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  #1  
Old November 4th 17, 08:01 PM posted to sci.astro.research
jacobnavia
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Posts: 103
Default Verifying

If there is anew kind of attractive force, unknown to us, that pulls
matter together, we should be able to see some effects of this feeble
force in our environment.

Now, consider the earth moon system. We have a mirror there, that can
reflect any laser beam to the earth.

The orbit of the moon should be affected if the geometry works. When the
moon is moving away from the center of the galaxy it should feel a
braking effect. Wehn it is approaching, an accelerating effect.

Over time these effects could accumulate. Contrary to the noise, the
acceleration should always have a vector pointing to the Sagitarius
constellation.

We have extremely precise clocks, and we have even detected
gravitational waves. I do not think that detecting this force is very
difficult, if it can be done at all, of course.

And if it is not detected, it is surely an argument againt that supposition.

There many reasons that the experiment could fail. Braking effects of
the tides, and many others, influences of other planets, etc. Taking all
that into account is a considerable work.

How big is that force?

Those stars must be pulled somehow, by this attractive force, so that
their rotation doesn't go down as distance increases. This force holds
the galaxy together.

But as distance increases, the force decreases. Nuclear force is very
strong but doesn't reach very far. Gravity is much weaker but reaches
farther, much farther.

But gravity decreases as the square of distance, and doesn't reach as
far as this new force, even feebler than gravity.

But it is feasible for astronomers to catch it now, they have all the
required technology.

Nobody is looking however.

Looking for perturbations in the orbits of the planets that point to the
center of the galaxy.

Ads
  #2  
Old November 5th 17, 08:05 AM posted to sci.astro.research
Jos Bergervoet
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Posts: 125
Default Verifying

On 11/4/2017 9:01 PM, jacobnavia wrote:
If there is anew kind of attractive force, unknown to us, that pulls
matter together, we should be able to see some effects of this feeble
force in our environment.


Only if it is strong enough at the (relatively) short distances
of "our environment".

Now, consider the earth moon system. We have a mirror there, that can
reflect any laser beam to the earth.


We also have satellites and spacecraft at larger distances.

...
We have extremely precise clocks, and we have even detected
gravitational waves. I do not think that detecting this force is very
difficult,


So you have information as to whether it is strong enough at the
relatively short distances of our environment, as mentioned above?

...
But gravity decreases as the square of distance, and doesn't reach as
far as this new force, even feebler than gravity.


OK, you propose a force decaying more slowly than 1/r^2

But it is feasible for astronomers to catch it now, they have all the
required technology.

Nobody is looking however.

Looking for perturbations in the orbits of the planets that point to the
center of the galaxy.


You are mistaken, people are constantly looking. Remember all
the activity related to the Pioneer anomaly, or more recently
(and based on the orbits of the planets) the search for planet
nine.

But all this analysis of forces (at the relatively short distances
of our environment) just hasn't (yet) provided any evidence for
the long-range force that you propose! You should be more patient.
(At least for planet nine now the evidence is mounting..)

--
Jos

  #3  
Old November 6th 17, 07:54 AM posted to sci.astro.research
Richard D. Saam
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Posts: 239
Default Verifying

On 11/5/17 2:05 AM, Jos Bergervoet wrote:

You are mistaken, people are constantly looking. Remember all
the activity related to the Pioneer anomaly

In reference to the Pioneer Anomaly
the most definite conclusion is based on the JPL report:
http://arxiv.org/abs/1204.2507

[[Mod. note -- Published as Phys Rev Lett 108, 241101.

The same authors' (Rutyshev et al) previous paper,
arXiv:1107.2886 = Phys Rev Lett 107, 081103,
is also essential reading.

