Astronomers probably should go on the quest for immortality since otherwise you are basically condemned to look at a still image. Even if that image contains a story from the earliest universe until now. It is a million states, but no real process.

What I find so fascinating is that the observations are still quite precise. How do you know the outer rims are rotating too fast? Couldn't this be some gravitational lensing and stars are actually much closer to the core than they appear?

How do you even begin to estimate the mass of a galaxy? How do you weight the behavior of a disc and combine it with keplers law to even see that something is wrong here? As a layman I would be perfectly happy with how galaxy are rotating... I find it fascinating that much is so precisely determined that we have to miss something.