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 and so we must consider whether we can see this motion or not.

Because of the large distances to stars, the predicted motion is small. Is it so small that we can't detect it?

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, recall that the distance to Proxima Centauri is about 10 kilometers. So, the angular distance it moves in one hour is

This works out to = 2 degrees or around one-millionth of one arc second!!. We must wait over 1 century in order to see Proxima Centauri move 1 arc second. Even after 1 century, such tiny motions are not detectable with the unaided human eye.

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