The slow stars around the Milky Way cause problems with dark matter theories.

" New research by MIT reveals that stars at the edge of the Milky Way move slower than anticipated, implying the galaxy’s core may contain less dark matter, challenging current astronomical theories. Credit: SciTechDaily.com" (ScitechDaily, Galactic Surprise: Milky Way’s Slower Outer Stars Suggest Dark Matter Overestimated)

The question of dark matter existence is interesting, and new observations challenge that theory. The prime question about dark matter is that nobody has any contact or observations about that thing, that causes gravitational effect. The thing that could explain why stars near the Milky Way edge behave as they behave is that there is less dark matter than researchers expected. 

Do stars around other galaxies act like those slow stars at the edge of the Milky Way?

Or the dark matter distribution around the galaxy is different than thought. Maybe dark matter forms larger or denser gobs around black holes than researchers calculated. And that means there is more dark matter around the center of the galaxy. And uneven distribution of that thing causes stars to move slower than they should at the edge of the Milky Way. 

What can also cause a dark gravitational effect than theoretical dark matter?   

If we think that the nature of gravity is it interacts with the environment. That thing can explain why there is a dark gravity effect. That source is unknown. In that model, some very thin energy beams act like thermal pumps that pull energy with them. That means the relativistic jets near black holes can explain that dark gravity effect. When a relativistic jet travels in the universe, that thing pulls energy with it. That causes a situation where quantum fields or energy around a relativistic jet falls to that jet. 

So if relativistic jets are longer than researchers calculated. That can form a situation, where gravity doesn't interact as calculated. Same way if some kind of beam travels through the universe that thing causes a similar effect to a thermal pump or relativistic jet. The colder areas in the microwave background show that some super-powerful relativistic jets may travel through the universe. 

Cosmic microwave background 

"Maybe" is a keyword in dark matter. 

And the reason for that is nobody has seen dark matter. There is the theory of WIMPs (Weakly Interacting Massive particles). But nobody saw any WIMP yet. So that causes questions about the dark matter existence. We know that the gravitational effect exists. In some models, WIMPs are quantum or atom-size black holes. Or maybe, there are just more black holes in the Milky Way than expected. 

WIMPs (Weakly Interacting Massive Particles) may be virtual particles. The energy whirls, standing gravity waves, and small cosmic voids can act like particles. 

But nobody knows the source of that effect. And that's why the dark matter should rename as "dark gravity". The question is what can cause a dark gravitational effect? The key question is what kind of particles are invisible? In some models, dark matter is an ordinary material that travels in energy beams of black holes. 

Those gamma- and X-rays can input very high energy levels in particles that travel in them. And that thing turns the energy level, and those particles' mass turns higher than it should be. When those particles travel out from those relativistic jets they release their energy as energy bursts. And that thing can connect those particles with dark energy. 

Another way standing gravitational waves can form a point that looks like a particle. Or maybe the small cosmic voids are the thing that forms dark matter. When those cosmic voids collapse they pull energy or quantum fields inside them. And then those quantum fields reflect from inside that thing. Those things can also explain dark energy. 

https://scitechdaily.com/galactic-surprise-milky-ways-slower-outer-stars-suggest-dark-matter-overestimated/