To expand on this, we also have mapped it out and know that the amount of dark matter varies wildly between galaxies, with some having basically none while others have far more dark matter than observable matter in them. There’s also a lot of stuff with the early universe that only works if you have something with gravity that doesn’t otherwise interact significantly with matter.
As Angela Collier puts it, dark matter is not a theory, it is a set of observations.
To expand on this, we also have mapped it out and know that the amount of dark matter varies wildly between galaxies, with some having basically none while others have far more dark matter than observable matter in them. There’s also a lot of stuff with the early universe that only works if you have something with gravity that doesn’t otherwise interact significantly with matter.
As Angela Collier puts it, dark matter is not a theory, it is a set of observations.