There is a clear explanation for why those galaxies have normal rotation rates. There are 6 known galaxies like this. Dark matter is dilated mass. Mass that is dilated is smeared through spacetime relative to an outside observer. It's the phenomenon our high school teachers were talking about when they said "mass becomes infinite at the speed of light". This does not mean that mass increases, it means mass is spread out from the vantage point of an outside observer. A graph illustrates its squared nature, dilation increases at an exponential rate the closer you get to the speed of light. A time dilation graph illustrates the same phenomenon, it's not just time that gets dilated. Dilation will occur wherever there is an astronomical quantity of mass because high mass means high momentum. This includes the centers of very high mass stars and the overwhelming majority of galaxy centers. The mass at the center of our own galaxy is dilated. This means that there is no valid XYZ coordinate we can attribute to it, you can't point your finger at something that is smeared through spacetime. In other words, that mass is all around us. Dilation does not occur in galaxies with low mass centers because they do not have enough mass to achieve relativistic velocities. All planets, all binary stars and all galaxies with low mass centers have normal rotation rates for this reason.
There is a clear explanation for why those galaxies have normal rotation rates. There are 6 known galaxies like this.
Dark matter is dilated mass. Mass that is dilated is smeared through spacetime relative to an outside observer. It's the phenomenon our high school teachers were talking about when they said "mass becomes infinite at the speed of light". This does not mean that mass increases, it means mass is spread out from the vantage point of an outside observer. A graph illustrates its squared nature, dilation increases at an exponential rate the closer you get to the speed of light. A time dilation graph illustrates the same phenomenon, it's not just time that gets dilated.
Dilation will occur wherever there is an astronomical quantity of mass because high mass means high momentum. This includes the centers of very high mass stars and the overwhelming majority of galaxy centers.
The mass at the center of our own galaxy is dilated. This means that there is no valid XYZ coordinate we can attribute to it, you can't point your finger at something that is smeared through spacetime. In other words, that mass is all around us.
Dilation does not occur in galaxies with low mass centers because they do not have enough mass to achieve relativistic velocities. All planets, all binary stars and all galaxies with low mass centers have normal rotation rates for this reason.