Re: Galilean transformation explanation of MMX

Hayek schrieb:

It is not a testimony as such, it is proof that Einstein understood
Mach's principle, it was even Einstein who gave it that name, and
that he wanted to incorporate it in GR.

Maybe he wanted that. I don't consider Mach's principle as being so
important.

More important than you think.

For what purpose?

It is given too little attention, but universities are trying to catch up.

I don't see why. In practice, GR works well when you consider the
energy-momentum densities and fluxes, plug them into the stress-energy
tensor, solve the field equations and get a spacetime geometry which
tells you how test particles move under the chosen setup.

I would express it somewhat different: "Inertia" means that a test
particle will move along a geodesic worldline, as far as it is not
influenced by external forces. The geodesics are a matter of the
geometry of spacetime, and this geometry is connected to the
energy-momentum densities and energy-momentum fluxes according to
Einstein's equations.

The geodesics confuse more than anything else.

Huh? Geodesics are the quintessence of GR, because they tell you what
happens to a test particle under the influence of energy-momentum
densities and fluxes in its environment. And that's just what you want
to know if you consider physical problems dealing with gravitation.

If the "movement through
time" is nothing else as the sum of the inertial field, then it is a
rather bizarre construct.

I don't know what you mean with "movement through time".

It is a mathematically correct model, but it
is very cumbersome. It is based on the assumption that time is a
separate dimension, which is baseless.

It's not "baseless". Just as any other theory, GR is reviewed with
regard to experiments and observations. As long as its predictions are
in accord with the observations, the theory is considered as being
correct. It's just that simple!

Next step : If mass creates inertia, more mass creates more
inertia. Mass does not only create gravitation but also inertia.

You can think of "mass" as being the proportionality factor between
force and acceleration, just like in classical mechanics. In general
relativity, "acceleration" means deviation from a geodesic.

But can the deviation be easier accomplished, like in zones of lower
inertia, or more difficult, in zones of higher inertia ? Is this
somewhere expressed as some "density" of the geodesics ?

I don't know what you mean with "zones of inertia". Deviation from a
geodesic path needs an external force, e.g. an electromagnetic force. I
also don't know what you mean with "density of geodesics". A geodesic is
a geometrical object, not a physical one (like the "orbit" of a
satellite is the geometrical line along it moves around the earth and
not a physical object).

The geodesics are really a poor tool, for explaining what really goes on.

They are really a powerful tool, as they explain e.g. how planets and
light rays move in the vicinity of the sun.

Realizing this, we look at the Eotvosch...

Eötvös - he was Hungarian.

I confused with the phonetic Utvusch.

Ok, the hungarian "s" is pronounced like the german "sch" (and the
english "sh"). The vowels are pronounced a bit different from "u"; in
german notation the name would sound like "Äötwösch".

...experiment again, and the equivalence principle, gravitational
mass always= inertial mass. Because they are caused by the same
field ?

AFAIK general relativity does not explain where the equivalence
principle comes from. It takes this principle as a prerequisite which
is based on experience.

I know this is a shaky argument, but it could be interpreted that way.
In each case, it certainly does NOT contradict my claim.

You did not say something solid on the origin of the equivalence
principle, did you? Physics does not consist of handwavy guesses like
"maybe they are caused by the same field, whatever field that may be".

[...]
General relativity just describes one single field, the gravitational
field. There is no such thing as a "field of inertia".

But then you reject Mach's principle entirely.

Why? AFAIK Mach only made the handwavy guess that the path of a freely
moving object may be determined by the objects in its environment. GR
takes this into account by plugging the "objects in its environment"
into the stress-energy tensor and solving the field equations which
yield the geodesics which describe the paths which freely moving objects
would follow.

If mass over there causes inertia over here, then mass creates inertia.

As I already explained, "inertia" just means that a freely moving object
follows a geodesic path, whereas deviation from that path would require
an external force. "Mass over there" just determines how geodesics run
through spacetime - inertia is a property of the test particle itself.

The Earth also creates inertia, explained as frame dragging.
If you look at the numbers, the frame dragging of the Earth, is of the
same order as the time dilation.

Frame dragging doesn't have much to do with time dilation.

In my view, the universe slows down the clock for a billion parts, and
the earth slows it down for one in a billion parts.

Your view about the universe doesn't have much to do with the universe
we are living in.

We are subjected to enormous gravitation from the masses of the
universe, but we do not feel it, since it cancels out, but we still
undergo the inertia.

Ok so far...?

No. You don't feel gravitation as long as you move along a geodesic.
If you deviate from the geodesic, you feel this as "acceleration".
For example, the "weight" of your body is caused by the solid ground
which constantly accelerates you away from freely falling into the
earth, which would be your geodesic path.

That is only a way of seeing things.

