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Spiral Galaxies -- is there a 1/R gravity force -- or Dark Matter?
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Spiral Galaxies -- is there a 1/R gravity force -- or Dark Matter?
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mad aetherist
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Spiral Galaxies -- is there a 1/R gravity force -- or Dark Matter?
«
on:
14/12/2018 00:34:26 »
In
spiral galaxies
the orbital speeds of stars do not appear to follow the expected Newtonian 1/RR relationship, they appear to follow a 1/R relationship. As there is no good theory for a 1/R relationship the preferred answer is that every galaxy contains hidden mass made up of some sort of
Dark Matter
.
I looked at the equation for
centrifugal force
which is F=Mvv/R.
And the equation for
gravity force
is F=GMm/RR.
This means that the
orbital speed
v=(GM/R)^0.5.
But if the equation for
gravity force
was F=GMm/R then v=(GM)^0.5.
This means that the graph for orbital speed versus radius should be a
horizontal line
(notice that R is missing)(R is not relevant). Cosmologists draw prediction curves for orbital speed versus radius in a spiral galaxy based on 1/R (merely to illustrate)(they don’t believe in 1/R), but these 1/R prediction curves are not horizontal straight lines, they are a curve dipping slightly below horizontal. I guess that this is because a spiral galaxy isn’t like a thin disc, it has a
bulge.
The bulge introduces some off-plane components of the gravity force & the components perpendicular to the plane cancel leaving just the Cosine.
The plots for the actual measured speeds for any particular spiral galaxy describe a curve dipping down below horizontal a little, following almost exactly their predicted 1/R curves.
On the other hand the predicted curves for 1/RR drop quickly towards the xx axis & are hopeless. There certainly is a problem with Newton.
Everyone agrees that the gravity force due to an
infinitely long cylinder
varies as per 1/R. A
thin slice
of that cylinder can represent a spiral galaxy. If u take away the remainder of the cylinder then praps the thin slice retains that there 1/R relationship. Or does it revert immediately to 1/RR?
I am mulling this 1/R stuff. Suggestions welcome.
«
Last Edit: 14/12/2018 00:42:04 by
mad aetherist
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