"Double-A" wrote in message
m...
"Mathew Orman" wrote in message
...
"Double-A" wrote in message
om...
"Mathew Orman" wrote in message
...


//But then there is that annoying physical evidence that seems to
//confirm the predictions made by GR and its concept of space-time?
//What do you do with that?

What evidence?


The precession of the perihelion of Mercury.

The bending of light near the Sun.


//Didn't you just contradict yourself?
No, the field is instantaneous and moving the source is not propagating.


If the gravitational field is instantaneous, then it is way different
than anything we observe in the material world. That would mean it is
absolutely inflexible and rigid. The material bodies causing
gravitational fields certainly cannot move instantaneously. If
something like a "Hand of God" gave the earth a shove, the earth would
be crushed by its own inertia. A gravitational field must contain
energy, since it can cause objects to move. Since energy equals mass,
you would think it would have some inertia. If moving an object meant
instantaneously moving its gravitational field, which stretches out to
infinity, you would think it would take an infinite force. It's one
thing to cause water to move across a wading pool by splashing your
arm into it. It's quite another thing to move the whole wading pool
at once.

Perhaps my analogies are not perfect, but I hope you can see what I'm
getting at.


//When the planets move, what causes the change gravitational pull on
//the Earth if not by propagation of the gravity field?
The change of field intensity that does not change the fields shape
around
the source is not called propagation or
wave propagation.
There are no electrical, magnetic or gravity waves.
The only known waves a electro-magnetic and mechanical.

//Any theory is fine, so long as you can get experimental and
//observational evidence to back it up.
Exactly means that false or misinterpreted evidence is not good enough.


//Are you an engineer?
Since 1978.

//You said you think clocks slow in the gravity near the Earth. What do
//you think about clocks traveling at near c? Do they also slow?
The motion is relative so clocks will only change periodic rate if the
ambient gravity
force changes. Objects cannot detect their own linear motion.
To accelerate clock to speed of c using non-destructive rate of ex. 10G
will take quite a while.
And than it would get destroyed in collision with space junk because
it cannot avoid collision at such relative velocity.
So forget the light speed travel!


You are evading the question.

Double-A

No, all answers are above
linear velocity has no effect on clocks periodic rate.
It is useless anyway because you cannot accelerate a clock to approach the
speed of light.
There is no mechanism that would allow propagation of waves in force field
gradient
of the same kind.
Mechanical waves cannot propagate in mechanical media gradient.
In fact mechanical wave propagation media gradients are commonly used to
dampen
the mechanical waves.
How do you imagine a disturbance in gravity force field gradient would
propagate
away from it's source?

Sincerely,

Mathew Orman
www.ultra-faster-than-light.com
www.radio-faster-than-light.com

"Mathew Orman" wrote in message ...
"Double-A" wrote in message
m...
"Mathew Orman" wrote in message
...
"Double-A" wrote in message
om...
"Mathew Orman" wrote in message
...


//But then there is that annoying physical evidence that seems to
//confirm the predictions made by GR and its concept of space-time?
//What do you do with that?

What evidence?


The precession of the perihelion of Mercury.

The bending of light near the Sun.


//Didn't you just contradict yourself?
No, the field is instantaneous and moving the source is not propagating.


If the gravitational field is instantaneous, then it is way different
than anything we observe in the material world. That would mean it is
absolutely inflexible and rigid. The material bodies causing
gravitational fields certainly cannot move instantaneously. If
something like a "Hand of God" gave the earth a shove, the earth would
be crushed by its own inertia. A gravitational field must contain
energy, since it can cause objects to move. Since energy equals mass,
you would think it would have some inertia. If moving an object meant
instantaneously moving its gravitational field, which stretches out to
infinity, you would think it would take an infinite force. It's one
thing to cause water to move across a wading pool by splashing your
arm into it. It's quite another thing to move the whole wading pool
at once.

Perhaps my analogies are not perfect, but I hope you can see what I'm
getting at.


//When the planets move, what causes the change gravitational pull on
//the Earth if not by propagation of the gravity field?
The change of field intensity that does not change the fields shape
around
the source is not called propagation or
wave propagation.
There are no electrical, magnetic or gravity waves.
The only known waves a electro-magnetic and mechanical.

//Any theory is fine, so long as you can get experimental and
//observational evidence to back it up.
Exactly means that false or misinterpreted evidence is not good enough.


//Are you an engineer?
Since 1978.

//You said you think clocks slow in the gravity near the Earth. What do
//you think about clocks traveling at near c? Do they also slow?
The motion is relative so clocks will only change periodic rate if the
ambient gravity
force changes. Objects cannot detect their own linear motion.
To accelerate clock to speed of c using non-destructive rate of ex. 10G
will take quite a while.
And than it would get destroyed in collision with space junk because
it cannot avoid collision at such relative velocity.
So forget the light speed travel!


You are evading the question.

Double-A

No, all answers are above
linear velocity has no effect on clocks periodic rate.

A very defining answer.

It is useless anyway because you cannot accelerate a clock to approach the
speed of light.
There is no mechanism that would allow propagation of waves in force field
gradient
of the same kind.