I tried to make clear that it's not very useful to talk about us being
"subjected to enormous gravitation". We are just like any other test
particle following our geodesic paths, as far as we are not influenced
by external forces.

Next step : clocks runs slower in gravitation, you call it
differently, but it is effectively saying the same.

I would express this somewhat different: In a gravitational field,
spacetime is curved, and due to this curvature signals from a clock
"down in the valley" will arrive in longer intervals "up on the hill"
as they were emitted. There is no physical effect which affects the
mechanisms of the clocks.

That is not correct. If, after some time, you reunite the clock from the
hill with the clock in the valley, the clock on the hill is ahead of
that from the valley.

That *is* correct. If you reunite the clocks after some time, they have
travelled along different worldlines through spacetime, corresponding to
different readings of the respective elapsed times.

I say : inertia was higher in the valley.
So the inertiameter ran slower.

Every clock runs at a speed of one second per second (trivial).

So if we put a clock in space, it runs faster, there is less
gravitation, if we put it on the surface, it runs slower more
gravitation, and then we put it at the center of the earth : NO
gravitation, we are weightless there. But the clock runs SLOWEST
there ! So clock speed has nothing to do with gravitation, but it
nicely follows the inertial field, or the inertial component of the
field created by mass.

As I tried to explain above, the "gravitational time dilation" is not
a matter of "clock speed" (every clock runs at a speed of one second
per second ;-)) but rather a matter of what happens to the signals
which were emitted by the clock until they arrive at the observer.

No, as I explained above, it is a real effect.

What is real is the length of the worldline sections as measured by the
respective times elapsed. There is no need for a physical influence
affecting the clock mechanisms.

If I go to berlin via Cologne or via Leipzig, my mileometer will measure
different distances, but there is no physical influence depending on the
route which affects the mechanism of my mileometer.

Illustrates in many
thought AND REAL experiments, like Hafele Keating. And Einsteins claim :
if I throw a clock in the air, and when it falls back into my hands, it
ran slower. Here the slowing is more due to the velocity effect.

It didn't run slower, it just travelled along a shorter worldline
section through spacetime, measuring a lesser amount of seconds elapsed.
There are no different sorts of seconds depending on the respective
worldline.

[...]
No, a clock just counts the cycles of a periodic process. To measure
inertia, you should apply a *constant* force.

Why ? Inertia limits accelerations and decelerations, so a rotation
would be good, making a mass go back and forth.

The period with which your mass is going back and forth depends on the
oscillation frequency of the force you apply to it. It is not a property
of the mass.

Besides, I have a tought experiment with a rotating ring, that rotates
one time a second, thus acts like a clock, and this yields the same
result, if you consider it as a clock and apply a time dilation factor,
or if you consider it as a rotating ring of mass, that undergoes higher
inertia.

That is why a clock is an inertiameter.

I don't know what you mean with "undergoing inertia".

[...]
If you can follow my reasoning so far, I will explain its
importance for understanding uncertainty.

I find several flaws in your reasoning.

There are some in yours too.

Then you should clarify them.

MfG,
Juergen
.

Relevant Pages

  • Re: Galilean transformation explanation of MMX
    ... Thus, inertia is not a property of mass an sich, but an external ... I would express it somewhat different: "Inertia" means that a test ... You don't feel gravitation as long as you move along a geodesic. ... But the clock runs SLOWEST there! ...
    (sci.physics.relativity)
  • Re: Time dilatation and a space referential
    ... If a mass affects ... > a clock, then lots of mass will also affect a clock, ... >> a property of the general relativity. ... it meanse inertia has varied. ...
    (sci.physics.relativity)
  • Re: Galilean transformation explanation of MMX
    ... The geodesics confuse more than anything else. ... And since both GR and QM do not, or barely take into account inertia, they are unable to explain what goes on and refuse any attempt at unification. ... Mass does not only create gravitation but also inertia. ... Bang your head against the wall and feel the inertia, watch the parts of your clock extracting the value of the inertial field, or the-inertia-causing-field, if that says it better. ...
    (sci.physics.relativity)
  • Re: Galilean transformation explanation of MMX
    ... mass of say galaxies and the universe, ... The geodesics are a matter of the geometry of spacetime, and this geometry is connected to the energy-momentum densities and energy-momentum fluxes according to Einstein's equations. ... Mass does not only create gravitation but also inertia. ... and due to this curvature signals from a clock ...
    (sci.physics.relativity)
  • Re: Never say absolute on sci.physics.relativity !
    ... Yep, the inertia went missing... ... Now you know what a clock does, in a gravitational field, so this field must have some properties other than just gravitational attraction. ... The earth has to rotate slower...by what mechanism this could be accomplished? ... This has been called the holy grail of physics. ...
    (sci.physics.relativity)
Loading