They may look like they are standing still, but galaxies are all spinning.  Spiral galaxies have the lovely regular spin of a disk, while elliptical galaxies are all over the place, a buzzing hive of stars.  We don’t see this rotation in real time because it takes millions of years for it to be noticeable.  The Milky Way takes 250 Million years to spin just once around it’s axis.  Looking at this rotation rate vs. distance from the galactic center was what originally led to the discovery of dark matter. Some galaxies do in fact spin slower than others, but how does...