Spiral Galaxies are binary systems

The nature of how gravity works has never been understood as regards galaxies.
And yet paradoxically, the simplicity of Newton’s inverse of the square law (g=m/r^2)
is elegantly precise when considering solar systems.

Near the center of a solar system, a body like Mercury will orbit quickest.
And yet with spiral galaxies the opposite very often holds true; with outermost stars exhibiting too much velocity.

The answer I have programmed by computer algorithm is extraordinarily simple:

Spiral galaxies are binary systems and thus have two centers of gravity.

A spiral galaxy consists primarily of two super-massive bodies which orbit each other whilst they also spin on their
own individual axes at a phenomenally high velocity. They are so massive and spin so quickly that stars (or pre-solar masses)
are thrown out at their respective equators. The newly formed stars then spiral outwards and thus take the shape of the
spiral arms of the galaxy. Their peculiar rotation curves are a result of this process without any change to Newton’s law of gravity.

This is described in a graphic which was generated in a gravity simulator:

In a system with a single center of gravity, the orbital body is pulled back inwards, and therefore takes on the shape of a classical orbit.
But when there are two centers of gravity, the main body moves away from the smaller orbital body, and so the gravitational force of
the main body is greatly diminished. The star then rotates outward, often reaching escape velocity.

The next image is a photograph is of spiral galaxy NGC 1365. Compare it to the computer generated image above.
It is quite easy to see exactly where the two super massive bodies are situated: