Articles by others on the same topic
Proper motion is the apparent angular motion of a star or other celestial object across the sky, as observed from a specific location over time. It is measured in arcseconds per year and represents the object's movement perpendicular to the line of sight from the observer. Proper motion is a consequence of the object's actual motion through space relative to the observer, combined with the effects of the observer's position (like being on Earth) and the object's distance.