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My understanding (limited, admittedly) is that there are a number of phenomenon that dark matter explains very well, galactic rotation among them. Alternative t
by mabbo 8y ago
My understanding (limited, admittedly) is that there are a number of phenomenon that dark matter explains very well, galactic rotation among them. Alternative theories of gravity that explain galactic rotation often don't fit all the others very well.
- karmakaze 8y agoDark matter doesn't 'explain' being itself a fudge factor. We give it a name to resolve observations that do not fit our models. We have a strong belief in gravitational laws and theory that we take it as fixed and make the rest fit as needed. Not having an alternate theory of gravitation that is as good makes this reasonable.
- mabbo 8y agoIt's far more than a simple fudge factor. It says that there is matter with mass, affecting other matter via gravity, but no other interactions seem possible with it. That is a sound, almost complete theory with some unknowns around why it doesn't otherwise interact, what it actually is. Dark matter also explains certain gravitational lensing phenomenon, aspects of the CMB, from mass location during galactic collisions (and more). Other theories can possibly explain one or some of those observations, but nothing does a good job (or a simple one) of explaining them all. Dark matter is real enough to make verifiable predictions in other places. Other theories don't.