The thermal modelling is discussed in more detail in
Rievers et al, New J Physcs 11, 113032
http://dx.doi.org/10.1088/1367-2630/11/11/113032
and the same authors' (Rievers et al) later paper
arXiv:1104.3985 = Annelen der Physik 523, 439
http://dx.doi.org/10.1002/andp.201100081
-- jt]]

It does not reflect the thermal and Doppler solutions over time.
With time, the constant Doppler solution
dominates the decaying thermal solution
as the Pioneers approach interstellar space.
The Doppler solution is real
versus
the 1000s of calculated decaying internal finite element
diminishing contributions.

This JPL analysis failure unnecessarily negates a major contribution
to science.
I am not talking about new physics but a confirmation of space time.
The JPL report has a geocentric/heliocentric view
and dismisses the universal view.

The JPL analysis is based on incomplete analysis of the data
assuming the decay for Pioneer acceleration aP

daP/dt = -k*aP model one

This fits the assumption that
the thousands of analyzed aP thermal components
are tied to the RTG half life with aP decay approaching zero with time.

A better fit to trajectory data is the 'aPinfinity' effect
as the Pioneers approached interstellar space:

daP/dt = -k*(aP - aPinfinity) model two

Initially, as the Pioneers pass Jupiter,
the thermal emission overwhelms
the anomalous acceleration (aPinfinity)
making it statistically insignificalt in this initial trajectory phase
but diminishes with time(model one)
with aP decay approaching aPinfinity
with time (model two)
as the Pioneers probe interstellar, intergalactic space
on leaving the solar system
with diminished internal thermal and external solar wind
considerations previously considered.

Statistically significant aPinfinity values a
Pioneer 10 aPinfinity 7.0x10^-10 m/sec^2
Pioneer 11 aPinfinity 8.2x10^-10 m/sec^2

These values may represent a constant for interstellar medium
within some standard deviation
or actually represent different values based on
differing Pioneer 10 and 11 directional probes of interstellar medium.
The interstellar medium may not be uniform.

Logically, in as much as aPinfinity
is a measure of space-Pioneer momentum transfer (spacetime viscosity)
then all transiting object motion would be affected.
This has implication for galactic and planetary system formation
as reflected in accelerations associated
with the Tully Fischer relationship.

Apparently there is still some unpublished Pioneer data
to further test this hypothesis.
Considering this data's importance to the scientific community,
it should be published.

RDS
  #4  
Old November 6th 17, 11:19 PM posted to sci.astro.research
Daniel S. Riley
external usenet poster
 
Posts: 4
Default Verifying

jacobnavia writes:
Now, consider the earth moon system. We have a mirror there, that can
reflect any laser beam to the earth.


Five, actually, regularly pinged looking for deviations:

"Tests of Gravity Using Lunar Laser Ranging" (2010)
https://link.springer.com/article/10.12942/lrr-2010-7

"Lunar laser ranging: the millimeter challenge" (2013)
https://arxiv.org/abs/1309.6294

see also

https://en.wikipedia.org/wiki/Apache...ging_Operation
https://tmurphy.physics.ucsd.edu/apollo/apollo.html

The latest observations are limited by the physical characteristics
of the reflectors.

Nobody is looking however.


??

-dan

[[Mod. note -- One particularly fascinating part of the lunar-laser-ranging
story is the unexpectation degredation of the retroreflectors, apparently
due to thermal gradients caused by lunar dust coating the reflector surfaces.
I think this was first published in https://arxiv.org/abs/1003.0713
and there's a nice summary and update in section 4.2 of the 1309.6294 paper.
-- jt]]
  #5  
Old November 8th 17, 07:33 PM posted to sci.astro.research
jacobnavia
external usenet poster
 
Posts: 103
Default Verifying

Le 05/11/2017 =C3=A0 09:05, Jos Bergervoet a =C3=A9crit=C2=A0:
So you have information as to whether it is strong enough at the
relatively short distances of our environment, as mentioned above?


Suppose some star S at 60 thousand light years from the center of the
galaxy. A normal star whose mass can be accurately determined.

Its speed can be measured, and its mass is known. Then, we subtract
gravity effects and we obtain the force that is necessary to accelerate
that star to its observed speed at 60000 light years from the center.

Supposing a roughly linear decay, here at only 30000 light years from
the center we should have half of that.

Looks simple but can't be that simple. I am surely missing something,
but what?

[[Mod. note -- There are a couple of things:
1. A solar-type star at a distance of 60,000 light-years has an
apparent magnitude of around 21, which is faint enough that
getting a good spectrum will take a lot of big-telescope time.
2. Once you get that spectrum you get the star's radial velocity
(its velocity along our line-of-sight to the star).
But if you want all 3 components of its vector velocity you
also need to measure its velocity perpendicular to our line-of-sight.
That means doing high-precision astrometry to measure how its
position gradually drifts relative to other more distant objects,
with corrections for the Earth's motion around the center of our
own galaxy. (This will be on the order of micro-arcseconds/year.)
This star is too faint for Gaia to give good data (Gaia's error
bars are up to 200 microarcseconds/year at magnitude 20), in
fact I can't think of any current telescope/detector that could
do relative astrometry at that accuracy level on an object that
faint in a reasonable amount of telescope time.
3. Suppose we somehow managed to measure all 3 components of the
star's vector *velocity*. That doesn't tell us anything about the
star's gravitational *acceleration* (we don't know that it's moving
in a circular orbit about the center of our galaxy!), which is the
quantity which is actually influenced by dark matter/modified gravity.
-- jt]]
  #6  
Old November 9th 17, 09:00 AM posted to sci.astro.research
jacobnavia
external usenet poster
 
Posts: 103
Default Verifying

Le 08/11/2017 à 20:33, jacobnavia a écrit :
Le 05/11/2017 Ã 09:05, Jos Bergervoet wrote:
So you have information as to whether it is strong enough at the
relatively short distances of our environment, as mentioned above?


Suppose some star S at 60 thousand light years from the center of the
galaxy. A normal star whose mass can be accurately determined.

Its speed can be measured, and its mass is known. Then, we subtract
gravity effects and we obtain the force that is necessary to accelerate
that star to its observed speed at 60000 light years from the center.

Supposing a roughly linear decay, here at only 30000 light years from
the center we should have half of that.

Looks simple but can't be that simple. I am surely missing something,
but what?

[[Mod. note -- There are a couple of things:
1. A solar-type star at a distance of 60,000 light-years has an
apparent magnitude of around 21, which is faint enough that
getting a good spectrum will take a lot of big-telescope time.


We have big scopes now. Or just choose a nearer one. The farther you go,
the more the discrepancyy between gravity and its observed speed should
be, as we read from the speed charts of stars around the center.

The difference is bigger when you get away from the galaxy, at the
outskirts.

2. Once you get that spectrum you get the star's radial velocity
(its velocity along our line-of-sight to the star).
But if you want all 3 components of its vector velocity you
also need to measure its velocity perpendicular to our line-of-sight.


Mmm the galaxy has a plane of rotation. Th center of the galaxy, that
star and we are rotating around the same central object, the galaxy, in
a plane.

The center, we, and that star are in the same plane. Are those
corrections really necessary?

That means doing high-precision astrometry to measure how its
position gradually drifts relative to other more distant objects,
with corrections for the Earth's motion around the center of our
own galaxy. (This will be on the order of micro-arcseconds/year.)
This star is too faint for Gaia to give good data (Gaia's error
bars are up to 200 microarcseconds/year at magnitude 20), in
fact I can't think of any current telescope/detector that could
do relative astrometry at that accuracy level on an object that
faint in a reasonable amount of telescope time.


We can use stars nearer of course. For instance at mag 20 if that is the
limit of Gaia. That would be a good start.

3. Suppose we somehow managed to measure all 3 components of the
star's vector *velocity*. That doesn't tell us anything about the
star's gravitational *acceleration* (we don't know that it's moving
in a circular orbit about the center of our galaxy!), which is the
quantity which is actually influenced by dark matter/modified gravity.
-- jt]]


"We don't know that is moving in a circular orbit"... wow, I always
thought that they are doing so, and that the "arms" we see are density
waves in the disc of stars circling the center.

