Proper Motions

The average star in our Galaxy moves at a speed of about 10 kilometers per second or, in terms of kilometers per hour, at a speed of about 36,000 kilometers per hour. This speed seems high, so

What kinds of numbers are we talking about?

Hmmmm, let's be more precise and ask the question,

Well, in one hour, the star moves a distance of 36,000 kilometers at most. If the closest star, Proxima Centauri, moved at this speed, would we be able to see the motion? To figure this out, we need to know the distance to Proxima Centauri. Proxima Centauri is about 10 kilometers from us. So, the angular distance it moves in one hour is

This works out to = 2 degrees or around one-millionth of one arc second!!. Such a tiny angle is not measureable with the unaided human eye over reasonable time scales!!!

Stars appear to be stationary on the sky because of their exceedingly large distances.