A universal model to explain this common rotation;
http://www.ptep-o...1-13.PDF
http://www.ptep-o...3-01.PDF
No fearie dust needed!

Periodic oscillators have a tendency to synchronize the periods of their oscillations.

This is an astonishing example.

Seems odd that the maximum number of rotations that the oldest galaxy could possibly have
made in universe is 14. I assume that the spun a lot faster when they were younger - yes?

I would imagine this is just a limit imposed by the origin of the universe. It just wasn't possible to have orbits longer than that so every galaxy has a similar rotation.

Mike McCulloch's quantised inertia theory ( https://link.spri...7-3128-6 ) predicted exactly this in 2016 - http://physicsfro...hsc.html

There is no dark matter.

Mike McCulloch's quantised inertia theory ( https://link.spri...7-3128-6

There is no dark matter.

From the paper: "so quantised inertia predicts a change in galaxy rotation with time". Isn't this excatly what is not observed if all galaxies rotate like clockwork? Or am I not getting something.

It was my understanding that our Milky Way rotated about once every 200 to 250 million years. So what gives?

Quote from link below:
"More mind-blowing is that this mass of stars, gas, planets and other objects are all spinning. Just like a pinwheel. It's spinning at 270 kilometers per second (168 miles per second) and takes about 200 million years to complete one rotation, according to the National Radio Astronomy Observatory. "

https://www.unive...otation/

Mike McCulloch's quantised inertia theory ( https://link.spri...7-3128-6

"6. If an object in deep space, far from other objects (in the low acceleration MiHsC regime) spins or moves, then objects nearby (cosmically speaking) should tend to spin or move in the same sense. This is similar to the Tajmar effect in the lab, also predicted by MiHsC."

Here is an article explaining it: https://arxiv.org...3266.pdf

It was my understanding that our Milky Way rotated about once every 200 to 250 million years. So what gives?

Our sun revolves around the galactic center every 200-250mn years. But not all parts of the galaxy rotate at the same speed. From the above article:

"But regardless of whether a galaxy is very big or very small, if you could sit on the *extreme edge* of its disk as it spins, it would take you about a billion years to go all the way round."

(emphasis mine)

While our sun is somewhat on the outskirts of our galaxy it's nowhere near the extreme edge.

So, am I understanding correctly that the "years per rotation" of a star about its galactic centre is NOT the same for every distance from the centre? I thought that was the whole reason dark matter was invented, to explain why rotational periods of stars are the same regardless of radius from centre.

They have finally figured it out that there is no dark matter at the center of galaxies, the article was posted here a couple days ago, read it here:

https://phys.org/...ark.html