The stars must be doing "some" kind of circle around the center since
the form of the galaxy (a rotating plane of stars ) indicates so. I even
thought that the sun was rotating about 1 rotation per 250 million
years, so it is around 20 galactic years old. I thought that the orbit
was a circle. Is that not correct?

If we approximate the orbit by some kind of circle, we approximate the
milky way to a center of gravity around the black hole in the central
buldge, we can calculate the gravity exerced by the (I suppose known)
mass of the galaxy and the speed that a star should have isn't it?

Very roughly. A more sophisticated thing would take into account the
form of the buldge, the mass of the plane inside the orbit, etc.

Dark matter scenarios suppose some form of invisible matter outside and
propose a vector that is in the opposite direction pulling the stars.
The force the stars feel would come from outside the galaxy in some kind
of halo.

Maybe we could look in the other direction. And if the force came from
the galaxy itself?

A second star we could use of course, is the nearest one, the sun. The
sun's orbit could tell us about the force effects here. Here we have
more data and less problems than with the star's far away. We know very
precisely the distance to the center, and the mass between us and the
center, so the effects of gravity could be calculated much more easily.

Is there any delta?
Has anyone done this calculations?

  #7  
Old November 9th 17, 09:00 AM posted to sci.astro.research
Richard D. Saam
external usenet poster
 
Posts: 239
Default Verifying

On 11/4/17 3:01 PM, jacobnavia wrote:
If there is anew kind of attractive force, unknown to us, that pulls
matter together, we should be able to see some effects of this feeble
force in our environment.

Now, consider the earth moon system. We have a mirror there, that can
reflect any laser beam to the earth.

The orbit of the moon should be affected if the geometry works. When the
moon is moving away from the center of the galaxy it should feel a
braking effect. Wehn it is approaching, an accelerating effect.

Over time these effects could accumulate. Contrary to the noise, the
acceleration should always have a vector pointing to the Sagitarius
constellation.

We have extremely precise clocks, and we have even detected
gravitational waves. I do not think that detecting this force is very
difficult, if it can be done at all, of course.

And if it is not detected, it is surely an argument againt that supposition.

There many reasons that the experiment could fail. Braking effects of
the tides, and many others, influences of other planets, etc. Taking all
that into account is a considerable work.

How big is that force?

Those stars must be pulled somehow, by this attractive force, so that
their rotation doesn't go down as distance increases. This force holds
the galaxy together.

But as distance increases, the force decreases. Nuclear force is very
strong but doesn't reach very far. Gravity is much weaker but reaches
farther, much farther.

But gravity decreases as the square of distance, and doesn't reach as
far as this new force, even feebler than gravity.

But it is feasible for astronomers to catch it now, they have all the
required technology.

Nobody is looking however.

Looking for perturbations in the orbits of the planets that point to the
center of the galaxy.

Mond derived a relationship

M = v^4/(a0*G)

to explain the Tully Fischer relationship
Baryonic mass M ~ (galactic rotation v km/sec)^4
https://en.wikipedia.org/wiki/Modifi...onian_dynamics
with the physically dissatisfying modified gravity explanation for an
anomalous acceleration 'a0'.

But assume the observed velocity dispersion
represents a tangential velocity(v) around galactic center
that is related to a radial velocity(vr = constant*v)
that is a measure of mass inflow to the galactic center
whose galactic time(t) is measured by a/v.

This is dimensionally expressed as:

v^2 = G*M/R = G*M/(vr*t) = G*M/(vr*vr/a)
= G*M/(constant*v*constant*v/a)

then

M = constant^2*v^4/(a*G)

with the same dimensional form as MOND
but with a more physically satisfying explanation

The above formula dimensionally matched to the experimental data
baryonic mass M ~ (galactic rotation v km/sec)^4
for the baryonic Tully-Fisher relation
http://arxiv.org/abs/1512.04543 figure 2
with constant ~pi
indicates reasonable acceleration(a) values
on the order of 10^-9 cm/sec^2
and galactic times on the order of a billion years.

