> Actually, I do; at least, I think that galaxies rotations are peculiar, but can be explained by the addition of unobserved matter. That was the original hypo

> Actually, I do; at least, I think that galaxies rotations are peculiar, but can be explained by the addition of unobserved matter. That was the original hypothesis. It's literally the first thing the theorists came up with. There's an anomaly -- the simplest explanation is there's more ordinary matter there that we can't see. But why can't we see it? Well, we see stars because they emit light, we see gas clouds because the reflect light, so there's gotta be more matter there that doesn't give off light. What do we call it? Well, it's matter, and it's dark, so let's call it dark matter. Hypothesis 1.0, there's additional ordinary matter that is unobserved, was invalidated. It's one of the things that we know for certain is false. At this point, honestly, additional unobserved ordinary matter theory is about as credible as luminiferous aether theory for explaining the propagation of light. It's not a dumb idea -- "There's more stuff" is the simplest explanation, as is "Waves travel through a medium, so there must be a medium". But after more and more observations start piling up that are incompatible with the hypothesis, it's time to move on. Ordinary matter as an explanation for galactic rotation curves has been dead for about 40 years.