The Effect of Gravitational Lensing on Dark Matter

The gas is all this electromagnetism going on, which is much, much more powerful than gravity. So you get this collision like effect in the metal. But if we calculate how much mass there is in the stars, that's not nearly enough. There should be more mass where the gases from the stuff we can see. And that means there must be invisible mass there where the stars are. We can't really explain this by modifying gravity as all the modifications to gravity,. at least sane ones, really only modify the strength of gravity on these scales. They don't modify the direction of it.