flow with someone in
great confidence not under any gravitational influence. shrug

Spatial curvature should exhibit similar manifestation. That means
you cannot tell if your straight-edge is curved or not. As far as you
are concerned, all straight-edges are straight in your own local
spacetime. Only by comparing with someone not under any gravitational
influence of what straight-edge would look like, you can conclude that
your straight-edge is curved. shrug

Spacetime curvature should be relative. Any conjecture tries to find
an absolute or a preferred state of curvature is just nonsense.
shrug

Fatty wrote:
I desagree with these statements;Using suitable caesium clock you can
make clear that a time dilation exists.You can measure it.
The principal assumption is that clock reacts as any piece of matter.
An atom is also a clock. We suppose that the clock reflects the "time"
and allows to measure the time dilation. Length dilation cannot be
measured inside the system (gravitational or moving )Time dilation can
be measured
Thank you for the comment
hippolyte Lapoyat

hanson wrote:
Time, never mind time-dilation or clocks, is a
discombobulated, pharisaic and ill defined
concept. Google for --[ "timne definition"]---
& you get some 200'000 different assertions
and arguments.

So, which one of those takes is your definition
of time in which your clocks appear and when
moving, exhibit a "dilation"?

And then if so, is it real or does that "dilation"
appear as such only to an ad hoc introduced
"observer" by you, to whom you, yourself, can
and will dictate any outcome that pleases you?
ahahahaha... ahahahanson

Koobee Wublee wrote:
Under gravitational influence, you cannot tell if your time is dilated
or not. To do so, you have to compare your time flow with someone in
great confidence not under any gravitational influence. shrug

Yes. Well, sort of -- "comparing time flow" is not really possible, one can only
compare clock rates via EM signals.


Spatial curvature should exhibit similar manifestation. That means
you cannot tell if your straight-edge is curved or not.

You can compare the straight-edge to a light ray. If you do so in several
different orientations, you can detect the presence of spacetime curvature,
assuming your measurement accuracy is sufficiently good.


As far as you
are concerned, all straight-edges are straight in your own local
spacetime.

Meaning, I assume, your local neighborhood, not some special or different manifold.

Yes, if you compare different straight-edges to each other. Not necessarily if
you compare to a light ray.


Only by comparing with someone not under any gravitational
influence of what straight-edge would look like, you can conclude that
your straight-edge is curved. shrug

No. A light ray can also display this, at least in principle. And it can do so
locally. But one needs extremely good measurement resolution, and in practice
here on earth this cannot be done.


Spacetime curvature should be relative. Any conjecture tries to find
an absolute or a preferred state of curvature is just nonsense.

This is just plain wrong. Spacetime curvature is represented by the various
curvature tensors. Tensors, of course, are "absolute" in that they are
independent of observer or coordinates. The COMPONENTS of tensors are definitely
dependent on coordinates, and are thus "relative"; not so for the tensors
themselves.


Tom Roberts

hippolyte Lapoyat wrote:
On May 6, 6:39 pm, Koobee Wublee wrote:
Under gravitational influence, you cannot tell if your time is dilated
or not. To do so, you have to compare your time flow with someone in
great confidence not under any gravitational influence. shrug

I desagree with these statements;Using suitable caesium clock you can
make clear that a time dilation exists.You can measure it.

Koobee happens to be correct here. Having a cesium clock does not permit you to
determine your gravitational "time dilation". You must compare to a distant
clock having known "time dilation", such as "someone in great confidence not
under any gravitational influence".

Of course the definition of the second includes the gravitational
"time dilation" on earth's geoid.


Tom Roberts

On May 7, 5:33*pm, Tom Roberts wrote:
hippolyte Lapoyat wrote:
On May 6, 6:39 pm, Koobee Wublee wrote:
Under gravitational influence, you cannot tell if your time is dilated
or not. *To do so, you have to compare your time flow with someone in
great confidence not under any gravitational influence. *shrug

I desagree with these statements;Using suitable caesium clock you can
make clear that a time dilation exists.You can measure it.

Koobee happens to be correct here. Having a cesium clock does not permit you to
determine your gravitational "time dilation". You must compare to a distant
clock having known "time dilation", such as "someone in great confidence not
under any gravitational influence".

* * * * Of course the definition of the second includes the gravitational
* * * * "time dilation" on earth's geoid.

Tom Roberts

I am not sure of my understanding: Do you trust the Hafele and
keating experiment? Nobody contests that the time dilation is given by
the equations (T-T')/T = gh/c2 in GR and (T-T')T=½ v2/c2 in SR when
speed and gravity are reduced tonewtonian values.
If you call (T-T')/T = H (dilation factor) all newton forces can be
expressed by a unique equation F=mc2gradH which means that time
dimlation is hidden factor that allows newton mechanics to work.
I know we are not living in the same continent. do we live on the same
planet?

Thank you for your comment and I would appreciate your answer

Hippolyte Lapoyat

I would have thought, your reference
to a "catenary approach" or what ever,
would show that your light "ray" is also going
to be bent ... not that there are any photons.

no-one replied to you, again, because
you didn't say a God-am thing.