Why not gravity waves?

Mechanical waves cannot propagate in mechanical media gradient.
In fact mechanical wave propagation media gradients are commonly used to
dampen
the mechanical waves.
How do you imagine a disturbance in gravity force field gradient would
propagate
away from it's source?


How does a stretched rubber band propagate away from its source when it breaks?

Sincerely,

Mathew Orman
www.ultra-faster-than-light.com
www.radio-faster-than-light.com

Double-A

Hi Double-A ,
You say :
" If moving an object meant
instantaneously moving its gravitational field ,
which stretches out to infinity ,
you'd think it'd take an infinite force . "


Why's that ?

We don't precisely know the effective distance
of any particular gravitational field .

And even if the effective distance was nearly infinite ,
that wouldn't mean that the gravitational energy
wouldn't be observed to be very finite .

P.S. Double-A ,
Why are you using Google instead of a newsreader ?
Doesn't your ISP allow it ?

Jeff Relf wrote in message ...
Hi Double-A ,
You say :
" If moving an object meant
instantaneously moving its gravitational field ,
which stretches out to infinity ,
you'd think it'd take an infinite force . "


Why's that ?

We don't precisely know the effective distance
of any particular gravitational field .

I may have overstated the case. Gravity might not extent to infinity,
but we know it at least extends as far as neighboring galaxies, and
that's millions of light years.

And even if the effective distance was nearly infinite ,
that wouldn't mean that the gravitational energy
wouldn't be observed to be very finite .

The point I was trying to make is that if changes in gravity travel
instantaneously, then to accelerate a gravitating body you would have
to simultaneously accelerate its gravitational field, which would
effectively be a perfectly rigid and inflexible construct extending
for millions of light years. Even if an average cubic kilometer of
the field were light as a feather, the inertia of the entire field
might be ponderous.

This is not what we observe, so I don't think gravity travels
instantaneously.

P.S. Double-A ,
Why are you using Google instead of a newsreader ?
Doesn't your ISP allow it ?

Using Google for posting adds an extra layer of anonymity.
It's like wearing a 2-ply condom!

Double-A

"Double-A" wrote in message
om...
Jeff Relf wrote in message
...
Hi Double-A ,
You say :
" If moving an object meant
instantaneously moving its gravitational field ,
which stretches out to infinity ,
you'd think it'd take an infinite force . "


Why's that ?

We don't precisely know the effective distance
of any particular gravitational field .

I may have overstated the case. Gravity might not extent to infinity,
but we know it at least extends as far as neighboring galaxies, and
that's millions of light years.

What evidence is there that the universe is infinite in any way?
The mathmatical construct made by a minor life form, on a
tiny ball, in a remote edge of a so-so galicy.... Infinity is but
the failure of human constructs to consider due to scale....




And even if the effective distance was nearly infinite ,
that wouldn't mean that the gravitational energy
wouldn't be observed to be very finite .

The point I was trying to make is that if changes in gravity travel
instantaneously, then to accelerate a gravitating body you would have
to simultaneously accelerate its gravitational field, which would
effectively be a perfectly rigid and inflexible construct extending
for millions of light years. Even if an average cubic kilometer of
the field were light as a feather, the inertia of the entire field
might be ponderous.

This is not what we observe, so I don't think gravity travels
instantaneously.

Unless you consider gravity as an effect of the separation
distance of groupings of locally bound particles... Where
the base gravitational constant ( actually variable on a
universal scale) varies locally as a increase in tensor
in relation to an observer being accelerated toward and
a decrease in tensor to an observer accelerated away from.
So a change in the UGC (Universal Gravitational Constant)
would be instantaneous but locally mediated by the local
groups of massive objects.




P.S. Double-A ,
Why are you using Google instead of a newsreader ?
Doesn't your ISP allow it ?

Using Google for posting adds an extra layer of anonymity.
It's like wearing a 2-ply condom!

Double-A

Ya worried about the black helo's and guys in dark glasses?

Hi Double-A ,
You say :
" Using Google for posting adds
an extra layer of anonymity . "


Do you use an NNTP client to read the groups ?

....
Anyways , back to the speed of gravity .

Check out Steve Carlip's Sci.Physics FAQ entry . ( below )

He says that the observed dampening of binary pulsar systems
shows that speed of gravity travels at the speed of light
... at least as far as the GR model is concerned .

( It's instant as far as the Newtonian model is concerned . )

And a GR-independent verification requires that
either LIGO et al. gain much more precision
or that a super nova happens real close .

