Comment by Buttons840
5 hours ago
Do all galaxies spin in the same way? Do we predict an equal proportion of dark matter in all galaxies based on observations? Or is there some variability?
5 hours ago
Do all galaxies spin in the same way? Do we predict an equal proportion of dark matter in all galaxies based on observations? Or is there some variability?
Yep, pretty much. They all have a flat rotation curve (which makes no sense unless gravity works differently or there is unseen mass), and that rotation correlates to the visible matter in the galaxy (the Tully Fischer relation).
Wouldn't we expect some galaxies to have more dark matter than others? Although, I guess if anything is big enough to converge to an average, a galaxy is.
Apparently they all have just the right amount arranged in the right way to give the same result in each case.
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