wrote:
In article ,
Richard Saam wrote:

An interesting calculation.

Here is another for Pioneer Spacecraft deceleration 'a'

a ~ 2*Area*rho*c2 / M
~ 2*(58,965 cm2)*(6.38E-30 g/cm3)*(3E10 cm/sec)^2 /(241,000 g)
~ 2.8E10-9 cm/sec2 for Pioneer spacecraft


I haven't paid attention to the Pioneer anomaly stuff lately, so
I apologize if I'm just being stupid, but I don't see the physics
behind this relation. In particular, I don't see how c gets involved.
If you assume that the spacecraft is moving at velocity v through a cloud
of stationary particles that bounce elastically off of it whenever they hit
it, then you get a relation something like the above, but with v instead
of c. That makes a big difference, of course.

The conceptual physics is very simple.
Assume that space is a continuous medium
with mass critical density of 6.38E-30 g/cm^3 .
Then think of an object passing through it
defined something like a ram jet engine
(analogous to atmospheric oxygen intake)
which takes in this space medium with neglible effect (m v^2)
but which expells it as m c^2
with resultant thrust in the same direction as intake
resulting in object deceleration.

Objects of different areas and masses could be designed to pass
through this space and would be deceleration probes of this medium.


In addition, the dark matter particles are thought to be weakly interacting,
so most of them pass right through Pioneer without exerting any force
on it at all.



Your average calculated local density of 7 x 10^{-25} g/cm^3
is quite a bit higher than 30 x 6.38E-30 g/cm^3 or 2E-28 g/cm^3
but there still remains a conceptual mechanism
on how dark matter influences solar objects
according to their area/mass
(Pioneer some and planets negligible).
Perhaps the local dark matter density is on the order of
30 x 6.38E-30 g/cm3 or 2E-28 g/cm^3.


The calculation I did was based on well-measured Galactic dynamics.
If you want to get a different answer, you'll have to come up with a different
explanation for the motion of stars in the Galaxy.

I have replicated your calculations and they are right.
I think you will agree
there are potentially many components to Galactic dynamics.

Richard