So 'a' can be interpreted as a deceleration
within galactic time-frame (t)
due to a drag like force (m*a)
on baryonic objects of mass m (dark matter?)
m*a ~ vacuum mass density * object crossection
optically unseen due to their
small size and diffuse distribution.

The implication is that these objects are much smaller than planets
but make up most of the galactic mass(M).

  #8  
Old November 9th 17, 09:01 AM posted to sci.astro.research
Richard D. Saam
external usenet poster
 
Posts: 239
Default Verifying

On 11/6/17 1:54 AM, Richard D. Saam wrote:
On 11/5/17 2:05 AM, Jos Bergervoet wrote:

You are mistaken, people are constantly looking. Remember all
the activity related to the Pioneer anomaly

In reference to the Pioneer Anomaly
the most definite conclusion is based on the JPL report:
http://arxiv.org/abs/1204.2507

[[Mod. note -- Published as Phys Rev Lett 108, 241101.

The same authors' (Rutyshev et al) previous paper,
arXiv:1107.2886 = Phys Rev Lett 107, 081103,
is also essential reading.

This reference is key;
Note Figure 1
The top panel represents modeling
daP/dt = -k*aP model one
and the bottom panel
daP/dt = -k*(aP - aPinfinity) model two
It is clearly evident that model two predominates.

The thermal modelling is discussed in more detail in
Rievers et al, New J Physcs 11, 113032
http://dx.doi.org/10.1088/1367-2630/11/11/113032
and the same authors' (Rievers et al) later paper
arXiv:1104.3985 = Annelen der Physik 523, 439
http://dx.doi.org/10.1002/andp.201100081

Presented data was below 45 AU where thermal effects predominate.

-- jt]]

It does not reflect the thermal and Doppler solutions over time.
With time, the constant Doppler solution
dominates the decaying thermal solution
as the Pioneers approach interstellar space.
The Doppler solution is real
versus
the 1000s of calculated decaying internal finite element
diminishing contributions.

This JPL analysis failure unnecessarily negates a major contribution
to science.
I am not talking about new physics but a confirmation of space time.
The JPL report has a geocentric/heliocentric view
and dismisses the universal view.

The JPL analysis is based on incomplete analysis of the data
assuming the decay for Pioneer acceleration aP

daP/dt = -k*aP model one

This fits the assumption that
the thousands of analyzed aP thermal components
are tied to the RTG half life with aP decay approaching zero with time.

A better fit to trajectory data is the 'aPinfinity' effect
as the Pioneers approached interstellar space:

daP/dt = -k*(aP - aPinfinity) model two

Initially, as the Pioneers pass Jupiter,
the thermal emission overwhelms
the anomalous acceleration (aPinfinity)
making it statistically insignificalt in this initial trajectory phase
but diminishes with time(model one)
with aP decay approaching aPinfinity
with time (model two)
as the Pioneers probe interstellar, intergalactic space
on leaving the solar system
with diminished internal thermal and external solar wind
considerations previously considered.

Statistically significant aPinfinity values a
Pioneer 10 aPinfinity 7.0x10^-10 m/sec^2
Pioneer 11 aPinfinity 8.2x10^-10 m/sec^2

These values may represent a constant for interstellar medium
within some standard deviation
or actually represent different values based on
differing Pioneer 10 and 11 directional probes of interstellar medium.
The interstellar medium may not be uniform.

Logically, in as much as aPinfinity
is a measure of space-Pioneer momentum transfer (spacetime viscosity)
then all transiting object motion would be affected.
This has implication for galactic and planetary system formation
as reflected in accelerations associated
with the Tully Fischer relationship.

