How the Edge of Our Galaxy Defies Known Physics

A speculative but interesting idea of dark matter is it is matter from other universes. There is no way of detecting dark matter using the three fundamental forces in the standard model, only gravity, because gravity, unlike the three other fundamental forces, is not bound to 3 spatial dimensions, which explains the numerous anomalies general relativity by itself can't explain, like the fast rotation of the galaxy. This could also explain that, despite our extreme efforts, have never detected the stuff before, because the liquid Xenon detector relied on the weak interaction to detect it, which is bound to our 3 spatial dimensions.