When Einstein published his relativity theories, he was not yet aware of what we now call the Big Bang.
That means he did not capture in GR one of the motions we are involved in. I call that motion the First Motion.
Our Milky Way is collectively moving in one singular direction, and all this material has been doing that for 13.8 billion years, since the CMBR.
Naturally, gravity is part of the picture. Yet the point is that it is not all-involved.
With GR incapable of explaining the exact amount of gravity needed to hold a galaxy together, this First Motion model has no problem explaining how part of the outcome is not based on gravity, but on the initial action of the materialization process.
I wrote an article on this, please find it attached.
I am certain it can use some help making it more professional. First perhaps, a good conversation?
Newton had his feet on the ground, but knew that we are on a planet moving through space.
Einstein appears to have his feet on space, and only then focuses in on matter. Very smart, but at the same time also the negative for a photograph, not the positive yet?
Can we bring our feet back to the ground, and explain all Einstein showed plus a little more?
Thank you for being curious, and potentially helping me out write a better article.