From :
http://math.ucr.edu/home/baez/physic...rav_speed.html

" While current observations
do not yet provide a direct model-independent
measurement of the speed of gravity ,
a test within the framework of general relativity
can be made by observing the binary pulsar PSR 1913+16 .
The orbit of this binary system is gradually decaying ,
and this behavior is attributed to the loss of energy
due to escaping gravitational radiation .
But in any field theory ,
radiation is intimately related to
the finite velocity of field propagation ,
and the orbital changes due to gravitational radiation
can equivalently be viewed as damping
caused by the finite propagation speed .
( In the discussion above ,
this damping represents a failure of the ' retardation '
and ' noncentral , velocity-dependent ' effects
to completely cancel . )

The rate of this damping can be computed ,
and one finds that it
depends sensitively on the speed of gravity .
The fact that gravitational damping is measured at all
is a strong indication that
the propagation speed of gravity is not infinite .
If the calculational framework
of general relativity is accepted ,
the damping can be used to calculate the speed ,
and the actual measurement confirms that the speed of gravity
is equal to the speed of light to within 1% .
( Measurements of at least one other binary pulsar system ,
PSR B1534+12 , confirm this result ,
although so far with less precision . ) "

"Paul R. Mays" wrote in message ...
"Double-A" wrote in message
om...
Jeff Relf wrote in message
...
Hi Double-A ,
You say :
" If moving an object meant
instantaneously moving its gravitational field ,
which stretches out to infinity ,
you'd think it'd take an infinite force . "


Why's that ?

We don't precisely know the effective distance
of any particular gravitational field .

I may have overstated the case. Gravity might not extent to infinity,
but we know it at least extends as far as neighboring galaxies, and
that's millions of light years.

What evidence is there that the universe is infinite in any way?
The mathmatical construct made by a minor life form, on a
tiny ball, in a remote edge of a so-so galicy.... Infinity is but
the failure of human constructs to consider due to scale....


I don't really like the word infinity either, but sometimes I use it
because I get too lazy to be more precise.



And even if the effective distance was nearly infinite ,
that wouldn't mean that the gravitational energy
wouldn't be observed to be very finite .

The point I was trying to make is that if changes in gravity travel
instantaneously, then to accelerate a gravitating body you would have
to simultaneously accelerate its gravitational field, which would
effectively be a perfectly rigid and inflexible construct extending
for millions of light years. Even if an average cubic kilometer of
the field were light as a feather, the inertia of the entire field
might be ponderous.

This is not what we observe, so I don't think gravity travels
instantaneously.

Unless you consider gravity as an effect of the separation
distance of groupings of locally bound particles... Where
the base gravitational constant ( actually variable on a
universal scale) varies locally as a increase in tensor
in relation to an observer being accelerated toward and
a decrease in tensor to an observer accelerated away from.
So a change in the UGC (Universal Gravitational Constant)
would be instantaneous but locally mediated by the local
groups of massive objects.




P.S. Double-A ,
Why are you using Google instead of a newsreader ?
Doesn't your ISP allow it ?

Using Google for posting adds an extra layer of anonymity.
It's like wearing a 2-ply condom!

Double-A

Ya worried about the black helo's and guys in dark glasses?


All I know is
1. I post with Google.
2. I don't see any black helicopters around my house.

Double-A

Jeff Relf wrote in message ...
Hi Double-A ,
You say :
" Using Google for posting adds
an extra layer of anonymity . "


Do you use an NNTP client to read the groups ?


Yes.

...
Anyways , back to the speed of gravity .

Check out Steve Carlip's Sci.Physics FAQ entry . ( below )

He says that the observed dampening of binary pulsar systems
shows that speed of gravity travels at the speed of light
... at least as far as the GR model is concerned .

( It's instant as far as the Newtonian model is concerned . )

And a GR-independent verification requires that
either LIGO et al. gain much more precision
or that a super nova happens real close .

From :
http://math.ucr.edu/home/baez/physic...rav_speed.html

" While current observations
do not yet provide a direct model-independent
measurement of the speed of gravity ,
a test within the framework of general relativity
can be made by observing the binary pulsar PSR 1913+16 .
The orbit of this binary system is gradually decaying ,
and this behavior is attributed to the loss of energy
due to escaping gravitational radiation .
But in any field theory ,
radiation is intimately related to
the finite velocity of field propagation ,
and the orbital changes due to gravitational radiation
can equivalently be viewed as damping
caused by the finite propagation speed .
( In the discussion above ,
this damping represents a failure of the ' retardation '
and ' noncentral , velocity-dependent ' effects
to completely cancel . )

The rate of this damping can be computed ,
and one finds that it
depends sensitively on the speed of gravity .
The fact that gravitational damping is measured at all
is a strong indication that
the propagation speed of gravity is not infinite .
If the calculational framework
of general relativity is accepted ,
the damping can be used to calculate the speed ,
and the actual measurement confirms that the speed of gravity
is equal to the speed of light to within 1% .
( Measurements of at least one other binary pulsar system ,
PSR B1534+12 , confirm this result ,
although so far with less precision . ) "


Interesting.

Double-A

Hi Double-A ,
Regarding pulsars you say : " Interesting . "


A pulsar spins extremely fast ,
but the earth is spinning too .

Gravity Probe-B is designed to measure
how the earth's " wobbly spin " , i.e. it's precessions ,
effect the moon .

Correct me if I'm wrong ,
but I think Newtonian gravity ,
with it's instant speed of gravity ,
could not fully account for the moon's orbit .

Hi Double-A ,
You say :
" I don't see any black helicopters around my house . "


That's because they're using those new stealth helicopters .
....
( Do I have to mention that I'm not being serious ? )