Apparently there is still some unpublished Pioneer data
to further test this hypothesis.
Considering this data's importance to the scientific community,
it should be published.

RDS


  #9  
Old November 10th 17, 07:10 AM posted to sci.astro.research
Jos Bergervoet
external usenet poster
 
Posts: 125
Default Verifying

On 11/9/2017 10:00 AM, jacobnavia wrote:
Le 08/11/2017 à 20:33, jacobnavia a écrit :
Le 05/11/2017 Ã 09:05, Jos Bergervoet wrote:
So you have information as to whether it is strong enough at the
relatively short distances of our environment, as mentioned above?


Suppose some star S at 60 thousand light years from the center of the
galaxy. A normal star whose mass can be accurately determined.

Its speed can be measured, and its mass is known. Then, we subtract
gravity effects and we obtain the force that is necessary to accelerate
that star to its observed speed at 60000 light years from the center.

Supposing a roughly linear decay, here at only 30000 light years from
the center we should have half of that.

Looks simple but can't be that simple. I am surely missing something,
but what?

[[Mod. note -- There are a couple of things:
1. A solar-type star at a distance of 60,000 light-years has an
apparent magnitude of around 21, which is faint enough that
getting a good spectrum will take a lot of big-telescope time.


We have big scopes now. Or just choose a nearer one. The farther you go,
the more the discrepancyy between gravity and its observed speed should
be, as we read from the speed charts of stars around the center.


But all this is known already (from the smaller scopes of
some years ago).

We know what the rotation curves are, so the acceleration of
stars on average is known, and it is known that this does not
fit with the gravity of known matter in the galaxies. So you
do not need the observations as you describe here to get this
information. What we do *not* know is:
1) Is there more matter than the known matter, so stronger
gravity and therefore restoring agreement with the movement?
2) Is there another force that adds to the effect of gravity
so together they give agreement with the motion?
The first possibility leads to the hunt for dark matter, the
second to the search for a "fifth force".

The observations with telescopes as discussed above will not
help with these questions at all, they will just reproduce the
already observed disagreement between motion and the gravity
of known matter. Which then leaves us again with the same two
questions.

--
Jos
  #10  
Old November 11th 17, 08:50 PM posted to sci.astro.research
jacobnavia
external usenet poster
 
Posts: 103
Default Verifying

Le 10/11/2017 =C3=A0 08:10, Jos Bergervoet a =C3=A9crit=C2=A0:

We know what the rotation curves are, so the acceleration of
stars on average is known, and it is known that this does not
fit with the gravity of known matter in the galaxies. So you
do not need the observations as you describe here to get this
information. What we do *not* know is:
1) Is there more matter than the known matter, so stronger
gravity and therefore restoring agreement with the movement?


That would be a nice solution. And if space between the stars wasn't
empty but filled with some kind of very thin gas?

2) Is there another force that adds to the effect of gravity
so together they give agreement with the motion?
The first possibility leads to the hunt for dark matter, the
second to the search for a "fifth force".


Dark matter was supposed to be in some kind of "halo" outside the
galaxy. The stars then, are pulled by the outside. A fifth force would
have a vector centered in the center of the milky way.

Is it possible then, to figure out this from the orbit of a known star,
say, the sun?

The observations with telescopes as discussed above will not
help with these questions at all, they will just reproduce the
already observed disagreement between motion and the gravity
of known matter. Which then leaves us again with the same two
questions.


A fifth force would perturb the orbit of the sun in a different way than
matter in a halo. Besides, even if it is weak it has been there since
eons. After all this time (age of the sun around 5GY) some perturbation
should be observable.

Shouldn't an analysis of the orbit of the sun give an answer to that?

[[Mod. note --
Interstellar space is indeed filled with a "very thin gas":
https://en.wikipedia.org/wiki/Interstellar_medium
https://en.wikipedia.org/wiki/Intracluster_medium
This is already included in counts of "known matter".
-- jt]]
 




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