Tom Wilson points out an Anthony Peratt paper which debunks Newtonian gravitation and the idiotic inverse square so-called "law": A New Look at Near Neighbors Part One. (Hat tip: Anaconda)
It is worth a few words here to summarize some very important seminal work in the paper by Anthony Peratt mentioned above. In his study, Peratt performed particle-in-cell computer simulations of Birkeland current interactions. The results illustrated how plasma dynamics lead to galactic structures evolving from double radio galaxies, to radio quasars, to ellipticals and then to spiral galaxies. This paper is thick with insight. There are some papers that you can read over and over and continually find new gems, this is one of those papers.
As Peratt's simulations revealed, a galaxy evolves as two (or more) Birkeland currents moving together with an attractive force proportional to the inverse of their linear distance (note it is not the inverse square law). In astronomical observations, the two Birkeland currents are detected as radio “lobes” due to synchrotron radiation.
As the two pinched Birkeland filaments come close to each other, intergalactic plasma is trapped, forming an elliptical core at the geometric center between the two filaments, which later becomes the nucleus of the galaxy. Magnetic fields between the filaments condense and aggregate the intervening plasma, raising its internal energies. The elliptical core at this point is analogous to a radio quasar.
The two Birkeland filaments (also concentrating matter within their magnetically pinched volume) torque around each other, changing the morphology of the core plasma (flattening the ellipse) and eventually evolving into trailing arms as electric current, axial to the arms, flows into the core of the galaxy. At that point the two Birkeland filaments merge with the core. So the core of a galaxy derives from whatever intergalactic plasma was trapped between the two (or more) Birkeland filaments and the arms of the spiral derive mostly from the pinched Birkeland filaments themselves. ...
4) M33 has been said to lack a super-massive black hole at its core (that is to say, the rotational velocity decreases closer to the galactic core).