What's so illogical about it? Galaxies are spinning as though there's matter that we don't see. Maybe there's matter that we don't see.

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MattPalmer1086 an hour ago | parent | next [-]

The fun question to ask is why almost all galaxies (no matter how they differ) spin as though a simple modification of gravity explains them. That dark matter is organising itself to produce the same outcome over many different circumstances!

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marcosdumay 7 minutes ago | parent | next [-]

> why almost all galaxies (no matter how they differ) spin as though a simple modification of gravity explains them

They don't. You can read exactly this article for 3 examples.

Modified Newtonian theories are anything but simple.

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Buttons840 an hour ago | parent | prev [-]

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?

	▲	MattPalmer1086 an hour ago \| parent [-]
		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).

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phkahler an hour ago | parent | prev [-]

I have yet to see a model of galaxy rotation that doesn't use the shell theorem, which does not apply to disks. I've seen it in very advanced (over my head) math stuff on Wikipedia.

Im half convinced its gonna be a stupid mistake like that. Whoever finds the correct "advanced" math that allows the mistake to be brushed under the rug could get a Nobel prize.