I'm Shocked -- SHOCKED -- To Find That Fluid Dynamics Is Going On Here!

On human spatial and time scales, stars seem motionless. Sure, they rise and set, but that's a reflection (literally) of the Earth spinning on its axis once a day. But the stars themselves move, orbiting the center of the galaxy. Stars are so terribly far away that this motion appears diminished to almost nothing; you need a telescope and lots of time to even measure it. But in real terms they're hauling mass; the Sun, as an example, is moving at a staggering 220 kilometers per second around the...